Edy Veneziano
email: edy.veneziano@u-paris.fr

Nominal and Verbal morphology in the early acquisition of French: A first study of the relation between comprehension and production

Keywords: Acquisition of French, 2-year-olds, Production and comprehension, Grammatical morphemes, Articles, Subject clitic pronouns

The chapter presents a study of the relation between the comprehension and production of articles and subject clitic pronouns in 2-year-old Frenchacquiring children. The production of grammatical morphemes occurring in the spontaneous speech of ten children was related to the performance these same children obtained in a comprehension task testing the children's understanding of the grammatical morphemes in question. Success in the task required children to retrieve the meaning of homophonous or nonce words on the sole basis of the category-specific grammatical morpheme preceding them -a definite article for nouns and a third person subject clitic pronoun for verbs. Overall, results indicate that comprehension and production are closely related. For the majority of the children, a high level of comprehension corresponded to a high level in production. The profile of one participant, and to a lesser degree that of two others, suggests that production might be ahead of comprehension. It should be noted, however, that in this study comprehension could not be assessed with the same degree of detail as spontaneous production. To shed further light on this issue, future studies should find a way to assess children's comprehension in finer detail, include additional participants, as well as plan studies where both production and comprehension are assessed on a longitudinal basis. Moreover, in order to better evaluate what children have acquired and how they have acquired it, it is suggested that studies of early language acquisition should include both comprehension and production as a standard method of analysis.

Introduction

As this volume attests, Dorit Ravid is a leading figure and a source of inspiration to many researchers in the field of language acquisition to which she has extensively contributed. Among the topics she has tackled is that of the acquisition of oral and written grammatical morphology and of the relation between them (e.g., [START_REF] Bar-On | Morphological analysis in learning to read pseudowords in Hebrew[END_REF][START_REF] Ravid | Morpho-syntactic constructs in the development of spoken and written Hebrew text production[END_REF]. This paper relates to this line of research by presenting a first study of the relation between the comprehension and production of grammatical morphemes -in particular articles and subject clitic pronouns-in 2-year-olds acquiring French.

One way to look at children's grasp of these morphemes is to consider how they comprehend and use them in nominal and verbal contexts. In French, as in many other languages, articles usually precede nouns while subjects, particularly subject clitic pronouns, precede verbs, either immediately -as in simple verb forms such as the indicative present (e.g., il mange 'he eats') -or distanced from the verb by one or more intervening elements -as in compound verb constructions when, for example, an auxiliary verb occurs between the subject and the past participle form (e.g., il a mangé 'he has eaten').

Consequently, the morphosyntactic context in which words occur is considered to largely contribute to determining their grammatical category (e.g., [START_REF] Clairis | Nom et verbe. Modèles Linguistiques, Tome VI[END_REF][START_REF] Lazard | La distinction entre nom et verbe en morphologie et en syntaxe[END_REF][START_REF] Maratsos | The internal language of children's syntax: The ontogenesis and representation of syntactic categories[END_REF]. Thus, if children understand the function of grammatical morphemes, they will also be able to assign noun or verb status to words they encounter for the first time and disambiguate the meaning of words in the event of homophony (e.g., for English, the meat vs. they meet; for French, le /li/ 'the bed' vs. je /li/ 'I read'). Furthermore, although there is hot a one-to-one relationship between word category and meaning, words that are nouns tend to refer to objects and entities, while words that are verbs tend to refer to actions or states.

In a recent study of 2-to 4-year-old children acquiring / speaking French, Veneziano and Parisse (2018) (hereafter referred to as V&P) assessed the children's understanding of grammatical morphemes such as definite articles and subject clitic pronouns by considering the meaning that children attributed to the word immediately following either the article (the nominal context) or the subject pronoun (the verbal context). The words were either homophonous in French or were nonce -invented and thus novel -words and could thus function as either nouns or verbs: only the preceding grammatical morpheme could be used to attribute either an object or an action/state meaning to them. So, if a child attributed the meaning suggested by the preceding grammatical morpheme to a homophonous or nonce word, and did so in a consistent and statistically significant way over the items proposed, we considered that the child understood the function of the grammatical morpheme in the utterance presented. The results of that study, as well as of earlier preliminary ones [START_REF] Veneziano | Retrieving the meaning of words from syntactic cues: A comprehension study of 2 to 4 yrs old French-speaking children[END_REF][START_REF] Veneziano | The Early Comprehension of Noun-Verb Distinction in French: An Experimental Method[END_REF], showed that, at all ages, children were able to retrieve the object or action meaning of homophonous or nonce words on the sole basis of the information provided by the type of grammatical morpheme preceding them. Although 4-year-olds outperformed the 2-and 3-year-olds, as a group, these younger children succeeded in the task as well. Wide individual differences were however observed, particularly in the younger group.

In the present study, we capitalized on 2-year-olds' individual differences in comprehension and on the collection of production data from this group of children in order to analyze the relation between comprehension and production of the above-mentioned grammatical morphemes by some of the 2-year-olds who participated in the V&P study. Comprehension was assessed using the results that children obtained in the comprehension task of the V&P study (see section 2.1 below for more details on the task). Production, consisting of the spontaneous speech the same children uttered while interacting with the experimenter before and during the comprehension task, was evaluated using a detailed method devised specifically for the present study (see section 2.2 below for details).

The relation between comprehension and production

Adults' comprehension and production of their native language tend to be at the same level of proficiency. Such a coincidence does not seem present during children's language acquisition and the level of concordance between the two modes of language functioning can itself be considered a developmental variable (e.g. [START_REF] Clark | Comprehension, Production, and Language Acquisition[END_REF].

In studies comparing production and comprehension where the latter was assessed in controlled situations, comprehension seemed to be either ahead of the children's production or the children behaved differently in the two modes. For example, [START_REF] Sachs | Comprehension of two-word instructions by children in the one-word stage[END_REF] found that children who only produced single-word utterances in their spontaneous speech could understand the meaning of word combinations even when their comprehension involved performing unusual or improbable actions on objects. [START_REF] Thomson | Who is 'Daddy' revisited: the status of two-year-olds' overextended words in use and comprehension[END_REF] found that children who overextended words in production did so to a much lesser extent in comprehension.

Comprehension also appears to be ahead of production for grammatical morphemes. Several experimental studies have shown some comprehension of grammatical morphemes before children are assumed to be able to systematically produce them in their speech. Perception studies have shown that infants are sensitive to the grammatical morphemes of the language they are exposed to [START_REF] Höhle | Functional elements in infants' speech processing: The role of determiners in the syntactic categorization of lexical elements[END_REF][START_REF] Kedar | Getting there faster: 18-and 24-month-old infants' use of function words to determine reference[END_REF][START_REF] Shi | Syntactic categorization in French-learning infants[END_REF][START_REF] Shi | Recognition and representation of function words in English-learning infants[END_REF]. In studies requiring the active response of the children, comprehension also seems to be ahead of production. Children in their second year, whose utterances did not contain function words, responded better to instructions expressed by utterances that contained grammatical morphemes than to utterances that did not [START_REF] Petretic | Does comprehension precede production? The development of children's responses to telegraphic sentences of varying grammatical adequacy[END_REF][START_REF] Shipley | A study in the acquisition of language[END_REF], or to utterances that contained ungrammatical function words (Gerken and MacIntosh, 1993). More recently, several experimental studies have shown that children can assign meaning to nonce words according to the syntactic context in which they occur: an object meaning when nonce words occur in a nominal context and an action meaning when they occur in a verbal context [START_REF] Bernal | Syntax constrains the acquisition of verb meaning[END_REF][START_REF] Cauvet | Function words constrain on-line recognition of verbs and nouns in French 18-montholds[END_REF][START_REF] Naigles | Children use syntax to learn verb meanings[END_REF][START_REF] Waxman | Twenty four-month-old infants' interpretations of novel verbs and nouns in dynamic scenes[END_REF].

Studies of perception and of early comprehension of grammatical morphemes therefore indicate that children have sensitivity and later some understanding of grammatical morphemes before they are assumed to produce them at all or produce them appropriately. However, these studies, for the most part, report group results and very little data exist on the development of both comprehension and spontaneous production of grammatical morphemes in the same children considered individually. The present study is a first attempt to fill this gap by providing data on the relation between comprehension and production in 2-year old children acquiring French. The study compares the results obtained in the V&P comprehension task by ten 2-year-olds to their production of grammatical morphemes as it occurred in their spontaneous speech. As will be made clearer later, five of these children successfully completed the V&P comprehension task (this group will be called Group S) and the other five did not successfully complete the task (this group will be called Group NoS).

Results of the present study will thus provide empirically founded data on how knowledge of this aspect of language stands in the two modes of functioning. In particular, we will test the hypothesis about the priority of comprehension relative to spontaneous speech production. If this hypothesis is correct, we should expect that the spontaneous production of articles and subjects by children in Group NoS should not show proficiency, whereas the children in Group S could have either low or high levels of production. In fact, given that the study provides only a snapshot of children's comprehension at one particular time, it is not possible to determine when they achieved their understanding. If this happened close to the time of participation in the task, production should not yet be mastered; instead, if comprehension was achieved some time before participation in the task, then production could be of a higher and similar level of mastery to that of comprehension. Moreover, given that the children who did not successfully complete the comprehension task are less advanced in their understanding of grammatical morphemes than the children who successfully completed it, it is expected that the level of production of children in Group NoS will be lower than that of the children in group S. In section 2.2 below we will describe the method of analysis devised in this study to classify children's production of grammatical morphemes in four levels of proficiency.

In addition to testing the hypothesis about the developmental priority of comprehension over production, the study of both modes of functioning in the same children will provide a more precise view of children's knowledge of nominal and verbal French grammatical morphemes, compared to when only one mode of functioning is analyzed, as is usually the case in early language acquisition studies. Moreover, the comparison will also enable the level of coincidence between the two modes of functioning to be assessed: when a child shows a high level of proficiency in one of the two modes of functioning, the distance between it and the other mode will provide insights into the child's overall level of mastery of the language aspect under study, the coincidence between the two being itself considered an additional indicator of mastery [START_REF] Campbell | The relationship between comprehension and production and its ontogenesis[END_REF][START_REF] Clark | Comprehension, Production, and Language Acquisition[END_REF].

In what follows, we will first provide details about the V&P comprehension task, as well as about the criteria used therein to consider that a child successfully completed it and their application to the present study. Then, we will consider the theoretical and empirical background to the analysis of production and present the method devised here to evaluate the children's use of grammatical morphemes, from the early production of fillers (known in the literature as underdetermined elements occurring where grammatical morphemes would be expected) to the production of the appropriate morphemes in 90% of the places where they are required, which is the acquisition criterion proposed by Roger Brown and his colleagues (e.g., [START_REF] Brown | A first language: The early stages[END_REF][START_REF] Cazden | The acquisition of noun and verb inflections[END_REF], and still in use today as the criterion for acquisition. Finally, we will present the results obtained in this first study and discuss their significance.

Evaluating the early acquisition of French grammatical morphemes 2.1. Comprehension of grammatical morphemes 2.1.1. General properties of the V&P comprehension task

The comprehension task applied in V&P and whose results are used in the present study has several original features that strongly suggest children's understanding of the grammatical morphemes involved when the task is successfully completed (see, for more details, Veneziano & Parisse, 2018):

1. In addition to nonce words -usually presented to the children in comprehension situations of a similar kind --it uses homophones, words existing in spoken French and found in a large sample of French child-directed speech (CDS) 1 . These words can have either action 1 In the V&P study, participants were not tested on their knowledge of the homophonous words used in the task. This knowledge in fact was not expected, since these kinds of comprehension tasks usually use only nonce or invented words which are by definition unknown to the children. Nonetheless, V&P analyzed a large sample of French CDS (child-directed speech) to examine whether the words were likely to have been heard by the children. French CDS from CHILDES [START_REF] Macwhinney | The CHILDES project: Tools for analyzing talk (3rd)[END_REF] and from the samples analyzed in Veneziano & Parisse (2010) (the two data sets containing in all 1,913,796 words), showed that, with the exception of the verb trancher [to or object meaning in the language. In the task, the meaning can be disambiguated only by correctly processing the grammatical functors preceding the homophonous word. For example, /pus/ can correspond to either the noun pouce 'thumb' or the verb pousse 'push', depending on whether it is preceded by the definite article /lə/ -/lə pus/ -in which case it is interpreted as 'the thumb' 2 -or by the subject clitic pronoun /il/ -in which case it is interpreted as /il pus/ 'he pushes'. The use of homophonous words that exist and have everyday meanings in the language has the advantage of providing the children with a more natural setting compared to a task where only nonce words are presented. Moreover, the use of homophones provides a good glimpse on how children process words that they are susceptible to encounter in their everyday interactions. The identification of homophones did not seem to render the task easier or more difficult for the 2-year-olds as the V&P study did not find significant differences in performance between the homophone and the nonce items 3 ; 2. The grammatical context necessary to distinguish nouns from verbs -and in the task, object from action meaning -was kept to its minimally contrastive expression: only a definite article for nouns or a subject clitic pronoun for verbs distinguished the two utterances;

3. Each child in the study dealt with equivalent numbers of noun and verb contexts for homophonous words. This allows a good assessment of children's capacity to provide differential interpretations according to the respective, minimally contrasted, grammatical contexts4 ; 4. The behavior on which children were evaluated required their active choice beween two images, one representing the object meaning and the other the action meaning of the homophone or nonce word.

The participants in the comprehension task of the V&P study

Ninety children participated in the V&P comprehension study, 30 in each of three age groups: 2, 3 and 4 years old. All children came from monolingual, French-speaking, middleclass homes and were interviewed in a quiet room of either the daycare center (for the 2-yearolds), or the public kindergarten (for the 3-and 4-year-olds) that the children attended in Paris. All the children were described as typically-developing by their professional caretakers or teachers. The parents of the participants gave their consent to their child's participation by signing an authorization form.

slice], all the French words used in the V&P comprehension task were present in the CDS samples analyzed, some occurring with greater frequency than others. Homophones were used similarly as nouns and verbs, with the exception of marche for which the verb ('walk') occurred more frequently than the noun ('step' in a stairway).

2 In French /lə/, /la/ and /le/ may be definite articles, respectively, masc. sing (le), fem sing (la)., and plural (les), or object clitics that occur before the verb. In the context of the V&P task, however, the interpretation of /lə/ and /la/ as preposed object clitics is not plausible for the structure presented --le X ---e.g., le /pus/ --where le as a preposed object clitic pronoun would imply an ungrammatical subjectless structure (*__le pousse '__it -masc sing -push(es). Such a structure is unlikely to be heard by the children: no such structure was found in several samples of CDS addressed to children of the same age range as that of the participants. Moreover, in many items, the clitic, if considered as a preposed object pronoun, would not be appropriate to refer to the object of the action pictured (e.g. le /pus/ would be inappropriate to refer to the table being pushed by a boy as it should have been la /pus/. In addition, in the V&P study, there was no statistically significant difference in the number of identification errors when the word in the la/le+word structure was a homophone whose interpretation was a transitive vs an intransitive verb. 3 The percentage of 2-year-olds successfully identifying the required numbers of items was 17% for nonce words and 23% for meaningful words, a difference that is not statistically significant (tested by a 2x2 contingency table: χ2 (1, N = 60) = 0.104, p = 0.747, ns.)

The material of the comprehension task in the V&P study

The children were presented with 15 items, 12 containing homophonous words and three nonce words (the entire list is given in Table 1 by type of word and alphabetical order within each type)5 . The meanings of the words presented in the noun and verb contexts were represented by pairs of pictures shown on a computer screen. For the homophones, one picture represented the word's object meaning and the other its action meaning, performed by a person. For nonce words, one picture represented an unfamiliar object that did not have a specific name in adult language, and the other represented a person performing an action that could not be described in French by a single existing verb (see Figure 1, which is a snapshot of the screen presented for a). a homophonous word; b) a nonce word). The children were asked to point to the picture corresponding to what they heard (see the procedure below).

--SeeTable 1 and Figure 1 at the end of the paper -Four lists of the same 15 items were compiled. Taken together, the lists were constructed in such a way as to control for the order in which the items were presented, for the noun or verb context for each homophonous or nonce word, and for the position on the screen of the picture corresponding to the requested item (on the right or on the left of the screen). In each age group, over all the participants, the four lists were presented the same number of times.

The procedure of the comprehension task in the V&P study

During the administration of the task, the children were seated beside the Experimenter and in front of a computer screen. With each item, the corresponding two pictures -an object and an action --simultaneously appeared side by side on the screen (see Figure 1). For each item, children were asked either: montre-moi 'show me': [definite article] X or [third person clitic pronoun] X, where X was either a homophonous or a nonce word both sounding the same in the two contexts (see table 1). For example, for the homophonous word /li/, the item presented was either montre-moi: le lit 'show me: the bed' or montre-moi: elle lit 'show me: she reads'. The pictures appearing on the screen were the same for both the noun and the verb context of the word.

The test items were preceded by four training items. The first two presented a single picture and were meant to ensure that the children knew how to point to pictures on the screen. The next two items presented, like the test items, two pictures simultaneously -first two objects, and then an object and an action performed by a person. These items were intended to ensure that the children understood the instruction and could point to one of the two pictures depending on what they heard. The testing phase began immediately after with the presentation of the 15 test items, one after the other, and for each item the experimenter asked the child to show either 'the X' or 's/he X' (see the example provided above), which the children did by pointing to the picture they thought corresponded.

All the sessions were videorecorded. The pointing responses of the children were coded during the experiment and were double-checked later from the video recordings.

The criteria of success for the comprehension task in the V&P and in the present study

Items were considered to be correctly identified when children pointed to the picture of an object for items presented in noun contexts, and to the picture of an action for items presented in verb contexts. An individual child was considered to have successfully completed the comprehension task beyond chance level when s/he correctly identified at least 12 out of the 15 items proposed6 . In the V&P study, this criterion was reached by 30% of the 2-yearolds, 33% of the 3-year-olds and 67% of the 4-year-olds, with statistically significant differences between the older group and the two younger onss. For meaningful homophones, the minimum number of items that children needed to correctly identify was 10 out of the 12 presented7 .

In the present study, we considered that a child had successfully completed the comprehension task when all the following criteria were met: 1. Success in at least 12/15 of the total number of items; 2. Success in at least 10/12 of the meaningful homophone items; and 3. Success in at least 2/3 of the nonce word items. Although this number of nonce items does not reach the .05 probability level set to guarantee success beyond chance level8 , this requirement prevents success to be granted on the exclusive basis of the successful identification of homophones and, together with the other two criteria, provides additional evidence that it is the grammatical context that determines the child's interpretation.

Production of grammatical morphemes 2.2.1. Acquisition in French-acquiring children

Children start by producing grammatical morphemes sporadically and only later on produce them systematically where they are expected (for French, e.g., [START_REF] Bassano | Acquisition du langage et grammaticalisation : le développement pour les noms et les verbes en français[END_REF] for Spanish, e.g., López-Ornat, 1997; for Italian, e.g., [START_REF] Pizzuto | The acquisition of Italian morphology: implications for models of language development[END_REF] for crosslinguistic studies see for example, [START_REF] Dressler | Studies in Pre-and Protomorphology[END_REF]. Following the early studies by Brown and collaborators (e.g., Brown, 1973;[START_REF] Cazden | The acquisition of noun and verb inflections[END_REF], it is customary to consider that a grammatical morpheme is acquired when it is appropriately produced in at least 90% of the contexts where its presence is required.

For French, articles are considered acquired when children produce them in at least 90% of the required prenominal positions and use the forms appropriately, conforming to the requirements of gender, number and definiteness --that is, le /lə/ (masc. sing. def), la /la/ (fem., sing., def), les /le/ (fem/masc, pl, def), un /oe ̃/ (masc, sing, indef), une /yn/ (fem, sing, indef), des /de/ (masc/fem, pl, indef)9 . Subject pronouns are considered to be mastered when they are produced in preverbal contexts appropriately and in at least 90% of the cases where they are required, either in the immediately adjacent position for simple verb forms (as in il part 'he leaves') or before an auxiliary or modal verb in compound verb forms (as in il a couru 'he has run' or elle veut dormir 'she wants to sleep') 10 .

For determiners, some data suggest that the 90% criterion is attained between 2;5 and 3;3, the latter age being when all the children in a cross-sectional study attained the criterion [START_REF] Bassano | Acquisition du langage et grammaticalisation : le développement pour les noms et les verbes en français[END_REF][START_REF] Bassano | Noun grammaticalization and determiner use in French children's speech: A gradual development with prosodic and lexical influences[END_REF]. For the production of subjects, the few studies that have specifically looked at this aspect for the entire child's production suggest that the age range is higher. At 2;9, the criterion was not attained in the longitudinal study of one child [START_REF] Bassano | Acquisition du langage et grammaticalisation : le développement pour les noms et les verbes en français[END_REF]. In the longitudinal study of 4 children, none of them showed that accomplishment by the end of the studies (between 2;0 and 2;7) [START_REF] Veneziano | Early verb constructions in French: Adjacency on the left edge[END_REF], and in a study of 3 children analyzed longitudinally until 2;7, only one child had attained the 90% criterion for subjects (Salazar Orvig, Marcos, & Maranhao Castro, 2021).

Development before the attainment of the acquisition criterion

Is it possible to evaluate the production of elements occurring in prenominal and preverbal contexts before children attain this high level of mastery?

In their second year of life, children start using syllabic, mostly vocalic, underdetermined elements -referred to in the literature as fillers -in prenominal and preverbal positions (e.g., [START_REF] Kilani-Schoch | Are fillers as precursors of morphemes relevant for morphological theory[END_REF][START_REF] Lléo | Filler syllables, proto-articles and early prosodic constraints in Spanish and German[END_REF][START_REF] Pepinsky | The status of 'filler syllables' in children's early speech[END_REF][START_REF] Veneziano | The emergence of noun and verb categories in the acquisition of French[END_REF][START_REF] Veneziano | Noun and Verb categories in acquisition: Evidence from fillers and inflectional morphology in French-acquiring children[END_REF][START_REF] Veneziano | The changing status of 'filler syllables' on the way to grammatical morphemes[END_REF]. While most studies consider fillers a single transitional phenomenon towards full-fledged grammatical morphemes, others show that fillers themselves undergo a progression, during which their meaning and function for the child develops (e.g. [START_REF] Kilani-Schoch | Are fillers as precursors of morphemes relevant for morphological theory[END_REF][START_REF] Peters | Language typology, prosody and the acquisition of grammatical morphemes[END_REF][START_REF] Peters | False starts and filler-syllables: Ways to learn grammatical morphemes[END_REF][START_REF] Veneziano | A System-Approach to the Analysis of "Fillers" at the Transition to Grammar[END_REF][START_REF] Veneziano | Noun and Verb categories in acquisition: Evidence from fillers and inflectional morphology in French-acquiring children[END_REF][START_REF] Veneziano | The changing status of 'filler syllables' on the way to grammatical morphemes[END_REF]. Concerning the early acquisition of French, previous studies have shown that it is possible to distinguish three periods in the production of fillers, all occurring before articles and subject clitic pronouns attain the Brown's acquisition criterion mentioned above [START_REF] Veneziano | Noun and Verb categories in acquisition: Evidence from fillers and inflectional morphology in French-acquiring children[END_REF][START_REF] Veneziano | The changing status of 'filler syllables' on the way to grammatical morphemes[END_REF]. The three periods of filler production for French-acquiring children were described as follows11 :

1. Premorphological period, in which fillers are phonologically underdetermined (essentially /ə/, /e/ and /a/ sounds) and occur in the immediately adjacent prenominal and preverbal positions. At this time, there is no significant difference between the fillers produced in the two positions, either in terms of the percentage of positions presenting a filler, or in terms of the types of elements produced in the two positions. Children appear to follow the dominant phonoprosodic characteristics of the language -in French, an iambic pattern constituted by a first unstressed syllable followed by an accented one of the consonant-vowel type (e.g., [START_REF] Demuth | A prosodic approach to filler syllables[END_REF][START_REF] Demuth | Prosodic constraints on children's use of grammatical morphemes[END_REF][START_REF] Kilani-Schoch | Are fillers as precursors of morphemes relevant for morphological theory[END_REF][START_REF] Pepinsky | The status of 'filler syllables' in children's early speech[END_REF][START_REF] Veneziano | Noun and Verb categories in acquisition: Evidence from fillers and inflectional morphology in French-acquiring children[END_REF][START_REF] Veneziano | The changing status of 'filler syllables' on the way to grammatical morphemes[END_REF][START_REF] Vihman | Is there a "Trochaic Bias" in early word learning? Evidence from infant production in English and French[END_REF]) -as well as the dominant distributional co-occurrences present in the input [START_REF] Taelman | Fillers as signs of distributional learning[END_REF][START_REF] Veneziano | The changing status of 'filler syllables' on the way to grammatical morphemes[END_REF].

2. Protomorphological period, in which both fillers and phonologically well-formed grammatical morphemes (henceforth WFGM) are produced. There is now a significant difference between the elements produced in prenominal and in preverbal positions: For example, /i/ is produced only in preverbal position and /o/ mainly in that position, while /ɛ / and /yn/ are produced only in the prenominal one (e.g., [START_REF] Veneziano | Noun and Verb categories in acquisition: Evidence from fillers and inflectional morphology in French-acquiring children[END_REF]; 3. Quasi-morphological period: This period is characterized by the predominance of WFGM over fillers. While the elements of this period are produced differentially before nouns and verbs, specific grammatical morphemes -in particular, articles and subject clitic pronouns -do not yet reach Brown's acquisition criterion of required presence (90% of obligatory contexts) and their use is not yet completely appropriate (i.e., they present errors of commission).

Method for the evaluation of the early production of French grammatical morphemes used in this study

In the present study, the development described above provided the basis for the evaluation of the spontaneous production of elements in prenominal and preverbal positions by children. We distinguished four levels (from low to high) in the production of these elements, each level being characterized by a number of features, as specified below: Level 1a. Fillers are the most frequently produced elements in prenominal and preverbal positions; b. There is no significant difference between the elements produced in the two positions; Level 2a. Both fillers and phonologically well-formed articles and subject clitic pronouns are produced; b. The types of elements produced in prenominal and in preverbal positions are significantly different; c. The elements occurring in preverbal subject position are only found in the immediate preverbal position of simple forms, such as the indicative present form, and not in the subject position of complex forms (Veneziano andClark, 2016, 2021); Level 3a. Phonologically well-formed articles and subject clitic pronouns12 are more frequent than fillers; b. The types of elements produced in prenominal and in preverbal positions are significantly different; c. There is some variety in the articles and subject clitic pronouns produced in the prenominal and in preverbal positions, respectively; d. The elements occurring in preverbal subject position are also found in larger constructions containing past participles preceded by an auxiliary verb (e.g., on a donné 'we have given') and/or infinitives preceded by a modal verb (e.g., il veut boire 'he wants to drink'). e. Neither articles nor subject clitic pronouns attain the criterial level of 90% of production in required contexts. Level 4 -To credit a child with this level, the child's production needs to show features a, b, c and d of level 3 above, as well as e. the appropriate presence of the target elements in 90% of contexts that require them.

Participants in the present study and analysis of the data

Before starting the comprehension task, each child in the 2-year-old group conversed with the experimenter about daycare and home activities, and exchanged about a picture book. This period of familiarization helped these young children to be more at ease during the comprehension task and allowed us at the same time to collect a sample of spontaneous speech from them. For this first study, from the sample of thirty 2-year-olds who participated in the V&P comprehension task««, we took the first two sets of five children that could be included in each of the following two groups: 1. Group Success (Group S) constituted by five children who succeeded in the comprehension task. These children reached the criterion described earlier for overall items (at least 12/15 correctly identified items), for meaningful homophones (at least 10/12 correctly identified items); and for nonce words (at least 2/3 items correctly identified). The age range of this group was 2;3 -2;9 (age expressed in years;months), the mean age 2;7, and the SD 2 months and 6 days; 2. Group No Success (Group NoS) included five children who did not successfully complete the task. These children did not attain the criterion of success on the items: They correctly identified fewer than 12/15 total items, fewer than 10/12 homophone items and fewer than 2/3 nonce items. The age range of this group was 2;3 -2;10, the mean age 2;6, and the SD 2 months and 6 days. The children in the two groups were presented with the same number of nominal and verbal contexts.

The spontaneous speech of the ten children --transcribed in CHAT format and linked to the videorecordings -was analyzed for the elements present in the prenominal and preverbal positions where respectively determiners and subjects are required. These positions were coded for the presence/absence of elements, and elements were then coded as being fillers or WFGM, as well as for appropriateness to the specific context. We also coded for types of verb forms (mostly indicative present, infinitive and past participle) and listed all the different types of determiners and subjects produced.

RESULTS

Relation between comprehension and production in the Group S

Table 2 presents the relevant data for Group S: from left to right, the sex and age of each child, the number of total and meaningful items successfully identified, and the production score obtained for articles and for subjects, and in parentheses the number of nouns or verbs on which the production level was based. As the table shows, four out of the five children in this group had a production score at level 4 (the maximum obtainable here) for both articles and subject clitic pronouns, the two grammatical morphemes used contrastively in the comprehension task. The fifth child, the youngest in this group (2;3), reached level 3: his production shared all features with the other children with the exception of the criterion of 90% of presence in contexts where the morphemes were required. Thus, on the whole, the spontaneous speech of children who successfully completed the comprehension task shows a level of mastery of at least the same level as that suggested by the children's performance in the comprehension task. Indeed, level 3 differs from level 4 only on the attainment of Brown's acquisition criterion. However, the proficiency level tested by the comprehension task shows an understanding of the function of nominal and verbal grammatical morphemes, not the obligatoriness of their presence. Thus production level 3 should be considered to show a similar level of proficiency as that manifested by successful completion of the V&P comprehension task.

Details on the spontaneous production of grammatical morphemes in the Group S

Level 4 of grammatical morphemes in spontaneous speech production can be exemplified by the profile of participant 1, which is representative of the profiles of the other three participants who obtained the same score.

For articles, all the elements were WFGM (criterion a); consequently, the elements occurring in prenominal position were different from those occurring in preverbal position (criterion b); the child produced a variety of article types: both definite and indefinite articles, masculine and feminine, as well as singular and plural forms (criterion c). In the relatively small sample of speech there was a large variety of articles such as la, le, les (the); des (some); un (a), and articles were produced in 100% of the contexts where they were required (criterion e of level 4). Concerning subject clitic pronouns, 88% were WFGM (including acceptable /i/ for /il/ (he) (criterion a); the child produced a variety of subject clitic pronouns as well as a subject NP (criterion c): je (I), il (he),, elle (she); subjects occurred before indicative present V-forms but also in a larger construction with an auxiliary between the subject and a past participle (j'ai fait 'I have made') (criterion d); and subjects were produced in 94% of the contexts where they were required (criterion e for level 4). The four children in group S who show this profile might even have, in production, compared to comprehension, a better understanding of how the grammatical morphemes tested in the V&P comprehension task work in their language. To clarify this point a comprehension task testing obligatoriness of use should also be devised and administered to 2-year-old children.

Relation between comprehension and production in the Group NoS

Table 3 presents the same kind of data as Table 2 for the children in Group NoS. As the table shows, in contrast to the children in Group S, none of the five children in this group reached level 4 in the spontaneous production of articles and subject pronouns and only one child reached level 3 for both grammatical morphemes. For articles, two more children scored at level 3; one child reached level 2 (predominance of fillers; differentiation in types between prenominal and preverbal positions) and one child scored at level 1 (the elements produced in the preverbal and prenominal positions were not significantly different from each other). For subject pronouns, in addition to the child who scored at level 3 for both articles and subjects, three children scored at level 2 and one child at level 1.

Table 3 -Sex and age (in years;months) of the children in Group NoS and results obtained on the comprehension task and on the spontaneous production (number of nouns and verbs in parentheses)

Comments on the results of spontaneous production

The results on the production of articles and subject pronouns are in line with those reported in the literature for French, where articles are reported to be acquired between 2;5 and 3;3 and subject pronouns from 2;7 and later. The analysis of the ten children studied here shows that levels 3 or 4 were attained for articles by children aged 2;3 to 2;10 and for subject clitic pronouns by children aged 2;3 to 2;9, within the range of the earlier studies. Moreover, here also the acquisition of articles seems to occur before that of subjects: eight of the ten children attained level 3 or 4 for articles but only 6 children did so for subjects.

Comparison between children in Groups S and NoS on the level of production of grammatical morphemes in their spontaneous speech

The level of production of articles and subject clitic pronouns of the children in Group S was significantly higher than that of the children in Group NoS. The mean level of Group S was 3.8 (SD = 0.447) and that of Group NoS was 2.4 (SD = 0.894). A t-test showed that the difference between the two groups is statistically significant (t = 3.13, p< 0.01, df =8, onetailed). This result indicates that children who show to have a good comprehension of grammatical morphemes also have a high score of production and, reciprocally, those who do not provide evidence of compehending the grammatical function of these morphemes also have a lower level of production in spontaneous speech.

SUMMARY AND DISCUSSION

The aim of this study was to provide some data on the relation between the comprehension and production of grammatical morphemes such as articles and subject clitic pronouns in French-acquiring children. To this end, we constituted two groups of 2-year-olds who had either successfully completed (group S) or not (Group NoS) the comprehension task in the V&P study and analyzed in detail the same grammatical morphemes as they occurred in the same children's spontaneous speech.

For comprehension, the children's correct choice in a sufficient number of items (statistically beyond chance level) revealed their ability to interpret the nominal and verbal grammatical contexts contrastively and was considered clear evidence of the children's understanding of the nominal and verbal grammatical morphemes involved.

The spontaneous production of these same grammatical morphemes was analyzed for the children in the groups S and NoS using a coding system specifically devised for this study. This scoring system, based on previous work on the development of fillers, allowed assessment on four levels: level 3 presents enough features to consider that the grammatical morphemes focused on here are used as appropriately and contrastively as in comprehension, while level 4, the highest level of the system, shows in addition the attainment of Brown's acquisition criterion (appropriate production of the grammatical morpheme in at least 90% of the positions where it is required). Results of the analysis of the production of the ten children showed that six of them attained level 3 or 4 for both articles and subject clitic pronouns, two children attained level 3 only for articles and had lower scores for subject pronouns, while the remaining two children scored at levels 1 or 2 for both.

The distribution of the children over these production scores is related to their results on the comprehension task: All the 5 children in group S showed proficiency in the production of the targeted grammatical morphemes: Four attained the highest score of 4 and one level 3 on both articles and subject pronouns , with the fifth child of thie group attaining level 3 on both grammatical morphemes In contrast, none of the children in Group NoS attained the highest level of production, whether for articles or for subject pronouns, and only one attained level 3 on the two morphemes. For the other four children in this group, two attained level 3 but only for articles, while the other scores were at levels 1 or 2. Consequently, the level of production attained by the children in Group NoS was significantly lower than that attained by the children in Group S.

The relation between comprehension and production

What do these results tell us about the relation between comprehension and production? Does comprehension precede production? Given that all the children in Group S have a production score of level 3 or 4, our results do not provide clear evidence that comprehension precedes production; rather, they suggest that good comprehension and good production of grammatical morphemes go hand in hand. It should however be noted that these results offer only a snapshot of the children's abilities at a particular time. Consequently, we do not know whether the children in Group S would have successfully completed the comprehension task before their production scored at level 3 or 4, a possibility that cannot be totally excluded.

Is there evidence that production precedes comprehension?

The results of the children in Group NoS present a mixed picture: As for the two children whose production scored at levels 1 or 2 for both articles and subject clitic pronouns, results indicate that production is not ahead of comprehension but, as for the children in group S, that comprehension and production correspond, here at a low level of understanding. For the child whose production scored at level 3 for both articles and subject pronouns, production appears to be ahead of comprehension. Concerning the two children whose production scored at level 3 for articles but scored at lower levels for subject pronouns, it might appear that the production of articles is ahead of comprehension. However, the comprehension task involves contrastive understanding of the two kinds of grammatical morphemes, something that is not involved in the appropriate and diversified use of articles only, so that, in these cases, the priority of production over comprehension cannot be established. These intermediate cases are nevertheless interesting in that they reveal some issues about how the two modes of functioning are assessed as well as the importance of the joint analysis of production and comprehension for a more comprehensive understanding of the way acquisition proceeds, points that will be taken up again below.

For Group S, it might be supposed that the production of the four children whose score was at level 4 for both articles and subject clitic pronouns shows a higher level of proficiency in production then what was revealed by the successful completion of the comprehension task. It should be noted, however, that the V&P comprehension task does not provide information about this feature and thus it could be the case that, if tested appropriately, these children would have manifested understanding of that requirement as well. Thus, although it might seem that production shows a higher level of mastery than that manifested in comprehension, further investigation is needed to clarify whether production precedes comprehension for this particular issue.

Thus, on the whole, the results of the two groups indicate that comprehension and production are closely related: For nine of the ten children studied here, a high level of comprehension corresponded to appropriate and diversified production of grammatical morphemes, while a low level of comprehension corresponded to a low level of production in at least one of the two grammatical morphemes under study.

One of the participants (Participant 10 in Group NoS) does not fit this overall trend. This child, whose production is at level 3 for both articles and subject clitic pronouns, seems to provide a counterexample to the general hypothesis that production is not ahead of comprehension, as he appears to have a higher level of performance in production than in comprehension. Two other participants in Group NoS might appear to be more advanced in production than in comprehension, but only for the production of articles, showing a level 3 of appropriateness and diversification for these morphemes.

Although these cases call for further research, it should be noted that, in the present study, production and comprehension were not evaluated with the same degree of detail. While it was possible to assess children's production of grammatical morphemes in a relatively fine-grained way, this was not possible for comprehension. The comprehension task could be scored only dichotomously as pass or fail. This is because, below the criterial number of items, success by chance alone could not be excluded. Thus, either children showed high level understanding of the grammatical function of both morphemes, or they could not be considered to have that understanding. Consequently, it was not possible to determine whether the children who did not reach the criterial number of items might have nevertheless used the immediately preceding syntactic context to attribute object or action meaning to the homophonous or nonce words, without yet having sufficient mastery to generalize their knowledge to the criterial number of items. In the case of Participant 10, however, this seems unlikely as this child correctly identified the lowest number of overall and of meaningful homophonous items in Group NoS (7 and 5, respectively) : his case seems a genuine counterexample that future research on a larger sample can clarify.

The joint study of production and comprehension in early language acquisition

The study presented here highlights the interest of analyzing both production and comprehension, not only to better assess the overall level of acquisition of the language aspects focused on, but also to gain further insights into the acquisition process. Cases such as that of Participant 10, and to a lesser degree Participants 7 and 9, discussed above, reveal the limitations of taking into account only the results of one mode of functioning. On the basis of comprehension alone, these children, having failed the task, were considered to have no understanding of the grammatical morphemes involved. Instead, on the basis of production alone, Participant 10 would have been credited with knowledge of the appropriate and diversified use of both articles and subject clitic pronouns, and the other two participants of having acquired articles and noun phrase structure. Taking into account both comprehension and production results calls instead for a more nuanced approach to these children's knowledge and for further investigatiobn. For example, it would be necessary to check whether other kinds of comprehension tasks would result in better performance, or whether the children's appropriate production reflects a genuine understanding rather than knowledge about surface regularities or heavy dependence on conversational support. In any case, assessment based on only one modality will be interpreted differently in the light of the results obtained on the other while further insights into how these children might go about acquiring the grammatical morphemes under study could be gained.

Another issue for which the analysis of both production and comprehension in the same children would provide interesting data is that of the degree of coincidence between the two modes of functioning. This is assumed to be lower in the language-acquiring child than in the expert language user. In the present study, production and comprehension appear for the most part to be close to each other at both the high and the low end of proficiency. Although these initial results need to be confirmed in a larger study, they nonetheless suggest that even in the early periods of language acquisition there seems to be more coincidence between the two modalities than might have been expected.

Issues for future research

As already mentioned, in the present study production could be assessed in greater detail than comprehension. Indeed, in order to guarantee that a child's correct responses were not due to chance, performance on the comprehension task could only be scored as pass or fail. Future research should find ways to provide a more nuanced evaluation of children's performance in the comprehension task. One possibility could be to increase the number of items, and/or the number of pictures to choose from (while keeping the task still manageable for young children), thus allowing the attribution of different scores according to the number and type of items correctly identified beyond the minimum number required. To make performance on comprehension and production more comparable, it would also be useful to introduce items that could check whether the children understand that the presence of grammatical morphemes is necessary within the nominal and verbal phrases.

Moreover, to precisely address the issue of the priority of one mode of functioning compared to the other, longitudinal data would be helpful. At the moment, we know of only one case study in which comprehension and production data on the acquisition of French grammatical morphemes are reported longitudinally [START_REF] Veneziano | Noun and Verb categories in acquisition: Evidence from fillers and inflectional morphology in French-acquiring children[END_REF][START_REF] Veneziano | Retrieving the meaning of words from noun and verb grammatical contexts: Interindividual variation in a comprehension study of 2-to 4-yearold French-acquiring children[END_REF]. The study concerned one French-acquiring child who was presented on a monthly basis with the V&P comprehension task at the child's home while the naturally-occurring spontaneous interactions between the child and familiar partners were recorded in hourly sessions. The results of that study showed that the child successfully completed the comprehension task for the first time four months after she attained level 2 in production and two months after the number of WFGM was greater than that of fillers. However, since the coding system for the analysis of the production of grammatical morphemes was not the same as that devised for this study, her level of production for articles and subject clitic pronouns should be reassessed to find out whether level 3 for both articles and subjects was attained before or after the successful completion of the comprehension task. This longitudinal approach would better allow to determine the developmental relation between the two modalities, although it would not be exempt from problems either, such as the increasing familiarity with the task items with their successive presentations.

As a final note, it should be pointed out that the results reported here concern the acquisition of French and thus they cannot be generalized cross-linguistically. Languages vary considerably in how they distinguish noun from verb contexts, in particular in relation to the degree to which they rely on nominal and verbal morphology, on the presence of nominal determiners, the obligatory or non-obligatory requirement of subjects (i.e., whether a language is pro-drop or not, e.g., [START_REF] Rizzi | Issues in Italian Syntax[END_REF], the use of serial verb constructions or whether a language is agglutinative or not. As a function of such language-specific features, children encounter different configurations that may lead them to pay attention to different cues that impact differently on how they go about learning grammatical morphology and the distinction between nouns and verbs. The complexity of verb morphology in Hebrew makes its acquisition a particularly interesting case in point (e.g., [START_REF] Ashkenazi | Breaking into the Hebrew verb system: a learning problem[END_REF]. Even if the present study only concerns the acquisition of French, it can nonetheless provide insights for language acquisition in general. The acquisition of category-specific grammatical morphemes and of the related noun-verb distinction is a process that spans over time and this likely applies to most languages as well as to both production and comprehension. Moreover, since production and comprehension data alone are likely to over-or under-estimate children's knowledge of the relevant features (e.g. [START_REF] Clark | Comprehension, Production, and Language Acquisition[END_REF], future studies of early language acquisition should integrate information from both modalities as a standard method of analysis in order to better evaluate what children have acquired and still need to acquire, as well as to understand how they have acquired it. b) Choice for nonce word /ʃim/: on the left, the correct choice when presented in noun frame (la chime) ; on the right , the correct choicewhen presented in verb frame (elle chime)

Figure 1 :

 1 Figure 1: Examples of screen displays (snapshots) for the items presented to the children

Table 2 -

 2 Sex and age (in years;months) of the children in Group S and results obtained on the comprehension task and on the spontaneous production (number of nouns and verbs in parentheses)

Table 1 :

 1 The 15 items used in the study, divided into homophonous and nonce words, and listed in alphabetical order within each category

	Homo		Nou	Pho	Eng	Ver	Pho	Engl
	phones	n context	netics	lish meaning	b context	netics	ish meaning
					homophonous words
	/bw		le	/lə	the	elle	/ɛl	she
	a/	bois		bwa/	wood	boit	bwa/	drinks
					(pieces of)
	/ku		la	/la	the	il	/il	he
	ʁ/	cour		kuʁ/	courtyard	court	kuʁ/	runs
	/fɛʁ		la	/la	the	elle	/ ɛl	she
	m/	ferme		fɛʁm/	farm	ferme	fɛʁm/	closes
	/ʒu/		la	/la	the	ils	/il	they
		joue		ʒu/	cheek	jouent	ʒu/	play
	/li/		le lit	/lə	the	elle	/ɛl	she
				li/	bed	lit	li/	reads
	/ma		les	/le	the	ils	/il	they
	ʁʃ/	marches	maʁʃ/	steps	marchent	maʁʃ/	walk
	/mɔt	la	/la	the	elle	/ɛl	she
	ʁ/	montre		mɔ̃tʁ/	watch	montre	mɔ̃tʁ/	shows
	/pɔ		la	/la	the	il	/il	he
	ʁt/	porte		pɔʁt/	door	porte	pɔʁt/	carries
	/pu		le	/lə	the	il	/il	he
	s/	pouce		pus/	thumb	pousse	pus/	pushes
	/ʁi/		le	/lə	the	elle	/ɛl	she
		riz		ʁi/	rice	rit	ʁi/	laughs
	/tεlε		le	/lə	the	il	/il	he
	fɔn/	téléphone	telefɔn/	telephone	téléphone	telefɔn/	telephones
	/tʁɑʃ	la	/la	the	elle	/ɛl	she
	/	tranche		tʁɑ̃ʃ/	slice	tranche	tʁɑ̃ʃ/	slices
					Nonce words
	/ʃim		la	/la		elle	/ɛl
	/	chime		ʃim/		chime	ʃim/
	/da		le	/lə		elle	/ɛl
	v/	dave		dav/		dave	dav/
	/gɔt		la	/la		elle	/ɛl
	/	gotte		gɔt/		gotte	gɔt/

The same lexical item was however not presented in the two grammatical contexts to the same child as that would have involved in addition the capacity for categorial flexibility.

A pilot study indicated that 15 was the total number of items that the children could reasonably attend to. The proportion of nonce words (20%) seemed appropriate so as not to compromise the naturalness of the experimental setting aimed at by the use of homophonous words.

The probability of correctly identifying 12 out of 15 items by chance is .011, with p = q = 0.5.

The probability of correctly identifying 10 out of 12 items by chance is 0.019, with p = q = 0.5.

The probability of correctly identifying all the three items by chance is 0.112, which is greater than the a level set at 0.05. In the Veneziano & Parisse study, all the three items were correctly identified by 17%, 37% and 57% respectively of the 2-, 3-and 4-year-olds.

There are also the partitive articles du (masc, sing), de la (fem, sing), used to refer to an unspecified quantity of food, liquid, or other uncountable matter.

The subject and the main verb may be separated by more than one element as, for example, when an object pronoun occurs in preposed position: je l'ai pris 'I it have taken ->I have taken it'.

The terms were also used byDressler and collaborators (e.g., Dressler, 1997) to describe periods in the overall development of children's grammar.

We included the phonologically close form /i/ for /il/ 'he' found in certain variants of everyday French, one of which is heard by the participants in the study.


PhD Lou-Lyne Leconte
email: lou-lyne.leconte@univ-reims.fr

Tatiana Reyes

"Understanding of consumers' behaviours towards ecodesigned products and services" 1

Keywords: sustainable development, strong sustainability, consumer's behaviour, ecodesign, qualitative methodology

This document provides an overview of a thesis aiming to understand consumers' behaviours towards ecodesigned products and services. After relevance and contribution of the thesis are discussed, a short literature review is performed. Contributions of scientific community about notions of consumer, sustainable development, strong sustainability and ecodesign as well as their interrelationships are exposed to better understand consumer's implications in sustainable development and ecodesign approaches. Then, the qualitative methodology followed in the early stages of the thesis, consisting in group meetings for an exploratory study; as well as the methodology planned for experts' interviews, participatory observation and individual and group interviews are addressed. Finally, a model details expected empirical results of the research.

Introduction

The proposed research is part of an interdisciplinary project carried out by three universities and funded by the National Agency of Research in France. This project, named Design technology for strong sustainability, or D-TechnoSS, aims to develop a new methodology of Design for Sustainability integrating human aspects, meaning consumers' behaviours. Thus, both engineering sciences and social sciences will be considered, each discipline giving rise to a thesis. D-TechnoSS falls in a strong sustainability paradigm, considering that planetary boundaries should not be exceeded [START_REF] Rockström | A safe operating space for humanity[END_REF], and that financial or technological capital cannot substitute natural capital [START_REF] Boutaud | L'empreinte écologique[END_REF]. As all the project members are French institutions, France will be the main studied area, but a comparative study implying a study in another country is not excluded.

The thesis in social sciences aspires to better understand consumers' behaviours, particularly to avoid possible rebound effects resulting from a misuse or excessive use of an ecodesigned product or service. Indeed, an innovation supposed to reduce energy or raw material consumption (and therefore environmental impact), can, by being used massively, increase production (and therefore environmental impact) [START_REF] Prieto | Idées reçues sur l'économie collaborative[END_REF]. Collaborative design or co-construction approaches with users could help prevent rebound effects, however, these methods remain marginal in ecodesign processes. A framework providing keys to better understand consumers' behaviours could facilitate this involvement of the user in the design phase. This is the reason why a thesis is conducted with the following research question: What are the (un)conscious factors that govern consumers' behaviours towards ecodesigned products and services? Nevertheless, if adoption of ecodesign practices is not accompanied by stabilization or reduction of production or consumption, environmental benefits achieved will be insufficient and planetary boundaries set by [START_REF] Rockström | A safe operating space for humanity[END_REF] would end up being reached. As a result, to respect planetary boundaries implies to fall within a strong sustainability paradigm. This is why this paradigm was chosen to conduct this research.

The thesis proposal is detailed in five chapters. First, its relevance and contributions are shown before a short literature review highlights scientific and operational obstacles by discussing relationships between consumers, sustainability and ecodesign. Then, the used and planned qualitative methodology is presented. In a fourth chapter, expected empirical findings are set out through a model. Finally, some issues that could be discussed with experienced scholars of EURAM Doctoral Colloquium conclude this proposal.

1) Relevance and contribution of the thesis

As relevance and contribution are intrinsically related, this section will address both from societal, theoretical and practical perspectives. The place of the thesis in interdisciplinary research is also discussed.

On a societal dimension, it can be assessed that human activities have increasing impact on nature [START_REF] Crutzen | Geology of mankind[END_REF] and despite growing awareness [START_REF] Boutaud | L'empreinte écologique[END_REF] and international mobilization [START_REF] Boutaud | Les limites planétaires[END_REF], the world's ecological footprint still exceeds ecological capacities. This statement enlightens two key elements of this research. On the first hand, it underlines the need for paradigm change that cannot occur without a consciousness change, meaning individual change, which reveals the importance to understand conscious and unconscious factors that drive consumers' behaviours. On the other hand, it shows the relevance of considering a strong sustainability approach as it implies to respect nature's regenerative capacity.

Theoretically, the thesis aspires to provide a deep understanding of individuals' behaviours regarding sustainability, and particularly ecodesign. Traditionally associated with energy issues, rebound effects apply to a growing number of innovations. For example, they can be observed in emerging consumption practices like sharing economy [START_REF] Prieto | Idées reçues sur l'économie collaborative[END_REF]. As these consequences are relatively recent and not well understand, the thesis' results could considerably contribute to knowledge in this field of study.

This thesis also has practical implications. In the context of ecological crisis, some companies involve in actions to reduce their environmental impact; ecodesign is one of them but, as explain above, it has limits like rebound effects. By providing knowledge about consumers' behaviours and their drivers to ecodesigners, the thesis could improve behaviours integration in ecodesign approaches. Beyond companies, a deep understanding of individual behaviours can reveal general tendencies that could also be useful for policymakers.

Finally, the thesis will contribute to interdisciplinary research by bridging the gap between social sciences and engineering sciences through sustainability, and more precisely between management and design. Indeed, as thesis are nodal elements of D-TechnoSS project, close collaboration will take place between the two PhD students. From a methodological point of view, it is too early to talk about relevance and contribution as chosen methods are not yet definitive.

2) Key literature

In this chapter, a short literature review divided in three sections is performed. The first one explains the choice to consider strong sustainability rather than a more consensual concept like sustainable development. The second one deals more precisely with consumers and their expectations and behaviours related to sustainability. The last one makes the connection between consumers and ecodesign, particularly throughout the involvement of consumers in ecodesign approaches.

From sustainable development to strong sustainability

The urgent need for action regarding sustainability has been established by numerous actors and institutions both at the scientific and political level (cf. Intergovernmental Panel on Climate Change's special report, 2018 2 and World Commission on Environment and Development's Brundtland report, 1987 3 ) and gave rise to sustainable development. The most accepted definition of sustainable development is the one of the Brundtland report, first text to mention the term: "development that meets the needs of the present without compromising the ability of future generations to meet their own needs" (World Commission on Environment and Development, 1987). The concept lies on three pillars: environmental protection, social equity and economic prosperity [START_REF] Pallemaerts | La Constitution économique européenne et le « développement durable de l'Europe » (et de la planète) : Balises juridiques pour une économie de marché verte et sociale ?[END_REF]. Although sustainable development has become popularized since Earth Summit in Rio in 1992 [START_REF] Latouche | L'imposture du développement durable ou les habits neufs du développement[END_REF], as shown by a growing scientific literature, it is questioned, mostly because of its economic component. Indeed, numerous authors point out the incompatibility of continued economic growth and respect of 2 Intergovernmental Panel on Climate Change. ( 2018). Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty. https://www.ipcc.ch/sr15/ 3 World Commission on Environment and Development. (1987). Our common future.

planetary boundaries [START_REF] Latouche | L'imposture du développement durable ou les habits neufs du développement[END_REF][START_REF] Bourg | Introduction[END_REF]. In the French-speaking world, debates about the appropriate translation of the "sustainable" part of "sustainable development" are added to these critics, six words were thus alternately used as a translation [START_REF] Latouche | L'imposture du développement durable ou les habits neufs du développement[END_REF].

While many authors, as [START_REF] Minton | The subjective norms of sustainable consumption: A cross-cultural exploration[END_REF], consider "sustainability" as synonym of "sustainable development", the French terminological issue led some researchers to favour "sustainability" rather than "sustainable development".

For [START_REF] Latouche | L'imposture du développement durable ou les habits neufs du développement[END_REF], sustainability occurs when human activities respect the regeneration capacity of the biosphere. This idea echoes the ecological footprint accounting system which "endeavours to represent the quantity of ecosystem regenerative capacity which has to be mobilize to provide the econosphere with the resources it needs and assimilate the waste it produces" (translation from Boutaud & Gondran, 2018, p.42). Indeed, using data to calculate the supply and the demand of ecological services, the biocapacity of nature (supply) and the ecological footprint (demand) can be determined; if the latter exceed the former, humanity lives on credit; however, if the latter respect the former, it is a sustainable situation. The research works of [START_REF] Rockström | A safe operating space for humanity[END_REF] then Stephen and al. (2015) also assess human environmental impact thanks to several variables having each a limit; the respect of these limits defines what they call "a safe operating space for Humanity".

Two ways to interpret these limits correspond to two visions of sustainability: although weak sustainability assumes that different forms of capital (natural, financial or technological) are substitutable and thus that natural capital can be replaced by technological or financial capital when it is bequeath to future generations, strong sustainability postulates the nonsubstitutability of capital and the importance to respect the regenerative capacity of nature [START_REF] Boutaud | L'empreinte écologique[END_REF].

According to Boisvert, the notion of strong sustainability takes root in economics during the 90's and is so far wide and imprecise; it would apply to the thought of a wide range of authors with more or less pronounced radicality, because it would postulate a partial (and not absent) substitutability of capital (Boisvert, Carnoye & Petitimbert, 2019). The thesis will not fall into this last meaning assigned by Boisvert but will consider the strong sustainability implying nonsubstitutability as defined by [START_REF] Boutaud | L'empreinte écologique[END_REF].

For [START_REF] Slim | Consommer moins pour vivre mieux[END_REF], strong sustainability approach can be related to some extent to degrowth, nevertheless, they estimate that degrowth, in contrast to strong sustainability, is subject to a radicality that hinders its appropriation by political authorities.

Responsible consumers

Although consumers constitute a wide and imprecise range of individuals, their definition reach a relative consensus to the extent that it can "be used without contradiction by a multitude of agents positioning from a particular point of view non-exclusive from others points of view" (translation from Pinto, 1990, p.196). Indeed, if the term "consumers" refers to a range of individuals proceeding to an act of purchase, including all social, professional, demographic or geographic categories, it encompasses almost the entire population. To reconcile definitions set out by economic sciences and human and social sciences, [START_REF] Pinto | Le consommateur : Agent économique et acteur politique[END_REF] considers the consumer both as an economic agent and a social actor; he performs acts that can be studied in a range of consumption practices, while being an individual provided with socio-demographic characteristics likely to have consciousness and mobilize. In this way, consumer as a social actor, also called political consumer by [START_REF] Nyström | Le Boycott[END_REF], would hold a counterpower allowing himself to put companies under pressure and influence their practices.

Consumers' behaviours vary according to individual and contextual factors, including attitude towards ecological information: reactance, indifference and environmental concern lead to diverging behaviours (Jaoued-Abassi & Gonzalez, 2017). Several authors mention the high demand from consumers about the responsible nature of products (Pense-Lheritier, 2013) and their growing sensitivity to sustainable development [START_REF] Puaut | L'éco-conception : Une valeur ajoutée pour les entreprises et un enjeu futur de compétitivité ? Annales des Mines -Réalités industrielles[END_REF]. The attention being given by consumers to ecological and/or ethical character of products, services and companies no longer seems to demonstrate. However, [START_REF] Couveinhes | Éditorial. Annales des Mines -Realites industrielles[END_REF] and [START_REF] Lavorata | Influence of retailers' commitment to sustainable development on store image, consumer loyalty and consumer boycotts: Proposal for a model using the theory of planned behavior[END_REF], although recognizing the strong interest of consumers for environment, report the absence of sustainable development as a purchase criterion, which means its subordination to other criteria like cost, quality or location. This finding could seem paradoxical to the extent that it could be expected that a consumer having environmental considerations would be willing to pay more or to make concessions for a product or service corresponding to his values. The theory of cognitive dissonance [START_REF] Festinger | A theory of cognitive dissonance[END_REF] and neutralization theory [START_REF] Sykes | Techniques of Neutralization: A Theory of Delinquency[END_REF] contribute to explain this phenomenon of discrepancy between attitude and behaviour.

However, new consumption patterns that have developed in the past few years can associate responsible consumption and reduced cost. It is the case of sharing economy, defined as "all practices and economic models based on the networking of resources, aimed at exchanging and sharing goods, services […] and technical infrastructure between individuals and to limit intermediaries between producers and consumers" (translation from Prieto & Slim, 2018, p.9).

Individuals appeal more and more to renting, second-hand purchase or carpooling and lead citizen initiatives like wardrobe sales or Repair Café. The sharing economy thus allows a better use of material goods, an increase in the duration of use, a relocation of exchanges and a reduction of waste production [START_REF] Prieto | Idées reçues sur l'économie collaborative[END_REF].

When perception of ecological products by consumers is considered, it can be found that consumers estimate that an ecological product is environmentally friendly, natural and sustainable; furthermore, the readiness of consumers to protect the environment as well as health and quality encourage buying these products; conversely, high cost and mistrust of the product could discourage the act of purchase [START_REF] Dekhili | Le concept d'éco-produit : Quelles perceptions pour le consommateur ?[END_REF]. Thus, environmental issues seem to be more considerate than social and human issues by consumers regarding ecological products.

Ecodesign and consumers

Consequence of growing environmental concerns, ecodesign emerged in the 90's [START_REF] Boks | Transitions in sustainable product design research[END_REF] as a possible lever to integrate sustainable development in companies and particularly to reduce their environmental impact [START_REF] Berneman | Démystifier la mise en place de l'écoconception[END_REF][START_REF] Zwolinski | Conception intégrée de produits durables : De l'éco-conception aux nouveaux paradigmes de production et de consommation[END_REF]. [START_REF] Berneman | Démystifier la mise en place de l'écoconception[END_REF] define ecodesign as "a mode of product design that integrate environmental factors throughout its whole life cycle" (translation, p.76).

But, as it will be shown, scientific community did not agree on the meaning to be assigned to the concept. Ecodesign has multiple definitions varying on three aspects. First, although numerous authors see ecodesign as a wish to reduce environmental impacts [START_REF] Puaut | L'éco-conception : Une valeur ajoutée pour les entreprises et un enjeu futur de compétitivité ? Annales des Mines -Réalités industrielles[END_REF][START_REF] Ceschin | Evolution of design for sustainability: From product design to design for system innovations and transitions[END_REF], others see also an attempt to reduce social or human impacts [START_REF] Caillol | Analyse de cycle de vie et éco-conception : Les clés d'une chimie nouvelle[END_REF][START_REF] Rochambeau | Un exemple d'écoconception dans les filières agricoles, agroalimentaires et agro-industrielles : Le pôle de compétitivité « AgriMip Innovation » en région Midi-Pyrénées[END_REF]. To designate the consideration of social criteria, in addition to environmental criteria, the term "eco-socio-design" is sometimes used and Brodhag (2014) even incorporate economic and political considerations to ecodesign.

A second aspect of ecodesign which is debated concerns the scale on which the approach focuses on: most of the authors [START_REF] Caillol | Analyse de cycle de vie et éco-conception : Les clés d'une chimie nouvelle[END_REF][START_REF] Ceschin | Evolution of design for sustainability: From product design to design for system innovations and transitions[END_REF] assign the ecodesign process to a product, whereas others expand it to a product-service system [START_REF] Brodhag | L'écoconception, un outil au coeur de l'économie circulaire[END_REF][START_REF] Zwolinski | Conception intégrée de produits durables : De l'éco-conception aux nouveaux paradigmes de production et de consommation[END_REF] or apply it to the scale of a sector [START_REF] Rochambeau | Un exemple d'écoconception dans les filières agricoles, agroalimentaires et agro-industrielles : Le pôle de compétitivité « AgriMip Innovation » en région Midi-Pyrénées[END_REF][START_REF] Bertoluci | Eco-concevoir pour l'industrie alimentaire : Quelles spécificités ? Marche et organisations[END_REF], an area [START_REF] Farreny | Transition towards Sustainable Cities: Opportunities, Constraints, and Strategies in Planning. A Neighbourhood Ecodesign Case Study in Barcelona[END_REF] or a system [START_REF] Cluzel | Proposition for an adapted management process to evolve from an unsupervised Life Cycle Assessment of complex industrial systems towards an eco-designing organisation: Concurrent Engineering[END_REF].

Finally, some authors see ecodesign as an improvement of an existing product [START_REF] Caillol | Analyse de cycle de vie et éco-conception : Les clés d'une chimie nouvelle[END_REF], whereas others also see it as an innovation tool to design a new product [START_REF] Puaut | L'éco-conception : Une valeur ajoutée pour les entreprises et un enjeu futur de compétitivité ? Annales des Mines -Réalités industrielles[END_REF][START_REF] Brodhag | L'écoconception, un outil au coeur de l'économie circulaire[END_REF]. Despite this diversity, most of the definitions mention the reduction of environmental impacts of a product, as the one proposed by Berneman and al. This statement resonates with consumers' perception to the extent that environmental issues seem to be more considered than social and human issues regarding ecodesigned or ecological products. This distinction between environmental and human aspects echoes to anthropocentric paradigm considering human being as separated of nature [START_REF] David | La lente consécration de la nature, sujet de droit[END_REF]. This majority definitions correspond to the term "ecological product" or "eco-product" that Elloumi Ayedi and Kammoun (2019) define as "a product which, compared to other conventional products of similar use, generate reduced impact on natural and human environment throughout its existence" (p.90).

It is certainly the difficulty to circumscribe ecodesign which explain a limited repository on the subject. Indeed, if ISO 14062 provides guidelines, there is no reliable label or certification that recognizes ecodesigned products or services. The use of the word "ecodesign" not being subject to controls, ecodesign-washing practices emerge (Bellini, 2021, october). Despite the differences existing about the definition of ecodesign, authors seem nevertheless to agree on two aspects. On the first hand, they consider the whole life cycle in the approach and, consequently, the life cycle analysis (LCA) is considered as the reference tool for ecodesign;

LCA is defined as "a tool that assesses the environmental impact and resource use throughout a product life cycle" (Shi & Li, 2019, p.329). On the other hand, the authors agree on the willingness displayed by the initiator of the ecodesign process to contribute to the reduction of societal problems, whether they are environmental and/or social.

For other authors, ecodesign is simply not or no longer enough to solve current environmental issues, either because it is not accompanied by a modification of consumption patterns [START_REF] Zwolinski | Conception intégrée de produits durables : De l'éco-conception aux nouveaux paradigmes de production et de consommation[END_REF] or because its potential for environmental improvement was exploited in its infancy to eliminate products' inefficiencies and that still possible improvements would generate only marginal environmental benefits associated with excessive costs [START_REF] Ryan | Learning from a Decade (or So) of Eco-Design Experience, Part I[END_REF].

Given the variety of meanings attributing to ecodesign and criticism about it, this research will consider ecodesign with a broad perspective, including traditional ecodesign as described by most authors, but also alternative design methods aiming to improve societal externalities, like lowtech or frugal innovation.

Consumer was integrated in approaches like user-centred design and design for sustainable behaviour, both approaches aiming at limited environmental impacts during the using phase of a product [START_REF] Boks | Transitions in sustainable product design research[END_REF][START_REF] Ceschin | Evolution of design for sustainability: From product design to design for system innovations and transitions[END_REF]. Nevertheless, user participation to design process, through collaborative or participative design methods used in ergonomy (Barcellini, Van Belleghem & Daniellou, 2013), mobility [START_REF] Laousse | Refaire société par la création de communautés d'innovation[END_REF] and health [START_REF] Grosjean | Le patient comme acteur du design en esanté : Design participatif d'une application mobile pour patients cardiaques[END_REF] seems relatively undeveloped so far.

Beyond design phase, using phase plays a crucial role to limit a product's environmental impacts. Indeed, just like the company which proposes the product, consumer plays a role in his behaviour when using it [START_REF] Puaut | L'éco-conception : Une valeur ajoutée pour les entreprises et un enjeu futur de compétitivité ? Annales des Mines -Réalités industrielles[END_REF][START_REF] Bertoluci | Eco-concevoir pour l'industrie alimentaire : Quelles spécificités ? Marche et organisations[END_REF]. Thus, as highlight [START_REF] Berneman | Démystifier la mise en place de l'écoconception[END_REF], "some products require […] a behaviour change from purchasers" (p.81). In this regard, the development of returnable containers can be mentioned: for this solution to be effective, it is essential that consumers develop the habit of returning reusable containers to store rather than throw them in the trash. These are conducive behaviours to a limitation of environmental impacts; however, some consumers' behaviours, whether they are conscious or not, may be harmful to the environment, going as far as generating greater impacts than a non-ecodesigned product. This phenomenon, as mentioned earlier, is named "rebound effects". Over the long term, ecological impact of rebound effects can be significant (Debref, 2016). To give examples of rebound effects, those generated by sharing economy and mentioned earlier can be described, they are divided in three categories. The first one is from a buyer or lessee perspective and consists in the purchase of more products due to reduced cost of each; the second one adopts the seller or lessor perspective and consists in the purchase of new products resulting from the sale or donation of second-hand products; the third perspective is related to travels generated by sharing economy that can create new environmental impacts [START_REF] Prieto | Idées reçues sur l'économie collaborative[END_REF].

3) Methodological approach

This research falls in a comprehensive paradigm and aspires to have a deep understanding of consumer's behaviour; in this regard, a qualitative approach is adopted. In this chapter, the methodology already applied to the beginning of the research and the one to come for next steps are detailed.

Used methods

An exploratory study was the first step to acquire general knowledge about consumers' perceptions, attitudes and behaviours regarding ecodesign and eco-responsible consumption.

Group meetings with students was the method used for this study. Three meetings were led with 3 to 10 participants each and about 15 questions were addressed. For comparison purposes, two segments of the population were interrogated: students in marketing, who did not have (precise) knowledge on sustainability issues, and students in environment and sustainable development, who are particularly aware of these issues. The two meetings with marketing students were performed on site at university and were part of their curriculum (and therefore mandatory), while the meeting with environment students had to be done on-line on a voluntary basis. These elements constitute limits to comparison. Thanks to meetings records, transcriptions of discussions were done and then allowed to get a first set of results.

Planned methods

A deeper analysis of the exploratory study still has to be done; Nvivo is the tool which will be used to that end.

Then, to determine more precisely the object of study and research questions, as segments of the population to study, products and services categories to consider and relevance of a country comparison, as well as get first feedback on methodology, interviews will be done with experts from research and business. Specialists in responsible consumption, ecodesign in the broad sense and from sectors not yet determined will be contacted, two experts for each category will be interviewed up to a maximum of 10 experts. These interviews will address approximately 10 questions and will last around 45min; they will probably be done on-line and then transcribed and analysed with Nvivo.

Once these preliminaries studies will be performed and research questions specified, the study allowing to answer these questions, the one which will contribute the most to the thesis, will begin. For the moment, only the planned methodology could be described, as it still needs to be validated. Interviews will be conducted to collect data on individuals' social context, education, knowledge on sustainability, perceptions of ecodesign, etc. At the same time, to deeply understand consumers' behaviours towards ecodesigned products and services, it appears crucial to study individuals in their ecological context, meaning in their daily life. This is the reason why a participatory observation will complement interviews. Indeed, interviews only would allow to grasp declared and not actual behaviours. As, on the first hand, participatory observation will not necessarily reveal expectations and motivations of individuals and, on the other hand, interviews may highlight attitudes rather than behaviours, it seems relevant to use a data triangulation process by combining both interviews and participatory observation.

Concretely, it is envisaged that researcher performs one-week immersion periods in several households and participates to key moments of interactions with products, like shopping, daily commute or meal preparation. To study both individuals having knowledge on sustainability and individuals who have not, it is planned to be in immersion a week in households which are strongly involved in sustainable behaviours (and who have an ecological habitat) and to invite some of their relatives they consider not having specific knowledge on sustainability (family, friends, neighbours…) for the weekend. During these immersion periods, individual and group interviews with the whole family, with each of its member and with their relatives will be conducted to know more about social context, individuals' values, perceptions, motivations, etc. and to understand dynamics and influences that operate between individuals.

For now, analysis methodology is still to determine, whether it is for participatory observation or interviews. At the end of the study, to ensure that researcher interpretations are consistent with participants' reality, these latter will be invited to read the study's results and give their opinion.

4) Expected empirical findings

Through literature and researcher's personal experience and intuitions, a range of factors influencing consumer's behaviour was set and then divided in four categories. The first category is relative to the social context in which an individual evolves throughout his life, it implies factors like norms, national culture, education, etc. The second category refers to the consumer's profile, meaning his socio-economic characteristics, knowledge, beliefs, values, etc. Third, the product's or company's profile deals about product's or service's and company's characteristics. And the last category is about the consumption context, meaning the time t when the consumer interacts with the product or service, whether it is during the purchasing phase or the using phase for instance, this category includes factors like available information or time, location and human environment. To illustrate these expected empirical findings, the following model was elaborated. Throughout the research, the model will evolve, some factors could be added while others will be removed. Furthermore, the researcher will be careful not to bias her observation and interpretations by being influenced or constrained by the model.

5) Outstanding issues

The thesis is in progress and several questions remain, on which it would be appreciated to benefit from expert advice. First, discussions to refine the research question could be addressed and particularly to determine which products and/or services categories as well as which population segments to consider. Similarly, relevance to lead a comparative study between countries can be discussed.

Feedback about methodology is also highly desirable, to assess relevance of the methodology proposed, to refine it or to explore other possibilities. On this matter, the researcher would like to express an interest in innovative methods.

Finally, exchanges could be made on the expected results model, possibly to discuss other variables than are not mentioned, to discuss the four chosen categories, etc. All other relevant advice that are not mentioned here would also be highly appreciated.

Figure 1 -

 1 Figure 1 -Expected factors influencing consumers' behaviours.

Thesis directed by Laure LAVORATA (1 This research is funded by the National Agency of Research as part of the D-TechnoSS project -ANR-20-CE10-0006.