Professeur Michel Barrouillet

Docteur Pierre Fayol

Professeur Perruchet

Dr E S Margianti

Wahyu Rahardjo

Tryda Cynthia

Dina Kusumastuti

Rahmat Sutrisno

Saadatun Nisa

Satria Ajie

Rahma Khairani

Gita Andria Puspita

Anna Andhita

Nandie Syarof

Hayati

Dwi Ratih

Reny Aryani

Vidya Nurina Yulianti

Quroyzhin Kartika Hadi

Rini

Darma Setya

Siti Rahma

Ajeng Cahyani

Agung Handoko

Djaka Kunandjaya

Yani Suryani

M Wachid

Al Wakhidan

MM S Pd

Drs Endang Wiharsa

Drs Subagya

Drs Bambang Supriyadi

Tito Suharwanto

MSi S Ip

Dra Agustyawati

SNE M Phil

MPd Drs Agus Suryabto

Dra Agustina Kaban

Slb-C Angkasa

Slb-C Asih

Budi Jakarta

Slb-Negeri C Lenteng

Agung Jakarta

Slb-C Merpati

Slb Negeri

Pembina Jakarta

Slb A Cahaya

Batin Jakarta

Slb Tan

Miyat Bekasi

Wiyata Guna

great family, my dearest husband, Colonel Tri Bowo

Budi Santoso

Hafidz Bagus

Prasetyo Adi

Ratriana Naila

A million

List of Tables

 Table 1.Age distribution of participants in the drawing hierarchical patterns experiment ……………………….…………………………………….. Table 2.

Age distribution of participants in the perceptual similarity judgment task ……………………………………………………………………... Table 3. Age distribution of participants in Experiment 3 …………………..... Table 4.

Age distribution of the participants in Experiment 4 …………………. Table 5.

Age distribution of participants in the naming task ………………….. Table 6.

IQ distribution of participants in the naming task ................................. Table 7.

Age distribution of participants of the drawing task .............................. Table 8.

IQ distribution of participants of the drawing task …………………... Table 9.

Age distribution of EB participants in the naming task ......................... Table 10.

Age distribution of EB participants who completed test performance in the drawing task ………………………………………………………... Table 11.

Distribution of the profiles in the naming task ………………………… Table 12.

Distribution of the profiles in the drawing task ………………………...

List of Figures

Figure 1.

Example of the principle of proximity …………………………...……. 4 Figure 2.

Example of the principle of similarity ……………………………….… 5 Figure 3.

Example of the principle of good continuation ……………………...… 5 Figure 4.

Example of the principle of closure …………………………………… 6 Figure 5.

General Model of Cognitive Procedure in Perception ………………… 6 Figure 6.

Template-based matching model ……………………………………… 7 Figure 7.

Prototype-based matching model …………………………………...…. 8 Figure 8.

Feature Based Matching Model as in Pandemonium Model …………. 9 Figure 9.

Example of geometric icons (geons) in Recognition-by-Components Theory …………………………………………………………....…….

GENERAL INTRODUCTION

PREAMBLE

The Development of Children's Perception of Hierarchical Patterns:

An investigation across tasks and populations

Perception of hierarchical patterns has its roots in Navon's experiment that used patterns which present at a double level of organisation, a global one (the whole shape) and a local one (the elements that constitute the whole). [START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF] proposed that shape description is first constructed and recognized at the level of overall or global shape while the detailed processing of the smaller components would intervene later, as confirmed by the global precedence effect.

Nowadays, a growing body of research has expanded the concept and has confirmed the relative dominance of global processing over local processing. In our thesis, we investigated the relative dominance of these processes by considering the effect of age, stimuli properties, duration of exposure to the stimuli and gender in a perceptual task and a drawing task, and we tested these effects mainly from a typical and atypical developmental perspectives. Our objectives were to understand more comprehensively the developmental characteristics of children's perception through the global and local processing of hierarchical patterns.

Typical developing children as young as 3 years of age, until 10 years of age, participated in our first, second, third and fourth experiments. We investigated global/local processing at these ages since research in young children in this domain are still scarce and the results are mostly contradictory. Manipulation of the patterns, such as consistent vs.

inconsistent and simple vs. complex, and also their durations of exposure (3 seconds for long duration and 300 msec for short duration) were meant to investigate in what extent these variables affected the relative dominance of global/local processing in children, in order to reveal the developmental milestones of children's global/local processing.

Our objective with regard to the involvement of atypical developing children with mental retardation as employed in our fifth experiment, was to investigate whether their global dominance responses which have been proved in other studies, could interfere with the automatic identification of familiar objects in meaningful patterns when they are located at the local level. We also aimed at analyzing whether the developmental aspects in processing at the global/local level were similar in these children to what was observed in typical developing children.

The last experiments of our thesis concerned the global/local processing in haptic perception in early blind children. To our knowledge, this is the first study concerning the global local processing in early blind children using Navon's stimuli. We aimed at revealing Preamble whether these children showed a local tendency as reported in the adults with blindness. The results will also illustrate the developmental trajectories of global/local processing in haptic perception, since early blind children at 6 to 18 years of age participated in the study.

Preamble CHAPTER 1. General Introduction

I. Perceptual Organization : Some Historical Points

The history of perceptual organization started centuries ago when philosophers raised questions about the sources and validity of human knowledge. Epistemologists attempted to understand how things could be learned, whether there were innate ideas (as supported by rationalism) or whether the experience as the result of human's contact with physical world through senses would independently caused the learning process (as supported by empiricism), or whether both of them originated human knowledge (as supported by Kantianism).

Immanuel [START_REF] Kant | The critique of Pure Reason[END_REF], in his work entitled The Critique of Pure Reason, stated that our understanding of the external world had its foundation in both the experience and a priori concepts. This led to the beliefs that our senses which were viewed as passive receptors, were actually active agents and pre-consciously attempted to make sense of their input as a result of brain's perceptual systems. Perceptual systems enabled organism to interpret and organize sensations to produce a meaningful experience of the world [START_REF] Lindsay | Human Information Processing[END_REF].

While sensation points to the immediate and tends to be an unprocessed result of stimulation in our sensory receptors, perception refers to the process whereby sensory stimulation is translated into organized experience.

The organized experience, or percept, is the result of the joint product of sensory stimulations, and of the processing itself. The brain's perceptual systems are structured in a modular way, with different areas of the brain which process different kinds of sensory information, and these different modules are interconnected and influenced each other.

In general, there are two main approaches in explaining the process of perception, i.e.:

 Bottom-Up Approach: Perception is built from a set of primary features to a representation in our cognitive system without involving higher cognitive processes. It assumes a passive and automatic processing during perception. This approach which was also known as a data-driven approach was supported by [START_REF] Gibson | The Ecological Approach to Visual Perception[END_REF] with the direct perception approach and also by [START_REF] Marr | Vision : A computational investigation into the human representation and processing of visual information[END_REF] who argued that high level perceptual experiences were derived from computations based on low level perceptions (such as edges and intensity changes).

 Top-Down Approach: Perception starts with a set of primary features but it is influenced by higher cognitive processes (such as knowledge, past experience and context). It assumes an active and volitional process at the basis of perception. This approach was supported by von Goethe, Mach and von Ehrenfels with a series of research by Wertheimer, Köhler, Chapter 1 : General Introduction Koffka, and Lewin, who proposed the gestalt principle. [START_REF] Gregory | Mirrors in mind[END_REF] also supported this approach with the constructivist approach, which stated that perception involves a process of constructing inferences from what we see. It involves an attempt of making a best guess or hypothesis about what we see. Prior knowledge and past experience are crucial in perception because when we look at something, we develop a perceptual hypothesis (which is based on prior knowledge and past experience), and the hypothesis can be confirmed or disconfirmed by the data we perceive.

The hypothesis referred to in the top-down approach triggered many researches to investigate the functional processes in the cognitive system. The most well-known research in the top-down approach was made by a group of psychologists who systematically studied perceptual organization in 1920's, in Germany. The concept of Gestalt was first introduced by Christian von Ehrenfels (1890), who proposed the concept of Gestalt-Qualität which refers to -form quality‖ or extra elements that accompanied the sensory processes and add bounding to the perceived object. This idea was then developed by Max Wertheimer in 1910, who concluded that the eye merely receives all the visual stimuli and the sensations are arranged by the brain into a coherent image. The law of prägnanz stated that the sensations are arranged in a manner that is regular, orderly, symmetric, and simple.

Gestalt psychologists, such as Wolfgang Köhler, Kurt Koffka, and Kurt Lewin, further refined Wertheimer's work to conclude that visual perception results from a process of organizing elements of sensations into various laws of grouping. The most important are the following :

1) The principle of Proximity. The principle of proximity or contiguity states that things which are closer together will be seen as belonging together as seen in Figure 1.

Figure 1. Example of the principle of proximity

A. 1 and 2 as one group, 3 and 4 as one group because of the proximity B. The dots will tend to be grouped in rows C. The dots will tend to be grouped in columns

                                
Chapter 1 : General Introduction

2) The principle of Similarity. Similarity means a tendency to see groups which have the same characteristics. The principle of similarity states that things which share the same visual characteristics as shape, size, color, texture, value, or orientation are seen as belonging together to the same entity as described by Figure 2.

Figure 2. Example of the principle of similarity

A. Color characteristics will be seen as group B. Shape characteristics will be seen as group

3) The Principle of Common Fate. The principle of Common Fate stated that elements in the same moving direction are perceived as collective or as unit. An example of common fate can happen when someone perceives a green snake lying on the grass. When it doesn't make any movements, it will not be noticed. As soon as the snake begins to move, our brain organizes it as a figure against a background, so we can notice it immediately.

4) The principle of Good Continuation. The principle of continuity predicts the preference for continuous figures. People tend to perceive a figure as two crossed lines instead of 4 lines meeting at the center, when a cross pattern presented. Figure 3 illustrates this principle :

Figure 3. Example of the principle of good continuation

5)

The principle of Closure. The principle of closure suggests that we tend to see complete figures even when part of the information is missing. This principle is related to the principle of good continuation when there is a tendency to fill-in missing information to make a whole. Figure 4 depicts an example of the Gestalt law of closure.

Chapter 1 : General Introduction White triangle and three gray circles tend to be seen although they do not exist.

These gestalt principles are well-known for their ability to clarify the phenomenon of perception. But with the development of cognitive psychology and computational neuroscience in the 1950s and 1960s, the gestalt theory has been criticized for being descriptive rather than explanatory. The operating principle of Gestalt which states that the brain is holistic, parallel, and analog with self-organizing tendencies was also against the idea proposed by cognitive psychology which stressed the importance of past experience and knowledge as well as the reality stimulation about the outside world in generating the process of perception. Indeed, cognitive psychology sustains that bottom up processing (data driven processing) and top-down processing (concept-driven processing) are mutually included in the process of perception [START_REF] Palmer | Visual Perception and World Knowledge : Notes on a model of Sensory-Cognitive Interaction[END_REF][START_REF] Norman | On the role of active memory process in perception and cognition[END_REF][START_REF] Lindsay | Human Information Processing[END_REF]. A general model of the cognitive procedure is reported in Figure 5 (Wang, 2002).

Figure 5. General Model of Cognitive Procedure in Perception (Wang, 2002, p.75) Empirical evidences have supported the idea that perceptual processing must include both data-driven processing and concept-driven processing, so perception researches in cognitive psychology have mainly concentrated on the issue of pattern recognition. Human's pattern recognition can be treated as a typical perception process which depends on human's

Chapter 1 : General Introduction available knowledge and experience and cannot be just innate and self-organized as in the gestalt's view.

II. Perceptual Organization : Towards Contemporary Questions

Modern cognitive psychology has proposed several theoretical models about human's pattern recognition, some of which are greatly affected by artificial intelligence. Among these models, we can mention the following :

1) The Template-based Matching Model. Human's memory stored plenty of various duplicates of real world patterns (templates). In the process of pattern recognition, the incoming sensory information is compared directly to the templates that have been stored in the memory. However, the real world patterns are various and may be different from the characteristics of the templates. If a corresponding template does not exist, the recognition of the pattern fails. Figure 6 depicts a template-based matching model.

Figure 6. Template-based matching model (Wang, 2002, p. 76) 2) The Prototype-based Matching Model. This model is also called the component-based matching model. This model was proposed in order to overcome the template-based matching because it is hard to explain an indisputable fact that people can rapidly recognize a new, unfamiliar pattern. With the prototype-matching, outside stimulation is only needed to approximately match the prototype, and a perfect matching is not required.

Figure 7 describes the prototype-based matching model, which also shows a drawback since it is only contains bottom-up processing, so this is still being a dispute now.

Chapter 1 : General Introduction Figure 7. Prototype-based matching model (Wang, 2002, p. 77) 3) The Feature-based Matching Model. Features are elements or component parts which form a pattern. The relation among these elements or component parts can also be called features. The feature-based matching model considers that pattern recognition can be accomplished when all complicated stimulations can be analyzed through differentiated and separated features. Through the computation of features' existence and comparison of this calculation value with the list of known feature's value, a pattern can be recognized.

The main difference between feature-based and template-based matching is that the preprocessing process can be easier and more flexible, since it is not necessary to consider the stimulation changes (by size, shape, etc.) because features and their relationships can be used as bases for matching and not the whole template necessarily. However, the same features can appear in different patterns, which can greatly lighten the burden of memory.

It has greater flexibility compared to the other pattern recognition models, but unfortunately when different patterns have the same feature, it can lead to difficulty in recognition and can cause wrong recognition. A feature-based matching model is described in Figure 8, by the Pandemonium Model [START_REF] Selfridge | Pandemonium: A Paradigm for Learning[END_REF] which proposed that -four demons‖ involved in pattern recognition :

 Image demons for the process of raw sensory input In this overview, it is interesting to mention a last model, that leads to the idea that pattern recognition (the whole) derived from an analogy of the combination of parts (local structures). Irving [START_REF] Biederman | Recognition-by-Components : A Theory of Human Image Understanding[END_REF] proposed the Recognition-by-Components


Theory (RBC) that can relate the classic principles of perceptual organization and pattern recognition. RBC theory states that perceptual recognition of object is conceptualized as a process of segmenting the image of the input into an arrangement of simple 3D geometric components such as blocks, cylinders, wedges, and cones as described in Figure 9. A modest set of generalized-cone components called geons (geometrical-icons) can be derived from contrasts of five readily detectable properties of edges in twodimensional image, which are:

 Curvature (various points of curves)

 Collinearity (points branching from a common line)

 Symmetry, and Asymmetry  Parallelism (two or more points which follow same direction)

 Contermination (a point at which two points meet and therefore cease to continue)

Chapter 1 : General Introduction These properties are generally invariant over any viewing position, image quality, and consequently allows robust object perception when the image is projected from a novel viewpoint when it is degraded. This is known as viewpoint invariance which enables us to recognize objects regardless of the viewing angle.

Geons Object

The RBC theory states that structural descriptions of objects are stored in human memory. It involved an analysis of the relations between the parts of the object, followed by an analysis of its structure and a search for the best structural match to recognize an object. This approach proposes that recognition of the overall configuration of -parts‖ of a scene could facilitate the recognition of the objects.

This idea seems contra-intuitive with the phenomenon of global precedence described by [START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF]. In his experiment using hierarchical letters as shown in Figure 10, [START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF] reported a priority of processing the global structure rather than the local details. [START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF] found that the nature of the large letter could interfere with decisions about the small letters, but the small letters had no effect on decisions about the identity of the large one. These findings propose that shape descriptions might be first constructed and recognized at the level of overall or global shape while the detailed processing of the smaller components would intervene later. Chapter 1 : General Introduction

III.

Perceptual Organization : The Navon's Approach

Navon's approach is based on the early studies of Aktualgenese which referred to the actualization of cognition that retraces growth patterns in phylo-ontogeny. [START_REF] Flavell | A microgenetic approach to perception and thought[END_REF] stated that thoughts and perceptions undergo a microdevelopment which is very brief, but theoretically important. This is an important point which differentiates

Navon's theory of global-to-local processing from the previous Gestalt theory, although at the surface, they seem to deal with the same idea that perception is a top-down process. Gestalt theory fails to elaborate on the developmental aspect in perception, as some criticism conveyed (Ash, 1998).

The functional importance of global-to-local processing lays on the fact that human perceptual processors do not passively receive input but actively select which parts of the surrounding stimulation is worth to be received, attended and processed, or in other words, perception is basically dynamic. An empirical evidence that laid the global/local processing approach of Navon was the word-letter phenomenon which was an excellent demonstration of how word improves recognition of letters [START_REF] Reicher | Perceptual recognition as a function of meaningfulness of stimulus material[END_REF][START_REF] Wheeler | Processes in word recognition[END_REF]. The pandemonium approach by [START_REF] Selfridge | Pandemonium: A Paradigm for Learning[END_REF] showed that similar patterns can be interpreted as two different letters depending on the context, which proves that the perceptual system ignores the details that are inconsistent with the interpretation indicated by the context. It supported the work by [START_REF] Pillsbury | A Study in apperception[END_REF] who demonstrated that readers might not be disturbed by omission or the substitution of letters in the text they read. [START_REF] Palmer | Visual Perception and World Knowledge : Notes on a model of Sensory-Cognitive Interaction[END_REF] showed that interpretation of ambiguous elements of a picture tended to the semantic structure of the whole scene even when it was distorted or when some details were deleted.

Navon evidenced that global features are perceived before the local ones because there are indications that people can take advantage of peripheral information [START_REF] Williams | The effect of target specification on objects fixed during visual search[END_REF][START_REF] Rayner | The perceptual span and peripheral cues in reading[END_REF] and within the angular span that can be perceived with high acuity in just one fixation, there seems to be a progression with exposure time from a very gross to very fine-grained recognition.

Motion perception also led Navon to the conclusion that the global is processed before the local. In his experiment [START_REF] Navon | Irrelevance of figural identity for resolving ambiguities in apparent motion[END_REF], it was found that in situations of ambiguous apparent motion, the global features had the effect of determining the type of motion experienced, while figural identity of the elements did not give the same effect.

Research by Meili-Dsworetzki (1956) with children at different ages responding at several ambiguous figures (e.g. a man made out of fruits), supported Navon's hypothesis because the results showed that children perceived wholes at an earlier age than parts.

However, the work of [START_REF] Elkind | Studies in perceptual development II : Part-whole perception[END_REF] found opposite effects with different set

Chapter 1 : General Introduction of figures. These empirical evidences led Navon to a conclusion that the general problem with these experiments was the lack of proper control over the stimulus material since global and local structures might differ in complexity, salience, familiarity, recognizability or relative diagnosticity for determining the identity of the whole (Navon, 1977, p.358). To overcome that problem, Navon proposed two major principles in his experiment, i.e. (a) control the global and local features and (b) independence of global and local features, so that the whole cannot be predicted from the elements and vice versa. In his seminal work, [START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF] conducted 4 experiments to prove the global precedence effect. He constructed tasks in which visual perception was restricted by visibility conditions and by limited attention in perceiving a compound letter (large letters that were made out of small letters).

In the first experiment, the participants were presented with letters on a Tektronix oscilloscope with a fast decay phosphor while listening to the utterances of the name of the [START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF]p. 360) SET OF VISUAL STIMULI

Chapter 1 : General Introduction

The results showed that the conflicting level led to increases of the reaction times in the auditory condition while the consistent levels led to the lowest reaction times.

The second experiment had the main characteristics as Experiment 1 (procedure, apparatus, and setting). The difference was in the set of visual stimuli used, because the stimuli had a global shape made of local characters. The subjects were given three consistency levels like in Experiment 1, with patterns illustrated in Figure 12. The second experiment included 2 parts; the first part used the global and local characters as described above, and the second part employed only one small letter (same size as local character) or one large bold letter (same size as the global level). When the subject was exposed to the global/local character, the results showed the high impact of the effect of consistency of auditory stimuli at the global level, but not at the local level. In the second part, the results showed that the effect of consistency was still highly significant, but it did not interact with the type of stimuli (small or large), demonstrating that it was not the smaller size of the elements per se that made them relatively or absolutely unnoticed in the global precedence effect (Navon, 1977, p.368).

Chapter 1 : General Introduction

The third experiment was designed to reveal whether the subjects had control on their own perceptual processes if any supplementary demand was employed during the experiment.

The auditory stimuli were removed in the third experiment. In the global-directed condition, the subject was supposed to indicate whether the global character was H or S (the rectangle global shapes were not used). In the local-directed condition, the subject was supposed to indicate whether the local character was H or S (the rectangle local shapes were not used).

The results showed that the global character was recognized faster than the elements.

Subjects processed the global pattern without being affected by the local features while they

were not able to process the local patterns without being aware of the global character. This revealed that attention could not be efficiently diverted from the whole and proved that global processing was a necessary stage of perception. The local features could still be processed if a strong effort was made.

The fourth experiment intended to examine whether there was any condition under which the local features could be processed less thoroughly than the global features, although both levels were equally critical for performance. The -same-different‖ judgements on pairs of patterns as presented in Figure 13 was used in a task that required the subject to place equal importance on both levels. The target and probe stimuli could be displayed simultaneously or sequentially and the subjects were asked to decide whether the patterns were the same or different. In the fourth experiment, Navon also designed a control session which used the same task, but he added two conditions: a spatial certainty condition where the patterns appeared at the centre of the field, and a spatial uncertainty condition, where the patterns appeared randomly in the field.

To control the subject's readiness, Navon employed two conditions which were temporal certainty (subjects were given both an auditory warning and fixation point before each trial)

and temporal uncertainty (when subjects did not have any warning signal). The examples of the display in each condition and session in Experiment 4 are described in Figure 14.

Chapter 1 : General Introduction Figure 14. Examples of the displays in each condition and session of Navon's fourth experiment 4 (Navon, 1977, p. 374) The results indicated clearly that the global differences were detected more frequently than the local differences. The short exposure resulted in a difficulty in processing the local elements despite that the spatial and temporal certainty conditions were meant to motivate the subjects to process at the local level. In the conditions of spatial uncertainty and temporal uncertainty, the longer exposures also led to more global than local processing. So the effect was not due to the fact that the global patterns were more likely to be perceived in case of brief exposure, since longer exposure also led benefitted to global processing.

On the basis of these four experiments, Navon suggested that only the global level was subject to interference by the auditory discrimination response. This global precedence effect is not an inherent property of visual perception because when subjects had to respond either just to the global level or just to the local level, the identity of the global cues that conflicted with the local ones inhibited the response to the local level, while the recognition of the local identity had no effect on global recognition. This confirms that people cannot skip global processing. Processing at the local level could operate if a deliberate attempt was made as shown in the last experiment, but the global differences were detected more often than the local ones. These results support the idea that global processing is done before more local analysis is completed and they constitute a body of evidence supporting the notion of global precedence.

The work of [START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF]

Global and Local Processing in Hierarchical Patterns : State of the Art

Many researches have been performed in the domain of hierarchical stimuli to reveal the global precedence effect since it has been proposed by [START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF]. Hierarchical stimuli are patterns which present a double level of organisation, a global one (the whole shape) and a local one (the elements that constitute the whole). The global precedence effect refers to the tendency to process the whole before the parts.

The global precedence hypothesis proposed by [START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF] had also been developed from the earlier assumption on serial processing (processing resources were first engaged with global information, and processing of local information was optional) but later the possibility of parallel processing of global and local information was suggested (including [START_REF] Navon | The forest revisited: More on global precedence[END_REF], with the global information being processed faster and thus being available earlier than the local one.

Global precedence hypothesis has been confirmed in a large body of research although it could depend on retinal location (Pomerantz,1983;[START_REF] Grice | Forests before trees? It depends where you look[END_REF], on the type of stimuli [START_REF] Kimchi | Form and Texture in Hierarchically Constructed Patterns[END_REF][START_REF] Martin | Local and global processing : The role of sparsity[END_REF][START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF][START_REF] Lamb | The processing of hierarchical stimuli : Effect of retical locos, locational uncertainty and stimulus identity[END_REF][START_REF] Lamb | The Role of Spatial Frequency in the Processing of Hierarchically Organized Stimuli[END_REF][START_REF] Love | A Structural account of global and local processing[END_REF]Poirel, Pineau, & Mellet, 2008), on the task given at test [START_REF] Martin | Local and global processing : The role of sparsity[END_REF][START_REF] Hoffman | Interaction between global and local levels of a form[END_REF][START_REF] Navon | How many trees does it take to make a forest[END_REF][START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF][START_REF] Farran | Divided attention, selective attention and drawing: Processing preferences in Williams Syndrome are dependent on the task administered[END_REF], on the duration of exposure of the stimuli [START_REF] Pomerantz | Global and local precedence : Selective attention in form and motion perception[END_REF][START_REF] Paquet | Global precedence: The effect of exposure duration[END_REF][START_REF] Ninose | The effect of prolonged viewing on the recognition of global and local levels of hierarchically constructed patterns[END_REF], and on developmental aspects [START_REF] Dukette | Children's analysis of hierarchical patterns: Evidence from a similarity judgment task[END_REF][START_REF] Kramer | Developmental sex differences in global-local perceptual bias[END_REF]Tada & Stiles, 1996;[START_REF] Burack | Age Differences in Visual Search for Compound Patterns: Long vs. Short Range Grouping[END_REF][START_REF] Mondloch | Developmental Changes in the Processing of Hierarchical Shapes Continue into Adolescent[END_REF][START_REF] Porporino | A developmental change in selective attention and global form perception[END_REF].

The nature of the stimuli in the global/local paradigm remains an interesting subject of research [START_REF] Navon | How many trees does it take to make a forest[END_REF][START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF][START_REF] Dukette | Children's analysis of hierarchical patterns: Evidence from a similarity judgment task[END_REF][START_REF] Love | A Structural account of global and local processing[END_REF][START_REF] Dukette | The effects of stimulus density on children's analysis of hierarchical patterns[END_REF][START_REF] Grill-Spector | Visual recognition : As soon as you know it is there, you know what it is[END_REF][START_REF] Poirel | Implicit identification of irrelevant local objects interacts with global/local processing of hierarchical stimuli[END_REF], 2008), as the task given during the experiment [START_REF] Kinchla | The Order of visual processing: -Top-Down‖, -Bottom-Up‖ or -Middle-Out‖[END_REF][START_REF] Grice | Forests before trees? It depends where you look[END_REF][START_REF] Pomerantz | Global and local precedence : Selective attention in form and motion perception[END_REF][START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF][START_REF] Sanocki | Time course of object identification : Evidence for a global to local contingency[END_REF][START_REF] Weber | Hierarchical visual processing is dependent on the oculomotor system[END_REF][START_REF] Ninose | The effect of prolonged viewing on the recognition of global and local levels of hierarchically constructed patterns[END_REF]. We will envisage these two aspects in our thesis.

Nowadays, the global/local paradigm has broaden its field of application; not only in the field of visual processing but also in auditory processing [START_REF] List | A mismatch negativity study of local-global auditory processing[END_REF][START_REF] Sanders | Local and global auditory processing : Behavioral and ERP Evidence[END_REF], including music perception [START_REF] Deruelle | Global and local music perception in children with Williams syndrome[END_REF]. It has also been applied to different cultures [START_REF] Davidoff | Local and global processing: Observations from a remote culture[END_REF][START_REF] Mckone | Asia has the global advantage : Race and Visual Attention[END_REF] and different individuals, especially older adults [START_REF] Georgiou-Karistianis | Age-related differences in cognitive function using a global local paradigm[END_REF] and psychopathological cases Chapter 1 : General Introduction like prosopagnosia [START_REF] Duchaine | No global processing deficit in Navon task in 14 developmental prosopagnosics[END_REF], individuals with mental retardation [START_REF] Birhle | Seeing either the forest or the trees: Dissociation in visuospatial processing[END_REF][START_REF] Porter | Global and local processing in William syndrome, autism, and Down Syndrome : Perception, attention, and construction[END_REF][START_REF] Dulaney | Global/local processing in mentally retarded and nonretarded persons[END_REF] and individuals with schizophrenia [START_REF] Poirel | Meaningfulness and global-local processing in schizophrenia[END_REF]. However, the global precedence hypothesis was not confirmed in individuals with early and late blindness by using haptic perception of form [START_REF] Heller | Global versus local processing in haptic perception of form[END_REF], individuals with autism and Asperger Syndrom [START_REF] Iarocci | Global-local visual processing in high functioning children with autism : structural versus implicit task biases[END_REF]Behrmann & Kimchi, 2003;[START_REF] Deruelle | Processing of compound visual stimuli by children with autism and Asperger syndrome[END_REF]Rondan & Deruelle, 2007;[START_REF] Scherf | Missing the Big Picture : Impaired Development of Global Shape Proceesing in Autism[END_REF], individuals with William Syndrome [START_REF] Rondan | Global and Local processing in Williams Syndrome : Drawing versus Perceiving[END_REF][START_REF] Farran | Divided attention, selective attention and drawing: Processing preferences in Williams Syndrome are dependent on the task administered[END_REF], with Alzheimer's disease [START_REF] Slavin | Local-global processing in Alzheimer's disease : An examination of interference, inhibition and priming[END_REF], individuals with obsessive compulsive personality [START_REF] Yovel | Who Sees Tress Before Forest? -The Obsessive-Compulsive Style of Visual Attention Zuidhoek[END_REF], individuals with simultanagnosia [START_REF] Jackson | Implicit processing of global information in Balint's syndrome[END_REF]Dalrymple, Kingstone, & Barton, 2006) and individuals with visual agnosia (Aviezer, Landau, Robertson, Peterson, Soroker, Sacher, Bonneh, & Bentin, 2007).

In the last thirty-years, many researchers have investigated the issue of local-global processing with Navon's stimuli and they have concluded that a variety of factors affect the global advantage effect. These factors are related to the stimulus and to the type task given at test. The main factors that have been investigated are the following : 1) Overall Visual Angle. The works of [START_REF] Kinchla | The Order of visual processing: -Top-Down‖, -Bottom-Up‖ or -Middle-Out‖[END_REF], [START_REF] Navon | Does global precedence really depend on visual angle?[END_REF], and Lamb & Robertson (1990) found that global and local reaction times depended on the set of visual angles presented. Global advantage was found with patterns subtending less than 7° of visual angle and a local advantage was found with larger patterns, of about more than 10° of visual angle.

2) Retinal Location (foveal vs. peripheral). [START_REF] Pomerantz | Global and local precedence : Selective attention in form and motion perception[END_REF], [START_REF] Grice | Forests before trees? It depends where you look[END_REF] and [START_REF] Lamb | The processing of hierarchical stimuli : Effect of retical locos, locational uncertainty and stimulus identity[END_REF] concluded that retinal location could affect the relative speed of processing. Global advantage was obtained with peripheral presentation, but not with central presentation. This result concerning retinal location indicated that there are relations between the foveal (central) vs peripheral location and spatial uncertainty (this resembled to Navon's fourth experiment). Spatial uncertainty led a global search through the peripheral area although the stimuli were presented in the fovea (central). This result led to broader studies because other aspects like eccentricity and acuity of the stimuli were suspected to influence the results in retinal location [START_REF] Navon | Does global precedence really depend on visual angle?[END_REF].

Chapter 1 : General Introduction 3) Sparsity and number of local elements. [START_REF] Martin | Local and global processing : The role of sparsity[END_REF], [START_REF] Navon | How many trees does it take to make a forest[END_REF][START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF] examined the effect of sparsity (the spacing between local elements) using a stroop-like task, a same-different task, and a simultaneous comparison task. [START_REF] Martin | Local and global processing : The role of sparsity[END_REF] reported global advantage with less sparse elements while local advantage emerged with the sparse ones. This result supported [START_REF] Navon | How many trees does it take to make a forest[END_REF] although the shape of the elements appeared to play an important role (the triangular patterns were influenced by sparsity but not the rectangular patterns). [START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF] suggested that sparsity and the number of local elements, other factor such as the contours of the global figure, the task demands and the -goodness‖ of the global figure might have an effect.

4) Goodness of form.

The -goodness‖ of the shape of the figure might have an effect in the global advantage effect and it has been investigated by [START_REF] Hoffman | Interaction between global and local levels of a form[END_REF], [START_REF] Secbrechts | Variation on parts and wholes : Infomration precedence vs. global precedence[END_REF], and [START_REF] Poirel | Implicit identification of irrelevant local objects interacts with global/local processing of hierarchical stimuli[END_REF] using several tasks (e.g. memory scanning task, sequential same-different task, identifying the identically pairs of items). -Good patterns‖ were processed faster when they constituted the relevant level and when the level of processing was irrelevant, good patterns slowed down the responses because of stronger response competition (Sebrechts & Fragala, 1985). The stimuli could also be either objects or non-objects (meaningfulness of the stimuli) and the results with children showed that the development of children's visual perceptual processing progressively evolved from a local preference at age of 4 to a global preference at age of 9 when objects or non-objects stimuli were used [START_REF] Poirel | First came the trees, then the forest: Developmental changes during childhood in the processing of visual local-global patterns according to the meaningfulness of the stimuli[END_REF].

5) Duration of exposure to the stimuli. [START_REF] Pomerantz | Global and local precedence : Selective attention in form and motion perception[END_REF] and [START_REF] Paquet | Global precedence: The effect of exposure duration[END_REF] showed that interference between the global and local letters was affected by exposure duration. When they presented compound letters for 10, 40, or 100 msec, unidirectional global to local interference was found at the shortest exposure duration.

6) Attention Allocation.

According to the work of [START_REF] Hoffman | Interaction between global and local levels of a form[END_REF], [START_REF] Ward | Determinants of Attention to Local and Global Features of Visual Forms[END_REF], [START_REF] Kinchla | Attending to different levels of structure in a visual image[END_REF], [START_REF] Paquet | Global precedence: The effect of exposure duration[END_REF], [START_REF] Robertson | Attentional Persistence for Features of Hierarchical Patterns[END_REF][START_REF] Ninose | The effect of prolonged viewing on the recognition of global and local levels of hierarchically constructed patterns[END_REF][START_REF] Ninose | The effect of prolonged viewing on the recognition of global and local levels of hierarchically constructed patterns[END_REF], the direction of attention to the global and local level of an object determined which level was processed first (global or local). So, it was concluded that attention played a role in the effect of global advantage.

7) Conspicuity of the stimuli.

There are several works related to the role of conspicuity of the stimuli with regard to the global advantage effect. Many studies related conspicuity to the difference of spatial frequency caused by the size of the elements (of the local and global elements) or their contrast-luminance [START_REF] Hoffman | Interaction between global and local levels of a form[END_REF][START_REF] Schyns | From blobs to boundary edges : Evidence for time and spatial scale dependent scene recognition[END_REF][START_REF] Lamb | Spatial Frequency and attention : Effects of level, target,and location-repetition on the processing of global and local forms[END_REF]. [START_REF] Hoffman | Interaction between global and local levels of a form[END_REF], [START_REF] Sanocki | Time course of object identification : Evidence for a global to local contingency[END_REF] and [START_REF] Schyns | From blobs to boundary edges : Evidence for time and spatial scale dependent scene recognition[END_REF] manipulated the sizes of stimuli and found that when the subject was presented with small and medium sizes, then a global advantage was obtained with the small sizes and a local advantage with the medium sizes. When the subject was presented with medium and large sizes, then a global advantage was obtained with the medium sizes and a local advantage with the large sizes. This proved that medium size stimulus could be processed both locally and globally. Other research has relied on the conspicuity of the stimuli based on contrast balanced theory [START_REF] Lamb | The Role of Spatial Frequency in the Processing of Hierarchically Organized Stimuli[END_REF][START_REF] Robertson | Attentional Persistence for Features of Hierarchical Patterns[END_REF][START_REF] Lamb | Automatic and controlled process in the analysis of Hierarchical Structure[END_REF]. Contrast balanced stimuli are stimuli in which the low spatial frequencies are eliminated so both the local and global forms must be identified using high spatial frequency information. The results showed that the global advantage in the nested letter was achieved if the nested letter stimuli were written on grey paper and the letter's colour was white, while the global advantage was not achieved if the white letter was outlined with black colour. The black outline is called contrast balancing and the effect reduced the spatial frequency (lower spatial frequency).

8) Structure or relational properties.

In the Gestalt theory, similarity and proximity elicit processes which confirm that the processing of the global pattern precedes the processing of the local pattern. In the work of [START_REF] Love | A Structural account of global and local processing[END_REF], geometrical shapes were used as local elements to reveal the role of relational properties. Using a same-different task, subjects had to decide whether the two patterns were the same or different. Figure 15 illustrated the stimuli. The results confirmed that global advantage is a process of grouping.

Chapter 1 : General Introduction Let's examine now more precisely the works done in a neuropsychological and developmental perspectives.

A. Neuropsychological Studies in Global-Local Processing

The aims of the studies in neuropsychology that have investigated the global-local paradigm were not only to reveal which processes in the brain are activated when perceiving the global figure and local elements, e.g. the mapping location of the activated brain, as in the work of [START_REF] Han | Interactions between spatial attention and global/local feature selection : an ERP study[END_REF], [START_REF] Lamb | Components mechanisms underlying the processing of hierarchically organized patterns : Inferences from patients with unilateral cortical lesions[END_REF] and [START_REF] Robertson | Interhemispheric Relations in Processing Hierarchical Petterns : Evidence from Normal and Commissurotomized Subjects[END_REF]. They also aimed at revealing the neural substrates [START_REF] Han | Neural Substrates Differentiating Global/local Processing of Bilateral Visual Inputs[END_REF]) and the development of hemispheric lateralization of these processes [START_REF] Moses | Functional MRI of global and local processing in children[END_REF][START_REF] Kimchi | Microgenesis and ontogenesis of perceptual organization: Evidence from global and local processing of hierarchical patterns[END_REF].

With regard to hemispheric differences in the perception of global/local information, some authors concluded that the right hemisphere (RH) was faster and more accurate in the identification of global components of the input and the left hemisphere (LH) was faster and more accurate in the identification of the local components [START_REF] Lamb | The processing of hierarchical stimuli : Effect of retical locos, locational uncertainty and stimulus identity[END_REF][START_REF] Robertson | Interhemispheric Relations in Processing Hierarchical Petterns : Evidence from Normal and Commissurotomized Subjects[END_REF][START_REF] Yovel | Hemispheric Asymmetries for Global and Local Visual Perception: Effects of Stimulus and Task Factors[END_REF]. Evidence from a variety of different methodologies supported this hypothesis that the RH is biased toward the processing of global input characteristics while the LH is biased toward the processing of local input characteristics. The spatial frequency characteristics of the stimuli could also explain the difference in processing global/local information. [START_REF] Lamb | The Role of Spatial Frequency in the Processing of Hierarchically Organized Stimuli[END_REF] examined the role of spatial frequency using the contrast balanced stimuli as explained before. Contrast balancing selectively removes low spatial frequency information. Thus, both local and global processing of the stimuli must be performed on the basis of high spatial frequency information alone. Removal of low spatial frequencies significantly disrupted global level processing, suggesting that the global advantage might result from a temporal advantage in the processing of low spatial frequency information.

The results proved that both hemispheres seem to be able to process a large range of stimuli, with differences arising between hemispheres for certain types of stimuli and/or greater efficiency for certain processes. In general, the RH seems to be biased to distribute attention over larger portions of the visual input than the LH, which seems to process object ‗parts' more effectively. Together then, spatial frequency and attention consideration predict that the RH will create categories on the basis of more ‗holistic' similarity (whole-object, whole-shape, etc), while, in contrast, the LH seems likely to categorize more readily on the basis of distinctive features (similarity of parts, details).

Chapter 1 : General Introduction

The work by [START_REF] Han | Neural Substrates Differentiating Global/local Processing of Bilateral Visual Inputs[END_REF] of analysis and that the relative use of these processes changes with age [START_REF] Moses | Functional MRI of global and local processing in children[END_REF].

B. Developmental Studies in Global-Local Processing

Issues concerning the development of local and global perception were typically centred on the question of the priority of hierarchical level. One early view was that children are primarily holistic or global processors, evidenced by infants' initial focus on the external contours of line drawings and later inclusion of interior details [START_REF] Quinn | Evidence for a Global Categorical Representation of Humans by Young Infants[END_REF][START_REF] Porporino | A developmental change in selective attention and global form perception[END_REF]. This notion of global precedence supported the evidence that young children tended to categorise objects on the basis of their overall similarity rather than on the similarity of the components [START_REF] Smith | Developmental trends in free classification : Evidence for a new conceptualization of perceptual development[END_REF].

However, the developmental sequence between local and global processing is more complex than originally suggested [START_REF] Burack | Age Differences in Visual Search for Compound Patterns: Long vs. Short Range Grouping[END_REF]. Young children could attend to both global and local attributes under appropriate conditions [START_REF] Tada | Children's Analysis of Spatial Patterns : An Assessment of their -errors‖ in copying geometric forms[END_REF][START_REF] Stiles | Global-Local Processing in Preschool Children[END_REF][START_REF] Dukette | Children's analysis of hierarchical patterns: Evidence from a similarity judgment task[END_REF], but they showed impairments under certain conditions.

For example, [START_REF] Prather | Developmental differences in part/whole identification[END_REF] found that children between the ages of 2 years 7 months and 5 years 7 months were able to name both parts and whole of simple pictures, but

Chapter 1 : General Introduction were less efficient in the naming of both aspects in more difficult pictures. This indicated that the capacity to perceive multiple aspects of a display could depend on the stimulus or task complexity. [START_REF] Dukette | Children's analysis of hierarchical patterns: Evidence from a similarity judgment task[END_REF] This result was also supported by the work of Tada and Stiles (1996) that examined the early development of spatial patterns analysis and focused on how pre-school children segmented and integrated the parts of simple spatial forms. They showed that young children analyzed spatial patterns in ways that differed systematically from older children and adults.

The youngest children segmented out simple, well-formed, spatially independent parts and used simple relational structures to bind these parts together. With development, children constructed forms that included increasingly complex parts and relations. [START_REF] Kramer | Developmental sex differences in global-local perceptual bias[END_REF] investigated the developmental sex differences in global-local perceptual bias. Previous developmental studies showed that boys tended to perform better than girls on tasks associated with the right hemisphere (spatial task), whereas girls performed better on tasks associated with left hemisphere (verbal task) [START_REF] Denckla | Rapid "automatized" naming of pictured objects, colors, letters, and numbers by normal children[END_REF][START_REF] Kirk | Evidence for early acquisition of visual organization ability: A developmental study[END_REF]. [START_REF] Kramer | Developmental sex differences in global-local perceptual bias[END_REF] showed that boys were significantly better at processing global information than girls at all ages (4 -12 years) and younger children of both gender were less capable at processing global information than older children. This is consistent with developmental models that suggest an early left-hemisphere advantage for girls and a righthemisphere advantage for boys.

V. Our approach

The growing body of research around Navon's global-local paradigm testifies for the interest of this paradigm in the understanding of human's perception. In the domain of cognitive psychology and developmental psychology, there are still a lot of questions that need further research.

The study of perceptual organization of parts versus whole in developmental psychology was originally triggered by questions regarding the development of general visual

Chapter 1 : General Introduction processing. Some early studies proposed that young children had limited ability in perceiving objects, so they would be able to attend to either only the whole, without the analysis of the local parts [START_REF] Gibson | The Ecological Approach to Visual Perception[END_REF]Vurpillot, 1976), or only to the parts without a comprehensive picture of the global shape [START_REF] Diamond | Developmental changes in the representation of faces[END_REF]Elkind et al,1964). The results of recent studies have indicated that these contradictory conclusions were more likely due to variations in stimulus complexity rather than to the limitations in children's perception. Indeed, preschool-age children seem able to attend to both the part elements and the whole shape in visual perception task [START_REF] Dukette | Children's analysis of hierarchical patterns: Evidence from a similarity judgment task[END_REF][START_REF] Prather | Developmental differences in part/whole identification[END_REF]Tada & Stiles, 1996;[START_REF] Tada | Children's Analysis of Spatial Patterns : An Assessment of their -errors‖ in copying geometric forms[END_REF]. Some studies indicate that part and whole processing, developed throughout early ages until late adolescent [START_REF] Harrison | Hierarchical forms processing in adults and children[END_REF][START_REF] Mondloch | Developmental Changes in the Processing of Hierarchical Shapes Continue into Adolescent[END_REF][START_REF] Porporino | A developmental change in selective attention and global form perception[END_REF][START_REF] Scherf | Emergence of global shape processing continues through adolescence[END_REF], but studies with younger children at pre-school ages are scarce [START_REF] Hadad | Developmental trends in utilizing perceptual closure for grouping of shape : Effects of spatial proximity and collinearity[END_REF][START_REF] Farran | Perceptual grouping and distance estimates in typical and atypical development : Comparing performance across perception, drawing and construction tasks[END_REF].

Previous studies also showed that children's perception seems to be influenced by stimulus complexity and by the type of task administered during the experiment [START_REF] Prather | Developmental differences in part/whole identification[END_REF][START_REF] Kinchla | The Order of visual processing: -Top-Down‖, -Bottom-Up‖ or -Middle-Out‖[END_REF][START_REF] Grice | Forests before trees? It depends where you look[END_REF][START_REF] Pomerantz | Global and local precedence : Selective attention in form and motion perception[END_REF][START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF][START_REF] Sanocki | Time course of object identification : Evidence for a global to local contingency[END_REF][START_REF] Weber | Hierarchical visual processing is dependent on the oculomotor system[END_REF][START_REF] Ninose | The effect of prolonged viewing on the recognition of global and local levels of hierarchically constructed patterns[END_REF]. Further systematic investigations are still worth conducting, in particular with regard to the effect of the task used. We will systematically introduce drawing tasks because they have been very rarely used in children within this domain of research, although drawing was proposed to be an effective task in revealing the visual perception of typically and atypically developing children [START_REF] Dukette | The effects of stimulus density on children's analysis of hierarchical patterns[END_REF][START_REF] Lange-Küttner | The role of object violations in the development of visual analysis[END_REF][START_REF] Porter | Global and local processing in William syndrome, autism, and Down Syndrome : Perception, attention, and construction[END_REF] [START_REF] Stiles | Effects of Early Focal Brain Injury on Memory for Visuospatial Patterns : Selective Deficits of Global -Local Processing[END_REF]. Individuals with WS (William Syndrome) do not have a local or a global processing bias when asked to identify stimuli, but do show a local bias in their drawing abilities [START_REF] Farran | Divided attention, selective attention and drawing: Processing preferences in Williams Syndrome are dependent on the task administered[END_REF]. However, while [START_REF] Porter | Global and local processing in William syndrome, autism, and Down Syndrome : Perception, attention, and construction[END_REF] reported a local advantage in the drawings of individuals with WS, and also a local bias in a non-constructional task, individuals with Down Syndrome (DS) performed better in drawing the global shape than the local elements (Bellugi, Birhle, Jeringan, Trauner & Doherty, 1990;Bellugi, Lichtenberger, Jones, Lai, & St George, 2000), and children with autism displayed normal global processing but not normal local processing [START_REF] Plaisted | Children with Autism Show Local Precedence in a Divided Attention Task and Global Precedence in a Selective Attention Task[END_REF]. The literature in children with Down Syndrome is contradictory, and nothing is known about the local/global processing in blind children.

Chapter 1 : General Introduction

The experiments that have been done in the present thesis are an extension of those previous works to reveal further characteristics of the development of children's perception in hierarchical patterns across tasks and populations. Perceptual tasks (a similarity-judgment task or a naming task) and drawing tasks have been implemented in all four experiments.

Manipulation of duration of exposure to the stimuli was also introduced in Experiment 1 to Experiment 4 since previous studies showed that interference between the global and local patterns was affected by duration of exposure in adults [START_REF] Pomerantz | Global and local precedence : Selective attention in form and motion perception[END_REF][START_REF] Paquet | Global precedence: The effect of exposure duration[END_REF]. A long duration (3 seconds) and short duration (300 msec) were applied with the typically developing children in Experiment 1 to Experiment 4, but no time restrictions were given to atypically developing children in Experiment 5 and Experiment 6.

We assumed that, in a drawing task, longer duration elicited more local-global integrated or correct responses in children across ages while short durations directed these children to respond with more non-integrated responses. Prolonged exposure seemed to reduce the efficiency of global processing [START_REF] Ninose | The effect of prolonged viewing on the recognition of global and local levels of hierarchically constructed patterns[END_REF], so we expected that, in a perceptual task, longer durations will also elicit local preference, while global preference will be more produced by the short durations.

Consistent and inconsistent visual hierarchical patterns were studied in Experiment 1

to Experiment 4 to reveal the interference effects between the global and local level. Similar consistent and inconsistent hierarchical patterns were used in Experiment 6, but in the form of haptically explored hierarchical patterns since early blind subjects participated in the experiment. Our hypothesis was that the interference effect by the inconsistent stimuli will inhibit the integrated responses in children, while the integrated responses will be more produced by the influence of consistent stimuli.

Simple and complex hierarchical patterns were conveyed in Experiment 3 and Experiment 4 with typically developing children, since previous studies proposed that younger children segmented out simple, well-formed, spatially independent parts and used simple relational structures to bind these parts together (Tada & Stiles, 1996). Based on this assumption, we expected that older children will process globally the complex hierarchical patterns more efficiently than the younger children. Since this comparison between simple and complex stimuli in the studies of hierarchical patterns was new in the literature, we considered this part of our experimental work as highly exploratory.

Meaningful (familiar objects) patterns and non-meaning (non-objects) patterns were applied in Experiment 5 in order to reveal whether meaning elicited local preference and local interference as proposed by [START_REF] Poirel | Implicit identification of irrelevant local objects interacts with global/local processing of hierarchical stimuli[END_REF]Poirel et al. ( ,2008)). Children with mental retardation participated in this experiment. Considering that global responses were dominant in children with mental retardation [START_REF] Birhle | Seeing either the forest or the trees: Dissociation in visuospatial processing[END_REF]Bellugi et al., 1990Bellugi et al., , 2000

Introduction

In this chapter, two experiments are reported that aimed at investigating the development of spatial analysis of hierarchical patterns in children between 3 and 9 years of age, using a drawing and a similarity-judgment task.

Drawing behavior has attracted the interest of developmental psychologists from the turn of the last century (e.g., [START_REF] Freeman | Strategies of representation in young children[END_REF][START_REF] Lange-Küttner | Drawing and the Non-Verbal Mind[END_REF][START_REF] Luquet | Le dessin enfantin [Children's drawing[END_REF][START_REF] Willats | Making sense of children's drawings[END_REF]. An original use of this nonverbal behavior was to investigate the development of spatial analysis of hierarchical patterns in children [START_REF] Dukette | The effects of stimulus density on children's analysis of hierarchical patterns[END_REF][START_REF] Lange-Küttner | The role of object violations in the development of visual analysis[END_REF][START_REF] Porter | Global and local processing in William syndrome, autism, and Down Syndrome : Perception, attention, and construction[END_REF]. The concept of hierarchical patterns can be traced back to [START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF], who designed compound figures made of large global letters (e.g., a large H that constitutes the global level) composed of small local letters that could be consistent (e.g., small Hs) or inconsistent (e.g., small Ss) with the global level to test the so-called -global precedence effect‖ (see also [START_REF] Kimchi | Primacy of wholistic processing and global/local paradigm: A critical review[END_REF][START_REF] Martin | Local and global processing : The role of sparsity[END_REF][START_REF] Navon | What does a compound letter tell the psychologist's mind?[END_REF]. Indeed, Navon (1977, p. 354) argued that -perceptual processes are temporally organized so that they proceed from global structuring toward more and more fine-grained analysis.‖ This hypothesis claims that when processing a visual object or a visual scene, the global properties are processed first, and the local properties are analyzed later. The originality of envisaging this issue through drawing behavior relies on the fact that drawing a hierarchical pattern, from memory or in a copying task, requires the integration of both processes, regardless of their respective priority in the very act of perceiving. there is no study with typically developing children in which performance was compared in a perceptual and in a constructional drawing task using the same hierarchical patterns and manipulating the same factors. In the present two studies, we aimed at investigating whether young children would display a global or a local bias in drawing hierarchical patterns and whether this bias would be specific to the constructional nature of the drawing task or would be identical in a perceptual task. Note that it was necessary to use a between-subjects design to prevent practice and priming effects between the drawing and perceptual tasks, yet limiting the comparison between drawing and perception.

The studies that have investigated this question of perceptual processing in typically developing children using perceptual tasks are more numerous than those based on drawing behavior. Most of them have concluded in favor of an initial local processing bias. In a forcechoice matching task, [START_REF] Kramer | Developmental sex differences in global-local perceptual bias[END_REF] reduced, the 4-year-old children did express more local choices than older children in the two conditions that did not intend to induce any specific choice. These results suggested that young children were capable of processing both levels of organization, though local processing had an initial advantage. Finally, [START_REF] Burack | Age Differences in Visual Search for Compound Patterns: Long vs. Short Range Grouping[END_REF] showed that age related performance improvements in a visual search task were more important in global than in local processing between 6 and 10 years of age.

However, the reverse finding of an initial global bias has also been revealed in the literature. When children were asked to decide under short exposure times whether two patterns were the same on the basis of the local elements or of the global shape, 6-and 10year-olds demonstrated a strong global bias, stronger than the one showed by adults [START_REF] Mondloch | Developmental Changes in the Processing of Hierarchical Shapes Continue into Adolescent[END_REF]. Children were also less accurate on local than on global trials, contrary to adults. At 14 years of age, performance looked adult-like.

This developmental pattern suggests a slower improvement with age in local than in global processing. [START_REF] Kimchi | Microgenesis and ontogenesis of perceptual organization: Evidence from global and local processing of hierarchical patterns[END_REF] demonstrated that both developmental trends were indeed likely to emerge, depending on contextual and task factors, in particular whether local elements in the hierarchical patterns were few large or many small.

More recently, [START_REF] Scherf | Emergence of global shape processing continues through adolescence[END_REF] argued that it is the formation of a precise integrated shape representation that would develop until late in adolescence. Finally, [START_REF] Poirel | First came the trees, then the forest: Developmental changes during childhood in the processing of visual local-global patterns according to the meaningfulness of the stimuli[END_REF] showed that a developmental change in preferential processing level occurred early in the first years of life, revealing a clear local preference at 4 years of age, followed by a global preference at 6 years of age.

What the literature makes clear is that many parameters determine whether a local or global bias emerges at the different ages in a perceptual task. In particular, the exposure duration of the patterns seems especially relevant to differences in the findings [START_REF] Kimchi | Primacy of wholistic processing and global/local paradigm: A critical review[END_REF]. None of the drawing studies carried out with typically developing children has tested the effect of stimulus duration. Yet, several studies have shown that short exposure times facilitated global precedence in adults when the density of local elements was standard (e.g., [START_REF] Kinchla | The Order of visual processing: -Top-Down‖, -Bottom-Up‖ or -Middle-Out‖[END_REF][START_REF] Martin | Local and global processing : The role of sparsity[END_REF][START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF][START_REF] Paquet | Global precedence: The effect of exposure duration[END_REF]. We therefore decided to present the hierarchical patterns under short or long exposure durations in both the drawing and perceptual tasks. Furthermore, [START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF] tested the interference effects between local and global levels comparing performance when consistent or inconsistent patterns were shown to the participants and revealed global-to-local interference (see also [START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF][START_REF] Kimchi | Primacy of wholistic processing and global/local paradigm: A critical review[END_REF][START_REF] Martin | Local and global processing : The role of sparsity[END_REF]. None of the drawing studies run with typically developing children has compared performance with consistent and inconsistent patterns.

Thus, the question is still open as to know whether typically developing children would

Chapter 2 : Children's spatial analysis of hierarchical pattern

Chapter 1 : General Introduction manifest possible interference effects in their drawings of inconsistent hierarchical patterns.

Finally, Poirel et al. (2008) demonstrated that a change in perceptual bias occurred early, between 4 and 6 years of age. We included children as young as possible in our experiments.

Children at 3 years of age are able to draw circles and squares. We built hierarchical patterns using these two shapes and tested children between 3 and 9 years of age.

Drawing hierarchical patterns requires children to process both levels of organization and to integrate one to the other. We focused on these two aspects and not on the accuracy with which each level was reproduced. Accuracy in drawing depends on several factors that do not all relate to how information is encoded (e.g., [START_REF] Miyahara | Effects of postural instability on drawing errors in children: A synchronized kinematic analysis of head drawing and body motion[END_REF]Vinter & Mounoud, 1991). Thus, we performed an analysis based on the categories of drawings made by children at the different ages. Young children seem able to attend to both the global and local levels [START_REF] Dukette | The effects of stimulus density on children's analysis of hierarchical patterns[END_REF]. However, if these levels are introduced in their drawings, we expected that young children would not be able to integrate them but would produce drawings with the local elements and the global shape juxtaposed or combined following other topological relationships. Several drawing studies have indeed revealed convergent findings showing that young children parse compound spatial patterns in independent parts, entertaining simple topological relationships (e.g., Akshoomoff & Stiles, 1995;[START_REF] Picard | Representational flexibility in chidren's drawing: effects of age and verbal instructions[END_REF]Tada & Stiles, 1996;Vinter & Marot, 2007). Thus, young children should draw preferentially isolated elements rather than the global shape. However, consistent patterns should enhance the production of integrated drawings, and short pattern durations should reinforce global processing.

Finally, our sample of children included both girls and boys because boys have been reported to make significantly more global perceptual judgments than girls [START_REF] Cahill | Sex-and Hemisphere-Related Influences on the Neurobiology of Emotionally Influenced Memory[END_REF][START_REF] Kramer | Developmental sex differences in global-local perceptual bias[END_REF]. This finding is consistent with developmental models that suggest an early left-hemisphere advantage for girls and a right hemisphere advantage for boys (Coluccia, Iosue, & Brandimonte, 2007). However, [START_REF] Dukette | Children's analysis of hierarchical patterns: Evidence from a similarity judgment task[END_REF] mentioned exactly the reverse result in 4-to 6-year-olds and in adults in a force-choice matching task, with female participants making more global level matches than male participants. Gender differences were therefore worth investigating.

Chapter 2 : Children's spatial analysis of hierarchical pattern

Chapter 1 : General Introduction

A. Experiment 1: Drawing hierarchical patterns in children

Method

Participants.

A total of 108 right-handed Caucasian children (55 girls, 53 boys), between 3 and 9 years of age, participated in the experiment. They were divided into seven age groups with age distribution as illustrated in Table 1. Each age group corresponded to one school level (3-to 5-year-olds: nursery and kindergarten levels). Handedness was assessed by testing children on eight items from [START_REF] Bryden | Measuring handedness with questionnaires[END_REF] test, four unimanual items (drawing, throwing a ball, holding scissors, and brushing teeth), and four bimanual items (closing a bottle, hitting a nail with a hammer, lighting a match, and drying a plate with a tea cloth). Only children who obtained a score above 6 were selected. The handedness test was carried out in a pre-experimental session and completed 1 week before the experiment. None of the children were educationally advanced or retarded, and their vision was normal. Children were largely from middle socioeconomic status families. They were tested individually in a quiet room at their schools. Informed written consent was obtained from parents of each child participating in the study.

Material.

Stimuli were displayed as bitmap files and were presented on a 36-cm -27-cm computer screen. Four targets were used in the familiarization phase: a big circle or square (diameter/side's length: 4 cm) and a set of five randomly arranged small circles or squares (diameter/side's length: 3 mm); all four targets were traced in a dashed line. The four targets shown in the test were as follows: a square made of small squares (consistent stimulus) or of small circles (inconsistent stimulus), and a circle made of small circles or of small squares.

Illustrations of the targets can be seen in Figure 16. The global shape was 4 cm of height and

Chapter 2 : Children's spatial analysis of hierarchical pattern

Chapter 1 : General Introduction width. Each small local shape was 3 mm high and 3 mm wide. There were 26 local elements in each larger shape, which corresponded to a standard condition with respect to the density effect [START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF][START_REF] Martin | Local and global processing : The role of sparsity[END_REF]. The target appeared centered in the upper half of the monitor screen. The location of the monitor was adjusted so that the viewing distance was at 60 cm. The middle of the screen corresponded to the participant's body midline.

Figure 16. Illustration of the target hierarchical patterns used in Experiment 1.

A. Consistent Stimuli 1 B. Consistent Stimuli 2 C. Inconsistent Stimuli 1 D. Inconsistent Stimuli 2
Procedure.

In a short familiarization phase, the children were introduced to the instructions and experimental conditions. They were instructed to copy as accurately as possible the model that appeared on the screen. They were told to concentrate their attention on the screen because the models would stay visible for a very short time on some trials. The experimenter gave them a sheet of paper (A5 format) and a black pencil and asked them to adopt a comfortable and stable posture for drawing. The four familiarization targets appeared for either a long (3-s) or short (300-ms) duration. The order of presentation of the stimuli was randomized. When the model disappeared, the participants were asked to make their drawing The procedure was basically the same in the experimental phase. The children were told that they would now see patterns such as a big square or circle made of small squares or circles. The experimenter showed them an example of the patterns to ensure that they were aware of the presence of the two levels of organization. The children were asked to focus

Chapter 2 : Children's spatial analysis of hierarchical pattern

Chapter 1 : General Introduction their attention on the monitor screen and to copy the pattern as accurately as possible. They produced a total of 16 drawings (2 consistent and 2 inconsistent patterns X 2 durations X 2 trials). A complete random order was used for the targets' presentation.

Data coding.

The drawings were sorted into five categories, illustrated in Figure 17.

• Correct integrated response: The overall global shape as well as the local elements were correctly reproduced (we did not code whether the size or the number of elements or the regularity of the distance between elements or the accuracy of the right angles in the squares were correct).

Figure 17. Illustration of the categories of responses in the drawing task.

Correct integrated responses

Inaccurate integrated responses

Global responses

Local responses

Non-integrated responses

• Inaccurate integrated response: The drawings comprised a global shape made of small elements (the two levels were present and integrated). However, the global shape was deformed or the local shapes were deformed or both the global and local shapes were

Chapter 2 : Children's spatial analysis of hierarchical pattern

Chapter 1 : General Introduction deformed (they were ellipses or rectangles, for instance). Only shape deformations were considered here.

• Global response: The overall global shape was reproduced with a continuous line, and the local elements were absent. We did not differentiate the cases in which the shape was deformed (the 3-year-old children were not all able to draw squares correctly).

• Local response: A series of small circles or squares was reproduced. The overall global shape was absent. The elements were either isolated or linked one to the other, or they formed a part of the target. The shape of the local elements was not coded. As illustrated in Figure 16, most of the drawings were ambiguous, mixing circles, ellipses, deformed squares, or rectangles.

• Nonintegrated response: The local elements were either juxtaposed or superposed to the global shape or nested (the superposed drawings were rare).

Two judges coded the drawings independently. They were naive to the experimental conditions (type of model shown, duration of exposure) in which each drawing was produced.

Their percentage of agreement was 91%. The disagreements were settled by the two judges working together, before data analysis.

The data were analyzed with nonparametric tests because homoscedasticity was not held in most of the cases. The Kruskal-Wallis test (H value) was used to test overall age differences, the Mann-Whitney test (U value) was used to test gender differences or age differences between two groups, and the Wilcoxon signed-rank test (T value) was used to test consistency and duration effects. We followed [START_REF] Neuhaüser | Round your numbers in rank tests: exact and asymptotic inference and ties[END_REF] advice for the use of appropriately rounded mean frequencies prior to the ranking procedure.

Results

Gender did not yield significant differences (all ps >.10) and was ignored in the reported analyses. Figure 18 depicts the results as a function of age and consistency for the integrated and nonintegrated responses.

Chapter 2 : Children's spatial analysis of hierarchical pattern

Chapter 1 : General Introduction No other significant differences were reported. Note that a qualitative analysis of the shape deformations did not reveal any systematic deformations of one level (local or global) as a function of the other (as, e.g., diffusion from the global shape to the local one or vice-versa).

Chapter 2 : Children's spatial analysis of hierarchical pattern

Chapter 1 : General Introduction

As depicted in Figure 18C, the nonintegrated responses dropped out rapidly between 3 and 4 years of age and disappeared at 6 years of age. The differences between the age groups were significant, H (6, N =108) = 50.5, p < .01. No other differences were significant (all ps > .10). Figure 19B shows that the global responses were rare and were produced only by the 3-to 4-year-olds (8% on average), H (6, N=108) = 18, p < .01. There were no other significant effects (all ps > .10).

B. Experiment 2: Perceptual similarity judgments of hierarchical patterns in children

The results of Experiment 1 suggest that local processing dominated first and that local and global processing started to be integrated at 5 years of age. Would a similarity judgment task show that global processing preference emerged somewhere around 5 years of age? We designed the similarity judgment task so that it was as similar as possible to the drawing task. The same consistent or inconsistent target patterns that were used in Experiment 1 were shown to children in Experiment 2 under the same exposure duration conditions.

Children had to decide which figure, among four choices, was the most similar to the target.

Following Poirel et al. (2008) and our findings in Experiment 1, we expected to observe a local bias in the choices made by the youngest children, which should be stronger under long than short target exposure durations. The results of Experiment 1 suggest that this local bias decreased in strength rapidly between 3 and 5 years of age. [START_REF] Dukette | Children's analysis of hierarchical patterns: Evidence from a similarity judgment task[END_REF] reported a preference for global responses from 4 years of age. We expected the transition between local and global preference processing to be located somewhere between 4 and 5 years of age.

As we have seen in Experiment 1 that consistent targets enhanced the integration between local and global processing in young children, the preference for global responses should be reinforced by pattern consistency.

Method

Participants.

A total of 224 right-handed Caucasian children (112 girls, 112 boys), between 3 and 9 years of age, participated in the experiment. They were divided into seven age groups of 32 children each, half female and half male as described in Table 2.

Chapter 2 : Children's spatial analysis of hierarchical pattern

Chapter 1 : General Introduction The criteria used to select the children were exactly the same as those described in Experiment 1. Participants in Experiment 2 were not in Experiment 1.

Material.

As in Experiment 1, the stimuli were displayed as bitmap files and were presented on a 36-cm x 27-cm computer screen. Two targets were shown in the familiarization phase: a circle and a square (diameter/side's length: 4 cm), traced in a continuous line. The same stimuli traced in a dashed line, together with a cross and a star (same size, traced in a dashed line), were used for the responses' choices. When the circle (or square) was presented, for instance, a dashed circle (or square), a dashed square (or circle), the cross, and the star were the choices.

The four targets shown in test were exactly the same as those used in Experiment 1.

The responses' choices included a square, a circleboth traced in a continuous line (height/width of 4 cm)-a set of seven small squares (3 mm), and a set of seven small circles (3 mm), traced in a continuous line and randomly arranged within a virtual 4-cm x 4-cm frame. Pilot testing showed that several local elements randomly displayed were a much more efficient stimulus than only two or three local elements. We used seven elements because we observed that young children drew on average seven elements in Experiment 1 when they produced local responses. The target appeared centered in the upper half of the screen, and the four responses appeared below the target, centered in the lower half. The location of the computer monitor was adjusted so that the viewing distance was at 60 cm, and the middle of the screen corresponded to the participant's body midline.

Procedure.

During the initial phase children were familiarized to the material and the instructions. They were presented with a target stimulus (circle or square) and were asked to select, among four choices (see Figure 20), the stimulus that was the most similar to the target.

Chapter 2 : Children's spatial analysis of hierarchical pattern The experimenter told the participants to focus their attention to the screen because the target would appear for a very short time in some cases. This phase included four trials (circle or square, presented in the two durations), and it was repeated once when children selected the wrong choices. The target remained visible for 3 s or for 300 ms, followed by an 800-ms blank screen, which was followed by the four choices. Children used a mouse to select the stimulus they considered most similar to the target, with children who were unable to use the mouse using their index finger to indicate their choice. In this last case, the experimenter clicked on the choice that the child has pointed to. The participants were asked to keep their position constant throughout the experiment. The experimenter checked the participant's position before triggering the next trial. Most children 3 years of age and some of the 4-year-olds needed a repetition of the familiarization phase.

The instructions given in the test phase were identical to those in the familiarization phase. Four targets were shown in the test phase: Two were consistent stimuli (circle made of small circles or square made of small squares), and two were inconsistent stimuli (circle made of small squares or square made of small circles). They were displayed either for 3 s (long duration) or for 300 ms (short duration), and the four choices appeared after a blank screen of 800 ms and remained visible on the screen until the children selected one response. The experimenter waited for the participants' ready signal before triggering the next trial. Each target was presented twice at each duration. The targets as well as the durations were randomized across the 16 trials. Four choices were presented to the participants: a circle, a square, a set of small circles, and a set of small squares. One corresponded to a global response (e.g., choice for the square when a square made of circles or squares was shown), one was a local response (e.g., choice for the set of squares when a square made of squares or a circle made of squares was presented), one was an erroneous global response (e.g., selection of the circle when the square made of squares or circles was displayed), and one was an At this age, the erroneous global responses were largely the most frequent errors, and they occurred significantly more often with inconsistent figures. This result is important because it reveals a phenomenon of diffusion from the local to the global level. Finally, like in the drawing experiment, no significant gender differences emerged in the present experiment.

This finding corroborates the results reported in a recent study in which no gender differences in perceptual processing biases were found [START_REF] Scherf | Emergence of global shape processing continues through adolescence[END_REF].

Discussion

The

A. Qualitative Changes in the Relationships Between the Local and Global Modes of

Processing

The results are congruent with regard to the type of processing that dominated at the youngest age. When the 3-year-olds were asked to draw the compound models, they reproduced only local elements in 50% of the cases. It was with approximately the same frequency that they selected the local responses in the similarity judgment task. These findings support the view that the local bias in drawing was not due to the constructional nature of the task [START_REF] Porter | Global and local processing in William syndrome, autism, and Down Syndrome : Perception, attention, and construction[END_REF], though evidence obtained with a within-subjects design would be still more convincing. They also confirm that local processing dominates the global one in young children [START_REF] Dukette | Children's analysis of hierarchical patterns: Evidence from a similarity judgment task[END_REF][START_REF] Kramer | Developmental sex differences in global-local perceptual bias[END_REF]Poirel et al., 2008).

This could be related to differential rates of development between the left and right hemispheres [START_REF] Molfese | Brain lateralization in children[END_REF], to reduced oculomotor exploration involving incomplete processing of visual scenes [START_REF] Kowler | Eye movements of preschool children[END_REF]Poirel et al., 2008), or to attentional functioning in young children who put more attention to parts than to the whole (Tada & Stiles, 1996). The extent to which top-down processes, such as identification or

Chapter 2 : Children's spatial analysis of hierarchical pattern

Chapter 1 : General Introduction naming processes (Poirel et al., 2008), were involved was not clear in our task, as young children might have a tendency to name the most numerous elements (thus, the local elements).

However, the drawing task showed that even at 3 years of age children were capable to attend to both levels of pattern organization, as shown by [START_REF] Dukette | The effects of stimulus density on children's analysis of hierarchical patterns[END_REF] in the 4-year-olds. In around 40% of the cases, the 3-year-old children produced drawings in which both levels were present, but these were either juxtaposed or superimposed or nested. Tada and Stiles (1996) et al., 2002), this independent functioning may be a consequence of the still immature interhemispheric communication in the integration of visual information. It is indeed only at around 2 years of age that processing between the two hemispheres starts to be coordinated [START_REF] Liegeois | When does interhemispheric coordination integration of visual events emerge in infancy? A developmental study on 19-to 28month-old infants[END_REF]. However, other accounts for the nonintegrated drawings can be proposed. They may denote the difficulties encountered by young children when they have to combine basic geometrical shapes in their drawings [START_REF] Freeman | Strategies of representation in young children[END_REF]. The nonintegrated drawings can also reveal the difficulties encountered by young children in the understanding of parts-whole relationships, as shown in drawing studies [START_REF] Picard | The development of context sensitivity in children's graphic copying strategies[END_REF]Tada & Stiles, 1996;[START_REF] Picard | Representational flexibility in chidren's drawing: effects of age and verbal instructions[END_REF]Vinter & Marot, 2007) or in cognitive tasks (e.g., [START_REF] Inhelder | The early growth of logic in the child: Classification and seriation[END_REF].

Important

B. Sensitivity to Pattern Consistency and Target's Exposure Time

As could be expected, correct integrated drawings were facilitated by consistent patterns as well as the choice at young ages for global responses in the similarity judgment task. More important, the most frequent errors in the perceptual task were the erroneous global responses made by the 3-year-olds in the face of inconsistent patterns. Adults were shown to be subject to interference effects revealing diffusion from the global (dominant level) to the local level in the face of inconsistent patterns [START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF][START_REF] Martin | Local and global processing : The role of sparsity[END_REF][START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF]. Our results suggest that a similar but reversed effect occurred at 3 years of age:

Children's errors revealed diffusion from the local (dominant level) to the global level. The results obtained from the manipulation of exposure times in the similarity judgment task are informative. The choice for local responses was more frequent with long than with short durations. In adults, [START_REF] Kimchi | Uniform connectedness and grouping in the perceptual organization of hierarchical patterns[END_REF] demonstrated that the global configuration of patterns made of many relatively small elements was primed at short exposures, whereas the local elements were primed at longer durations. The converse pattern of results was shown with configurations made of few, relatively large elements. She suggested that grouping many relatively small elements relies on rapid and effortless processes, whereas the individuation of many small elements would occur later and would be attention demanding (see also [START_REF] Kimchi | Microgenesis and ontogenesis of perceptual organization: Evidence from global and local processing of hierarchical patterns[END_REF]. In line with this theory, long durations should make it possible to select local responses. This is exactly what we observed in Experiment 2 in the 3-to 6-year-olds, that is, until global processing preference was clearly established.

In the drawing experiment, exposure times had only a marginally significant impact.

Drawing local elements tended to be more frequent after short than long durations in the 3year-olds. This effect was in opposition with the one obtained in the perceptual experiment, but it was only marginal, making its interpretation uncertain. [START_REF] Kimchi | Form and Texture in Hierarchically Constructed Patterns[END_REF], and since, a lot of researches have employed geometrical forms as we also did in the two previous experiments [START_REF] Navon | How many trees does it take to make a forest[END_REF][START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF][START_REF] Love | A Structural account of global and local processing[END_REF].

Simple and complex geometrical forms were contrasted because Tada & Stiles (1996) showed that the youngest children segmented out simple, well-formed, spatially independent parts and used simple relational structures to bind these parts together. As they got older, children constructed forms that included increasingly complex parts and relations. This result agrees with those which propose that younger children process the local elements before the global shape. We expected that, in the drawing task, the younger children should produce more non-integrated responses to the complex pattern than to the simple ones. They should be more inclined to reproduce the parts of the patterns than the frame. In the similarity judgment task, the younger children should select more local responses for the complex figures than for the simple ones.

A. Experiment 3: Drawing simple and complex hierarchical patterns in children 4-10 years of age

Method

Participants.

One-hundred-twenty one children (62 girls), aged between 4 and 10 years, participated in the experiment. They were divided into 6 age groups (see table 3). Each age Material.

Stimuli were displayed as bitmap files and were presented on a 36 cm x 27 cm PC screen. Four targets were used in the familiarization phase: a big circle or square (diameter/side's length: 4 cm). A set of 5 small circles or squares, randomly arranged (diameter/side's length: 0,3 cm), traced in dashed line.

The four targets in the experiment were: a square divided into 2 rectangles or into 2 triangles (figures with simple internal parts, hereafter called -simple figures‖), or into 4 squares or into 4 triangles (figures with complex internal parts, hereafter called -complex figures‖) as shown in Figure 22. The global shape's height and width were 4 cm. Each small local shape's height and width were 0.3 cm. There were 26 local elements in each larger, global level shape, which corresponded to a standard condition with respect to the density effect [START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF][START_REF] Martin | Local and global processing : The role of sparsity[END_REF][START_REF] Navon | How many trees does it take to make a forest[END_REF]. The target appeared centered on the top of a monitor screen. The location of the PC monitor was adjusted so that the viewing distance was 60 cm, and the middle of the screen corresponded to the participant's body midline. The visual angle for the global shape was 11° and the visual angle for the local shape was 0.87°.

Procedure.

In a short familiarization phase, the children were introduced to the instructions and experimental conditions. They were instructed -to copy as accurately as possible the model which appeared on the screen‖. They were told to concentrate their attention on the screen, because the models to copy would stay visible for a very short time on some trials. The experimenter gave them a sheet of paper (half of A4 format) and a black pencil, and asked them to adopt a comfortable and stable posture for drawing. Four familiarization targets appeared, either with a long (3 sec) or a short duration (300 msec). The order between these stimuli was randomized. When the model disappeared, the participants were asked to make their drawing, without any time constraints. When the drawing was finished, the experimenter took away the response sheet of paper, gave a new one to the participants, and waited for their ready-signal before launching the appearance of the next model. The children produced 8 drawings in this familiarization phase. All children noticed the difference in size of the figures and reproduced a big and a small circle or square (though the square shape was often deformed by the youngest children).

The procedure was basically the same for the experimental phase. The children were told that they would now see patterns like a big shape made of small shapes. The experimenter showed them an example of these patterns, to ensure that they were aware of the presence of the two levels in the patterns. They were asked to focus their attention on the monitor screen and to copy the pattern as accurately as possible. Every child received 2 trials with each pattern in 2 durations, so in overall, each child produced 16 drawings (4 targets x 2 durations x 2 trials). The order of presentation of these trials was randomized.

Data Coding.

A close inspection of the entire set of drawings showed that a double coding of the data was necessary: a coding of the reproduction of the frame/parts of the targets on the one hand and a coding of the presence/absence of the local elements or global shape on the other hand. The first data coding will be mentioned as frame-part analysis and the second data coding will be mentioned as categorization analysis. The two codings were introduced to get  Part incorrect : the parts were not correct or the shape was deformed. For instance, the internal diagonal inside the simple target pattern was reproduced as a vertical or the internal -×‖ parts inside the complex target pattern was reproduced as a -+‖.

 Frame absent: the frame was not present in the drawing (only the part was reproduced).

 Part absent : the parts were absent (only the frame was reproduced).

 Partial response : only a part of the frame was drawn (partial frame), the internal parts were partially reproduced (partial response). For instance, the internal -×‖ part inside a complex pattern target was reproduced as a unique diagonal.

The second type of coding (categorization analysis) was largely inspired by the drawing experiment reported in chapter 2; only one category of drawing was new. There were thus 5 categories as illustrated in Figure 24.  Non-integrated response: the local elements were either juxtaposed or superposed to the global shape, or included into it.

 Global response: the global shape was reproduced with a continuous line, more or less accurately, the local elements are absent.

 Local response: a series of small circles was reproduced on a line or on two lines connected by a more or less right angle or as agglomerates. The elements were either isolated or juxtaposed one to the other.

 Combined response: this category did not appear in Experiment 1 and 2. The frame was reproduced in a continuous line, without the local elements while the local elements were drawn for the internal parts or vice-versa as depicted in Figure 24.

Results

Non-parametric tests were used for data analysis because the assumption on normal distribution and homoskedasticity was not met in most of the cases, although the data set was large. The Kruskal-Wallis test (H value) was applied to test overall age differences, the Mann-Whitney test (U value) to test age and sex differences between two groups and the Wilcoxon signed-rank test (T value) to test differences in the complexity of the pattern and duration.

The frame-part analysis will be reported before the categorization analysis. The effect of duration was not significant for three drawing responses, which were :

Results of the frame-part analysis of drawing

the frame correct responses (all ps > .10), the frame incorrect responses (all ps > .10) and the frame absent responses (all ps > .10), even at 4 years of age as shown in Figure 26A, 26B and 26E respectively. In all the other cases, duration had an impact on the responses produced by the children. As illustrated in Figure 26C, the part correct responses were more frequently produced with the long durations (88.1%) than the short durations (67.85%). The effect of duration was significant, T (N = 121) = 69, p < .01, except at 4 years of age and at 9 years of age (all ps > .10).

For the part incorrect responses displayed in Figure 26D, a significant effect of duration was found in all ages, T (N = 121) = 198, p < .01, with the short durations eliciting more these responses (14.9%) than the long durations (5.8%), except at 4 years of age and at 9 years of age (all ps > .10). Finally, the partial responses (Figure 26G) were more induced by the short durations (7%) than by the long durations (3.7%), T (N = 121) = 48, p < .05. This occurred particularly at 5-6 years of age, T (N = 41) = 0, Z = 2.6, p < .01, where the short durations (12.1%) elicited more these responses than the long durations (3.6%).

Note that the effect of sex on the frame-part analysis was never significant, regardless of the type of responses (all ps < .10). So this factor was ignored in the rest of the analysis.

Results of the categorization analysis of the drawing responses

Let's examine now the results issued from the categorization analysis of the drawing responses in global, local, integrated, non integrated and combined responses. Figure 27 depicts these results as a function of age for the simple and complex stimuli. On the contrary, the non-integrated responses declined with age as described in The global responses showed a marginally significant effect of age, H (5, N=121) = 9.60, p = .08, as illustrated in Figure 27D. Indeed, if we compared the 4-5-6 year-old children to the 8-9 year-old children, we find that the former produced more global responses (32.4%) than the later (11.7%), (U=914, n 1 =61; n 2 =40), p < .01. The effect of complexity was again not significant (all ps > .10).

B. Experiment 4: Similarity judgment task with simple and complex hierarchical patterns

Experiment 3 suggested that children were constructing independently an analysis of the frame and the part before they were able to draw an integrated response, associating correctly the two analyses. The frame-correct analysis increased more rapidly than the partcorrect analysis; it emerged between 4 and 5 years of age, and it seemed stable. The complexity of stimuli influenced only the part analysis, with the complex figures less well reproduced than the simple ones at younger ages. It did not influence the other responses.

Duration had also a greater impact on part analysis than on frame analysis. With regard to the issue of local-global processing, the results showed that local processing dominated at younger ages and that local and global processing started being integrated at the age of 5.

In Experiment 4, a similarity judgment task was employed to test whether global processing preference would emerge somewhere near 5 years of age, and whether the complexity of the hierarchical patterns would have an impact on this preference. The similarity judgment task was designed so that it was as similar as possible to the drawing task.

Method

Participants.

One-hundred children (49 girls), aged between 4 and 10 years, participated in the experiment. They were divided into 5 age groups as described in table 4. Each age group corresponded to one school level (4-5-year-olds: nursery and kindergarten levels). The criteria used to select the children were exactly the same as those described in the previous experiments and none of them participated in these previous experiments.

Material.

Like in Experiment 3, the global shape was 4 cm of height and width and each small Procedure.

During an initial familiarization phase, children got used with the material and the instructions. They were presented with a target stimulus (circle or square) and were asked to select, among four choices (see Figure 29), the stimulus -which was the most similar‖ to the target, -which looked most alike‖. The experimenter told the participants to focus their attention on the screen because, in some cases, the target would appear for a very short time.

This phase included 4 trials (circle or square, presented in two durations), and was likely to be repeated once if children selected the wrong choices. The target remained visible for 3 sec or for 300 msec, followed by a blank screen during 800 msec before the 4 choices appeared. The children clicked with the mouse on the stimulus they considered as most alike to the target.

The participants were asked to keep their position constant throughout the experiment. The experimenter checked this point each time before launching the next trial.

The familiarization phase was useful to make the children familiar with the pace of the presentation of the targets and with the instructions. Some of the children aged 4 years needed a repetition of the familiarization phase. The instructions given in the experimental phase were identical to those in the familiarization phase. Four targets were shown in the test phase: 2 were simple stimuli and 2 were complex stimuli. They were displayed either for 3 sec (long duration) or for 300 msec (short duration), and the 4 responses' choices appeared after a blank screen of 800 msec and remained visible on the screen until the children selected one response. The experimenter waited for the participants' ready-signal before launching the next trial. Each target was presented twice in each duration. The targets (simple or complex) as well as the durations (short or long) were randomized across the 16 trials. Four choices were presented to the participants in each of simple and complex target as shown in Figure 29.

For each stimulus, the choices corresponded to a global response (for instance, choice for the square divided by a diagonal), a local response (for instance, choice for the set of small circles), a global partial response (for instance, selection of the triangle as part of square that was divided by a diagonal) and integrated partial response (for instance, choice for the set of circles that resembled to global partial choice). The location of the four responses' choices at the bottom of the screen (left, right or middle) was randomized.

Results

The results are depicted in Figure 30 A marginally significant effect of complexity was found at 10 years of age, T (N = 20) = 1.88, p = .059, but contrarily to the former result in older children, the global responses were more aroused by the simple stimuli (37.5%) than by the complex stimuli (25%).

The children selected the local responses rarely, on average only in 4% of the cases.

Nevertheless, the youngest children did it more often than the oldest ones, H No effect of duration were found in the local responses as depicted in Figure 31B and also in the integrated-partial responses as illustrated in Figure 31D (all ps > .10).

Chapter 3 : Children's Spatial Analysis of Simple and Complex Hierarchical Patterns

Chapter 1 : General Introduction

Discussion

In this study, the frame and part analysis yielded new findings on how children integrated spatial information in the drawing of hierarchical patterns. Before they reproduced an integrated, a local or a global response, children were constructing the frame and part analysis.

In overall, the results showed that age had an important impact on the development of frame-part analysis. Frame correct responses increased rapidly between 4 and 5 year of age, and then it seemed stable. Part correct responses also increased with age but less rapidly than the frame correct responses. A reverse result was shown for all the incorrect frame-part and absent frame-part responses, as these responses tended to decrease as age increased. The significant shift in the frequencies of these responses was also found between 4 and 5 years of age.

Complexity of the stimuli significantly influenced the part-correct responses, the partincorrect responses and the partial responses and did not influence any frame responses. A similar result was observed for the effect of duration that was found only in the production of part-responses. Long durations triggered more part-correct responses, while the partincorrect, the part-absent and the partial responses were more produced under of short durations, which could mean that short durations caused more defaults in the drawing of the parts than of the frame.

Age had also an important effect in the categorization analysis.

Introduction

The aim of this research was to study spatial analysis abilities in children with Mental Retardation (MR) in a naming task and a drawing task, using hierarchical meaningful patterns. We expected that meaning would interact with the global precedence principle advocated by [START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF], enhancing therefore a local analysis when meaning was identified at the local level, not at the global level. Furthermore, we aimed at confirming a major global bias in children with mental retardation, though some contradictory results exist in the literature.

There are several studies in the literature that had investigated the perception of hierarchical patterns in people with mental retardation. Some authors working with children with William Syndrom (WS) reported that these children were more accurate in drawing the local elements than they were in drawing the global shape (Bellugi et al., 2000;Rondan et al., 2007;[START_REF] Nakamura | Development of visuospatial ability and kanji copying in Williams Syndrome[END_REF]. Other studies in children with Down Syndrome (DS) revealed that these individuals performed better in drawing the global shape than the local elements [START_REF] Birhle | Seeing either the forest or the trees: Dissociation in visuospatial processing[END_REF]Bellugi et al.,1990;Bellugi, Lichtenberger, Mills, Garaburda & Korenberg, 1999). [START_REF] Farran | Divided attention, selective attention and drawing: Processing preferences in Williams Syndrome are dependent on the task administered[END_REF], reported that individuals with WS showed local bias only in drawing and not in a perceptual task requiring stimulus identification. They suggested that the local bias was not due to perceptual processing but from difficulties in integrating the parts into a whole when producing the drawing. This work was supported by [START_REF] Porter | Global and local processing in William syndrome, autism, and Down Syndrome : Perception, attention, and construction[END_REF] were well-known by the children (eg. star, umbrella, cups, etc) and non-meaningful hierarchical patterns included abstract objects that did not resemble to any object that might be known by children.

Studies that have been done with meaningful hierarchical patterns were pioneered by [START_REF] Poirel | Implicit identification of irrelevant local objects interacts with global/local processing of hierarchical stimuli[END_REF]Poirel et al. ( , 2008)). Using a same/different task in adults (deciding whether two patterns were the same or different), they revealed that (a) target differences were detected more rapidly when the level contained at least one meaningful object; (b) when the irrelevant level contained a pair of non-objects, global preference effects emerged; but when it contained a meaningful object, then local-level targets were detected more rapidly than global-level targets, (c) irrelevant objects did not influence reaction times when there were objects at both levels in the target level. The presence of an object (familiar pattern) triggered an automatic identification process that facilitated performance when it occurred at the target level, and interfered with performance when it occurred at the irrelevant level. These results thus suggested that when a familiar or identifiable object was present, an extra process was triggered and interfered with the performance in the comparison task. Therefore, the authors proposed that there are at least two processes working in parallel in the task, namely an object identification process and a structural analysis. Object identification was involved when a pattern depicted a familiar object, and structural analysis was involved in the comparison between the two patterns displayed during the comparison task. These results not only challenged the global precedence effect in a way that the global level was not always processed before the local one; they also showed that local interference existed.

The authors continued this work to reveal whether this automatic object identification followed the same characteristics in children (Poirel et al., 2008). Children 4 to 9 years of age participated in the study using a similarity judgment task. As in adults, the results showed that children detected the pictures as the same or different more accurately if the stimuli were objects. This finding supported the idea that the identification process was facilitated by the familiar patterns.

This question of the influence of meaning in the processing of hierarchical patterns was interesting to introduce in children with mental retardation. Indeed, we can suspect that the effect of meaning will be important in children with mental retardation, because of their less efficient executive functions. We also expect that the use of objects at the local level will enhance local processing in these children.

Method

Participants.

Ninety-four children (36 girls) with mental retardation aged 6 to 14 years participated in the experiment. They were divided into 3 groups of age (see table 5). There was no clear information about the etiology of mental retardation for each child, but most of them showed mental retardation due to organic causes. None of them had a William Syndrome, however.

Three groups of IQ were used in this experiment (see table 6). All participants attended specific educational schools in Jakarta (Indonesia) and they were all monolingual Indonesiannative speakers. Children came from families with low to middle-high socioeconomic status.

They were observed individually by an experimenter in a quiet room in their school. Informed consent was obtained from parents of each child participating in the study. In the drawing task, some children (N = 8) did not participate because they felt that they were not able to complete the task and they refused to be persuaded. Eighty-six children aged between 6 and 14 years (33 girls) completed the drawing task. They were also divided into three age groups (see table 7) and into three groups of IQ's as described in table 8. Material.

The hierarchical meaningful stimuli were built running a preliminary experiment.

Thirty-five children with MR aged 7 to 14 years were asked to name or identify 16 pictures (Figure 32). Twelve object pictures were chosen from educational books for pre-school Object pictures with the highest percentages of recognition were chosen as meaningful stimuli, while the non-object pictures with the lowest percentages were chosen as non-meaningful stimuli. Seven objects (boat, eyeglass, umbrella, cup, fork, star, and spoon) had the highest percentages (88.57% to 97.14%) and 2 non objects (Non-Object 1 and Non-Object 2) had the lowest percentages of recognition (11.43% and 5.72%).

Eight hierarchical stimuli were assessed to determine the validity of the task. The global shape consisted of 40 local elements [START_REF] Poirel | Implicit identification of irrelevant local objects interacts with global/local processing of hierarchical stimuli[END_REF] Six judges were involved in the validity phase. They gave ranks of suitability for each stimulus whether it had the characteristic of -wholeness‖. The ranking score extended from 1 = not suitable at all to 5 = very suitable. The results showed that four hierarchical stimuli had individually higher mean of ranking scores (range from 3.66 to 4.16) than the total mean of ranking score (3.104). Those four hierarchical stimuli were utilized in the main experiment (Figure 33). In a short familiarization phase, the children were introduced to the instructions and experimental conditions. They were instructed to identify the pattern they were being to see on the screen and then -to copy as accurately as possible the model which appeared on the screen‖. They were told to concentrate their attention to the screen. One hierarchical pattern was used in the familiarization phase (a triangle for the global shape and circles as local elements) to train the participants with the instructions. The experimenter gave them one sheet of paper (A4 format) and a black pencil, and asked them to sit comfortably at a distance of about 60 cm from the screen. The participant's body midline corresponded to the middle of the screen. There was no time constraint although the experimenter noted how much time the children needed to finish every pattern. When the pattern on the screen was identified, the children were instructed to draw the pattern. A further probing was applied by the experimenter before the drawing task, if the children did not answer very clearly, especially for the non-object patterns. As drawing was finished, the experimenter took away the response paper and gave a new one to the participants. The experimenter waited for the participant's readiness signal before displaying the next hierarchical stimulus.

Data Coding.

We proceeded to a close inspection of the entire set of data in the naming task and in the drawing task. This enabled us to sort the responses into different categories as follows for the naming task first :

 Integrated response : Children named the local elements as well as the whole shape. Since the patterns contained non-objects, a probing was needed, for the responses not being confused with non-integrated responses. When children could not described clearly a nonobject but they mentioned the shape of this non-object, then the answer will be considered as integrated response. The same condition applied if children named the non-object pattern using the name of an object that resembled to the non-object pattern (eg. a boat made of little stars for the local bias-induced pattern or a flag made of small shoes for the neutral pattern).

 Non-integrated response : Children responded with objects which did not correspond to the given pattern. For the non-objects, children's answer was considered as non-integrated if  Global response: global shapes were reproduced, but the local elements were absent.

 Local response : a series of local elements were reproduced, but they were either isolated or linked one to the other, yet forming only a part of the target, so that the global shape was absent.

Two judges coded the drawings independently. The percentages of agreement between the two judges were 86% for the integrated responses, 97.2% for the undifferentiated/syncretic responses, 97.3% for global responses and 84.2% for the local responses. Since there should only be one score for each hierarchical stimulus in the analysis, the judges had to settle any disagreement in their scoring.

Results

C. Results from the naming task

The data were analyzed by using non-parametric tests because the assumption for the homoscedasticity was not met in most of the cases. The Kruskal-Wallis test (H value) was applied to test overall age differences, the Mann-Whitney test (U value) to test age and IQ differences between two groups, the Friedman Anova test (F value) was used to test the effects induced for the different patterns and the Wilcoxon signed-rank test (T value) was employed to test differences between two patterns. Two analysis of the data were completed :

one taking age as the main independent factor, and one taking IQ as the main factor. They are presented separately. The integrated responses illustrated in Figure 36C showed a significant age effect when they were produced by the global bias-induced pattern, H (2, N = 94) = 6.38, p <.05. The integrated responses were more frequent in older children (22.6%) than in the younger ones

Analysis as a function of age

(1.2%).

The non-integrated responses, shown in Figure 36D, were rare at all ages, and they did not show any interesting effects as a function of age or patterns (all ps > .10).

Analysis as a function of IQ

The same analysis was applied grouping the data as a function of IQ, as illustrated in No significant effect of patterns was found in the production of integrated responses (all ps >.10).

The non-integrated responses illustrated in Figure 38D showed a significant effect of IQ for the global bias-induced pattern, H (2, N = 94) = 6.31, p < .05. The frequency of the responses was lower in the higher IQ-group (11.5%) than in the lower IQ-group (18.9%).

In this study, sex was worth to be investigated since it was considered as a factor that may contribute in children's perceptual analysis. However, no significant sex differences emerged in the present experiment (all ps > .01), so no further analysis was reported in this study. Sex had no significant effects on the drawing responses (all ps >.10), so it will not be reported further in this study.

D. Results from the Drawing Task 1. Analysis as a function of age

A more detailed examination of the data was needed in order to understand how these responses developed as a function of the type of patterns. In our experiment, age showed no effect in the naming task, neither in the drawing task of meaningful hierarchical patterns. This result could be well understood since the psychological development of children with mental retardation is more based on their mental age rather than on chronological age as used in this study. On the other hand, IQ was found significant in the production of non-integrated responses in the naming task and in the production of undifferentiated/syncretic responses in the drawing task, these responses being less frequent in the higher IQ-group than in the lower IQ-group. IQ also appeared significant in the production of total-integrated responses (naming-task) and integrated responses (drawing-task), where the integrated responses were more produced in the higher IQ-group.

Analysis as a function of IQ

These results are coherent with other findings concerning the involvement of cognitive mechanisms in the perceptual analysis (Poirel et al, 2008;[START_REF] Singh | Interhemispheric Interaction During Global-Local Processing in Mathematically Gifted Adolescents, Average-Ability Youth, and College Students[END_REF] Although pictures in raised-line drawings [START_REF] Heller | Tactile picture perception in sighted and blind people[END_REF][START_REF] Heller | Pattern Perception and Pictures for the Blind[END_REF])-as well as on comparative approaches to the neural substrates [START_REF] Streri | Hemispheric asymmetry in infancy : Global or local processing of objects in the haptic mode[END_REF][START_REF] James | The neural basis of haptic object processing[END_REF] or comparisons of contextual or individual effects, such as gender effects (Vecchi, 2001;Zuidhoek, Kappers, & Postma, 2007). Another interesting issue in the comparison between haptic and visual perception relates to the respective roles of global and local processing [START_REF] Garner | The processing of information and structure[END_REF][START_REF] Cook | Perceptual sensitivity to dimensional and similarity relations in free and rule-governed classification[END_REF]. Berger and Hatwell (1993) showed that analytical strategies predominate over holistic strategies in haptic perception.

Developmental trends were also examined by [START_REF] Berger | Developmental trends in haptic and visual free classifications : Influence of stimulus structure and exploration on decisional Process[END_REF] whose results contradicted those obtained in visual studies. In visual perception, access to the local dimensional structure takes longer and demands more attention than access to the global structure and, consequently, occurs later in the course of information processing. In haptic perception, in contrast, access to the global structure of the object should occur at a later stage of processing. Indeed, the sequential local exploratory movements prevent blind people from accessing global information, which therefore needs to be mentally reconstructed later by combining and integrating the precise information gathered locally. This idea that global processing develops later than local processing in haptic perception has found support in the work of [START_REF] Lakatos | Haptic form perception : relative salience of local and global features[END_REF] who reported that the ability to distinguish between 3D objects was increasingly based on local features as the exploration time decreased.

Consequently, at the developmental level, younger children should exhibit a local processing bias in haptic perception, whereas a global bias should develop at older ages, a prediction that has received support from a number of studies [START_REF] Berger | Developmental trends in haptic and visual free classifications : Influence of stimulus structure and exploration on decisional Process[END_REF][START_REF] Schellingerhout | Evolving patterns of haptic exploration in visually impaired infants[END_REF][START_REF] Streri | The development of haptic abilities in very young infants : From perception to cognition[END_REF]. To our knowledge, no previous developmental study has as yet addressed this issue in blind individuals.

Furthermore, contradictory findings were reported by [START_REF] Norman | The visual and haptic perception of natural object shape[END_REF] who argued that both touch and vision are sensitive to an object's global or overall shape. Pinneau and [START_REF] Pinneau | Intermodal transfer of spatial arrangement of the components parts of an object in 4-5 month-old infants[END_REF] found that 5-month-old infants are able to process haptically both the contour of an object and its local features. In this study, the children seemed to prefer to use the right hand (left hemisphere control) to discriminate features or local elements and the left hand (right hemisphere control) for the global contour. Thus, the extent to which haptic perception can inform individuals about both the global structure and the local organization of an object is still uncertain.

The aim of the present study was to investigate this issue in haptic perception in blind children by using hierarchical patterns of the type initially proposed by [START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF]. Many researchers have used hierarchical patterns in order to study visual perception in both adults (e.g., [START_REF] Navon | Does global precedence really depend on visual angle?[END_REF][START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF][START_REF] Kramer | Developmental sex differences in global-local perceptual bias[END_REF][START_REF] Love | A Structural account of global and local processing[END_REF][START_REF] Lamb | The Role of Spatial Frequency in cued shift of attention between global and local forms[END_REF][START_REF] Davidoff | Local and global processing: Observations from a remote culture[END_REF] and children (e.g., [START_REF] Dukette | Children's analysis of hierarchical patterns: Evidence from a similarity judgment task[END_REF]Tada & Stiles, 1996;[START_REF] Burack | Age Differences in Visual Search for Compound Patterns: Long vs. Short Range Grouping[END_REF][START_REF] Kimchi | Microgenesis and ontogenesis of perceptual organization: Evidence from global and local processing of hierarchical patterns[END_REF]Vinter, Puspitawati, & Witt, 2010). However, to our knowledge, only one study has focused on the haptic perception of hierarchical patterns in early-blind (EB) and late-blind (LB) participants [START_REF] Heller | Global versus local processing in haptic perception of form[END_REF]. These authors employed two types of hierarchical stimuli, i.e. large Braille patterns (e.g., -R‖) made up of smaller standard-size Braille letters (e.g., -c‖s) and large geometrical forms made of embossed dots. The participants were asked to name the explored shapes. ). This study demonstrated the interference produced during a tactile Braille reading experience in EB individuals who had been asked to explore spatial patterns. It also revealed the important role played by the material given to blind participants in enhancing either local or global processing. However, only adults were tested and the question remains as to whether EB children also produce predominantly global responses when required to name hierarchical geometrical patterns. We considered this to be quite unlikely, considering that the haptic system attributes a greater weight to local then global features during the initial steps of processing [START_REF] Lakatos | Haptic form perception : relative salience of local and global features[END_REF].

Chapter 5 : Global and Local Processing in Early Blind Children

The present study is the first to investigate the issue of local and global processing using tactile versions of Navon figures in a large corpus of EB children. We employed consistent and inconsistent geometrical hierarchical stimuli in order to reveal potential interference effects between the two types of processing, as has been observed in some studies dealing with visual perception [START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF][START_REF] Martin | Local and global processing : The role of sparsity[END_REF][START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF][START_REF] Kimchi | Primacy of wholistic processing and global/local paradigm: A critical review[END_REF][START_REF] Mondloch | Developmental Changes in the Processing of Hierarchical Shapes Continue into Adolescent[END_REF]Vinter et al, 2010). Indeed, the use of In order to investigate in depth the capacity of blind people to process information locally and globally, we used both a naming task, as in [START_REF] Heller | Global versus local processing in haptic perception of form[END_REF], and a drawing task. During haptic perception, humans base their classification of an object on its various parts [START_REF] Lederman | Haptic Classification of common objects : Knowledge-driven exploration[END_REF], 1993;[START_REF] Klatzky | Visual and haptic exploratory in children's judgements about tool function[END_REF]Vinter & Chartrel, 2008). Haptic classification is initially based on separate dimensional features, thus indicating analytical processing, before these local features are subsequently integrated during a global processing stage (Berger & Hatwell, 1993[START_REF] Robertson | Attentional Persistence for Features of Hierarchical Patterns[END_REF]. We therefore expected children in the younger age groups to produce primarily local responses in the naming task whereas the older children should produce either more global responses, as can be predicted from the Heller and Clyburn's results, or more integrated responses. A drawing task, which is associated with considerable planning and motor requirements (van Sommers, 1989), was used to reveal the extent to which the children were able to coordinate a global and a local analysis of the patterns. Children may indeed attend to these two components without, however, being able to coordinate them [START_REF] Dukette | Children's analysis of hierarchical patterns: Evidence from a similarity judgment task[END_REF]Vinter & Marot, 2007;Vinter et al., 2010). The ability of blind people to draw was reported in 1939 when Löwenfeld explored creativity in blind children. This ability was studied in more detail by

Kennedy and his colleagues (D'Angiulli, [START_REF] D'angiulli | Blind children recognizing tactile pictures respond like sighted children given guidance in exploration[END_REF][START_REF] Kennedy | Drawings from Gaia, a blind girl[END_REF][START_REF] Kennedy | Haptics and Projection : Drawings by Tracy, a blind adult[END_REF][START_REF] D'angiulli | Structural equivalence are essential, pictorial conventions are not: Evidence from haptic drawing development in children born completely blind[END_REF], who demonstrated that congenitally blind individuals are able to produce contour line drawings that capture the global shape of models. However, Vinter, Fernandes and Claudet (2009) reported that in around half of the drawings of familiar objects collected from EB children aged between 6 and 14 years, the elements making up the whole depicted object were drawn in a disconnected or juxtaposed way. This may indicate that blind individuals experience a specific difficulty in integrating local elements to produce a global shape. We therefore expected young blind children to mainly draw the local features of the patterns since only late in childhood would they be able to integrate local and global information in their drawings. Finally, since gender Chapter 5 : Global and Local Processing in Early Blind Children may play a significant role in haptic perception in blind individuals (Vecchi, 2001), we decided to include, as far as this was possible, an equal number of EB boys and girls. Vecchi (2001) showed that blind females tended to develop less efficient strategies than blind males when active processing was required in a complex task. This suggests that blind females might process information differently from males when confronted with inconsistent hierarchical patterns.

As revealed by the Heller and Clyburn study (1993), it is very likely that the material used to build tactile versions of geometrical Navon figures greatly affects blind people's ability to identify local or global components. We therefore ran a series of preliminary studies in order to test different materials. The results of these pilot studies are worth reporting because they provide important information about how to build tactile versions of Navon figures, and also because they can account for some of the differences obtained in our main experiment as well as in the Heller and Clyburn study (1993).

Pilot Studies

The stimuli tested in the first preliminary experiment were designed using Braille characters that formed squares or circles as local elements. As can be seen in Figure 43A, the standard-size Braille letters f, d, j and h were combined to form square local elements, while Figure 43B illustrates how the Braille letters i, c, e, e, c, i were combined to form circular local elements. There were 12 local elements in the overall global shape which was printed with a Braille printer so that the size and the space between elements were standard in the same way as in Braille text. The length of the sides of the square local elements was 1 cm x 1.25 cm (6.25 cm x 7.25 cm for the global shape). The diameter of the circular local elements was 1.5 cm (10 cm for the global shape). Thirty EB children aged between 6 and 16 years participated in this first preliminary study. There were 14 girls (mean age = 11.14 yrs, SD = 3.9) and 16 boys (mean age = 11.42 yrs, SD = 3.3). All the children involved in the pilot studies came from the same institutions and presented the same types of etiologies as those participating in the main experiment (see the method section). The children were asked to accurately explore the patterns in order to name them. The results showed that all the participants were puzzled by the patterns. Most of them (93.3%) perceived the Braille characters (and in particular the combination of f, d, j and h), but none of them recognized the global form or the local shapes. They therefore recognized the Braille material and used exploratory Braille reading procedures just as they do when reading Braille. Furthermore, because of the constraints linked to the use of a Braille printer, the density of elements was not high in these patterns. This may have reinforced local processing, although the current Chapter 5 : Global and Local Processing in Early Blind Children years, took part in this third pilot study: 15 boys (mean age = 10.64 yrs, SD = 3.4) and 15 girls (mean age = 11.85, SD = 3.5). As expected, performance was better in this study: 37.5% of the participants perceived both components in the patterns, 24.5% identified the local shapes, while 15% correctly identified the global shape. Nevertheless, 23.3% still had difficulty in identifying the shapes.

Since there were a large number of errors in this third preliminary experiment, we decided to use a different design after listening to the participants' accounts in the debriefing session during which they expressed the difficulties they experienced in perceiving a coherent shape on the basis of lines interspersed with blank spaces. This finding mirrors the observation made by [START_REF] Overvliet | Haptic search is more efficient when the stimulus can be interpreted as consisting of fewer items[END_REF] that haptic searches are more efficient when the stimuli are interpreted as consisting of fewer items. Consequently, in the fourth preliminary study, the local elements consisted of block patterns instead of lines in an attempt to reinforce the impression that the local elements constituted complete entities (see Figure 1E). Another group of 30 blind children aged 6 to 16 years participated in the fourth preliminary study, 14 girls (mean age = 12.02, SD = 3.22) and 16 boys (mean age = 11.46, SD = 2.4). The results revealed that only 2.6% of them gave erroneous identification responses, 45% identified the two components, 18.3% the global shape only and 34.2% the local elements only. This design using thermoformed block patterns was selected for use in the main experiment since it appeared to be the one best suited to the haptic sensitivity of EB children.

Method

Participants.

One hundred and ten blind children aged 6 to 18 years (50 girls, 60 boys) participated in the experiment. They were totally blind or with minimal light perception (OMS categories: 4 and 5) from birth or early infancy under14 month-age. They were divided into five age groups (see table 9). None of them participated in any earlier preliminary studies. All the participants were attending special schools for blind and visually impaired children in six large cities in Indonesia (Jakarta, Bandung, Cimahi, Yogyakarta, Klaten and Solo). None of them presented any associated disorders of relevance for our study, in particular psychiatric, cognitive or neurological disorders. Indeed, they were all enrolled in the school grade that corresponded to their age (none of them were educationally advanced or retarded). Their blindness was due to congenital glaucoma, congenital cataract, Leber's congenital amaurosis, retrolental fibroplasia, retinoblastoma, microphthalmia, optic nerve atrophy, glioma, or anophtalmia. Most of the participants came from families with a medium or low socioeconomic status. However, all the children from low socioeconomic status families were living in school-organized hostels rather than with their families. The schools which took part in the study were supported either by the Ministry of Social Services in Indonesia or by other social organizations. Informed written consent was obtained from the parents as well as from the directors of the hostels in the case of the children who lived there.

The experiment was conducted in accordance with the tenets of the World Medical Association Declaration of Helsinki on Ethical Principles for Medical Research Involving Human Subjects.

Chapter 5 : Global and Local Processing in Early Blind Children

Material.

Four hierarchical patterns printed as block patterns using thermoformed shapes were employed (see Figure 1E) for the naming and drawing tasks. The consistent stimuli were a big square made up of small squares and a big circle made up of small circles. The inconsistent stimuli were a big square made up of small circles and a big circle made up of small squares.

The patterns were printed individually on A5 format cards. The length of the sides of the square local elements was 1 cm, and the length of the side of the global shape was 6 cm. The diameter of the circular local elements was 1 cm and that of the global shape was 6 cm. The patterns consisted of 14 local circles and 16 local squares, respectively.

In the drawing task, the children were given a raised-line drawing kit. The drawings were produced using ballpoint pen on plastic sheets (21 cm x 14.7 cm) placed on a rubberized board. The pressure of the ballpoint pen on the plastic sheet produced a raised line, thus making it possible to provide haptic feedback during drawing execution.

Procedure.

The experiment began with an initial familiarization phase. There were 4 familiarization stimuli (thermoformed shapes) which consisted of one big circle of 6 cm in diameter, one big square with a side length of 6 cm, 5 randomly arranged small circles with a diameter of 1 cm and 5 small squares with a side length of 1 cm, also arranged randomly. The children were asked to name the shape of the explored patterns and, during the second part of the familiarization phase, draw them as accurately as possible using the raised-line drawing kit. Guidance was given by the experimenter if needed (guidance in moving the pen during drawing, verbal guidance during the exploration and also the naming of the shape, especially for the youngest children). During this familiarization phase, the experimenter made sure that the children named the patterns of 6 cm diameter/side length -big‖ and those of 1 cm diameter/side length -small‖. The experimenter allowed the children to practice drawing circles and squares if they were not satisfied with their performance. It was during this familiarization phase that the experimenter identified the children who refused to draw the patterns. After the children had named and drawn the four stimuli once, the experimenter tested the participants' understanding by presenting them with the four familiarization patterns again, in a random order, and asking them to name the shape that they perceived together with its size (i.e., big circle, small circles, big square, small squares). All the children succeeded in this examination phase. The familiarization phase took between 20 and 30 minutes. Each child was tested individually in a quiet classroom.

The experimental phase involved a very similar procedure. The children were comfortably seated at a table, and the experimenter placed the card on which the thermoformed pattern was printed on the table at a location aligned with the midline of each Chapter 5 : Global and Local Processing in Early Blind Children child's body. The experimenter helped the children place their hands on the card and asked them to explore the shape of the printed pattern accurately in order to name it using precise terminology. The card was then removed and a second pattern was presented for naming. The patterns were presented in a random order. The responses given by the children were recorded by a second experimenter who could not see which pattern was placed in front of the child.

The naming task was followed by an interval of 10-15 minutes. The experimenter informed the children who were willing to participate in the drawing task that they would now be required to explore patterns accurately in order to be able to draw them. They were not informed that the patterns were the same as those already explored in the naming task. The cards were again placed on the table one at a time for exploration. When the children said that they were ready to start drawing, the card was removed, the drawing material was placed at the same location, and the experimenter asked the children to reproduce the pattern as accurately as possible. The four stimuli were presented randomly, one at a time. No guidance or feedback was given during the naming or drawing task. The order of the two tasks was fixed. This was firstly due to the fact that during the familiarization phase, we had seen that fewer children were willing to draw than to name the patterns, and secondly because the literature reports that sketching explored line drawings facilitates their identification, thus suggesting that drawing could have a subsequent positive effect on naming (Witjntjes, van Lienen, Verstijnen, & Kappers, 2008).

Data Coding.

The verbal responses given by the children in the naming task were coded into four categories as described below:

 Integrated Response: The children correctly identified both the global and local shapes and their integration, stating that the pattern was a big square made up of small squares/circles, or a big circle made up of small circles/squares.

 Global Response:

The children correctly identified the global shape but did not mention or describe the local elements. Once the response was provided, the experimenter systematically asked -is there anything else you can perceive in this pattern?‖. When the identification response was global, some of the children said that there was a hole or a space inside the square/circle, whereas others did not report perceiving anything else. When the children did not spontaneously specify the size of the shape they perceived, the experimenter systematically asked them: -can you tell me about the size of the square/circle?‖. The response was considered global when the children only mentioned a big square or circle, often accompanied by finger movements tracing the outline of the global shape.

Results

Non-parametric tests were used for the data analysis because homoscedasticity did not apply in most cases. The Kruskal-Wallis test (H value) was employed to test overall age differences, the Mann-Whitney test (U value) to test sex or age differences between two groups, and the Wilcoxon signed-rank test (T value) to test differences relating to pattern consistency.

A. Results from the naming task. No effect of consistency was found, T (N = 93)= 115, p = .12.

Non-integrated responses (Figure 46E) were produced only rarely (M = 2.4%, SD = 12), reaching a peak value of only 8.3% (SD = 26) at 9-10 years of age. Age, consistency and gender all failed to induce any significant differences (p s > .20). 12. Finally, we computed the Spearman-rank correlations between performance in the naming and drawing tasks. To do this, we limited the number of participants considered in the naming task to those who also drew the patterns. The 3 response categories that were common to both tasks were considered. The children who produced integrated, global or local responses in the naming task also tended to provide integrated (r = .50, p < .01), global (r = .26, p < .05) or local (r = .29, p < .01) responses in the drawing task.

Discussion

The aim of the present study was to build tactile versions of Navon's geometrical patterns in order to investigate the type of processinglocal or globalthat is predominant at different ages in EB children and the age at which these visually disabled children are able to integrate and coordinate the two types of information. To our knowledge, this study is the first to adopt a developmental approach to the assessment of local and global processing in EB children by using tactile Navon figures. We employed both a naming task, as in the Heller and Clyburn study (1993) investigating EB and LB adults, and a drawing task as used in a small number of studies involving sighted children [START_REF] Dukette | The effects of stimulus density on children's analysis of hierarchical patterns[END_REF][START_REF] Lange-Küttner | The role of object violations in the development of visual analysis[END_REF]Vinter et al., 2010) or children with mental retardation [START_REF] Birhle | Seeing either the forest or the trees: Dissociation in visuospatial processing[END_REF][START_REF] Farran | Divided attention, selective attention and drawing: Processing preferences in Williams Syndrome are dependent on the task administered[END_REF][START_REF] Porter | Global and local processing in William syndrome, autism, and Down Syndrome : Perception, attention, and construction[END_REF]. The results yielded by these two tasks were quite similar results across ages, as the significant inter-task correlations attest. This finding confirms the validity of the drawing task as a way of addressing this issue, even in blind individuals.

Indeed, the two tasks revealed that EB children mainly produced local responses at ages of between 6 and 10 years and that the proportion of local responses decreased with age.

These findings were replicated when the data were analyzed at an individual level in which a predominant processing profile was assigned to each participant. The initial dominance of local processing appears to be consistent with the work conducted by [START_REF] Berger | Developmental trends in haptic and visual free classifications : Influence of stimulus structure and exploration on decisional Process[END_REF], who concluded that dimensional local relations organize haptic perceptual classification in young sighted children. Similarly, [START_REF] Lakatos | Haptic form perception : relative salience of local and global features[END_REF] reported that blindfolded sighted adults, who were asked to judge whether two objects were the same or not, relied more heavily on local than on global features during the initial stages of haptic exploration. In a study of blind individuals, [START_REF] Heller | Global versus local processing in haptic perception of form[END_REF] showed that adults produced more local than global responses when required to name compound Braille stimuli.

Chapter 5 : Global and Local Processing in Early Blind Children

Our study extended this investigation to EB children, and confirmed the initial dominance of local processing in haptic perception up to the age of around 10 years. It is worth pointing out that when young sighted children are required to perform the visual exploration of hierarchical patterns, they also display an initial bias toward local processing which, however, continues until only about 6 years of age (e.g., [START_REF] Poirel | First came the trees, then the forest: Developmental changes during childhood in the processing of visual local-global patterns according to the meaningfulness of the stimuli[END_REF]Vinter et al., 2010). The protracted dominance of local processing in the development of EB children is probably due to the sequential nature of the exploratory manual movements that are used by blind people to process shapes and prevent fast access to the global shape. Access to the global shape of unknown patterns requires highly developed mental capabilities for the coordination and integration of information and these capabilities need time to develop.

In both the naming and the drawing task, the younger participants produced fewer global than local responses. However, the fact that the latter type of response was still present

shows that young EB children can attend to both local and global information. At the age of about 11-12 years, the frequencies of the two types of responses were quite similar before decreasing in both tasks as the number of integrated responses increased. Unlike [START_REF] Heller | Global versus local processing in haptic perception of form[END_REF] who reported that EB adults named the global shape more often than the local elements when exploring embossed dot patterns, at no stage during our study did we observe a predominance of global over local responses. Furthermore, the older children tended to provide integrated rather than global responses in the naming task. These discrepancies between our study and that conducted by Heller and Clyburn are very probably due to the material used to build the tactile Navon patterns. Indeed, in our second pilot experiment in which we used material identical to that employed by [START_REF] Heller | Global versus local processing in haptic perception of form[END_REF], EB children again produced more global responses than local or integrated ones. The tactile versions of the Navon figures employed in the present experiment were probably more similar to their usual visual counterparts than those used in the Heller and Clyburn study (1993) or our first three pilot studies because they reinforce the impression that the local elements are complete entities and make it possible to interpret the tactile information as consisting of fewer items [START_REF] Overvliet | Haptic search is more efficient when the stimulus can be interpreted as consisting of fewer items[END_REF].

In line with the fact that the global shape is harder to access during haptic exploration our study confirms this ability emerges at a later stage of development. It is possible to argue that the greater difficulty in accessing the global shape of tactile images experienced by EB children is related to the way they explore the patterns. More specifically, the enclosure procedure could be beneficial to global shape processing, while the encoding of local shape information could be facilitated by the use of the contour-following procedure. However, [START_REF] Lakatos | Haptic form perception : relative salience of local and global features[END_REF] noted that neither contour-following nor enclosure were associated with a predominant emphasis on either local or global features when adults were required to judge whether two haptically explored patterns were identical or not. This observation might, Chapter 5 : Global and Local Processing in Early Blind Children of course, be different in the case of children. However, our informal observations of how children explored the Navon figures point to the same conclusion since our participants always made use of enclosure and frequently had recourse to contour-following. This in no way means that the procedure adopted for haptic exploration is of little relevance for shape and object recognition, as has been clearly shown by [START_REF] Kalagher | Developmental change in young children's use of haptic information in a visual task : The role of hand movements[END_REF] and D'Angiulli and [START_REF] D'angiulli | Guided exploration enhances tactual picture recognition in blindfolded sighted children: implications for blind children[END_REF][START_REF] D'angiulli | Children's tactual exploration and copying without vision[END_REF]. However, it does indicate that the enclosure and contour-following procedures, which are suitable for the extraction of the properties of a shape [START_REF] Lederman | Extracting object properties through haptic exploration[END_REF] et al., 2010). This suggests that the development of local and global processing generally proceeds in the same way in sighted and blind children and that there is a protracted period during which local processing dominates in blind children, with the result that they exhibit a developmental lag when the performances of the two populations are compared in a drawing task. The non-integrated drawings may indicate difficulties in the understanding of part-whole relationships as certain drawing studies have indicated (e.g., Tada & Stiles, 1996;Vinter & Marot, 2007). Indeed, a recent study assessing the tactile functioning of children with congenital blindness reported that items measuring the understanding of part-whole relationships were among those that these children found difficult to master [START_REF] Withagen | Tactile Functioning in Children Who are Blind : A Clinical Perspective[END_REF].

In the present experiment, the EB children had to name and draw consistent and inconsistent tactile Navon figures. A small number of significant effects relating to pattern Chapter 5 : Global and Local Processing in Early Blind Children consistency were observed in the naming task only. Local responses were more frequent for inconsistent than consistent figures, while global responses occurred more frequently in the case of consistent than inconsistent patterns. These findings may illustrate the use of a hypothesis testing strategy as described by Alexander, Johnson and Schreiber (2002) in their study of haptic exploration in children aged 4-9 years. These authors reported that whereas children who had considerable knowledge of the explored object domain (dinosaurs) identified the objects correctly, they also made more errors associated with the use of a hypothesis testing strategy. Their identification of highly pertinent local features that they knew to be critical for the identification of a specific type of dinosaur sometimes led them to draw incorrect conclusions when asked to judge whether or not two dinosaurs were identical.

Instead of fully exploring the two models, these children displayed a confirmatory bias based on the identification of distinctive local features. Perhaps the EB children in our study tended to make the assumption that the pattern was unique when they perceived that the local elements had the same shape as the global configuration. In contrast, when there was a mismatch between the local shapes and the global configuration, the assumption was in favor of the dominant local information. If this account is correct, it would suggest that the way pattern consistency is manipulated differs greatly between haptic and visual exploration. It is unlikely that interference effects would occur during haptic exploration, as they do in the visual mode, because of the extended timecourse of global information processing in the haptic mode. This would explain why we observed only a small number of erroneous responses in the drawing task when compared to a similar experiment run with sighted children (Vinter et al., 2010).

Finally, some differences between EB girls and boys were observed in the experiment. In both the naming and drawing tasks, the girls produced local responses more frequently than the boys. This result provides support for the findings reported by Steri et al.

(1996) which suggest that girls process haptic information analytically and discriminate details, especially when employing the right hand. It is also consistent with developmental models that suggest that the left hemisphere is favored early in girls (Collucia, Iosue, & Brandimonte, 2007), as the left hemisphere has been found more efficient than the right one for local information processing (e.g., [START_REF] Lamb | Attention and interference in the processing of global and local information : Effects of Unilateral Temporal-Parietal Junction Lesions[END_REF]. Furthermore, in the naming task, the boys produced integrated responses more frequently than the girls. Vecchi (2001) found that blind males developed more efficient strategies than females when active processing was required in a complex task. The gender differences we observed might primarily be due to similar differences in information processing strategies, with the boys deploying more efficient strategies for the coordination of local and global information in response to the more complex patterns (the inconsistent patterns). However, they may also be due to more basic differences in haptic perception, given that Zuidhoek et al. ( 2007) found

Chapter 5 : Global and Local Processing in Early Blind Children that males performed better than females in a variety of tasks assessing the haptic perception of orientationDefining more precisely what may underlie the gender differences observed in our experiment appears therefore delicate, and further research on this topic is needed for clarification. The only gender difference that is coherent with the overall literature was obtained in the drawing task, where the boys produced more scribbled drawings than the girls.

Many studies have revealed that girls achieve better performances than boys in tasks requiring fine motor abilities (e.g., [START_REF] Fairweather | Sex differences in cognition[END_REF][START_REF] Kraft | Sex-related differences in cognition : Development during early childhood[END_REF].

In conclusion, it is important to recall that this experiment is the first to investigate how EB children process local and global information in tactile Navon figures. For this reason, we tested a large sample of children on the basis of two different tasks. Replications will be needed in order to confirm our main finding that the development of local and global processing seems to proceed in similar ways in sighted and EB children even though there is a protracted period during which local processing dominates in blind children.

Chapter 5 : Global and Local Processing in Early Blind Children tasks [START_REF] Feeney | Spatial analysis : An examination of preschoolers' perception and construction of geometric patterns[END_REF], while some others stated that depending on the children's age, perceptual and drawing tasks may provide different results in terms of children's capacity to segment a whole pattern [START_REF] Bouaziz | Contribution of the visual perception and graphic production systems to the copying of complex geometrical drawings: A developmental study[END_REF]. [START_REF] Farran | Perceptual grouping and distance estimates in typical and atypical development : Comparing performance across perception, drawing and construction tasks[END_REF] supported also this idea as their study proved that the cognitive demands of drawing and construction tasks led participants to correctly perceive an image before reproducing it part by part until a complete reproduction has been achieved, while the perceptual forced-choice task showed an opposite result, with children tending to process the pattern from global to local. This contradictory literature showed that it was worth including perceptual and drawing tasks in our thesis in order to achieve a more comprehensive understanding about children's spatial analysis of the hierarchical patterns.

In overall, we employed three kinds of tasks, which were a similarity judgment task, a naming task and a drawing task. The similarity judgment task of hierarchical patterns was first used by [START_REF] Kimchi | Form and Texture in Hierarchically Constructed Patterns[END_REF]. [START_REF] Goldmeier | Similarity in visually perceived forms[END_REF] stated that similarity cannot always be defined as partial identity, neither as identity of relational proportions because similarity is often based on the singular whole qualities which determine the phenomenal appearance of a figure. Thus, the similarity judgment task can illustrate the tendency to global and local preference (as in the work of [START_REF] Farran | Perceptual grouping and distance estimates in typical and atypical development : Comparing performance across perception, drawing and construction tasks[END_REF] but is mute to the question of how one process can be integrated with the other. In order to apprehend the integration question, we introduced the drawing task that precisely necessitated that children combined a local and global analysis of the patterns, since drawing task required planned behavior with the capacity to manage part-whole relationships [START_REF] Lange-Küttner | Drawing and the Non-Verbal Mind[END_REF]. The naming task was more similar to the drawing task than to the similarity-judgment task following this line of reasoning. (between 3 to 13 months of age) analyzed haptic abilities [START_REF] Streri | Hand preferences in 4-month-old infants : Global or local processing of objects in the haptic mode[END_REF], eye fixations [START_REF] Colombo | Individual Differences in Infant Fixation Duration : Dominance of Global versus Local Stimulus Properties[END_REF]Stoecker, Colombo, Frickm, & Allen, 1998) and visual-evoked potentials (Norcia, Pei, Bonneh, Hou, Sampath, & Pettet, 2005). Face

Chapter 6 : General Discussion and Conclusion stimuli were also used to reveal this global-local processing in babies (Schwarzer & Zauner, 2003). Research with children at older ages (from 3 to 14 years of age) utilized tasks more similar to the ones used with adults. Similarity judgment tasks [START_REF] Neiworth | Global and local processing in adult humans (Homo sapiens), 5-year-old children (Homo sapiens), and adult cotton-top tamarins (Saguinus oedipus)[END_REF]Rondan et al., 2008;Poirel et al, 2008;[START_REF] Deruelle | Processing of compound visual stimuli by children with autism and Asperger syndrome[END_REF][START_REF] Mondloch | Developmental Changes in the Processing of Hierarchical Shapes Continue into Adolescent[END_REF], Faran & Cole, 2008), orientation judgment tasks [START_REF] Stiles | Global-Local Processing in Preschool Children[END_REF], divided and selective attention tasks [START_REF] Plaisted | Children with Autism Show Local Precedence in a Divided Attention Task and Global Precedence in a Selective Attention Task[END_REF][START_REF] Porporino | A developmental change in selective attention and global form perception[END_REF], naming or indicating tasks [START_REF] Iarocci | Global-local visual processing in high functioning children with autism : structural versus implicit task biases[END_REF]Scherf, Behrman, Kimchi, & Luna, 2009;[START_REF] Rinehart | Atypical interference of local detail on global processing in high-functioning autism and Asperger's disorder[END_REF], matching forced choice tasks (Harisson & Stiles, 2009[START_REF] De Lillo | A Comparative Analysis of Global and Local Processing of Hierarchical Visual Stimuli in Young Children (Homo sapiens) and Monkeys (Cebus apella)[END_REF][START_REF] Plaisted | The Microgenesis of Global Perception in Autism[END_REF]Vinter et al, 2010) and drawing tasks (Stiles, Stern, Appelbaum, Nass, Trauner, & Hesselink, 2008;Rondan et al, 2008;Abreu, French, Cowell, & deSchonen, 2006;Faran & Cole, 2008;Vinter et al, 2010).

This body of research showed contradictory results. Some authors proposed that children at younger ages attended to local information more than children at older ages [START_REF] Colombo | Individual Differences in Infant Fixation Duration : Dominance of Global versus Local Stimulus Properties[END_REF][START_REF] Kramer | Developmental sex differences in global-local perceptual bias[END_REF][START_REF] Dukette | Children's analysis of hierarchical patterns: Evidence from a similarity judgment task[END_REF][START_REF] Frick | Temporal sequence of global-local processing in 3-month-old infants[END_REF][START_REF] Burack | Age Differences in Visual Search for Compound Patterns: Long vs. Short Range Grouping[END_REF]Poirel et al., 2008) but some others showed the same global precedence effect as in adults [START_REF] Stoecker | Long-and Short-Looking Infants‗ Recognition of Symmetrical and Asymmetrical Forms[END_REF][START_REF] Mondloch | Developmental Changes in the Processing of Hierarchical Shapes Continue into Adolescent[END_REF] and still others proposed that children can attend to both the local and global level, depending on contextual and task factors, the integration between the two levels of analysis developing until late in adolescence [START_REF] Kimchi | Microgenesis and ontogenesis of perceptual organization: Evidence from global and local processing of hierarchical patterns[END_REF]Schref et al., 2009). Our results

showed that local and global processing co-exist first without integration, this period being accompanied by a dominance of local processing, and then when they start to be integrated, this is accompanied by a global dominance effect.

Only Experiments 1 and 2 with typically developing children included children as young as 3 years of age. Our results revealed that children at 3 years of age showed a dominance of local performance, both in the similarity judgment task and in the drawing task.

These results confirmed that that local processing dominates the global one in young children [START_REF] Dukette | Children's analysis of hierarchical patterns: Evidence from a similarity judgment task[END_REF][START_REF] Kramer | Developmental sex differences in global-local perceptual bias[END_REF]Poirel et al., 2008). Interestingly, the local Do these developmental trends also characterize the atypically developing children studied in our thesis? Of course, the comparison cannot be direct between these populations, mainly because only the drawing task was common to all studies. Instead of a similarity judgment task, relevant to reveal processing preferences, we adopted a naming task with the blind children and those with mental retardation. The naming task does not indicate directly processing preferences. It is closer to the drawing task, requiring integration between the two levels of processing, without the procedural constraints linked to drawing in se. Furthermore, we did not include children as young as 3 to 5 years of age in the blind study and the mental retardation study, thus limiting our comprehension of early development in these atypical populations.

Keeping in mind these limits, the answer to the question of knowing whether development proceeds similarly to what was observed in typically developing children is -yes‖ for what concerns the blind children, although large differences appeared with regard to the ages of the main milestones. We noted that local processing, enhanced by haptic perception, decreased as age increased, as well as global processing, to the benefit of integrated responses. This was observed as well in the naming as in the drawing task.

However, there was a clear protracted period of local processing dominance in blind children. By contrast, the study with children with mental retardation did not provide results as clear as those with blind children with respect to development. Global processing dominance characterized these children with intellectual impairment whatever the age, the task, and the type of pattern (even the local bias-induced pattern elicited on average more global responses). This result fits with other findings, showing that children with mental retardation performed better in drawing the global shape than the local elements (Bellugi et al, 1990;Bellugi et al., 2000[START_REF] Porter | Global and local processing in William syndrome, autism, and Down Syndrome : Perception, attention, and construction[END_REF]. Only one age effect was significant in the naming task: when children were exposed to the global-bias induced pattern, the integrated responses were more frequent in older children than in the younger ones. Although this age effect goes in the -good‖ direction (increase of integrated responses as age increases), it seems too isolated to be meaningful. One can argue that this result could be expected since the psychological development of children with mental retardation is more based on their mental age than on their chronological age. Indeed, we found more significant IQ effects in our study. The nonintegrated responses (naming task) and the syncretic responses (drawing task) were less frequent in the higher IQ-group than in the lower IQ-group. Inversely, the production of totalintegrated responses in the naming-task and of integrated responses in the drawing task was larger in the higher IQ-group than in the lower IQ-group. These results are coherent with findings concerning the involvement of cognitive mechanisms in the perceptual analysis (Poirel et al, 2008;[START_REF] Singh | Interhemispheric Interaction During Global-Local Processing in Mathematically Gifted Adolescents, Average-Ability Youth, and College Students[END_REF].

However, these results tended to indicate that between 6-10 and 13-14 years of age, there is almost no development of perceptual analysis in these children with mental handicap.

In one way, we could say that this demonstrates that children with mental retardation do not differ from typically developing individuals: they display a large global preference effect.

This is what [START_REF] Dulaney | Global/local processing in mentally retarded and nonretarded persons[END_REF] concluded in their own study. However, the absence of significant evolution in the range of ages we studied continues to borrow us 3 .

3 We decided to run other analyses that were lacking in Chapter 4, testing for age effects inside each IQ group, despite that the distribution of the participants across ages was not regular. The higher IQ group included 7 children aged 6-10 years, 8 aged 11-12 years and 11 aged 13-14 years in the naming task, 7/7/9 in the drawing task. The lower IQ group included 20/7/10 children in the naming task, 19/6/9 in the drawing task. No age effects emerged in the low IQ group, whether the production of local, global and integrated responses were considered in the naming or drawing task (all p s >.50). The results were a little bit more positive with the higher IQ group, but only at a descriptive level. The global responses decreased between 11-12 and 13-14 years of age and the integrated responses increased in the same period, in the naming and drawing tasks, but the differences failed to reach significance (p s > .20). It is nevertheless encouraging, because the low number of participants par age group may be the reason why statistical significance was not reached.

The literature is not clear about the precise reason why people with mental retardation display this large global dominance effect. What seems clear is that the way visual information is processed in people with mental retardation is affected as compared to normally developing people, and also as compared to individuals with William Syndrome. Indeed, Bellugi et al.

(1999) reported that the functioning of both the ventral and dorsal visual systems is affected in adults with Down Syndrome.

B. Contextual effects on local and global processing

Our studies demonstrated that local and global processing in children were sensitive to contextual effects, as also revealed in the literature [START_REF] Prather | Developmental differences in part/whole identification[END_REF][START_REF] Kinchla | The Order of visual processing: -Top-Down‖, -Bottom-Up‖ or -Middle-Out‖[END_REF][START_REF] Grice | Forests before trees? It depends where you look[END_REF][START_REF] Pomerantz | Global and local precedence : Selective attention in form and motion perception[END_REF][START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF][START_REF] Sanocki | Time course of object identification : Evidence for a global to local contingency[END_REF][START_REF] Weber | Hierarchical visual processing is dependent on the oculomotor system[END_REF][START_REF] Ninose | The effect of prolonged viewing on the recognition of global and local levels of hierarchically constructed patterns[END_REF]. We tested two types of contextual effects:

effects related to pattern properties (consistency, complexity, meaningfulness, duration) and effects related to gender.

Effects of different pattern properties

We investigated the effect of consistency of the hierarchical patterns in the two first experiments. The use of consistent and inconsistent stimuli had its roots in Navon's experiment (1977) with compound letter stimuli, followed by other studies using other forms of hierarchical patterns as geometrical or numerical patterns [START_REF] Kimchi | Primacy of wholistic processing and global/local paradigm: A critical review[END_REF][START_REF] Han | Factors affecting the global and local processing of visual compound stimuli[END_REF]Tanaka, Onoe, Tsukada & Fujita, 2001;[START_REF] Mondloch | Developmental Changes in the Processing of Hierarchical Shapes Continue into Adolescent[END_REF][START_REF] Kimchi | Microgenesis and ontogenesis of perceptual organization: Evidence from global and local processing of hierarchical patterns[END_REF]Vinter et al., 2010). The pattern is defined as consistent when the global and local levels are (Robertson et al.1993;[START_REF] Weissman | Global-Local Interference Modulated by Communication Between the Hemispheres[END_REF][START_REF] Christman | Individual Differences in Stroop and Local-Global Processing: A Possible Role of Interhemispheric Interaction[END_REF]. These interference effects were worth investigating in children, in particular in young children who still have immature interhemispheric communication [START_REF] Moses | Functional MRI of global and local processing in children[END_REF]. Consistent and inconsistent haptic hierarchical patterns were also introduced to the early blind children with the same objective as in typical developing children. years of age, this result evidencing an apparently reverse interference effect with regard to the one reported in adults. Indeed, adults were shown to be subject to interference effects revealing diffusion from the global (dominant level) to the local level in the face of inconsistent patterns [START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF][START_REF] Martin | Local and global processing : The role of sparsity[END_REF][START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF], while in our results, Consistency appears to have some effect also in haptic perception of hierarchical patterns. Consistent patterns induced more global responses in a naming task from early blind children, while more local responses were reported in case of inconsistent patterns. We have suggested that these findings may illustrate the use of a hypothesis testing strategy as described by Alexander, Johnson and Schreiber (2002) in their study of haptic exploration in children aged 4-9 years. Perhaps, EB children in our study tended to make the assumption that the pattern was unique when they perceived that the local elements had the same shape as the global configuration. In contrast, when there was a mismatch between the local shapes and the global configuration, the assumption was in favor of the dominant local information. If this account is correct, it would suggest that the way pattern consistency is manipulated differs greatly between haptic and visual exploration. It is unlikely that interference effects would occur during haptic exploration, as they do in the visual mode, because of the extended time course of global information processing in the haptic mode.

Chapter 6 : General Discussion and Conclusion

The second pattern property that was investigated in this thesis was related to the potential effect of pattern complexity with regard to global-local processing. We must recognize that we did not have a lot of expectations about the effect of this factor, due to the lack of corresponding studies in the literature. Our intuition was that the more complex the pattern was, the stronger global processing should be. Our results confirmed partially this intuition. In the similarity judgment task, more global responses were indeed provided in face of complex patterns but only by the younger children aged below 8 years. The reverse result emerged in the older children, with more global responses in face of simple patterns. The results from the drawing task pointed also to an opposition between younger and older children. More part-correct responses were obtained in face of simple patterns at younger ages, while in older children, the complex patterns did elicit better part-correct analysis.

Young children produced also more partial responses in face of complex than simple patterns.

Taking together, these results may suggest that complexity drew attention to the parts in the older children, enhancing a correct part analysis and diminishing slightly global dominance.

In younger children, complexity acted negatively on part analysis, thus enhancing global dominance.

The third pattern property investigated in our experiments concerned the meaningfulness of the shapes located at the global or local level in hierarchical patterns.

Previous studies that have introduced objects in the building of hierarchical patterns, suggested that objects should arouse automatic identification. Automatic identification at the global or local level should influence global or local precedence respectively [START_REF] Poirel | Implicit identification of irrelevant local objects interacts with global/local processing of hierarchical stimuli[END_REF](Poirel et al., , 2008)). These authors proposed that introducing objects at global or local level should not only challenged the global precedence effect in a way that the global level should not always be processed before the local one (depending on which level the meaningful objects were located), but they also showed that local interference existed. Their results confirmed that the presence of an object (familiar pattern) triggered an automatic identification process that facilitated performance when it occurred at the target level, and interfered with performance when it occurred at the irrelevant level. Our aims were similar to those suggested by [START_REF] Poirel | Implicit identification of irrelevant local objects interacts with global/local processing of hierarchical stimuli[END_REF]Poirel et al. ( , 2008) ) in using meaningful (familiar object) and non-meaningful (nonobject) stimuli at both the global and/or local level in a naming task and a drawing task administered to children with mental retardation. Previous studies indicated that children with mental retardation showed global bias in attention with difficulties in processing at the local level [START_REF] Birhle | Seeing either the forest or the trees: Dissociation in visuospatial processing[END_REF][START_REF] Porter | Global and local processing in William syndrome, autism, and Down Syndrome : Perception, attention, and construction[END_REF]. By introducing meaningful objects at the local level, we expected to enhance local analysis in children with mental retardation.

Our results showed that global processing dominated the children's responses both in the naming and drawing tasks. This was not particularly reinforced by the presence of Finally, the fourth pattern property that was tested in our experiments concerned the duration of exposure of the hierarchical patterns. Previous studies showed that interference between the global and local levels was affected by exposure duration [START_REF] Pomerantz | Global and local precedence : Selective attention in form and motion perception[END_REF]Paquet & Merickle, 1984[START_REF] Kimchi | Selective attention to global and local levels in the comparison of hierarchical patterns[END_REF][START_REF] Mottron | A study of perceptual analysis in a high-level autistic subject with exceptional graphic abilities[END_REF][START_REF] Plaisted | Children with Autism Show Local Precedence in a Divided Attention Task and Global Precedence in a Selective Attention Task[END_REF][START_REF] Kimchi | Microgenesis and ontogenesis of perceptual organization: Evidence from global and local processing of hierarchical patterns[END_REF]. More precisely, these authors presented compound letters at various durations of exposure and reported that a unidirectional global to local interference was found at the shortest exposure duration. Longer exposure durations were found to elicit more local responses since prolonged viewing reduces the efficiency of global processing [START_REF] Ninose | The effect of prolonged viewing on the recognition of global and local levels of hierarchically constructed patterns[END_REF] and short durations on the other hand, were found to facilitate the global precedence and global interference effects (Allison & Fernandes, 2006;[START_REF] Wang | Local bias and localto-global interference without global deficit : A robust finding in autism under various conditions of attention, exposure time, and visual angle[END_REF][START_REF] Hibi | Attentional level and negative priming in hierarchical patterns[END_REF]. Some authors suggested that duration related to attentionnal processes in the analysis of hierarchical patterns. Inhibitory mechanisms (suppression of distraction derived from the analysis of unattended objects) to local elements would be present when subjects directed their attention to the global level with the short durations, whereas at the long exposure durations, inhibitory mechanisms to local elements would not be present, thus leading to a more local advantage [START_REF] Robertson | Attentional Persistence for Features of Hierarchical Patterns[END_REF][START_REF] Hibi | Attentional level and negative priming in hierarchical patterns[END_REF].

In our thesis, manipulations of durations of exposure were introduced in Experiment 1 to Experiment 4 with the typically developing children. A long duration (3 seconds) and short duration (300 msec) was applied. Our study confirmed that when children were presented with patterns at long and short durations in the similarity judgment task, their choices for local responses was more frequent with long than with short durations. This result was mainly found in children aged 3 to 6-years, that is, until global processing preference was clearly established. It is interesting to note that the higher production of local responses under Chapter 6 : General Discussion and Conclusion long stimulus durations in comparison with short durations clearly argues against the oculomotor hypothesis evoked by some authors to account for the local dominance at early ages [START_REF] Kowler | Eye movements of preschool children[END_REF]Poirel et al., 2008). These effects of duration were much less clear in the experiment involving complex hierarchical patterns.

Manipulation of duration in the drawing task with consistent and inconsistent stimuli showed only a marginally significant impact. Short durations tended to elicit more local responses, mainly in the 3-year-olds. This effect was in opposition with the one obtained in the perceptual experiment, but it was confirmed by our third experiment concerning the simple and complex stimuli, where short durations tended to elicit more local responses in the younger children (4-year-olds). This opposition points to the difference between the similarity judgment task and the drawing task. Only the drawing task requires the formation of a representation of the stimulus. In the similarity task, different possible choices are provided.

Thus, duration may have an effect on the formation of a complete representation of the perceived pattern particularly in young children. This interpretation is coherent with the results obtained in the experiment concerned with the complex hierarchical patterns. Indeed, they showed that a correct part-whole analysis was better achieved when the patterns were presented at long durations.

Gender effect

Gender was the last variable that we included in the study because the literature seems to be quite contradictory with regard to the impact of sex on local/global processing: In some studies, boys have been reported to make significantly more global perceptual judgments than girls [START_REF] Cahill | Sex-and Hemisphere-Related Influences on the Neurobiology of Emotionally Influenced Memory[END_REF][START_REF] Kramer | Developmental sex differences in global-local perceptual bias[END_REF]. This is consistent with developmental models that suggest an early left-hemisphere advantage for girls and a righthemisphere advantage for boys [START_REF] Denckla | Rapid "automatized" naming of pictured objects, colors, letters, and numbers by normal children[END_REF][START_REF] Kirk | Evidence for early acquisition of visual organization ability: A developmental study[END_REF][START_REF] Coluccia | The relationship between map drawing and spatial orientation abilities: A study of gender differences[END_REF].

However, [START_REF] Dukette | Children's analysis of hierarchical patterns: Evidence from a similarity judgment task[END_REF] mentioned exactly the reverse result in 4-to 6-year-olds and in adults in a force-choice matching task, with female participants making more global level matches than male participants. For their own, Kimchi, Amishav and Sulitzeanu-Kenan (2009) did not report any gender differences in global-local processing. Gender differences were therefore worth investigating.

Unfortunately, most of our results showed that the effects of gender were not significant. Only in our last experiment concerning the haptic global-local processing with early blind children, significant effects of gender were reported. Some authors have investigated gender effects in haptic perception (Vecchi, 2001;Zuidhoek et al., 2007). Vecchi (2001) showed that blind females tended to develop less efficient strategies than blind males when active processing was required in a complex task. This could suggest that blind females Chapter 6 : General Discussion and Conclusion might process information differently from males when confronted with inconsistent hierarchical patterns.

In both the naming and drawing tasks, the girls produced local responses more frequently than the boys. This result provides support for the findings reported by Steri et al. (1996) which suggest that girls process haptic information analytically and discriminate details, especially when employing the right hand. It is also consistent with developmental models that suggest that the left hemisphere is favored early in girls (Collucia et al., 2007), as the left hemisphere has been found more efficient than the right one for local information processing (e.g., [START_REF] Lamb | Attention and interference in the processing of global and local information : Effects of Unilateral Temporal-Parietal Junction Lesions[END_REF]. Furthermore, in the naming task, the boys produced integrated responses more frequently than the girls. Vecchi (2001) found that blind males developed more efficient strategies than females when active processing was required in a complex task. The gender differences we observed might primarily be due to similar differences in information processing strategies, with the boys deploying more efficient strategies for the coordination of local and global information in response to the more complex patterns (the inconsistent patterns). However, they may also be due to more basic differences in haptic perception, given that Zuidhoek et al. ( 2007) found that males performed better than females in a variety of tasks assessing the haptic perception of orientation. It is worth pointing out that this issue on gender differences remains quite confused. [START_REF] Kimchi | Gender differences in global-local perception? Evidence from orientation and shape judgments[END_REF] did not report any gender differences in global-local processing, but their study concerned adults and included visual tasks. Furthermore, the literature shows that gender differences exhibited in visual tasks (for instance, in the rod-andframe task or in the water-level task, Voyer & Bryden, 1993[START_REF] Robert | Water-level representation by men and women as a function of rod-and-frame test proficiency and visual and postural information[END_REF] are eliminated in tactile versions of these tasks (e.g., Walker, 1972;Robert, Pelletier, St Onge, & Berhiaume, 1994). Defining more precisely what may underlie the gender differences observed in our experiment appears therefore delicate, and further research on this topic is needed for clarification. The only gender difference that is coherent with the overall literature was obtained in the drawing task, where the boys produced more scribbled drawings than the girls. Many studies have revealed that girls achieve better performances than boys in tasks requiring fine motor abilities (e.g., [START_REF] Fairweather | Sex differences in cognition[END_REF][START_REF] Kraft | Sex-related differences in cognition : Development during early childhood[END_REF].

Conclusion

The effects of age, pattern properties, duration and gender showed that there were quite clear evidences that there are different characteristics that marked the milestone of preference emerged at 4 years of age, and then the two levels of processing begin to integrate at 5 years of age, followed by further refinement until 9 years of age, and probably still later.

Before 5 years of age, children can actually attend to both levels of perceptual analysis, but it seems that these processes operate independently, as could be suspected from the immature interhemispheric communication [START_REF] Liegeois | When does interhemispheric coordination integration of visual events emerge in infancy? A developmental study on 19-to 28month-old infants[END_REF]. This is also highly congruent with predictions that can be drawn from some of the neo-Piagetian theories that claim that 3-yearolds can focus only a single dimension of a task, whereas 5-year-olds can focus on two [START_REF] Case | The role of central conceptual structures in the development of children's thought[END_REF][START_REF] Halford | Children's understanding: The development of mental models[END_REF][START_REF] Pascual-Leone | A dialectical constructivist view of developmental intelligence[END_REF], and also related to the difficulties encountered by young children in the understanding of parts-whole relationships, as shown in drawing studies [START_REF] Picard | The development of context sensitivity in children's graphic copying strategies[END_REF]Tada & Stiles, 1996;[START_REF] Picard | Representational flexibility in chidren's drawing: effects of age and verbal instructions[END_REF]Vinter & Marot, 2007) or in cognitive tasks (e.g., [START_REF] Inhelder | The early growth of logic in the child: Classification and seriation[END_REF]. This

Figure 10 .

 10 Figure 1.Example of the principle of proximity …………………………...……. 4 Figure2.Example of the principle of similarity ……………………………….… 5 Figure3.Example of the principle of good continuation ……………………...… 5 Figure4.Example of the principle of closure …………………………………… 6 Figure5.General Model of Cognitive Procedure in Perception ………………… 6 Figure6.Template-based matching model ……………………………………… 7 Figure7.Prototype-based matching model …………………………………...…. 8 Figure 8. Feature Based Matching Model as in Pandemonium Model …………. 9 Figure 9. Example of geometric icons (geons) in Recognition-by-Components Theory …………………………………………………………....……. Figure 10. Navon's Compound Letter ……………………………………………... Figure 11. A Schematization of the experimental task in Navon's first experiment ........................................................................................ Figure 12. A. The set of stimuli in Navon's second experiment (part 1) B. The set of stimuli in Navon's second experiment (part 2) ................ Figure 13. Set of stimuli in Navon's fourth experiment ........................................... Figure 14. Examples of the displays in each condition and session of Navon's fourth experiment ..................................................................................... Figure 15. Illustration of stimulus in the relational properties experiment ............... Figure 16. Illustration of the target hierarchical patterns used in Experiment 1 …. Figure 17. Illustration of categories of responses in the drawing task ….…………. Figure 18. Percentages of responses in the drawing task as a function of age and consistency ……………………………………………………………..Figure 19. Percentage of responses in the drawing task in Experiment 1 as a function of age and duration ………………………………………… Figure 20. Example of choices in perceptual similarity judgment task for experiment 1 …………………………………………………………… Figure 21. Percentage of responses in the similarity judgment task in Experiment 2 as a function of age and consistency …………………………………… Figure 22. Illustration of the target hierarchical patterns used in Experiment 3 …… Figure 23. Illustration of the types of responses coded in the frame/parts analysis ……………………………………………... Figure 24. Illustration of the types of responses categorized in drawing Simple and complex hierarchical patterns …………..………………… Figure 25. Percentages of responses in the frame-part analysis as a function of age for the simple and complex hierarchical patterns ……………………… Figure 26. Percentage of responses in the frame-part analysis as a function of age and duration …………………………………………………………… Figure 27. Percentages of the different types of drawing responses in the categorization analysis as a function of age …………………… Figure 28. Percentage of responses in drawing for categorization analysis as a function of duration and age ……………………………………… Figure 29. Illustrations of the response choices in the similarity judgement task ………………………………………………………………...…… Figure 30. Percentage of responses as a function of age and patterns in the similarity judgment task ......................................................................... Figure 31. Percentages of responses as a function of age and duration in the similarity judgment task ........................................................................... Figure 32. Pictures of objects and non-objects used in the preliminary experiment ……………………………………………………………... Figure 33. Stimuli used in the main experiment …………...…………………….... Figure 34. Examples of drawings for data coding ……………………………….

Figure 35 .

 35 Figure 35. Percentages of responses (global, local, integrated and non-integrated) in the naming task as a function of age ................................................... Figure 36. Percentages of responses as a function of patterns and age in the naming task .............................................................................................. Figure 37. Percentages of responses in the naming task as a function of IQ ............ Figure 38. Percentages of responses in the naming task as a function of IQ ............. Figure 39. Percentages of responses (global, local, integrated and non-integrated) in the drawing task as a function of age .................................................. Figure 40. Percentage of responses as a function of patterns and age in the drawing task ............................................................................................ Figure 41. Percentage of responses in the drawing task by IQs ............................... Figure 42. Percentages of responses as a function of patterns and IQ in the drawing task ............................................................................................. Figure 43. Examples of stimuli in the pilot studies ……………...………………... Figure 44. Examples of children's drawing based on the categorization in data coding ………………………………………………………………….. Figure 45. Percentage of responses in the naming task as a function of age and consistency …………………………………………………………….. Figure 46. Percentages of responses in the drawing task as a function of age and consistency ……………………………………………………………..

Figure 4 .

 4 Figure 4. Example of the principle of closure

  Figure 8. Feature Based Matching Model as in Pandemonium Model (Figure taken from http://www.psych.utah.edu/psych3120-classroom/pandemon.gif)

Figure 10 .

 10 Figure 10. Navon's Compound Letter

  letters H and S randomly (auditory stimuli vs. visual stimuli). Each subject faced three conditions of temporal overlap between the auditory and the visual stimuli : -40 msec, 0, or 40 msec. There were also three consistency levels (a) consistent, if the auditory stimulus consisted of the same letter than the visual stimulus; (b) conflicting, if the auditory stimulus differed from the visual stimulus; (c) neutral, if the visual stimulus was a rectangle. A schematization of the experimental task in Experiment 1 is described in Figure11.

Figure 11 .

 11 Figure 11. A Schematization of the experimental task in Navon's first experiment[START_REF] Navon | Forest before the trees: The precedence of global features in visual perception[END_REF] p. 360)

Figure 12 .

 12 Figure 12.A. The set of stimuli in Navon's second experiment (part 1) B. The set of stimuli in Navon's second experiment (part 2) (taken fromNavon, 1977, page 365)

Figure 13 .

 13 Figure 13. Set of stimuli in Navon's fourth experiment Relationship Target Stimulus Probe Stimulus

  has opened a new beginning in the history of perceptual organization. It opened a broad area of research in perceptual organization in cognitive, developmental, and clinical psychology. Chapter 1 : General Introduction IV.

Figure 15 .

 15 Figure15. Illustration of stimulus in the relational properties experiment (fromLove at al, 1999, p. 293)

  without any time constraints. When the drawing was finished, the experimenter took away the sheet of paper, gave a new one to the participants, and waited for their ready-signal before triggering the display of the next model. The children produced eight drawings in the familiarization phase. All children noticed the difference in size of the figures and reproduced a big and a small circle or square.

Figure 18 .

 18 Figure 18. Percentages of responses in the drawing task as a function of age and consistency

Figure 19

 19 Figure 19 reports the results as a function of age and duration for the global and local responses.

Figure 19 .

 19 Figure 19. Percentage of responses in the drawing task in Experiment 1 as a function of age and duration

  [START_REF] Dukette | The effects of stimulus density on children's analysis of hierarchical patterns[END_REF] and[START_REF] Lange-Küttner | The role of object violations in the development of visual analysis[END_REF] also studied the integration of local and global information in children's drawing. Our results are similar to those of Dukette and Stiles in that from 4 years of age, children incorporated both local and global elements into their drawings. On the other hand, Lange-Küttner found that 5-year-olds often drew using only the global elements of the stimulus. We never observed the use of only global elements at any of age, and Dukette and Stiles did not report only global elements in drawings in their study.In the current study, if children used only a single dimension, it was invariably the local dimension. These unidimensional responses were seen primarily at 3 years of age, were rare at 4 years of age, and completely disappeared between 5 and 6 years of age. In our study, the integrated responses, either correct or inaccurate, developed rapidly between 3 and 5 years Chapter 2 : Children's spatial analysis of hierarchical pattern Chapter 1 : General Introduction of age. At 6 years of age, children produced correct integrated responses in more than 70% of the cases, and these responses characterized almost 100% of the drawing production at 9 years of age. Would the developmental trajectory shown in this drawing experiment be revealed in a perceptual task? The perceptual task used in Experiment 2 was based on patterns' similarity judgments.

Chapter 2 :

 2 Figure 21 depicts the frequencies of global, erroneous global and erroneous local responses as a function of age and consistency, and of local responses as a function of age and duration.

Figure 21 .

 21 Figure 21. Percentage of responses in the similarity judgment task in Experiment 2 as a function of age and consistency (A = global responses, C = erroneous global responses, D = erroneous local responses) or a function of age and duration (B = local responses)

Chapter 3 :

 3 Children's Spatial Analysis of Simple and Complex Hierarchical Patterns Chapter 1 : General Introduction group corresponded to one school level (4-5-year-olds: nursery and kindergarten levels).Their vision was normal or corrected to normal and none of these children were educationally advanced or retarded. Children essentially come from families with middle socioeconomic status. They were all monolingual French-native speakers. They were observed individually in a quiet room at their schools. Informed written consent was obtained from parents of each child participating in the study.

Figure 22 .A

 22 Figure 22. Illustration of the target hierarchical patterns used in Experiment 3 A. Simple Stimuli 1 B. Simple Stimuli 2

Chapter 3 :

 3 Children's Spatial Analysis of Simple and Complex Hierarchical Patterns Chapter 1 : General Introduction a more comprehensive view on children's ability to integrate spatial information into their drawing ability. The coding of the reproduction of the frame/parts structure necessitated 7 categories, with examples depicted in Figure 23.

Figure 23 .

 23 Figure 23. Illustration of the types of responses coded in the frame/parts analysis Frame Correct

Figure 24 .

 24 Figure 24. Illustration of the types of responses categorized in drawing simple and complex hierarchical patterns Correct Integrated Response

Figure 25

 25 Figure25depicted the results as the function of age for the simple and complex stimuli. A significant effect of age for the production of frame correct responses was found in this study (H (5, N=121) = 63.31, p < .01). The frame correct responses increased significantly rapidly between 4 and 5 years of age (U=69, n 1 =20; n 2 =21), p < .01 as described in Figure25Aand then seemed stable after the age of 5 years. No significant effect of complexity was found for the frame correct responses (all ps > .05).

Figure

  Figure25Brepresents the frame incorrect responses, which evolved significantly with age, (H (5, N=121) = 45.75, p < .01). A significant decline was observed between 4 and 5 years of age (U=127.5, n 1 =20; n 2 =21), p < .05, and none of the children gave frame incorrect responses after 6 years of age. No effect of complexity was found in all ages (all ps > .05).The age evolution for the part correct responses was significant, H (5, N=121) = 49.83, p < .01 as depicted in Figure25C. A significant transition was also found between 4 and 5 years of age (U=71, n 1 =20; n 2 =21), p < .01, the part correct responses increasing abruptly between the two ages. The simple patterns elicited more part correct responses (62.80%) than the complex ones (52.4%) at 4-5 years of age, T (N = 41) = 49.5, p < .05, while the reverse tended to occur at 7-8 years of age, T (N = 40) = 70, p = .06.A significant effect of age was also found in the production of part incorrect responses as described in Figure25D, H(5, N=121) = 18.88, p < .01. The part incorrect responses decreased as age increased. A significant transition emerged between 4 and 7 years of age (U=112.5, n 1 =n 2 =20), p < .01. The complex patterns tended to elicit more part incorrect responses than the simple ones at 4-5 years of age, T (N = 41) = 71.5, p = .07 Figure25Edepicted the results for the frame absent responses and it also showed a significant decrease of these responses when age increased, H (5, N=121) = 44.06, p < .01. The significant transition was found between 4 and 5 years of age, (U=111.5, n 1 =20; n 2 =21), p < .05, and there was no significant effect of complexity (all ps > .10).

Figure

  Figure 25F depicted the results for the part absent responses. The figure showed a radical decline between 4 and 5 years of age, H (5, N=121) = 40.34, p < .01. These responses decreased progressively from 4 years to 5 years of age, (U=76.5, n 1 =20; n 2 =21), p < .01, and remained at a low level in children at older ages. No effect of complexity was reported (all ps > .10).

Figure

  Figure 26F depicted the results for the part absent responses, where an effect of duration was again found, T (N = 121) = 21, p < .01. Short durations yielded more these responses (10.5%) than the long durations (4.75%). The effect of duration was found at 4 years of age, T (N = 20) = 8, p < .05, but not at 9 years of age (p < .10).

Chapter 3 :

 3 Figure 27. Percentages of the different types of drawing responses in the categorization analysis as a function of age

Figure

  Figure 27B, H (5, N=121) = 20.75, p < .01, but they were rare, even in the younger ages and they

Figure

  Figure27Cdepicted the significantly decreasing local responses when age increased, H (5, N=121) = 39.30, p < .01. A significant transition appeared between 4 and 5 years of age (U=123, n 1 =20; n 2 =21), p < .05, and after the age of 6 years, none of the children produced local responses. No effect of complexity was found across ages (all ps >.10).

Figure

  Figure27Edescribed the combined responses which showed a significant effect of age, H (5, N=121) = 12.612, p < .05, with these responses decreasing with age although they remained at low frequencies (2.1%), compared to the other responses. No effect of complexity was found (all ps > .05).

Figure 28

 28 Figure 28 expressed the frequencies of these categories of drawing responses as a function of duration for the different age groups.

Figure 28 .

 28 Figure 28. Percentage of responses in drawing for categorization analysis as a function of duration and age

Chapter 3 :

 3 figure, among four alternatives, was the most similar to the target. We expected to observe a local bias in the choices made by the youngest children, which should be stronger under long rather than short target exposure durations. Experiment 3 did not show any important influence of complexity of the hierarchical patterns on the drawing responses; we expected similar findings in the similarity judgment task. However, the effect of stimulus duration should be greater than to the one seen in Experiment 3.

  Figure 29. Illustrations of the response choices in the similarity judgment task SIMPLE STIMULI 1

Chapter 3 :

 3 Children's Spatial Analysis of Simple and Complex Hierarchical Patterns Chapter 1 : General Introduction

  (A=global responses, B=local responses, C=global-partial responses, D=integrated-partial responses) as a function of age for the simple and complex patterns.

Figure 30 .

 30 Figure 30. Percentage of responses as a function of age and patterns in the similarity judgment task

  (4, N = 100) = 25.41, p < .01 as illustrated in Figure 30B. The choice for these responses vanished at 8 years of age and the shift in the local responses between 4 and 8 years of age yielded significance, (U = 76, n 1 = n 2 = 20), p < .01. An effect of stimulus complexity was significant at 5 and 6 years of age, T (N = 40) = 9, Z = 2.35, p > .05, the simple patterns eliciting more local responses (8.1%) than the complex patterns (4.1%). The choice for the global-partial responses diminished significantly with age as seen in Figure 30C, the youngest children opting for them in 14.4% of the cases while this percentage dropped to 1.6% at 10 years of age, H (4, N = 100) = 21.76, p < .01. Between 4 and 6 years of age, there was a marginally significant drop of these responses, (U = 132, n 1 = n 2 = 20), p = .065. The effect of stimulus complexity yielded no significance for the global-partial responses (all ps >.10). Finally, the integrated partial responses (Figure 30D) displayed the more interesting significant evolution with age, H (4, N = 100) = 19.65, p < .01. They decreased between 4-5-6 Chapter 3 : Children's Spatial Analysis of Simple and Complex Hierarchical Patterns Chapter 1 : General Introduction years of age (U = 85.5, n 1 = n 2 = 20), p < .01, but after 8 years of age, a significant tendency to increase was observed (U = 126.5, n 1 = n 2 = 20), p < .05. At 5 and 6 years of age, a significant effect of stimulus complexity was found, T (N = 40) = 35, Z = 2.19, p < .05, with the simple stimuli eliciting more integrated partial responses (8.1%) than the complex stimuli (3.8%). Let's examine now the impact of pattern duration. The results are shown in Figure 31.

Figure 31 .

 31 Figure 31. Percentages of responses as a function of age and duration in the similarity judgment task

  They were no longer observed at 8 and 10 years of age. The global-partial responses showed a similar evolution, disappearing at older ages, and on the contrary, the integrated-partial responses showed a tendency to increase in older children. The effect of complexity was evidenced in the choice for local responses and for integrated-partial responses. The simple patterns elicited more these responses than the complex ones. No effect of complexity was found in the global-partial responses. Duration on the other hand had a significant impact only on the global responses and global-partial responses. The short durations elicited more global responses although it only occurred at 8 years of age. On the contrary, the long durations elicited more global-partial responses in children at 5 years of age. From these two explanatory experiments, we can conclude that the children's spatial analysis of simple and complex hierarchical patterns developed from local to global at younger ages (between 4 to 5 years of age), these local and global responses beginning to integrate at between 6 to 7 years of age. These conclusions were supported by the evidence that younger children produced more local responses than older children in the drawing task and in the similarity-judgment task. The frame-part analysis ensured this idea since children at younger ages gave more incorrect responses in drawing the global level or the frame. The global responses were dominant after 5 years of age in the similarity-judgment task, illustrating the global advantage effect. In the drawing task, they showed a tendency to decrease as age increased, because this task required an integration of the tow processes to be successfully achieved. Indeed, when the global responses decreased, responses based on Chapter 3 : Children's Spatial Analysis of Simple and Complex Hierarchical Patterns Chapter 1 : General Introduction integration began to consistently increased, as evidenced by the production of more frame and part-correct responses in the drawing task and of correct-integrated responses in the similarity-judgment task.Complexity of the patterns enhanced the production of incorrect and partial responses, both in the drawing task and in the similarity-judgment task in children at younger ages. On the contrary, after 6 years of age, complexity of the patterns elicited more part correct responses. This finding might support the idea that children at older ages attended to more detailed information in order to integrate the two levels of analysis (global and local) in the responses. This conclusion is coherent with the evidence that long durations elicited more part-correct responses in children. The significant effect of durations was also consistently found in the production of incorrect part responses and partial responses in the drawing task where short durations elicited more incorrect and partial responses.

Chapter 4 :

 4 Spatial Analysis of Hierarchical Meaningful Patterns in Children with Mental Retardation Chapter 3 : Children's Spatial Analysis of Simple and Complex Hierarchical Patterns Chapter 1 : General Introduction Thus, the objective of utilizing a naming task and a drawing task of hierarchical patterns with meaningful and non-meaningful objects was to investigate whether the meaning of objects at the local level would challenge the global advantage's tendency in children with mental retardation.

  children and also designed by us, and 4 non-object pictures were designed by us using the object design from Microsoft-Word 2007. When children named the object correctly or understood what the object was, explaining the use of the object, they got a score of 1 (0 for incorrect response). They got a score of 0 if they could not explain or did not understand what a non-object was and 1 if they confused the non-object with some object that they knew.

Figure 32 .

 32 Figure 32. Pictures of objects and non-objects used in the preliminary experiment Non-Object 1

Figure 33 .

 33 Figure 33. Stimuli used in the main experiment

Chapter 4 :Figure 34 .

 434 Figure 34. Examples of drawings for data coding

Figure 35

 35 Figure 35 illustrated the overall responses of children across meaningful and nonmeaningful hierarchical patterns in the naming task as a function of age.

Figure 36 .

 36 Figure 36. Percentages of responses as a function of patterns and age in the naming task

Chapter 4 :

 4 figure elicited more local responses (31.9%) than the global bias-induced figure (9.5%). The local-bias patterns induced more local responses (31.9%) than the neutral pattern (20.2%), T (N = 37) = 40, Z = 2.21, p < .01. Thus, a local preference emerged when a meaningful object was used at local level, although the global responses dominated most of the responses in children with mental retardation.

Figure 37 .

 37 Figure 37. Three groups of IQs were reported in the analysis. The first group was composed of children with IQs (Wechsler scale) = 50-60 (henceforth called lower IQ-group), the second group were made of children with IQs = 61-65 (henceforth called middle IQ-group) and the third group included children with IQs = 66-70 (henceforth called higher IQ-group). Children's responses grouped by IQs showed a dominance of global responses. A significant effect of IQ was marginally found in the integrated responses, H (2, N = 94) = 5.27, p =.071 and non-integrated responses, H (2, N = 94) = 5.38, p =.067. Children in the lower IQgroup produced less integrated responses (4.3%) than children in the higher IQ-group (17.3%).

Figure 38 .

 38 Figure 38. Percentages of responses in the naming task as a function of IQ

Figure

  Figure 38B showed no significant effect of IQ in the production of local responses, but there was a significant effect of the patterns, F (N = 94, df = 3) = 33.38, p < .01, in each IQgroup (all ps < .01). The local-bias induced pattern and competition-induced pattern elicited more local responses (31.9%) than the global bias-induced pattern (9.6%), T (N = 94) = 0, Z = 4.01, p < .01. A similar difference occurred between the local bias-induced pattern and the neutral pattern, T (N = 94) = 40, Z = 2.21, p < .05, mainly in the lower IQ-group , T (N = 37) = 5, Z = 2.07, p < .05, where again the local-bias induced pattern and competition-induced pattern elicited more local responses (31.9%) than the neutral pattern (20.2%).

Figure

  Figure 38C depicted the results for the integrated responses. Although they remained at low frequencies (only about 9.6%), a marginally significant effect of IQ was found in the integrated responses elicited by the global bias-induced pattern, H (2, N = 94) = 4.86, p =.087.The integrated responses were more produced in the higher IQ-group (19.2%) than in the lower IQ-group (2.7%). A marginally significant effect of IQ was also found in the integrated responses aroused by the neutral pattern, H (2, N = 94) = 5.55, p =.062. They were more

Figure 39

 39 Figure 39 illustrated the responses of children across meaningful and non-meaningful hierarchical patterns in the drawing task as a function of age.

Figure 39 .

 39 Figure 39. Percentages of responses (global, local, integrated and non-integrated) in the drawing task as a function of age

  Figure 40 illustrated these results.

Figure 40 .

 40 Figure 40. Percentage of responses as a function of patterns and age in the drawing task

Figure

  Figure 40B illustrated the local responses. The competition-induced pattern elicited more local responses (20.9%) compared to the neutral pattern (18.6%), to the global biasinduced pattern (10.4%) and even to the local bias-induced pattern (16.3%), F (N = 86, df = 3) = 7.56, p < .05. However, considered separately, only the difference between the global bias-

Figure

  Figure 40D illustrated the undifferentiated/syncretic responses in function of age. No significant results were found, whether they concerned age or patterns (all ps > .10). The percentage of these responses remained low across ages and patterns (5.5%).

Figure 41

 41 Figure 41 described the frequency of the drawing responses as a function of IQ.

Figure 41 .

 41 Figure 41. Percentage of responses in the drawing task by IQs

Figure 42 .

 42 Figure 42. Percentages of responses as a function of pattern and IQ in the drawing task

Figure

  Figure 42B illustrated the local responses. An effect of pattern was obtained, F (N = 86, df = 3) = 7.56, p < .05. Surprisingly, the local responses were more induced by the competition pattern (20.9%), followed by the neutral pattern (18.6%) and afterwards by the local biasinduced figure (16.3%). No other significant results were found (all ps >.10). The integrated responses as a function of pattern were shown in Figure 42C. Significant effects of IQ were found for almost all patterns. Integrated responses elicited by

  the global responses dominated the childrens' responses as mentioned before, our study found pattern's effects on the production of global and local responses. The global bias-induced pattern and the neutral pattern elicited more global responses, both in the naming task and drawing task, while the local responses were more elicited by the local biasinduced pattern and the competition-induced figure. In the drawing task, the competitioninduced pattern elicited more local responses than the local bias-induced pattern. This result supports the fact that local interference was manifest, because interference of local elements with the global pattern was evidenced.These findings are coherent with the work by[START_REF] Poirel | Implicit identification of irrelevant local objects interacts with global/local processing of hierarchical stimuli[END_REF]Poirel et al ( ,2008) ) who suggested that meaningful objects could elicit global or local preference depending on the level at which they were assigned. Global preference occurred when the hierarchical pattern involved meaningful objects at the global level (this corresponds to the global bias-induced pattern and competition-induced pattern in our study) or when the pattern consisted of non-meaningful objects at both the global level and local level (corresponding to the neutral pattern in this study). On the other hand, local preference occurred when the meaningful objects were designed as local components (corresponding to the local bias-induced pattern and competition-induced pattern in our study). research conducted in the domain of haptic perception has compared normal sighted, late blind, and early blind individuals in order to reveal the role of visual experience and visual imagery in haptic perception (e.g., D'Angiulli &[START_REF] D'angiulli | Children's tactual exploration and copying without vision[END_REF][START_REF] Norman | The visual and haptic perception of natural object shape[END_REF][START_REF] Dulin | Special needs education in the blind population : Effects of prior expertise in raised line drawings on blind people's cognition[END_REF]. These studies have concentrated on comparing behavioral performances -for instance, naming

  inconsistent patterns enabled Vinter et al. (2010) to observe local-to-global interference in young sighted children in a pattern similarity judgment task in which these young children exhibited a clear local processing dominance. Thus, presenting inconsistent patterns should enable us to observe whether EB children manifest interference effects in their haptic perception in the same way that sighted children do in visual perception.

Chapter 5 :

 5 Figure 44. Examples of children's drawing based on the categorization in data coding

Figure 45

 45 Figure 45 indicates the frequencies of integrated, global and local naming responses as a function of age and pattern consistency. As shown in Figure 45A, the number of integrated responses varied significantly across ages, H (4, N=110) = 30.1, p < .01, becoming more frequent with increasing age. From 23% (SD = 37) at 6-8 years of age, the number of such responses reached 48% (SD = 43) at 13-15 years of age and represented 81% (SD = 30) of the responses given by the oldest adolescents. The transition that occurs between 9-10 and 13-15 years of age reached significance, U = 180.5, n 1 = 23, n 2 = 24, p < .05. Boys produced integrated responses more often (M = 54%, SD = 44) than girls (M = 37%, SD = 42), U = 1179, n1 = 50, n2 = 60, p < .05, and this gender difference was more pronounced in the case of inconsistent patterns (p = .03) than consistent patterns (p = .07). No significant effect of pattern consistency appeared, T (N = 110) = 192, p > .50.

Figure 45 .

 45 Figure 45. Percentage of responses in the naming task as a function of age and consistency

  17) than an integrated profile (n = 7), chi-square (1) = 6.1, p < .05, or a global profile (n = 8), chi-square (1) = 4.83, p < .05. It was not until the period between 13 and 15 years of age that the integrated profile (n = 11) predominated over the global one (n = 1), chi-square (1) = 11.1, p < .01, and 16 to 18 years of age for the integrated profile (n = 21) to predominate over the local profile (n = 0), chi-square (1) = 33.6, p < .01.B. Results from the drawing task.

Figure 46

 46 Figure 46 presents the frequencies of occurrence of the different response categories obtained in the drawing task as a function of age and consistency.

Figure 46 .

 46 Figure 46. Percentages of responses in the drawing task as a function of age and consistency

Finally

  , the frequency of scribbling responses (Figure46F) varied significantly as a function of age, H (4, N=93) = 36, p < .01, being quite frequent at 6-8 years of age (M = 50%, SD = 46) and then declining abruptly to reach a low level of occurrence at 9-10 years of age (M = 6.7%, SD = 25), U= 37.5, n 1 = 12, n 2 = 15, p < .05. Boys produced more scribbles (M=15.1%, SD = 34) than girls (M=1.9%, SD = 8.7), as the significant gender effect shows, U = 906.5, n 1 = 53, n 2 = 40, p < .05. No other significant differences were found (p > .20).The children were considered individually and assigned to one of 6 different profiles depending on their performance in the drawing task: scribbling dominant (we applied the same criteria as in the naming task, 75 to 100% of scribbling responses), local dominant, global dominant, integrated dominant, non-integrated dominant or mixed profile. The assignment of the children to these profiles is indicated in Table

  dominance period was associated with the demonstration of local to global interference, the erroneous global responses in the drawing task being largely the most frequent errors, and they occurred significantly more often with inconsistent figures. This association paralleled the one shown in adults of global dominance with global to local interference effects.However, if local processing dominated first, the drawing task showed that children as young as 3 years of age actually attended to both the global and local level, but these modes of spatial information processing operated independently, as if they did not refer to a unique entity, as shown by the high percentages of non-integrated responses. If we assume that global processing tends to rely on the right hemisphere and local processing on the left Chapter 6 : General Discussion and Conclusion between 4 and 5 years of age. At 5 years of age, children produced correct integrated responses in about 70% of the cases, and these responses characterized almost 100% of the drawing production at 9 years of age. Furthermore, none of these 9 years-old children displayed any more non-integrated responses or partial or absent responses. These developmental changes in the integration between the global and local processing were significantly confirmed across stimuli (consistent vs inconsistent, simple vs. complex).

  Let's see now to what extent these trends in local-global processing could be affected by different contextual factors.

  matched and the pattern is considered as inconsistent when the global and local levels do not match. The aim of introducing consistent and inconsistent stimuli is to reveal interference effects between global and local processing. Global interference refers to the reaction time delay for local identification caused by the inconsistency at the global level. Local interference refers to the reaction time delay for global identification caused by the inconsistency at the local level. Previous studies suggested that these interferences are modulated, in part, by interhemispheric transfer

Chapter 6 :

 6 General Discussion and ConclusionIn relation to the similarity-judgment task, our study found that the consistent stimuli elicited more global responses at young ages in typically developing children. Typically developing children produced more integrated responses in face of consistent than inconsistent patterns in a drawing task. These two effects are in line with the literature and suggest that pattern consistency reinforces global processing dominance and facilitated the integration with local processing. Coherently, the inconsistent patterns elicited an increase of inaccurate integrated drawings. If we assume that these patterns required more effortful processing, interference effects between local and global processing could be enhanced by these patterns, leading to less accurate reproduction of each level. More interestingly, inconsistent patterns elicited erroneous global responses in the similarity judgment task at 3

  children's errors at 3 years of age revealed diffusion from the local (dominant level) to the global level. In our view, the opposition between the adults' results and the young children's results (global to local versus local to global interference) is only apparent because in the two cases, there is interference from the dominant to the non dominant level of analysis. The errors demonstrated by older children in the drawing task in face of inconsistent patterns (erroneous local responses) confirmed this analysis. Indeed, insofar as erroneous local responses to inconsistent targets revealed global to local diffusion, this effect emerged only on average across ages, congruent with the fact that on average, global processing dominated over local processing.

  meaningful objects at the global level (global bias-induced patterns), since the global Chapter 6 : General Discussion and Conclusion responses were also highly induced by the neutral pattern (non-object figures at both levels). More interestingly, as expected, in the naming task, the local responses were more elicited by the local bias-induced pattern (meaningful objects at the local level) and also by the competition-induced pattern (meaningful objects both at the global and local level), in comparison to the neutral pattern. Although the frequencies of the local responses were low as compared to the global responses, these findings evidenced the emergence of a local preference when meaningful objects were present at the local level. The results obtained in the drawing task were less clear in this respect. The competition-induced pattern elicited more local responses than the local bias-induced pattern, but this was observed only in one age group. Whatsoever, it testifies for the fact that local interference can exist in children with mental retardation. Otherwise, the global responses were more frequent for the global biasinduced pattern than for the neutral pattern, thus showing that global processing could still be reinforced in children with mental retardation.

  children's development of global-local processing. Concerning age, we can conclude that until 3 years of age, typical developing children showed local preference. The move to global Chapter 6 : General Discussion and Conclusion

  developmental sequence of local-global processing was similar between the typical developing children and early blind children, although there is a protracted period of local processing dominance in EB children. According to our study, the local processing dominance in EB children continued until about 10 years of age and, at the age of about 11-12 years, the frequencies of global responses increased and were quite similar to the frequencies of local responses (thus proving that EB children can attend to both local and global information). Both of these responses decreased as the number of integrated responses increased in children at older ages, so that the integrated responses became the predominant response category and still continued to increase in children at older ages. These age changes were only suitable to describe the development in typical developing children and early blind children, but not in children with mental retardation.Indeed, in these children, no age effect emerged, only IQ effects, and these last effects were not as strong as age effects in typically developing children. There was a clear global processing dominance in these children across ages and also across IQs, though the integrated responses developed as a function of IQ in the drawing task. However, interference effects existed in these children, as shown by the increase of local processing when meaningful objects were located at the local level. This means that these children are able to attend to both processes, but local processing needs to be enhanced by external cues.[START_REF] Dulaney | Global/local processing in mentally retarded and nonretarded persons[END_REF] also showed that local processing can be enhanced in persons with mental handicap by appropriate training. Of course, we can wonder to what extent the heterogeneity of our population of children with mental retardation did not prevent to obtain clearer developmental trends in these children. Replications with better control of the etiology of the intellectual impairment seem necessary. The age range of our sample of children with mental retardation was also not sufficient, as it did not include young children, who could more inclined to process at a local level if development of perceptual analysis bears some similarity between typically developing children and children with mental retardation. We can also wonder to Chapter 6 : General Discussion and Conclusion

  ).

	Inter-individual characteristics affect children's visual perception. Some early studies
	showed that atypically developing children develop different patterns of visual perception
	compared to typically developing children. Children with Perinatal Right Hemisphere Focal
	Brain Lesions (RPL) were selectively impaired on global accuracy and children with Perinatal
	Left Hemisphere Focal Brain Lesions (LPL) on local accuracy

EXPERIMENTAL SECTION CHAPTER 2. Children's spatial analysis of hierarchical patterns: Construction and perception 1

	Chapter 1 : General Introduction	Chapter 1 : General Introduction
	2006), we expected that meaning would elicit local preference in these children when
	meaningful objects were used as local elements.
	The contradictory results in the literature regarding typically and atypically
	developing children also lead to an urge to study children's visual perception across
	populations. Typically developing children aged 3 to 10 years participated in Experiment 1 to
	Experiment 4, children with mental retardation aged 6 to 14 years participated in Experiment
	5, and early blind children aged 6 to 18 years participated in Experiment 6. Typically
	developing children can attend to both the local and global level at younger ages, but the
	ability was more easily disrupted compared to older children or adults. This led to an
	expectation that there is an effect of age in children's responses to hierarchical stimuli. The
	local preference should be often found in the younger children compared to the older children
	and then global and more integrated responses should dominate. On the other hand, we
	expected that the atypically developing children with mental retardation would follow a
	global to a local analysis as age increased and should combine these analyses into integrated
	responses at older ages. Contradictory results were expected in atypically developing children
	with early blindness. Early blind adults were suggested to have dominant local responses
	(Heller & Clyburn, 1993), so we expected that early blind children would develop from non-
	integrated responses to local responses, and then, with the developing ability to respond at the
	global level, children should be able to integrate these responses in older ages.
		; Porter & Coltheart,

Table 1 .

 1 Age distribution of participants in the drawing experiment

	No	Age group	N	M / F	Mean	SD
	1	3	15	6 / 9	3.3	0.30
	2	4	16	8 / 8	4.6	0.28
	3	5	15	7 / 8	5.6	0.31
	4	6	15	8 / 7	6.4	0.32
	5	7	15	8 / 7	7.5	0.28
	6	8	16	8 / 8	8.6	0.27
	7	9	16	8 / 8	9.4	0.33
	Total		108	53 / 55

Table 2 .

 2 Age distribution of participants in the perceptual similarity judgment task

	No	Age group	N	M / F	Mean	SD
	1	3	32	16 / 16	3.5	0.29
	2	4	32	16 / 16	4.6	0.27
	3	5	32	16 / 16	5.5	0.27
	4	6	32	16 / 16	6.6	0.30
	5	7	32	16 / 16	7.5	0.28
	6	8	32	16 / 16	8.4	0.29
	7	9	32	16 / 16	9.5	0.30
	Total		224	112 / 112

  reported similar results in the copying of compound figures. Likewise,Vinter and Marot (2007) mentioned that young children tended to copy stairs-like patterns (made of embedded rectangles) as a series of independent and juxtaposed rectangles. Thus, at 3 years of age, children were capable of perceiving both the local and global organization of

compound patterns, but these modes of spatial information processing operated independently, as if they did not refer to a unique entity. If we assume that global processing tends to rely on the right hemisphere and local processing on the left hemisphere (e.g., Moses

  Congruent with this developmental sequence, the local bias shown in the perceptual task in the youngest children disappeared when both levels of organization started to be integrated. A global processing preference emerged at 5 years of age in this perceptual task. This evolution with age found in the similarity judgment task appeared in line with previous findings, though some divergences were worth pointing out. The local bias lasted until 5 years of age inPoirel et al.'s (2008) study, until 6 years of age inKramer et al.'s (1996) study, and was obtained only under low elements density in[START_REF] Dukette | Children's analysis of hierarchical patterns: Evidence from a similarity judgment task[END_REF] study. It was obtained under normal elements' density conditions and disappeared between 4 and 5 years of age in our study. However, none of these studies used the same experimental conditions. Note that the global processing preference as measured by similarity judgments does not mean that children process the global shape first and then the local elements. Other types of tasks are needed to trace the time course of each process. Using appropriate tasks,

	Chapter 2 : Children's spatial analysis of hierarchical pattern
	Chapter 1 : General Introduction
	second developmental change occurred between 4 and 5-6 years of age. It was indeed from 5
	to 6 years of age onwards that children produced correct integrated responses more frequently
	than local responses. The global bias in drawing, as reported by Lange-Küttner (2000), was
	not observed at all in our own drawing study. Children at this age clearly attended to both
	levels of organization, and they were able to successfully plan their drawing behavior,

changes occurred after 3 years of age. The nonintegrated responses dropped abruptly between 3 and 4 years of age, whereas the production of integrated responses, whether correct or inaccurate, increased significantly. Whereas the 3-year-olds either considered only one component of the target (the local one) or one component at a time (nonintegrated responses), the 4-year-olds started to process the two components together. A integrating accurately the two components. No further qualitative change occurred, but a progressive performance refinement was shown between 6 and 9 years of age.

[START_REF] Scherf | Emergence of global shape processing continues through adolescence[END_REF]

have indeed shown that it is only late into adolescence that evidence of global precedence can be found. This perceptual global bias means that children are more likely to base their similarity judgments between two patterns on their global shapes than on their local elements, these two levels of organization being perfectly attended to, as shown by the drawing task.

  To our knowledge, this is the first time in the literature that this effect is reported in young children. It should be further investigated, adapting the methods used with adults to these

	young children. Interestingly, insofar as erroneous local responses to inconsistent targets
	revealed global to local diffusion, this effect emerged only on average across ages, congruent
	with the fact that on average, global processing dominated over local processing.
	In the case of drawing, pattern consistency had an impact on the integrated responses,

not on the local or global responses. The inconsistent patterns elicited an increase of inaccurate integrated drawings. If we assume that these patterns required more effortful Chapter 2 : Children's spatial analysis of hierarchical pattern Chapter 1 : General Introduction processing, interference effects between local and global processing could be enhanced by these patterns, leading to less accurate reproduction of each level.

Children's Spatial Analysis of Simple and Complex Hierarchical Patterns in a Drawing and Similarity Judgment Task Introduction The

  aim of the two studies reported in chapter 3 is to investigate how children perceive and draw simple and complex hierarchical patterns. Such comparison between simple and complex patterns has yet not been studied in the literature. It is important to note that the present two experiments are clearly exploratory, due to the lack of corresponding studies in the literature.

Further studies investigating specifically the role of exposure times in drawing hierarchical patterns are needed to make this issue clearer.

CHAPTER 3.

The geometrical forms designed for these experiments were estimated to be appropriate to the age of the children. However, because of the complex figures, children as young as 3 years of age were not able to participate in the experiments. Thus, the youngest age group included in the present studies was 4 years old. At 4 years of age, children are more familiar with geometrical forms than letters or numbers. The use of geometrical forms in the study of global and local processing has been initiated in the study of

Table 3 .

 3 Age distribution of participants in Experiment 3

	No	Age group	N	M / F	Mean	Range
	1	4	20	10 / 10	4.5	3 yr 11 mo-4 yr 9 mo
	2	5	21	10 / 11	5.3	4 yr 9 mo-5 yr 9 mo
	3	6	20	10 / 10	6.5	6 yr 0 mo-6 yr 9 mo
	4	7	20	10 / 10	7.4	6 yr 11 mo-7 yr 9 mo
	5	8	20	10 / 10	8.3	7 yr 10 mo-8 yr 8 mo
	6	10	20	10 / 10	10.5	9 yr 11 mo-10 yr 10 mo
		Total	121	60 / 61

Table 4 .

 4 Age distribution of the participants in Experiment 4.

	No	Age group	N	M / F	Mean	Range
	1	4 yrs	20	13 / 7	4 yr 4 mo	3 yr 10 mo -4 yr 7 mo
	2	5 yrs	20	8 / 12	5 yr 5 mo	4 yr 11 mo -5 yr 9mo
	3	6 yrs	20	9 / 11	6 yr 5 mo	6 yr 0 mo -6 yr 10 mo
	4	8 yrs	20	9 / 11	8 yr 4 mo	7 yr 10 mo -8 yr 9 mo
	5	10 yrs	20	12 / 8	10 yr 4 mo	9 yr 10 mo -10 yr 9 mo
		Total	100	51 / 49

  5% of the children who showed frame-correct responses at the age of 4 (100% at the age of 7). Part-correct responses were shown by 36.25% of the children at the age of 4 and gradually increased to 90.6% at the age of 7 without reaching 100% at the age of 9 (it presumably continued to develop after the age of 9).

	Chapter 3 : Children's Spatial Analysis of Simple and Complex Hierarchical Patterns
	Chapter 1 : General Introduction
	by 42.In this study, the development of spatial analysis in drawing was globally not
	influenced by the complexity of the pattern and by the duration of the display. The effect of
	complexity and duration only significantly influenced the reproduction of parts.
	The findings obtained in the similarity judgment task confirmed that that age had a
	significant effect on global responses, local responses, global-partial responses and integrated-
	partial responses. The predominant responses were clearly the global responses: at 4 years of
	age, children selected these responses in already more than 60% of the cases. A peak was
	reached at 8 years, followed by a slight but not significant decline at 10 years. Furthermore,
	Duration had an effect on the local responses, with the short durations eliciting more
	local responses than the long durations. It occurred at younger ages (4 years of age) and this
	might support other findings which proposed that local preference existed in children at
	younger ages.
	This study suggests that the integration between local and global levels of
	organization in drawing seems to emerge at 5 years of age. Before 5 years of age, children
	are able to focus on the global level or local level, but they cannot coordinate and integrate

The correct integrated responses increased progressively and significantly with age, while the other responses (non-integrated, global and local responses) significantly tended to decrease as age increased. As compared to the local responses, the global responses dominated, and they decreased after 6 years of age. This shows that children at younger ages can attend to both the local and global level but these responses tended to decrease as children get older and began to integrate the local and global level into an integrated response.

the two levels (76.25% of drawing performance at the age of 4 was either local, or global, or non-integrated). The dominance of global processing accounted for the more rapid development of the drawing of the frame, as compared to the drawing of the parts, evidenced these global responses were more enhanced by the complex figures in children between 4 to 6 years of age, but at older ages (8 years of age and henceforth), the simple figures elicited more the global responses than the complex figures. The choice for the local responses was very rare in the present experiment, even at the youngest ages (less than 10% of the cases).

  4 : Spatial Analysis of Hierarchical Meaningful Patterns in Children with Mental Retardation Chapter 3 : Children's Spatial Analysis of Simple and Complex Hierarchical Patterns Chapter 1 : General Introduction Studies that have introduced objects in the building of hierarchical patterns were based on the assumption that objects should arouse automatic identification. Automatic identification at the global or local level should influence global or local precedence respectively. Based on this idea, the present study will use objects as meaningful stimuli and non-objects as non-meaningful stimuli. Meaningful hierarchical patterns included objects that

	A drawing task was used in this research since studies investigating the global-local
	preference in a drawing task were scarce and showed contradictory results (Lange-Küttner,
	2000; Dukette & Stiles, 2001; Vinter et al., 2010). According to Lange-Küttner (2000), most
	children in younger ages (5 year-olds) tended to draw global shapes when they were asked to
	copy hierarchical patterns, while older children (11 year-olds) produced correct drawings both
	at the local and global level. A study by Dukette and Stiles (2001) with children aged 4 to 8
	years and adults showed that the youngest children had more difficulties in reproducing the

, who reported local advantage in the drawings of individuals with WS, while global advantage was found in individuals with DS. These different findings showed that further investigation of spatial analysis in hierarchical stimuli in children with mental retardation was needed.

global shape than the local elements if they drew under constrained task conditions (like drawing from memory rather in copying condition), although they were able to attend to both levels of analysis.

Chapter

Table 5 .

 5 Age distribution of participants in the naming task

	No Age group	N	M / F	Mean	SD	Range
	1	6-10 yrs	37 21 / 16	9 yr 4 mo	1 yr 3 mo	6 yr 5 mo-10 yr 11 mo
	2	11-12 yrs	26 14 / 12	12 yr 0 mo	0 yr 6 mo	11 yr 0 mo-12 yr 11mo
	3	13-14 yrs	31	23 / 8	13 yr 10 mo	0 yr 7 mo	13 yr 0 mo-14 yr 10 mo
		Total	94 58 / 36
	Table 6. IQ distribution of participants in the naming task
	No	IQ group	N	M / F		Mean	SD
	1	50-60		37	24 / 13		54.13	4.00
	2	61-65		31	20 / 11		62.96	1.30
	3	66-70		26	14 / 12		68.34	1.85
		Total		94	58 / 36

Table 7 .

 7 Age distribution of participants of the drawing task

	No	Age group	N	M / F	Mean	SD		Range
	1	6-10 yrs	35	20 / 15	9 yr 3 mo	1 yr 4 mo		6 yr 5 mo-10 yr 11 mo
	2	11-12 yrs	23	11 / 12 11 yr 10 mo 0 yr 6 mo		11 yr 0 mo-12 yr 11mo
	3	13-14 yrs	28	22 / 6	14 yr 0 mo	0 yr 7 mo	13 yr 0 mo-14 yr 10 mo
		Total	86	53 / 33
	Table 8. IQ distribution of participants of the drawing task
	No	IQ group		N	M / F	Mean	SD
	1	50-60		34	22 / 12	54.38	4.07
	2	61-65		29	19 / 10	62.96	1.32
	3	66-70		23	12 / 11	68.56	1.82
		Total		86	53 / 33

Table 9 .

 9 Age distribution of EB participants in the naming taskSome of the children (N = 17) refused to draw the patterns because they did not feel able to perform this task and wanted to avoid being placed in a difficult situation. The number of participants who performed the drawing task was consequently lower than that reported earlier. Ninety-three children aged between 6 and 18 years (40 girls, 53 boys) completed the drawing task. They were also divided into five age groups (see table10).

	No	Age group	N	M / F	Mean	SD
	1	6-8	15	10 / 5	7.5	0.88
	2	9-10	23	7 / 16	9.11	0.47
	3	11-12	20	12 / 8	11.11	0.53
	4	13-15	24	16 / 8	14.4	0.93
	5	16-18	28	15 / 13	17.6	0.88
	Total		110	60 / 50

Table 10 .

 10 Age distribution of EB participants who completed test performance in the drawing task.

	No	Age group	N	M / F	Mean	SD
	1	6-8	12	8 / 4	7.6	0.76
	2	9-10	15	4 / 11	9.11	0.50
	3	11-12	16	11 / 5	12.0	0.51
	4	13-15	22	15 / 7	14.4	0.91
	5	16-18	28	15 / 13	17.6	0.88
	Total		93	53 / 40
	None of these children performed drawing activities very frequently: around 20% of

them drew on an occasional or regular basis while 80% drew only rarely or infrequently. The youngest children (6-8 years of age) were learning Braille, while those in the other age groups regularly practiced Braille reading and writing.

Table 11 .

 11 Table 11 indicates the assignment of the EB children to these profiles as a function of their age. Distribution of the profiles in the naming task This table confirms the predominance of local processing in the youngest age groups. More children in the first two age groups (6 to 10 years of age) exhibited a local profile (n =

	Age	Local	Global	Integrated	Mixed profile	Total
	group
	(yrs)
	6-8	7 (46,7%)	4 (26,6%)	3 (20%)	1 (6,7%)	15
	9-10	10 (43,5%)	4 (17,4%)	4 (17,4%)	5 (21,7%)	23
	11-12	5 (25%)	5 (25%)	8 (40%)	2 (20%)	20
	13-15	8 (33,33%)	1 (4,2%)	11 (45,8%)	4 (16,66%)	24
	16-18	0 (0%)	0 (0%)	21 (75%)	7 (25%)	28
	Total	30	14	47	19	110

Table 12 :

 12 Distribution of the profiles in the drawing taskIn the same way as for the naming task, this table confirms that more of the children in the first two age groups exhibited local processing dominance (n = 11) than integrated processing dominance (n = 3), chi-square (1) = 7, p < .01. The level of dominance of these two types of processing was reversed from 13-15 years of age onwards, chi-square (1) = 3.54, p = .06. The fact that only a small number of children exhibited a global dominance profile in the different age groups indicates that this response was quite infrequent.

	Age group	Scribbling	Local	Global	Integrated	Non-	Mixed	Total
	(yrs)					integrated	profile
	6-8	5 (41,6%) 5 (41,6%)	0 (0%)	0 (0%)	0 (0%)	2 (16.7%)	12
	9-10	1 (6,66%)	6 (40%)	2(13,33%)	3 (20%)	1(6,66%)	2 (13,33%)	15
	11-12	0 (0%)	4 (25%)	2 (12.5%)	6 (37.5%)	0 (0%)	4 (25%)	16
	13-15	1 (4,54%) 5 (22.7%)	1 (4.54%)	11 (50%)	0 (0%)	4 (18.2%)	22
	16-18	0 (0%)	6 (21.4%)	2 (7.1%)	16 (57.1%)	0 (0%)	4 (14.3%)	28
	Total	7	26	7	36	1	16	93

  , probably do not account for the dominance of one or other type of processing, in the same way that oculomotor activity is possibly not sufficient to account for local or global dominance in visual tasks. This suggests that the dominance of local over global processing in haptic perception in EB children is probably due more to the integrative steps involved in the processing of shapes and objects than to more peripheral information gathering activities.Absent in the drawing task and present at a low level in the naming task at 6-8 years of age, the integrated responses increased with age. They became the predominant response

category as of 11-12 years of age in both tasks, thus demonstrating that the difficulty in producing integrated responses was not due to specific graphic difficulties experienced by EB children. The short period of training provided during the familiarization phase was efficient enough to permit all the children who agreed to produce drawings to draw small and big circles and squares (although often with considerable distortions). Although there were very few non-integrated responses in which the local and global components were present but juxtaposed, it is interesting to note that these occurred primarily at 9-10 years of age and disappeared at 13-15 years of age. Young sighted children who were asked to copy similar geometrical Navon figures also primarily produced local or non-integrated responses before integrated responses became dominant at 6 years of age (Vinter

What about the age effect on local and global perception ?

	Let's consider first the developmental trends evidenced in typically developing
	children. Previous studies suggested that age matters in the processing the hierarchical
	patterns, so children at various ages were involved in our experiments. Research with infants

[START_REF] Porter | Global and local processing in William syndrome, autism, and Down Syndrome : Perception, attention, and construction[END_REF]

used such a naming task to study global-local processing in atypical developing children. We also employed this task with the two populations of atypical children we have studied, children with mental retardation and blind children.

We suggest discussing our results in terms of global/local preference or advantage, global/local interference and local-global integration with regard to the effect of age, stimuli, duration and gender across typical and atypical developing children.

A.

  The protracted dominance of local processing in the development of blind children is certainly due to the sequential nature of the exploratory manual movements that are used by blind people to process shapes and prevent fast access to the global shape. Access to the global shape of unknown patterns requires highly developed mental capabilities for the coordination and integration of information and these capabilities need time to develop. At the age of about 11-12 years, the frequencies of global and local responses were quite similar General Discussion and Conclusion just before the integrated responses became more frequent than the local responses, and they disappeared at 13-15 years of age.

	(thus proved that EB children can attend to both local and global information) before
	decreasing in both tasks as the number of integrated responses increased in children at older
	ages. The integrated responses became the predominant response category at 11-12 years of
	age in both tasks, thus demonstrating that the difficulty in producing integrated responses was

not due to specific graphic difficulties experienced by EB children. Although there were very few non-integrated responses in which the local and global components were present but juxtaposed, it is interesting to note that these occurred primarily at 9-10 years of age, that is Chapter 6 :

This chapter has been submitted for publication in Child Development. We reproduced most part of this paper here. Chapter 5 : Global and Local Processing in Early Blind Children

Acknowledgements

Another great appreciation to the Indonesian Ministry of Education, especially to the Directorate General of Higher Education who supports with the scholarship.

the global bias-induced pattern showed a significant effect of IQ, H (2, N = 86) = 7.52, p < .05, with children in the higher IQ-group producing more integrated responses (39.1%) than the children in the lower . A significant effect of IQ was also found for the competition-induced pattern, H (2, N = 86) = 5.578, p < .05, and for the neutral pattern, H (2, N = 86) = 6.49, p < .05 where again children in the higher IQ-group produced more integrated responses than the children in the lower IQ-group. No differences between patterns appeared (all ps > .10), which means that the use of meaningful or non-meaningful patterns might not affect the integration of local and global processing in the children's drawing.

Figure 42D represents the syncretic responses as a function of patterns. No significant effects of pattern were found (all ps > .10) but a significant effect of IQ was found except for the responses elicited by the global bias-induced pattern. Syncretic responses elicited by the competition-induced pattern and by the local bias-induced pattern, showed significant result, H (2, N = 86) = 8.02, p < .05, where none of the children in the higher IQgroup produced syncretic responses, while 14.7% of children in the lower IQ-group performed these responses. Syncretic responses elicited by the neutral pattern also showed significant result, H (2, N = 86) = 9.75, p < .01, where 17.64% children in the lower IQ-group produced syncretic responses (17.64%) and none of the children in the higher IQ-group produced it.

Discussion

The aim of the study was to analyze spatial analysis of hierarchical meaningful stimuli in children with MR using a naming task and a drawing task. Previous studies with meaningful stimuli showed that objects with meaning elicited an automatic identification process and promoted a global/local bias depending on the level at which the meaning was affected. Many studies in global/local processing that involved children with mental retardation showed contradictory results [START_REF] Birhle | Seeing either the forest or the trees: Dissociation in visuospatial processing[END_REF]Nakamura et al., 2009, Bellugi et al., 1990;Bellugi et al., 2000). By using hierarchical meaningful stimuli in a drawing task, we aimed to investigate whether meaning would interfere with the global/local processing in children with MR.

Four patterns were utilized in this study. The results showed that the global responses dominated largely, not only for the global bias-induced pattern, but also for the other patterns presented in the study. Even when global processing was clearly not enhanced by the pattern (e.g. with the local bias-induced pattern), the global responses were still dominating. This result fits with other findings, showing that children with mental retardation performed better in drawing the global shape than the local elements [START_REF] Birhle | Seeing either the forest or the trees: Dissociation in visuospatial processing[END_REF]Bellugi et al., 1990;Bellugi et al., 2000). The second preliminary study used shapes made of embossed dots as described in the Heller and Clyburn study (1993). The local elements used as stimuli had a diameter or side length of 1 cm and were made up of small dots as illustrated in Figure 43C. The diameter or side length of the global shape was 6 cm. The density of elements was increased in comparison with the previous patterns. The square global shape consisted of 16 local elements and the circular global shape of 14 local elements. The same participants as in the first preliminary study were asked to identify the shapes three weeks after the previous pilot study.

62.5% of them failed to identify the shapes (either local or global) because of a difficulty in perceiving an overall organization on the basis of a set of dots. 22.5% of the participants detected the global shape by perceiving the outline of the figure, 5% identified the local shapes and 10% identified both components.

In the third preliminary study, the thermoformed patterns were of the same size and The term of global/local processing bias described the same phenomenon where the global processing bias refers to the preference for the whole pattern and local processing bias described the preference for detail-level information or preference for the local elements [START_REF] Farran | Divided attention, selective attention and drawing: Processing preferences in Williams Syndrome are dependent on the task administered[END_REF][START_REF] Johnson | System factorial technology provides new insights on global-local information processing in autism spectrum disorders[END_REF].

Our studies did not only concern the process of perception but also involved the integration of the perceptual processes into the drawing ability. Studies on drawing behavior showed that changes during development result from changes in the mental representations used to plan behavior and in the capacity to manage part-whole relationships (Vinter, Picard & Fernandes, 2008). Although a drawing task may be more complex than a perceptual task as it needs additional requirements in terms of planning and motor demands (van Sommers, 1989), some studies confirmed that drawing hierarchical patterns constitutes a way to approaching how children perceive these patterns [START_REF] Feeney | Spatial analysis : An examination of preschoolers' perception and construction of geometric patterns[END_REF][START_REF] Bouaziz | Contribution of the visual perception and graphic production systems to the copying of complex geometrical drawings: A developmental study[END_REF]Tada & Stiles, 1996;[START_REF] Dukette | Children's analysis of hierarchical patterns: Evidence from a similarity judgment task[END_REF].

However, these studies showed contradictory results because some authors suggested that the whole object is segmented into parts in a similar way both in perception and drawing

Chapter 6 : General Discussion and Conclusion hemisphere (e.g., [START_REF] Moses | Functional MRI of global and local processing in children[END_REF], this independent functioning may be a consequence of the still immature interhemispheric communication in the integration of visual information. It is indeed only at around 2 years of age that processing from the two hemispheres starts to be coordinated [START_REF] Liegeois | When does interhemispheric coordination integration of visual events emerge in infancy? A developmental study on 19-to 28month-old infants[END_REF].

After 3 years of age, an important change occurred as testified by the results obtained in the similarity judgment task with global processing preference emerging at 4 years of age and these responses increasing as children get older. It can be said that when children had to decide whether a compound figure bore more similarity with its global shape or with an arrangement made of its local elements, they tended to select more and more often the global shape and less and less often the local elements as age progressed. These tendencies were found across different stimuli (consistent vs inconsistent and simple vs complex), independently also to the duration of exposure of the targets. Note that the complexity of the figures tended to reinforce this global processing preference, as could be seen when the results from the two first experiments are compared with those of Experiments 3 and 4.

Indeed, the patterns used in the two first experiments are even simpler than the so-called -simple‖ patterns employed in Experiments 3 and 4. And our results showed that global processing preference was on average higher in these two last experiments. The same trend emerged in the drawing task, since the global responses were produced at a quite high level in Experiment 3 when compared to Experiment 2. However, the tendency of the two levels of perceptual analysis to operate independently was still evidenced in children at 4 years of age, as revealed by the frame-part analysis in the drawing task (Experiment 3) that showed more part-absent and frame-absent responses at this age.

Note that this schema of two levels of analysis, independent, with the local level stronger in a first step (3-4 years), and then the global level increasing (4-5 yrs), may seem in contradiction with the results obtained in Experiment 3 (drawing task), concerning the framepart analysis. Indeed these results suggest that the frame-correct analysis develops earlier and faster than the part-correct analysis. It is important to point out that these results cannot be compared directly to those obtained in the perceptual task. Drawing correctly the frame in Experiment 3 means drawing a square, while drawing correctly the parts means drawing crossed lines, obliques or triangles, that is figures more complex to reproduce. The sensitivity of part-correct analysis to the duration of exposure of the targets, and not of the frame-part analysis, is coherent with this suggestion of higher complexity of the former as compared to the later.

To continue with development, our results indicate that once global processing preference emerged (as revealed by the similarity judgment task), the integration between the two levels of perceptual analysis developed (as revealed by the drawing task). Indeed, in Neuroscience Research, 39, 469-472. van Sommers, P. (1989). A system for drawing and drawing-related neuropsychology.

Cognitive Neuropsychology, 6, 117-164. Vecchi,T. (2001)