Noëlle Carbonell

Suzanne Kieffer

Keywords: multimodal interaction, multimedia presentations, visual search, spatial oral messages, speech and graphics, usability experimental study

A preliminary experimental study is presented, that aims at eliciting the contribution of oral messages to facilitating visual search tasks on crowded visual displays. Results of quantitative and qualitative analyses suggest that appropriate verbal messages can improve both target selection time and accuracy. In particular, multimodal messages including a visual presentation of the isolated target together with absolute spatial oral information on its location in the displayed scene seem most effective. These messages also got top-ranking ratings from most subjects.

CONTEXT AND MOTIVATION

Multimodality: State of the Art

Numerous forms of speech-based input multimodality have been proposed, implemented and tested. Combinations of speech with gestural modalities have been studied extensively, especially combinations of speech with modalities exploiting new input media, such as touch screens, pens, data gloves, haptic devices. Both usability and implementation issues have been considered; see, among others, (Oviatt, De Angeli and Kuhn, 1997) 1 or [START_REF] Robbe | Expression constraints in multimodal human-computer interaction[END_REF] 2 for the first category of issues, [START_REF] Nigay | A Design Space for Multimodal Systems: Concurrent Processing and Data Fusion[END_REF] for the second category. Contrastingly, speech combined with text and graphics has only motivated a few studies. As an output modality, speech is mostly used either as a substitute for standard visual presentation modes (cf. phone services) or for supplementing deficiencies in visual exchange channels. Recent research efforts have been focusing on two main application domains: -Providing blind or partially sighted users with easy computer access (e.g., [START_REF] Grabowski | Data visualisation methods for the blind using force feedback and sonification[END_REF][START_REF] Yu | Haptic graphs for blind computer users[END_REF], and -Implementing appropriate interaction facilities in contexts of use where access to standard screen displays is difficult or even impossible. This is the case, for instance, in contexts where only small displays are available (e.g., PDAs and wearable computers), or in situations where the user's gaze is involved in other activities (e.g., while driving a car); see, for instance, [START_REF] Baber | Computing in a multimodal world[END_REF] concerning the first class of situations, and (De Vries and Johnson, 1997) concerning the second one. However, there is not yet, at least to our knowledge, a substantial amount of scientific work on the integration of speech into the output modalities of standard user interfaces, that is interfaces intended for standard categories of users using standard application software in standard environments and contexts of use; graphical user interfaces (or GUIs) implementing direct manipulation design principles [START_REF] Shneiderman | Direct manipulation: a step beyond programming languages[END_REF]) are still prevailing. Published research on output forms of multimodality including speech amounts to usability studies of the role of oral comments in multimedia presentations, such as [START_REF] Faraday | Designing Effective Multimedia Presentations[END_REF], and contributions to the automatic generation of multimedia presentations (cf. [START_REF] André | The Design of Illustrated Documents as a Planning Task[END_REF][START_REF] Maybury | Universal multimedia information access[END_REF]. This lack of interest for output forms of multimodality on the part of the research community may result, at least partly, from the fact that, although multimedia and multimodality refer to different concepts, these terms are often used as synonyms, especially when applied to system outputs. Precise definitions are presented in the next paragraph. [START_REF] Coutaz | A taxonomy for multimedia and multimodal user interfaces[END_REF], (Maybury, 1993;2001) and [START_REF] Bernsen | Foundations of multimodal representations, a taxonomy of representational modalities[END_REF], among others, define 'media' and 'modalities' contrastingly.

Definitions: Multimodality versus Multimedia

They use the first term for referring to the hardware and software channels through which information is conveyed, and the second one for designating the coupling of a medium with the interpretation processes required for transforming physical representations of information into meaningful symbols or messages. In other words, and focusing on output media and modalities: '… by media we mean the carrier of information such as text, graphics, audio, or video. Broadly, we include any necessary physical interactive device (e.g., keyboard, mouse, microphone, speaker, screen). In contrast, by mode or modality we refer to the human senses (more generally agent senses) employed to process incoming information, e.g., vision, audition, and haptics.' [START_REF] Maybury | Universal multimedia information access[END_REF] To characterize the various possible combinations of modalities, taxonomies have been proposed. In [START_REF] Coutaz | A taxonomy for multimedia and multimodal user interfaces[END_REF], multimodality is characterized in terms of the strategies available for coordinating the use of different modalities temporally and semantically.

In addition, [START_REF] Coutaz | Four easy pieces for assessing the usability of multimodal interaction: the CARE properties[END_REF] defines four properties which prove useful for comparing modalities in terms of their expressive power (i.e., complementarity versus equivalence), and for defining their semantic contribution when used in multimodal contexts (i.e., redundancy versus complementarity).

As for Bernsen's taxonomy (cf. [START_REF] Bernsen | Foundations of multimodal representations, a taxonomy of representational modalities[END_REF], it is a thorough inventory of the output modalities available to user interface designers.

Motivation and Objectives

The definition of the information content and semantics of multimedia presentations is commonly viewed as the responsibility of experts in the specific application domain considered. It is seldom viewed as lying within the scope of research on human-computer interaction. Therefore, the frequent assimilation of multimodality to multimedia may explain why the design of appropriate multimodal system responses has raised but little interest in the user interface research community, especially from an ergonomic angle, save for studies focused on specific categories of users or specific contexts of use.

However, if standard users are offered speech facilities together with other input modalities, it is mandatory that the system responses are not limited to visual messages. Communication situations where one interlocutor can speak and the other cannot, are rather unusual. Research is then needed on the usability and software issues concerning the generation of appropriate multimodal system responses in standard human-computer interaction environments, and for standard user categories, including the general public.

The main objective of the preliminary experimental study presented here is to contribute to scientific advances in this research area, in-as-much as it addresses one of the major usability issues relating to the generation of effective oral system messages, namely: How to design oral messages which facilitate the visual exploration of crowded displays?

In particular, how to design messages which effectively help users to locate specific graphical objects on such displays?

Resorting to deictics and visual enhancements of graphical targets is a solution which seems "natural". However, it is no more effective than the sole visual enhancement of the target.

Another approach is to implement a human-like animated embodiment of the system, to visualise it on the screen and to endow it with a pointing device; see, for instance the PPP3 persona which impersonates a car dealer, and uses a pointing stick for attracting the user's attention on the assets of the currently displayed car [START_REF] André | WIP and PPP: A Comparison of two Multimedia Presentation Systems in Terms of the Standard Reference Model[END_REF]. However, the contribution of personae to the usability and effectiveness of human-computer interaction is still unclear (cf. [START_REF] Mulken | An Empirical Study on the Trustworthiness of Life-Like Interface Agents[END_REF]. Further testing is required in order to determine the usefulness of visual system embodiments in graphical user interfaces.

These reasons explain why we chose to focus first on assessing whether oral messages including spatial information actually facilitate the visual exploration of complex displays, especially the localization of graphical targets, in the context of standard human-computer interaction and environment.

We selected visual search as the experimental task for the following reasons. It is one of the few human visual activities, besides reading, that have motivated a significant amount of psychological research (cf. Henderson and Hollingworht, 1998;[START_REF] Findlay | Eye Guidance and Visual Search[END_REF][START_REF] Chelazzi | Serial attention mechanisms in visual search: A critical look at the evidence[END_REF]. The design of numerous computer applications may benefit from a better knowledge of this activity, especially applications for the general public such as:

• Online help to current interactive application software. For instance, novice users interacting with present graphical interfaces are often confused by the increasing number of toolbars and icons displayed concurrently. • Map reading environments (cf. geographical applications), and navigation systems in vehicles. • Data mining in visualisations of very large data sets; see, for instance, the complex hyperbolic graph visualisations proposed in [START_REF] Lamping | A Focus + Context Technique Based on Hyperbolic Geometry for Visualizing Large Hierarchies[END_REF], or the treemap representations in [START_REF] Fekete | Interactive information Visualization of a Million Items[END_REF], and [START_REF] Shneiderman | The Eyes Have It: A task by Data Type Taxonomy for Information Visualizations[END_REF][START_REF] Card | The structure of the information visualization design space[END_REF]Card, Mackinlay and Shneiderman, 1999) for a general overview of visualisation techniques and their use.

The methodology and experimental set-up of the experiment presented here are described in the next section, together with the underlying scientific hypotheses. Then, quantitative and qualitative results are presented and discussed in section 3. Future research directions stemming from these results are described in the general conclusion (cf. section 4).

METHODOLOGY AND EXPERIMENTAL SET-UP

Overall experimental protocol

To assess the potential contribution of oral spatial information to facilitating visual search, we designed a preliminary experiment with:

• target presentation mode as independent variable, • target search+selection time and target selection accuracy, as dependent variables.

Eighteen subjects were to locate and select visual targets in thirty six complex displayed scenes, using the mouse. They were requested to carry out target localization and selection as fast as they could. Colour displays only were used.

Each scene display was preceded by one out of three possible presentations of the corresponding target:

• Display of the isolated target at the centre of the screen during three seconds (visual presentation or VP);

• Oral characterization of the target (i.e., name of the relevant graphical object), plus spatial information on its position in the scene (oral presentation, OP); • Simultaneous display of the visual and oral presentations of the target (i.e., multimodal presentation, MP). These three sets of thirty six dual stimuli4 defined three experimental situations, namely the VP, OP and MP conditions. In the MP condition, the visual and oral presentations used in the VP and OP conditions respectively were presented simultaneously.

Subjects were randomly split up into three groups, so that each subject processed twelve pairs of stimuli per condition, and each pair of stimuli was processed by six subjects.

In order to neutralize possible task learning effects, the processing order was counterbalanced inside each group of subjects as follows: VP-PO-MP (three subjects), and OP-VP-MP (three subjects). All subjects performed the MP condition last.

The size of groups in usability studies or cognitive ergonomics experimental studies seldom exceeds six subjects, most likely because analysing the behaviours of subjects performing realistic tasks in realistic environments is indeed a costly undertaking; for instance, (Ahlberg, Williamson and Shneiderman, 1995) reports an experimental evaluation of three different user interfaces (meant for exploring information spaces) which also involved eighteen subjects split up into three groups of six subjects each, one group per user interface.

The overall set-up is summed up in table 1.

Group VP OP MP Group OP VP MP G1 P1 P2 P3 G4 P2 P1 P3 G2 P3 P1 P2 G5 P1 P3 P2 G3 P2 P3 P1 G6 P3 P2 P1
Experimental design choices were mainly motivated by the intent to assess the soundness of the three following working hypotheses which use the VP condition as the reference situation: A. Multimodal presentations of targets will reduce selection times and error rates in comparison with visual presentations.

B. Oral presentations of targets will also improve accuracy, compared to visual presentations. C. The type of spatial information included in oral target presentations of will influence selection times and error rates. In particular, absolute and relative spatial indications will prove more effective than references to a priori knowledge (cf. subsection 2.3), and absolute spatial information will be more effective than relative spatial indications.

These hypotheses are based on common sense reasoning, in the absence, at least to our knowledge, of earlier published results and models stemming from experiments comparable to ours, that is involving similar tasks and interaction environments.

Targets were unique graphical objects in the scenes including them. In addition, oral messages were designed so as to designate targets unambiguously. However, since they were presented out of context, they might be easily confounded with other graphical objects in the scene during visual search for the target. Then, unambiguous linguistic designations of targets being likely to prevent selection errors due to possible visual confusions, it follows that accuracy would be higher in the OP and MP conditions than in the VP condition.

As regards selection times, we assumed that subjects would use the spatial information included in oral messages, and that this information would enable them to focus visual search for the current target on a rather limited area in the scene. Scenes being complex and displayed on a rather large screen 5 , we should then observe sensibly shorter selection times in the OP and MP conditions than in the VP condition.

Concerning hypothesis C, absolute spatial information implies a one-step target localization process, while relative spatial information induces a two-step visual search; the latter is then less effective than the former as regards selection time, cognitive workload and accuracy. As for references to a priori knowledge, they involve more complex cognitive processes than the two previous types of spatial information; in addition, cultural knowledge varies greatly among users.

In the remainder of the section, further information is given on: the criteria used for selecting visual scenes and targets (2.2); the structure and information content of oral messages (2.3); subjects' profiles (2.4); the experimental set-up (2.5); the methodology adopted for analysing subjects' results (2.6).

Scene Selection Criteria

Most visual scenes were taken from currently available Web pages in order to provide subjects with realistic task environments.

They were classified according to criteria stemming from Bernsen's taxonomy of output modalities (cf. [START_REF] Bernsen | Foundations of multimodal representations, a taxonomy of representational modalities[END_REF], our aim being to investigate the possible influence of the type of visual scenes displayed on target selection times and accuracy.

Our classification was derived from the graphical categories in Bernsen's taxonomy as follows. We focused on static graphical displays exclusively6 , on the ground that the localization and selection of moving targets in animated visual presentations is a much more complex activity than the selection of still targets in static visual presentations. Issues relating to the exploration of visual animated scenes will be addressed at a later stage in our research.

We established two main classes of static presentations:

• Class 1 comprises displays of structured or unstructured collections of symbolic or arbitrary graphical objects, such as maps, flags, graphs, geometrical forms (cf. classes 9, 11, 21, 25 in Bernsen's taxonomy); • Class 2 includes displays of realistic objects or scenes, namely photographs or naturalistic drawings figuring complex real objects (e.g., monuments) or everyday life environments, such as views of rooms, town or country landscapes, … (cf. class 10 in Bernsen's taxonomy).

Half of the thirty six visual scenes belonged to class 1, and the other half to class 2. Class 1 and class 2 scenes in each of the three subsets described in subsection 2.1 (cf. table 1) were randomly ordered.

Targets were objects or component parts of complex objects (cf. the complex real objects in class 2).

They were chosen according to the following criteria. An acceptable target was a unique definite graphical object that could be designated unequivocally by a short simple verbal phrase. Although all targets were unique, some of them could be easily confused (visually) with other objects in the scene. In order to avoid task learning effects, target visual properties7 and position were varied from one scene to another.

Message structure and content

All messages included a noun phrase meant to designate the target unequivocally. For instance, "the pear" refers to the target unequivocally in the realistic scene reproduced in figure 1.

For any target, we chose the shortest simplest noun phrase that could characterize it without ambiguity and redundancy. For instance, one of the scenes represented geometrical figures and included several squares. The target we chose was the smallest square and the only pink one. We referred to one of these features, the colour, to appropriately reduce the scope of the substantive "square" in the oral message; "the pink square" is a noun phrase that refers to the target without ambiguity or redundancy. On the other hand, the use of the substantive "pear" is sufficient for referring unambiguously to the target in the scene reproduced in figure 1. We experimented three types of spatial information in the verbal phrases referring to target locations, using an ad hoc classification inspired by the taxonomy presented in (Franck, 1998):

• Absolute spatial information (ASI), such as "on the left/right" or "at the top/bottom"; • Relative spatial information (RSI), for instance "on the left of the apple" (cf.

figure 1);

• Implicit spatial information (ISI), that is spatial information that can be easily inferred from common a priori knowledge and the visual context; for instance, it is easy to locate and identify the Mexican flag among twenty other national flags from the simple message "The Mexican flag.", if the scene represents a planisphere, and national flags are placed inside the matching countries (cf. figure 2).

Messages included one or two spatial phrases, according to scene complexity; one or two types of spatial information, namely ASI+RSI or ASI+ISI, were grouped in phrase pairs.

Careful attention was paid to the choice of spatial prepositions [START_REF] Burhans | Domain Specific Understanding of Spatial Expressions[END_REF].

In order to make the assessment of hypothesis C possible, all messages had the same syntactical structure, in order that information content was the only factor pertaining to the design of messages that could influence localization times and selection errors. The following structure, which emphasizes spatial information, was adopted for most messages, some ISI messages including no spatial phrase:

[Spatial_phrase] + Noun_phrase (designation) This structure was preferred to the usual one (Noun_phrase+Spatial_phrase), based on the assumption that information in messages would be more effective if it was presented in the same order as it would be processed by the user.

Subjects' Profiles

As this study involved a restricted number of subjects ( 18) and was a first attempt at validating hypotheses A, B and C, we defined strong constraints on subjects' profiles in order to reduce inter-individual diversity, especially regarding task performance, and limit the number of factors that might influence subjects' performances.

To achieve homogeneity, we selected 18 undergraduate or graduate students in computer science with normal eyesight8 and ages ranging from 22 to 29. Thus, all participants were expert mouse users with alike quick motor reactions, familiar with visual search tasks, and capable of performing the chosen experimental tasks accurately and rapidly.

Experimental Set-up

First, the experimenter presented the overall experimental set-up. Then, after a short training (6 target selections in the VP situation), each subject processed 12 scenes per situation, in the order VP+OP+MP or OP+VP+MP.

Before each change of condition (i.e., before each change in target presentation), the experimenter explained the new specific set-up to the subject.

For each visual scene:

• The target was first presented, during three seconds:

either visually in a fixed-size box in the centre of the screen, or orally (together with a blank screen), or orally and visually, simultaneously. • Then, a button appeared in the centre of the screen together with a written message requesting the subject to click on the button for launching the display of the scene. Therefore, at the beginning of each target selection step, the mouse was positioned in the centre of the screen, making it possible to compare subjects' selection times. • The next target was presented as soon as the subject had clicked on any object in the current displayed scene.

At the end of the session, subjects had to fill in a questionnaire requesting them to rate the difficulty of each task using a four degree scale (ranging from "very easy" to "very difficult"). The session ended up in a debriefing interview.

Analysis methodology

Quantitative results comprise:

• average {localization + selection} times, and • error (i.e., wrong target selections) counts or percentages, computed over all subjects and scenes, as well as per class of scenes and per type of oral message.

We tested the statistical significance of these quantitative results whenever a sufficient number of samples was available.

Qualitative analyses of subjects' performances, especially comparisons between the numbers of target selection errors in the VP, OP and MP conditions, provided useful information for defining further research directions.

In order to elicit the possible factors at the origin of selection errors, scenes and targets were characterized using the following features:

• Scene characterization:

complexity (according to the number of displayed objects); and, for class 1 scenes only, visual structure (e.g., random layout of objects; tree, crown or matrix structures; …). • Target characterization:

position on the screen (centre, left, …); visual salience; familiarity versus unfamiliarity (oddness); ambiguity (i.e., the number of possible visual confusions with other graphical objects in the scene).

Quantitative and qualitative results are presented and discussed in the next section.

RESULTS: PRESENTATION AND DISCUSSION

Quantitative Results

Results were computed over 34 scenes; two scenes (both in class 1) had to be excluded from both quantitative and qualitative analyses by reason of technical incidents. Therefore, the corpus of experimental data we actually used comprised the results of 612 visual search tasks performed by 6 different subjects, that is 204 per condition (VP, OP, or MP).

Statistical tests, mainly t-tests, were performed on these performance data (successes/failures and execution times), especially on the three sets of data collected in the three conditions.

Global Analysis

Presentation. Concerning the order of conditions (VP then OP, versus OP then VP), comparisons between subjects' performances in each of the two groups yielded no significant inter-group differences. These results indicate that no perceptible task learning effect occurred in the course of the experiment. The absence of any such effect is not surprising, due to the low number of tasks in each condition (i.e., 12) and the brief duration of the overall session (about 10 min).

p<0.0001

Therefore, learning effects may be rightly excluded from the factors to be considered in the interpretation of the quantitative and qualitative results of our analyses, even as regards the MP condition although it was performed last by all subjects.

As for selection accuracy, oral messages proved much more effective than visual target presentations, as shown by comparisons between the VP and OP conditions (cf. table 2).

The total number of errors in the OP condition decreased by 55%. However, selection was slower in the absence of prior visualizations of isolated targets, that is in comparison with the VP and MP conditions. Average selection time in the OP condition increased by over 38% compared to the OP condition.

These differences are statistically significant.

Table 2 also shows that multimodal presentations of targets reduced both selection times compared to oral presentations, and error rates in comparison with visual presentations, both results being statistically significant. These results are in keeping with the previous ones.

Interpretation and discussion. As regards accuracy, spatial indications and target verbal designations included in messages may have reduced the frequency of visual confusions, the former by reducing the scope of the visual search for the target, the latter by preventing confusions between the target and graphical objects of similar visual appearance in the scene.

Significantly lower average selection time in the OP condition, together with a much higher standard deviation, may be explained by the fact that subjects were unfamiliar with the visual search tasks they had to carry out in the OP condition; this situation being rather unusual compared to the VP and MP situations which occur frequently in everyday life. Therefore, the higher variability of selection times in the OP condition may be assumed to reflect the high inter-individual diversity of cognitive abilities and processes.

However, the slower selection times observed in the OP condition may be explained more satisfactorily by the intrinsic differences between the tasks subjects had to perform in the OP and the VP conditions. Visual search of a visually known graphical target is a much less complex task than searching for a graphical object that matches a given verbal specification, even if only a part of the scene needs to be explored thanks to spatial verbal information. [START_REF] Bieger | Comprehending spaatial and contextual information in picture-text instructions[END_REF] observed similar effects on the performances of subjects in an experiment that aimed at comparing the efficiency of text and graphics for presenting various types of information in instructional material. In particular, concerning spatial information9 , Bieger and Glock found that subjects who were to use textual presentations of spatial information made fewer task execution errors than those who were given graphical presentations of the same information; on the other hand, the latter completed the prescribed tasks faster.

However, further comparisons between this study and ours would be meaningless, due to important design differences between the two experimental protocols: in Bieger's and Glock's study, the tasks subjects had to carry out were procedural assembly tasks (versus target selection in our experiment), and the modalities considered were text and graphics (versus speech and graphics).

Concerning subjects' performances in the MP condition, comparisons with their performances in the other conditions suggest that, in this condition, they succeeded in making the most of the information provided by each modality, thus compensating for the weaknesses of each unimodal presentation mode. A likely interpretation is that they achieved:

easy disambiguation of possible confusions between targets and other objects of similar appearance in the scene, thanks to spatial and denominative verbal information; and rapid identification of targets thanks to visual information, matching based on visual characteristics being faster than identification based on abstract properties or stereotyped mental representations, which involves complex decision-making processes.

Surprisingly enough, spatial verbal information which, according to our hypotheses, should accelerate target localization, did not actually contribute to reducing selection times significantly, or so it seems. This finding, together with the slower selection times observed in the OP condition may be explained within the framework of current visual perception models which assume that eye-movements are less influenced by cognitive (topdown) processes than by visual stimuli (bottom-up processes) during visual exploration tasks [START_REF] Henderson | Eye Movements during Scene Viewing: an Overview[END_REF]. On the other hand, visual exploration in search of a graphical object matching a verbal specification is a task that combines complex, hence slow, cognitive processes with perceptual activity. These differences may explain why slower selection times were observed in the OP condition than in the VP and MP conditions, and why spatial information did not noticeably reduce selection times in the MP condition compared to the VP condition.

This interpretation of the noticeable differences observed between average selection times in the three conditions, fits in with Rasmussen's cognitive model [START_REF] Rasmussen | Information processing and human-machine interaction: an approach to cognitive engineering[END_REF], provided that the search of a visually known target is assimilated to a skilled or automatic activity, and the search of a visually unknown target from a verbal specification of its characteristics as a problem-solving activity. The model then predicts that selection time of the known target will be shorter than that of the unknown target, based on the assumption that automatic or skilled responses to stimuli amount to the activation of precompiled schemata or the compilation and activation of pre-defined schemata respectively, while problemsolving involves more complex cognitive processes.

The application of this model to the MP condition suggests the tentative conclusion that subjects used both sources of information optimally within an overall opportunistic strategy favouring visual search over more complex matching processes, matching processes being activated only in cases when visual information is insufficient or ambiguous.

However, although Rasmussen's model constitutes an appropriate framework for predicting subjects' performances, it is too general to provide any meaningful insight into how the strategy underlying these performances is implemented, that is, how multimodal stimuli are processed, how the results of modality specific processes are integrated and unified to produce meaningful coherent interpretations and appropriate actions or motor responses .

Subjects' performances are indeed compatible with cognitive models of multimodal input processing that postulate the existence of high level interactions between unimodal perceptual and interpretative processes rather than early low-level interactions (cf., for instance, [START_REF] Engelkamp | Modality and modularity of the mind[END_REF].

However, further research is needed in order to determine which type of interaction (competition, synergism or complementarity) would best account for subjects' results within the framework of our experimental protocol.

For instance, reducing progressively the duration of visual target presentations in the MP condition appears as a promising, but difficult to implement, experimental paradigm for increasing our knowledge of the cognitive processes involved in the processing of multimodal inputs [START_REF] Massaro | Personal communication[END_REF].

Future work. To achieve significant advances in the investigation of multimodal perception and interpretation processes, experimental approaches have to overcome major difficulties.

In particular, homogeneous sets of visual search tasks are needed in order to make it possible to achieve meaningful reliable intra-and inter-subject comparisons, as the same scene cannot be processed in the three conditions by the same subject.

The "difficulty" of the visual search tasks proposed to our subjects varied greatly from one scene to another. For instance, in the VP condition, all subjects (6) failed to select the correct target for one scene, and only 8 scene+target pairs occasioned 26 out of the 31 errors observed in this condition. We are currently refining our visual and semiotic characterizations of scenes and targets in order to be capable of defining and generating sets of really equivalent scenes.

The number of participants and scenes should also be increased considerably, so that a greater number of more sophisticated inter-related hypotheses can be tested simultaneously, and their soundness evaluated accurately, thanks to the possible application of appropriate statistical techniques.

Ergonomic recommendations. To conclude, the quantitative results presented in this section contribute to validating hypotheses A and B. However, further research is needed to determine whether the significantly longer selection times observed in condition OP are mainly due either to the differences between the tasks subjects performed in the OP condition and those they carried out in the VP and MP conditions, or to the fact that subjects were unfamiliar with the tasks they carried out in this condition.

These results also suggest useful recommendations for improving user interface design.

In order to facilitate visual search tasks in crowded displays without resorting to standard visual enhancement techniques, two novel forms of user support may prove useful alternatives: a. If accuracy only is sought for, an oral message comprising an unambiguous verbal designation of the graphical target and spatial information on its location in the display will prove sufficient. b. If both accuracy and rapidity are sought for, a multimodal message will be more appropriate, that is a message comprising a context-free visual presentation of the target together with an oral message including the same information as mentioned in recommendation a.

However, further experimental research is needed to confirm these recommendations beyond doubt, in-as-much as they have been inferred from a relatively small sample of experimental data and measurements. In addition, oral and multimodal messages should be compared, in terms of effectiveness and comfort, with other forms of user support, such as target visual enhancement through colour, animation, zooming, etc. Until a sufficient amount of experimental data has been collected, recommendations a. and b. should be considered as tentative.

Analyses of results per class of scenes and type of messages (i.e., type of spatial information) are presented next. These analyses make it possible to refine and enrich our initial working hypotheses.

Detailed analysis

Results per class of scenes. Subjects' results, grouped per scene class and target presentation mode, are presented in table 3. Error percentages were computed over:

-96 samples per condition for class 1 (due to the exclusion of two class 1 scenes as explained at the beginning of section 3), and -108 samples per condition for class 2.

No statistical analysis was performed on these results by reason of the rather small number of samples in each set.

Multimodal messages proved most effective, in comparison with visual and oral presentations, especially for scenes representing symbolic or arbitrary objects. For scenes in class 1, comparisons between the three conditions indicate that errors were reduced in the MP condition by 12.6% (compared to the VP condition) and 5.3% (compared to the OP condition), while average selection times decreased by 0.24 and 1.27 seconds respectively. In short, concerning class 1 scenes, 86% of the selection errors observed in the VP condition did not occur in the MP condition, and selection times were one third longer in the OP condition than in the MP condition. As for realistic scenes, the average selection time in the MP condition is similar to the VP one (2.40 sec. versus 2.43 sec.) and markedly inferior to the OP one (3.58 sec.), whereas the number of selection errors is similar to the OP one, and inferior to the VP one (by 10.2%).

These results confirm the main hypothesis proposed in the previous subsection for interpreting global results, namely that, in the MP condition, subjects took advantage of both the visual and oral information available, especially for processing class 1 scenes.

For instance, we observed that some subjects lacked the a priori knowledge required for taking advantage of the implicit information conveyed by ISI messages; visual information can prove most helpful for achieving successful target identification in such cases. On the other hand, class 1 scenes which consisted in collections of symbolic or arbitrary graphical objects (e.g., flags or geometric figures) favoured visual confusions between targets and similar objects in the displayed collections; verbal designations and spatial information undoubtedly helped subjects to solve possible visual "ambiguities". The fact that average selection times were consistently longer for class 1 scenes than for class 2 scenes can be explained as follows.

If the target is a familiar object (such as a pan) in a familiar realistic scene (a kitchen, for instance), visual exploration of the scene is facilitated by a priori knowledge of the standard structure of such environments and the likely locations of the target object therein. Such knowledge is not available in the case of unrealistic class 1 scenes; the structure of such a scene and the possible locations of the target in it cannot be foreseen using a priori knowledge, so that a more careful search, or even an exhaustive exploration, of the scene is necessary for succeeding in locating the target.

This hypothesis may also explain why multimodal target presentations proved most effective for scenes belonging to class 1: both oral and visual information contributed to compensate for the lack of pragmatic a priori knowledge.

Results per type of messages. Five categories of verbal messages were experimented (cf. subsection 2.3). Messages were classified according to the type of spatial information they comprised: absolute (ASI), relative (RSI), implicit (ISI), plus absolute-relative (ASI+RSI) and absolute-implicit (ASI+ISI). Subjects' results, grouped according to these categories, are presented in table 4. Subjects' performances in the VP condition are also reported although messages were excluded from target presentations in this condition; they serve as references in the assessment of the effectiveness and efficiency of the user support provided by oral messages in the two other conditions (OP and MP). As the number of scenes varied from one class of messages to the other, percentages were computed for each condition over 48 samples (ASI), 72 samples (RSI), 24 samples (ISI), 36 samples (ASI+RSI), and 12 samples (ASI+ISI)10 .

For each category of messages, comparisons between results achieved by subjects in the VP, OP and MP situations suggest that absolute and/or relative spatial information improved selection accuracy markedly (cf. the ASI, RSI and ASI+RSI types of messages). However, the usefulness of ISI messages seems questionable, at least in the OP condition. Their effectiveness in the MP condition denotes the complexity of the interpretation processes at work in the interpretation of multimodal stimuli.

Average RSI and ISI selection times were much longer in the OP condition (4.03 and 6.12 respectively) than in the other conditions (i.e., 2.86 and 1.84 for VP, 3.12 and 2.1 for MP).

For RSI messages, this effect may be due to the complexity of the visual search strategy induced by relative spatial information when the target is unknown visually. In such cases, the search strategy is likely to include two successive steps: first, localization of the reference object, then exploration of its vicinity in search of the target [START_REF] Gramopadhye | Visual Search and Visual Lobe Size[END_REF]. Each step being longer than the search for a visually known target, the resulting global selection time is necessarily much longer than in the other conditions where the target is visually known.

This interpretation may also explain why RSI messages did not affect selection times in the MP condition noticeably. The target being in the vicinity of the reference object and having been viewed previously, it can be recognized through peripheral vision, so that one eye fixation only is required for locating both the reference object and the target (cf. [START_REF] Van Diepen | Functional Division of the Visual Field: Moving Masks and Moving Windows[END_REF].

However, it is also possible that, in the MP condition, subjects tended to adopt a simpler search strategy based exclusively on the available visual information (hence comprising a single visual search step) whenever the oral message induced a complex slow selection strategy. This second interpretation has the advantage to explain why both RSI and ISI messages exerted no perceptible influence on selection times in the MP condition.

As for ISI messages, their exploitation involves complex cognitive processes which may slow down target selection in the OP condition. The poor results observed in the OP condition may also suggest that the usefulness of ISI messages is intrinsically limited.

To sum up, whereas the inclusion of any category of verbal spatial information in multimodal target presentations seems worthwhile, absolute spatial information should be preferred over other information types in the design of oral target presentations, in order to improve both selection times and accuracy. However, these observations, which refine hypothesis C (cf. subsection 2.1), should be viewed as working hypotheses rather than reliable, or even tentative, conclusions. Their appropriateness has to be assessed through careful systematic experimentation on a large scale. Analysis of eye-movements (by means of an eyetracker) would provide invaluable information on visual search strategies, especially on the exact influence of the information content of oral messages on these strategies.

Qualitative analyses

Qualitative analyses were focused on the subjects' errors exclusively, with a view to:

• getting a better understanding of the contribution of verbal messages to assisting users in visual search tasks, and • obtaining useful knowledge for improving message design.

Analyses use the detailed characterizations of scenes and messages listed in subsection 2.6, as well as the subjects' subjective ratings of the difficulty of the prescribed visual search tasks (cf. the post-session questionnaires mentioned in subsection 2.5).

Scenes were filtered so that, in each condition, only the scenes which had occasioned more than one error were considered, on the basis of the following assumption:

For a given scene in a given condition, the reasons for the failure of one single subject are more likely to originate from the subject's capabilities than from the scene characteristics or the message information content.

Visual condition

The main plausible factors at the origin of selection errors observed in the VP condition are presented next. Percentages represent:

the number of errors which a given characteristic of the scene may explain, by itself or in conjunction with other factors; computed over the total number of filtered errors (i.e., 26).

Factors are listed in decreasing order of the percentages of errors they contribute to account for:

• Concerning targets: lack of salience (85%), eccentric position in the scene (69%), possible confusions with other objects (69%), unfamiliarity (50%).

• Concerning scenes: crowded (69%), unstructured (46%), figuring geometric forms (42%). This analysis of subjects' errors in the VP condition will be used as a reference in the next subsection which is focused on errors in the OP and MP conditions.

Oral and multimodal conditions

Five scenes in the OP condition and only two scenes in the MP condition occasioned more than one error, against eight in the VP condition. In addition, 24 errors in the VP condition were "corrected" in the OP condition, so that seven out of the eight scenes occasioning more than one error in the VP condition yielded error-free results in the OP condition. These comparisons bring out the usefulness of oral messages for improving target selection accuracy.

However, four scenes yielding error-free results in the VP and MP conditions occasioned ten out of the twelve 11 filtered errors observed in the OP condition 12 . Therefore, it is likely that the main factor at the origin of these errors is the poor quality of the information content of the oral messages paired off with these scenes.

The analysis of these four messages, together with the information provided by questionnaires and debriefings, support this conclusion. Four errors were motivated by an ISI message which referred to knowledge unfamiliar to the majority of subjects. A too complex ASI+ISI message (structure and length) referring to knowledge some subjects were unfamiliar with may account for two other errors. As for the two remaining pairs of errors, they may be reliably ascribed to the use, in both verbal target designations, of technical substantives the exact meanings of which were unfamiliar to some subjects.

The fact that none of these errors occurred in the MP condition, together with the fact that two scenes only occasioned the four 13 filtered errors observed in this condition, illustrates the advantages of combining visual and verbal information in target presentations.

Two errors occurred on a "difficult" scene which occasioned six errors in the VP condition (crowded scene, and non salient unfamiliar target easy to confound with other objects), and two errors in the OP condition (use of technical vocabulary). The other two errors were occasioned by a scene which was processed successfully by all subjects in the OP condition, but occasioned three errors in the VP condition. This may hint that the processing of multimodal incoming information is controlled or influenced by visual perception strategies rather than by high level cognitive processes.

In short, the qualitative analysis of errors confirms the usefulness of oral messages for improving the accuracy of visual target identification, provided that:

messages are short, their syntactical structure straightforward, the vocabulary familiar to users, and above all, their information content is appropriate.

Subjects' subjective judgements

Subjects expressed positive judgments on the contribution of oral messages to facilitating visual search tasks in the post-experiment questionnaires. The MP condition achieved the highest rate of subjective satisfaction as shown in table 5. The majority of subjects (72%) rated the execution of visual search tasks in the MP condition as "very easy", whereas a minority of 22% only applied this rating to the OP and VP conditions. The VP condition got the lowest ratings.

In addition, the MP condition, compared to the VP and OP conditions, was judged most efficient, in terms of rapidity, by fourteen subjects.

11 out of 14.

12 Error patterns for these images were as follows: 4, 2, 2, 2.

13 out of 8.

Thus, the majority of subjects considered implicitly that oral messages had helped them to achieve the prescribed search tasks, especially when verbal information was associated with a visual presentation of the target.

Finally, the majority of subjects (66%) preferred the MP condition to the others. Nevertheless, three subjects complained of the content or wording of some oral messages. Criticisms concern, for one subject, messages without spatial information (two messages), for the second one, the use of a somewhat technical word outside his vocabulary (one message), and for the last one, the length and complexity of RSI messages. In addition, a fourth subject considered oral messages were not useful in the MP condition.

To conclude, the MP condition came first in the subjective judgments of most subjects, as regards both the utility and usability of oral messages. These results are encouraging in view of the numerous potential interactive applications involving visual search tasks.

However, voluntary participants in experimental evaluations of novel artifacts or techniques are prone to judge them positively (experimental bias), especially if the evaluation consists in a single session like ours. Their judgments may evolve under the influence of experience. Further usability studies are needed, in particular for assessing how future users will appraise the support provided by oral messages after extensive practice in real contexts of use.

CONCLUSION

A preliminary experimental study has been presented, which aims at eliciting the contribution of oral messages to facilitating visual search tasks on crowded visual displays.

Results of quantitative and qualitative analyses suggest that appropriate verbal messages can improve both search accuracy and selection times. In particular, multimodal messages including absolute spatial oral information on the target location in the visual scene, together with a visual presentation of the isolated target, are most effective.

This type of messages also got the highest subjective satisfaction ratings from most subjects. Subjects' acceptance, even in an experimental environment, is a valuable asset.

Numerous potential applications exist. Facilitating visual search could indeed improve the efficiency and usability of present human-computer interaction sensibly, as direct manipulation of GUIs is the prevalent user interface design paradigm for the moment.

However, these results are only tentative, by reason of the relatively small number of subjects involved in the experiment (18), the limited number of scenes they had to process (12 per condition), and the coarseness of the measures used which were restricted to search accuracy and selection times (including search, identification, and selection of the target). In addition, qualitative analyses (focused on subjects' errors) suggest the possible influence, on subjects' results, of factors that were not systematically taken into account in the design of our experimental protocol. Our current short term research directions are based on these observations. We are currently planning a series of experimental studies focused on in-depth investigation of the possible influence, on search accuracy and selection times, of the visual characteristics of scenes and targets, namely scene structure or target position. In particular, structure seems a factor capable of facilitating the exploration of class 1 scenes significantly (see Cribbin and Chen, 2001a), whereas the efficiency of relative spatial information can be influenced by the proximity of the target to the salient object [START_REF] Gramopadhye | Visual Search and Visual Lobe Size[END_REF].

Each of these experiments will be designed along the same lines as the one presented here, and implemented using a similar experimental protocol. However, it will address a few specific related issues and involve a large number of participants, in order to make it possible to refine and enrich the results of the initial study presented here.

In addition, to achieve sound meaningful interpretations of future quantitative experimental results, we shall compare them with qualitative eye-tracking data obtained from a carefully selected sample of participants.

We believe that a better understanding of visual search strategies, of their interindividual diversity [START_REF] Cribbin | Exploring cognitive issues in visual information retrieval[END_REF], their sensitivity to the visual characteristics of the scenes displayed, and their evolution under the influence of oral support, will prove useful for improving the design of oral user support in visual search tasks. In particular, such knowledge could help designers to tailor the information content and wording of oral messages to individual search strategies and visual scene characteristics.

A further step may be to compare, in terms of effectiveness and usability, oral support to visual search with various visual enhancements of targets.

Figure 1 :

 1 Figure 1: Basket with fruit (class 2 picture). Oral message: "On the left of the apple, the pear."

Figure 2 :

 2 Figure 2: National flags (class 1).Oral message: "The Mexican flag."

Table 1

 1

	: Overall task set-up.
	G i : group of 3 subjects (3 x 6 = 18 subjects)
	P i : set of 12 visual scenes (3 x 12 = 36 scenes)

Table 2 :

 2 Results per target presentation mode. Upper half: best results are in bold type, and lowest ones are underscored. Lower half: significant statistical results are in bold type.

	Target	Number of	Average	Standard deviation
	presentation mode	errors	selection time (sec.)	(sec.)
	VP	31	2.83		1.70
	OP	14	3.92		3.50
	MP	8	2.70		1.93
	Target	Number of errors	Average selection time
	presentation mode				(sec.)
	VP versus OP	t= -2.70	p=0.007	t=+3.79	p=0.0002
	VP versus MP	t=-3.94	p<0.0001	t=-0.70	p=0.4852
	OP versus MP	t=-1.31	p=0.189	t=-4.20

Table 3 :

 3 Results per target presentation mode and class of scenes. Percentages were computed over the total number of samples (selection tasks) per condition.

	Target	Error	Average	Standard deviation
	presentation mode	percentage	selection time (sec.)	(sec.)
	VP-C1	14.6	3.27	1.94
	VP-C2	15.7	2.43	1.39
	OP-C1	7.3	4.30	4.09
	OP-C2	6.5	3.58	2.87
	MP-C1	2	3.03	2.36
	MP-C2	5.5	2.40	1.36

Table 4 :

 4 Results per target presentation mode and type of verbal message. Best results in the OP condition are in bold type, and lowest ones are underscored. Percentages were computed over the total number of samples per message type. (Results in the VP condition are reported, VP being used here as the reference condition).

	VP	Condition	(reference)
	Scenes grouped per	Percentage of	Average selection	Standard
	message type	errors	time (sec.)	deviation (sec.)
	ASI	10.4	2.87	1.19
	RSI	26.4	2.86	2.14
	ISI	4.17	1.84	0.57
	ASI+RSI	13.89	3.57	1.99
	ASI+ISI	8.33	3.54	0.98
		0P	Condition
	ASI	0	2.91	3.41
	RSI	8.33	4.03	5.94
	ISI	16.67	6.12	3.78
	ASI+RSI	5.56	3.82	3.78
	ASI+ISI	16.67	5.19	3.37
		MP	Condition
	ASI	4.17	2.42	1.41
	RSI	8.33	3.12	2.43
	ISI	0	2.1	1.06
	ASI+RSI	0	2.82	1.84
	ASI+ISI	0	2.98	2.53

Table 5 :

 5 Subjects' judgments (on task difficulty) and preferences. Percentages were computed over the total number of subjects.Highest values in each line are in bold type.

	Condition	"Very easy"	"Easy"	"Difficult"	"Very difficult"
	VP	22%	28%	39%	11%
	OP	22%	61%	17%	0%
	MP	72%	17%	11%	0%
	Top-ranking	VP		OP	MP
	preference	17%		17%	66%

On speech and pen.

On speech and finger gestures on a touch screen.

PPP means 'Personalized Plan Based Presenter'. See also Candace Sidner's robot, a penguin which can point at locations on large horizontal displays with its beak[START_REF] Sidner | Hosting activities: experience with and future directions for a robot agent host[END_REF].

That is 108 pairs of stimuli (36 scenes x 3 presentation modes), each pair consisting in a presentation (visual, oral or multimodal) of a target followed by the display of the scene including this target.

Scenes included several scores of graphical objects and were displayed on a 21 inches screen.

cf. the five types of static graphical presentations inBernsen's taxonomy, namely classes 9, 10, 11, 21, 25.

These properties mainly include: colour, shape, orientation and size (within the limits of the fixed size target presentation box).

save for one subject who was slightly colour-blind.

Namely the final position and orientation of elements in the workspace (assembly tasks).

That is 192 samples instead of 6 x 34 = 204 samples (cf. the two scenes which were excluded). Two additional scenes (6 x 2 samples) were not taken into account because the corresponding messages did not include any spatial information, the visual salience of the target making such information superfluous.


Corinne Bigot

'Locking the Door': Self-deception, Silence and Survival in Alice Munro's 'Vandals'

Keywords:

This paper focuses on 'Vandals' by Canadian short story writer Alice Munro (Open Secrets, 1994). The story explores the complex relationship between abuse (here, the sexual abuse of children), silence and self-deception. This paper aims to read 'Vandals' as a trauma narrative which internalises the rhythms, processes and uncertainties of traumatic experience within its very structure (Vickroy, 2002). The paper will consider Munro's narrative and stylistic choices to represent the unrepresentable and the impact of traumatic memory. I will also consider how Munro addresses the issue of survival, showing that as she denies closure, and provokes "emphatic unsettlement' (LaCapra), Munro exposes the silencing force of trauma and unhealed wounds in order to call on her readers to break the compact of silence.

published in Trauma Narrative and Herstory, edited by Sonya Andermah & Silvia Pellicer, Palgrave Macmillan 2013 victims, as well as the question about the survival of abuse. Cathy Caruth's seminal essay, Unclaimed Experience, has provided the theoretical background on these points [START_REF] Caruth | Unclaimed Experience. Trauma, Narrative and History[END_REF], since the main concern of 'Vandals' is to point to unhealed wounds that linger on the body and on the intrusive memories that haunt the present lives of the protagonists.. I propose to read 'Vandals' as a trauma narrative as defined by Vickroy since it 'internalize [s] the rhythms, processes and uncertainties of traumatic experience' within its structure (2002, p. 3).

Moreover, Munro's refusal to provide closure and a final resolution at the end of the narrative has led me to consider Dominic LaCapra's notion of 'emphatic unsettlement' [START_REF] Lacapra | Writing History, Writing Trauma[END_REF] to describe the effect of Munro's story upon her readers.

Witnessing the unspeakable, representing the unrepresentable "So did you read my signs?" is the question that Ladner, who owns a nature reserve, asks Liza and Kenny, the two young children he finds lurking on his property (Munro, 1994, p.285). The topography in 'Vandals', as Robert McGill puts it, 'is everywhere written over with texts' (McGill, 2002, p.106) -letters carved on a tree, signs with the animals' names and details about their habitats, notices forbidding people to trespass, and boards with quotations by Aristotle and Rousseau. The signs that the characters may fail to understand challenge the reader to decipher the signs of a narrative in which the abuse is never acknowledged by the victims, the perpetrator or the bystander. The short story opens with a letter written by a woman called Bea to her former neighbour, Liza, who is now in her twenties. Bea thanks Liza for having checked on her property while Bea cared for her partner in the hospital. The letter, which also mentions the man's death, is never sent. The rest of the first section is devoted to Bea's reminiscences about her past and her life with her partner, Ladner. The second part describes Liza and her husband's visit to Bea and Ladner's house, which Liza trashes for no apparent reason. The third part, whose focalizer is Liza, offers a new version of the past, as it gradually emerges that Liza and her brother were abused by Ladner, a fact which Bea did not see, or chose not to see. In 'Vandals', Munro explores themes such as guilt and denial as she documents the complex relationships between abuse, silence and self-deception.

Ladner's creation -the nature reserve-and his job -he is a taxidermist -will play a key role in the revelation of the abuse and, its effects. and the silence that has covered it up.

Ladner has created what is called a 'remarkable kind of nature preserve' (Munro,p.266) with exhibits of 'lifelike birds and animals' which he constructs with wire armatures, papiermâché, wood, clay and the animals' skins. It is a simulacrum of the Ontario countryside, and this is made clear by the repeated emphasis on the fact that, on the reserve and with these animals, 'nothing is real' (286). There, Bea is said to mistake what is unreal for what is real.

As Foy, Dawson and Ventura have pointed out, one of the central and unresolved questions in the story is whether Bea knew about the abuse (Foy, 1999;[START_REF] Dawson | Skinned': Taxidermy and Pedophilia in Alice Munro's "Vandals[END_REF]Ventura, 2007).

Early in the narrative, a sign on a trail that reads 'Nature never deceives us; it is always we who deceive ourselves-Rousseau' (271) alerts to the possibility that the characters in the story are prone to self-deception. Liza seems to believe that Bea did not do anything to protect the children because she did not see what was happening: '[w]hat Bea has been sent to do, she doesn't see.' (293). Bea's inability to see is constantly underscored, for instance, on her first tour of Ladner's property, she confuses mushrooms with rotten apples (272) and mistakes a 'wire armature' for a real body (273). However, after an unpleasant incident with Ladner, Liza wonders whether Bea has not 'made a bargain not to remember' (293), which suggests that Bea may have decided she had better ignore what was happening with the children. Bea seems to epitomize what Judith Herman calls 'the universal desire to see, hear, and speak no evil' (Herman, 1992, p.7), she seems to have succumbed to 'the temptation to look the other way' (Herman, 1992, p.8), which is a frequent reaction to child abuse in those who have witnessed it. Carrie Dawson points out that Ladner's 'diorama functions as a symbol of the often complex relationships between ways of knowing and of not knowing, of preserving disbelief in the face of knowledge too horrible to contemplate.' (Dawson, 2005, pp.70-71) In the short story, much emphasis is put on the animals' eyes: the children are said to help Ladner by fitting eyes into the fake bodies (Munro, 1994, p.285) and to squish 'eyeballs into jelly' (286), and also Bea notices an animal's empty eyeholes during her first visit (273). The ever-present eyes point to Bea's inability or refusal to see that her partner is abusing Liza and her brother ; however,yet they may also serve to emphasise Liza's incomprehension about the fact that no one seems to see what is going on, as the narrator underlines that '[o]nly Liza sees.' (293) However, as Ladner's own eyes in the rape scene are said to shine 'out of ambush' (292) suggests that the eyes the motif may also evoke may also convey Liza's feelings of being unable to escape the predator's watchful eyes when she was a child, this would explain why, as she trashes Ladner's house many years later, she shouts "Bull's eyes" when a bottle hits the stove (280): her cry resonates as a cry of revenge. ). Also, the skinned animals function as powerful metaphors throughout the story, conveying the children's silenced suffering. As Ladner's work with the animals is being described, there are repeated remarks about body parts such as the animals' innards, or 'guts' and their skins. Attention is drawn to the holes in these bodies -'empty eyeholes', 'mouth holes'(273) -and, through the verbs describing Ladner's work, to the violent acts of skinning and scraping bodies (286). The children are repeatedly associated to animals, for instance, when Bea first meets Liza and Kenny, she asks them what kind of animal they would be if they could turn into animals (284), and Ladner only refers to them as 'the kids'.

The word 'kid' in the English language can also refer to the leather made from the kid's skin, therefore, this phrase takes on a sinister connotation in the context of the taxidermist's world which may give some clue about his secret perverse activities. The diorama that exhibits the animals' bodies should be read, as both Carrie Dawson and HélianeVentura explain, as a story about the violation and manipulation of bodies (Dawson, 2005, pp.73-74;Ventura, 2007, p.313). It is through the metaphor of taxidermy that Munro effectively discloses the sexual and moral violence that Kenny and Liza have been enduring. The metaphor actually enables Munro to evoke the feelings that victims of child abuse usually experience and repress, as Tal's incest narratives and Herman's study of child abuse reveal (Herman, 1992, pp.96-114;Tal, 1996, pp.155-198). In its original meaning, trauma first referred to a wound to the body, so the image of the skinned animals proves to be a very effective means to convey the physical and spiritual wound inflicted upon the children. It also effectively suggests that Liza and Kenny can only 'inscribe the traumatic experience as metaphor', a device which, as Tal explains, is often used by the victims when they try to talk about the abuse (Tal, 1996, p.16).

Thus, Liza thinks of a 'ripping open' (Munro,p.288) when she tries to describe the effect of Ladner's mocking of Bea:, the verb denoting physical violence reveals she is aware that with Ladner, psychological and physical violence are linked. Furthermore, the image of the skinned animals is also a very effective means to convey the picture the children have of themselves as violated animals, evoking the self-devaluation, loss of self-esteem, and repression of emotions young victims of sexual abuse often feel (Tal, 1996, pp.155-198).

The children are said to be helping Ladner in his job, and if it is accepted that taxidermy is used in this short story as a means to reveal the abuse, then, the fact that Kenny and Liza help Ladner construct the fake bodies suggests that the fiction of their happy life together is a construct in which all of them are complicit. For 'Vandals' also addresses the disturbing issue of the victim's role in preserving the abusive relationship with the abuser and the abuser's partner. The abusive relationship, as Tal's narratives and Herman's study show, both depends on the man's position of power, which ensures silence and secrecy, and relies on the special bonds the abuser forges with his young victims (Herman, 1992, pp.96-114;Tal, 1996, pp.155-198). Ladner's role as an instructor is emphasized, as he teaches the children about birds, trees, animals, the solar system (Munro,p.286). Ladner, the magician who can turn wood and clay into lifelike animals, is also a shape-shifter who can 'switch from one person to another person' (289). In other words, he changes his role from the children's teacher to their abuser, while assuming the mask of a father-like figure. Ladner, who has taught the children about the secrets of the nature reserve and has organized their activities there, is in charge of what Liza calls his 'territory' and the description of Ladner's nature reserve in section three, whose focalizer is Liza, shows that she has internalized his logic. Leaving her father's garden to enter Ladner's 'territory' means leaving the normal world behind to adopt and accept Ladner rule: 'when you cross the road, as Liza is doing now (...) when you cross into Ladner's territory, it's like coming into a world of different and distinct countries.' (291) The divisions Liza sees in the garden, as she distinguishes places where 'serious instruction' about trees and animals occurs from places where the children play, and places where sexual intercourse occurs (291), reveal her attempt to recreate some order out of the chaos she has endured in that territory. However, Ladner has created a world in which several realities coexist and also interlap. In this way,, the children do not know how to differentiatate between games and sexual games: 'what was terrible was always funny, badness was mixed up with silliness, you always had to join him with dopey face and voices and pretending he was a cartoon monster.

You couldn't get out of it, or event want to' (290).

In 'Vandals', Munro rather convincingly explores the complicated bonds between an abused child and her parents which Herman describes in her chapter on child abuse: victims often develop attachments to their abuser, which they will strive to maintain, while attempting to preserve faith in their parents (Herman,p.98;p.107). Liza's inability to escape from her abuser is on a par with her attachment to him, which is revealed when she thinks of their relationship as 'the secret life she had with him' (Munro,. As the use of the pronoun 'she' shows, Liza actually feels that she is a partner rather than a victim in this relationship, which is a means for her to minimize, if not deny, what is taking place with Ladner. Minimizing or excusing the abuse, as Herman's study underlines, frequently occurs in cases of child abuse as the child strives to preserve her attachment to her parents (Herman, 1992, pp.101-102) and although Ladner is not the children's father, he has become a substitute for the father-figure. Ladner has managed to preserve a very strong bond with the children, and more specifically with Liza. He makes sure that the children are on his side by making them laugh at Bea when she tries to join them in the pond, in fact, Liza is aware of Ladner's strategy when she imagines him saying: 'see how vain she is (...) pretending not to know we despise her' (288). Liza's love for Bea is emphasized but it is shown to be made of conflicting feelings, it is both a need to protect Bea and be protected by her:

And 'it it was this collection of flaws [...] that Liza especially loved. Also she loved the dampness that was often to be seen in Bea's eyes [...] her love was one of expectation, but she did not know what is was that she expected. ' (287) Although she claims not to know it, Liza expects Bea to rescue her from the abuse, however, Liza will conclude that Bea is too innocent to understand her relationship with Ladner, so she will never ask for Bea's help. As Dawson has convincingly argued, Liza's position amid the birds after she leaves the pond evokes the myth of Philomela who, after having been raped in a cabin in the woods, had her tongue cut out to prevent her from telling her story, and was eventually turned into a bird (Dawson, 2005, p.75). Philomela wove a tapestry to tell her sister her story, while in 'Vandals' Liza, who never talks about the abuse, draws Bea's attention to clues that indirectly point to it. She shows Bea their initials carved on a tree that stands in the middle of the path ( 289), yet it is her brother Kenny who shouts "Pull down pants!"(289) as he draws Bea's attention to the other series of letters on the tree, P.D.P. which, as Ventura points out, 'clandestinely level an accusation at Ladner, who is revealed as the PeDoPhile' (Ventura, 2007, p.312).

In keeping with this, tThe readers, as McGill notes, are constantly encouraged to read the landscape (McGill, 2002, p.110), since topography in 'Vandals' plays a key part in conveying the character's silenced emotions and the resurfacing of their traumatic memories. 'Vandals', as a trauma narrative, attempts to engage its readers with 'personalized, experientially oriented means of narration that highlight the painful ambivalence' of traumatic memory (Vickroy, 2002, p.3). In the section which describes Liza's return to Ladner's place many years later, much emphasis is put on the white landscape and its few black landmarks, a black swamp, and 'black trunks against the snow" (Munro, p.277). First, the black trees flashing against the white background as the characters drive past them are said to be 'faintly sickening' (277), which suggests, in the context of the black marks against a white background, that deciphering the signs may prove to be an unpleasant experience for readers and characters alike. When the characters stop the snowmobile, they find themselves 'stuck in the solid middle of the winter day' (277), and attention is drawn to trees which are 'plastered with snow, clotted with it (277) and a black swamp which is 'choked with snow' (277). It is only after reading the next section where the abuse is disclosed that readers understand that this anthropomorphic landscape revealed the feelings Liza could not express. forIn the third section, the description of Ladner's garden takes the form of a guided tour, with the pronoun 'you' apparently inviting readers in: 'when you cross the road-as Liza is doing now, trotting on the gravel-when you cross into Ladner's territory' (291). The narrative, which is both marked by these shifts in pronouns verbal tenses (from the past to the present, and from the present to the past), aims to place readers in Liza's 'disoriented position through shifts in time, memory and affect' (Vickroy, 2002, p.28). The change in the use of pronouns, which also appear when Liza evokes their games with Ladner, as quoted above, also brings to mind the dissociative strategies victims of sexual abuse usually resort to. They are a common defense mechanism which enables the child to deny the reality of what is happening to her (Herman, 1992, pp.101-103;Tal, 1996, p.171). As she walks in the garden towards the house, Liza is trying to dissociate herself from her plight, projecting her pain and shame on the garden, as the tour ends on 'places where Liza thinks there's a bruise on the ground, a tickling and shame in the grass' (291). 'Vandals' demonstrates that trauma, as Caruth posits, 'is not locatable in the simple violent or original event in an individual's past, but rather in the way that its very unassimilated nature returns to haunt the survivor later on (Caruth, 1996, p.4).

Then, the description of the garden is interrupted by three italicized segments which, with a final italicized sentence, frame a middle section, in normal typeface. The passage interrupts the course of the narrative and disrupts normal reading, as it is only by connecting the segments to the middle section that the readers can understand that a traumatic memory is resurfacing to the present moment of the narration, which emphasises the traumatic nature of the character's past experiences: P.D.P. Squeegey-boy. Rub-a-dub-dub.

When Ladner grabbed Liza and squashed himself against her, she had a sense of danger deep inside him, a mechanical sputtering, as if he would exhaust himself in one jab of light, and nothing would be left of him but black smoke and burnt smells and frazzled wires. Instead, he collapsed heavily, like the pelt of an animal flung loose from its flesh and bones. He lay so heavy and useless that Liza and even Kenny felt for a moment that it was a transgression to look at him. He had to pull his voice out of his groaning innards, to tell them they were bad.

He clucked his tongue faintly and his eyes shone out of ambush, hard and round as the animals' glass eyes. -bad-bad. (292) Again, 'Vandals' proves to be a trauma narrative, as, as it has internalized the rhythms and processes of traumatic experience' in the form of the text itself (Vickroy, 2002, p.3). Liza is assailed by traumatic memory, a 'disjointed sensory and affective memory', taking the form of an image that possesses the character against her will (Caruth, 1991, p.3). Herman states that 'the traumatic moment becomes encoded in an abnormal form of memory which breaks spontaneously into consciousness' (Herman, 1992, p.37). Traumatic memories, she explains, are 'encoded in the form of vivid sensations and images' (Herman, 1992, p.38). Vickroy also states that in trauma narratives such memories are 'explored through affective and unconscious associations' (Vickroy, 2002, p.3). In the passage above, these associations are conveyed through the floating of segments in italics, where the language of childhood mixes with and is perverted by words said by the abuser and which Liza remembers now. This fragment from the nursery rhyme together with the childish words remind readers that those who are abused in the narrative weare children. Furthermore, this fragment can be read as a symbol of the actual bodily contact between abuser and victims, as the last italicized segment whose repetitive pattern serves to mimic the assault depicts.

Bad

In the middle section, the sexual assault is told only indirectly, from the point of view of a child who tries to dissociate herself from the rape. The description rests on similes such as 'the jab of light' which both convey the violence of the act itself and bring to mind the strategies of indirect telling, through metaphors, that victims of sexual abuse use when they try to tell what happened to them (Tal, 1996, p.16). The passage evokes the dissociative strategies used by victims of child abuse, their powerlessness and their problematic perceptions (Herman, 1992, p.43age). Perception, Herman explains, 'may be numbed or distorted, with partial anesthesia, or the loss of particular sensations' (Herman, 1992, p. 43).

In 'Vandals', the narrative focuses on the man's emotions, so that Liza's feelings seem to be obliterated. Liza's own torn body is absent from the narrative, instead, attention is drawn to Ladner's. In the last paragraph of the middle section, the similes convey Liza's confusion.

Ladner is seen as a predator when his eyes are said to 'shine out of ambush, and a victim since the similes turn him into the animals he skins: Liza sees a 'pelt', 'wires', animals' glass eyes' and 'innards'. The similes also reveal Liza's own lack of agency since she attributes her own powerlessness to her abuser. Herman and Tal's highlight the victim's usual sense of powerlessness and her belief that she is the one to be blamed (Herman, 1992, pp.96-114;Tal, 1996, pp.155-198). Indeed, the depiction of the assault in 'Vandals' shows that the abuser has successfully shifted the blame since the children feel they are the one who have broken the rules: 'it was a transgression to look at him'. As the final italicized segment shows, Liza has indeed internalized the logic of the perpetrator; .'bad-bad-bad' testifies to a double violence: the echo mimics the physical violence endured by the children while the word itself testifies to the moral violence perpetrated on the child who believes she is guilty, and relives her shame as she hears the word again and again. Munro often uses italics to represent words that resurface in a character's memory and haunt her, for instance, in 'The Children Stay', italics are used when the heroine who is about to lose her children suddenly remembers the words by which her baby daughter called her (Munro, 1998, 212). The shift in tenses and the confusing chronology also emphasizse that the frontiers between past and present and between body and mind are blurred as traumatic memory resurfaces. As they are Cconfronted to the puzzle they have to decipher, readers are able to experience Liza's struggle with her traumatic memory.

'Vandals' illustrates the tension between remembering and suppressing trauma as it conveys the violence of traumatic memory through its typography and offers a topography which exposes readers to the full impact of traumatic experience, from the suffering the children keep silent about to the revenant quality of their traumatic past.

Survival of trauma? Re-encountering the past

In section two, the reader learns of Liza's life as an adult, and her immersion in religious zeal, suggesting an attempt to repress what she herself calls her 'wild' past (Munro, 1994, p.281) through a very ordered world. Yet, this vision is questioned when her husband, Warren, remembers Liza's wild dancing at a party: 'she tore her way through music, supplicated and curled around it, kicked loose' (281, italics mine). This description conjures up the vision of a wounded girl who is ultimately locked away from everyone, including her husband. Part two demonstrates that the question of survival after traumatic experience lies at the heart of the short story, since it depicts Liza's trashing of Ladner's house when she is in her twenties. Liza's acts of vandalism are directly linked to to the abuse as herLiza's acts of violence in Ladner's the house are conveyed in words that evoke sexual violence: books are 'torn apart' (280), Liza is said to 'yank out drawers' ( 280) and emphasis is put on the 'ripping of books and paper' (280). The 'funny noise' Liza makes when she violently pulls the drawers out, described as the 'admiring cluck of her tongue' ( 279), echoes Ladner's clucking his tongue in the rape scene (292). Ttearing the books and animals apart is her Liza's means to play out what was done to her. Liza herself points to this connection as she inflicts an injury to herself with her words: "Liza Minnelli, stick in your belly!" (283) These words draw attention to her wounded body and, by making the invisible wound visible, they also represent an attempt to speak out -either because she is repeating what Ladner said to her or because it is her means to voice her feelings about the psychological and physical damage she has endured. Thus, these words ultimately suggest an attempt to come to terms with the traumatic experience. As Liza is said to utter these words 'peacefully' (283), they point to the healing power of words survivors of child abuse feel when they are able to talk about the abuse instead of denying it (Tal, 1996, pp.168-174).

Liza's trashing of the house, therefore, can be seen as the therapeutic re-enactment of the abuse, giving her the empowerment that survivors experience when they remember and acknowledge the abuse. For Liza's dismembering the house and the animals can be read, as Ventura suggests, as 'a remembering of the self' (Ventura, 2007, p.317). When they enter the house, Liza's husband remarks it is 'like going back in time' (Munro,p.280) and when they leave, he smashes a window 'big enough so a kid could get in' (294). Taking Liza to the house and helping her to trash it, Warren has enabled the kid to go back and re-enact the past, a therapeutic re-enactment which, as Liza's remark indicates, has been vital to her survival: "you saved my life.'' (Munro,p.294) However, remembering is a painful process too, and Liza's own wounded body is strikingly evoked when she smashes a bottle of liqueur against a window: 'a pool of beautiful liquid streamed out from it. Dark-green blood. The window glass had filled with thousands of radiating cracks and turned as white as a halo.' ( 281) The blood, the cracks in the window and the 'ripping' of the books evoke a violated body and, as Liza's gestures repeat the violence that has torn her apart, the traumatic memory reactivates the wounds. Yet, beauty results from this gesture and the past, as it is violently re-enacted, seems to engender its own creative force. As Ventura has demonstrated, the passage is endowed with a striking artistic dimension (Ventura, 2001, p.315) when Liza steps back 'admiring what she'd managed so far' (Munro,p.282,my italics). As Liza uses sticks of charred wood to make black marks on the rug (282), suggesting charcoal used in drawing and sketching, and she eventually uses a magic marker to write on the wall (282), she turns her work into a graphic tale of her abuse for Bea and Ladner to read Pointing out the dissociation between affect and representation that victims of trauma suffer from, Dominic LaCapra suggests that 'working through trauma involves the effort to articulate or rearticulate affect and representation in a manner that may never transcend but may, to some viable extent counteract, a reenactment, or acting out, of that disabling dissociation (LaCapra, 2001, p.42).

The wounding words Liza tells, the violent acts she inflicts upon the house and the animals are attempts to articulate her affects and work through trauma.

Liza, however, chooses reticence or cryptic answers when faced with her husband's questions. When asked to justify her act of vandalism, Liza first deflects the question and then openly blames Bea for having phoned her many years after the events to offer her money (275), which indicates that she hasaw Bea's offer as another proof of her silence. Liza's accusation brings to mind a typical strategy used by victims of incest who often blame the mother (Tal, 1996, pp.154-248). Although Ladner and Bea are not the children's parents, Liza's reflection that they are 'like a family' (Munro,p.286) indicates that the abusive relationship can be likened to incest. The fact that Liza still proves incapable of naming and blaming Ladner suggests she has not yet managed to come to terms with the real facts.

Although Liza phones Bea to report the act of vandalism, she says nothing about her role, which reinforces these two women's silence about the past. At the end of the story, readers are left with the disconcerting feeling that silence has prevailed. Thus, Liza's attempt to come to terms with her past becomes quite fragile and uncertain, suggesting that the resolution of the trauma is never final and that recovery is never complete (Herman, 1992, p.212).

Central to Munro's representation of traumatic experience and survival is the image of the wound that obliquely resurfaces in the final section of the story. As Liza and Warren are about to leave Ladner's place, Liza draws Warren's attention to the cedars in the gardenwhich were described as dark and secret rooms -and eventually, to the letters carved on the birch tree: "And that one with the bark like gray skin? That's a birch. See, it had letters carved on it, but they have spread out, they just look like any old blotches now." (Munro,p.294) Echoing the earlier passage when Liza showed Bea these letters, the gesture conveys her wish to talk about her past and understand that this may prove impossible since the barely legible blotches suggest that traumatic wounds are invisible to others. As the bark is compared to 'skin', and the letters to 'blotches' (294), the letters turn into a scar that only Liza can see.

The scar is a recurring image in Munro's fiction; it features prominently in 'Rich as Stink' whose teenage heroine is caught up in a complicated love relationship between her mother, her mother's lover and the man's wife [START_REF] Munro | Rich as Stink[END_REF]. In this story, the girl is severely burnt when the veil she wears catches fire, and a few years later she reflects that, although no one seems to notice how much she has changed, she knows she has, and she embodies the change that she only can see in her scar. In both 'Vandals' and 'Rich as Stink', the scar suggests that no child can find herself entangled in her elders' lives and emerge unscarred, yet it is also the scar that helps the character to make sense of, if not to articulate, what happened to them. In Munro's fiction, the scar is the locus of remembering and of suffering. In 'Vandals', it enables Liza to point to an unhealed wound that she imagines to linger on her body. Seeing the scar means remembering and re-enacting the traumatic wound., The fact that the letters are hardly visible reveals how difficult it is for others to understand the traumatic experience the character has endured, all the more so as Warren's lack of interest is emphasized (Munro, 1994, p.294). Although Warren's lack of interest may allude to a patriarchal discourse neglecting women's (hi)stories -suggested by both his position on the sofa, with his back to Liza when she starts trashing the house, and his dismissing of her actions as a child's tantrum (280) -Warren's inability to notice what is around him (279) connects him with Bea, which evokes a larger desire to preserve silence on the issue of sexual abuse of children. This is 'a wrong', Tal points out, 'that the larger society refuses to acknowledge' (Tal, 1996, p.171).

Although 'Vandals' can not be read as a testimonio due to its fictional nature (Felman and Laud, 1992), it aims at breaking the silence on sexual abuse by highlighting the silences around the children's ordeal: the indirect telling that prevails throughout the story is a means to force the reader to reflect on 'universal desire to see, hear, and speak no evil' (Herman, 1992, p.7).

Preserving her characters' silence is for Munro a means to deny them closure and to highlight how difficult it is to communicate traumatic experience. Thus, the opening sentence of the final section provides readers with a disconcerting vision after Liza has trashed the house: 'Liza locked the door as you had to, from the outside.' (293) The phrase 'as you had to' warns that the gesture is crucial to one's surviving. Yet, it is unclear whether by locking the door Liza is 'liberating her past or sealing her own 'shaded and secret rooms'' (Levene, 1999, p.857). As Warren is the focalizer of the final section, the opening phrase can be read as Warren's approbation of his wife's desire to remain silent about her past. SSpeaking to Eleanor Wachtel in a 1993 interview, Munro used a similar image, as she explained that she had always been interested in the fact that in the course of their lives people could become a totally different person: 'so you've got all these rooms in your head that you've shut off but that you can remember.' (Munro, 1993, p.110) The locked door at the end of 'Vandals' may therefore suggest Liza'san attempt to refuse to dwell on her past. Munro's explanation, however, reveals that shutting off the rooms does not free the character from her past, it can only betray an attempt to prevent others from knowing it. In 'Vandals', Munro underlines the difficulty to communicate traumatic experience. Commenting on the readers' position at the end of the story, McGill remarks that 'Munro finished by asking readers to question the degree of intimacy they really gain as readers.' (McGill, 2002, p.114).

Conclusion

Many gaps remain to be filled in this reticent narrative, where paragraphs often conclude with brief sentences that withhold explanation.: Liza's own choice of silence, '[s]he knew not to talk so much about what she knew (Munro, 1994, p.286), is revealed in a one-line paragraph followed by a textual blank space so that readers may be literally left with the space to ponder this chilling nugget of wisdom, which brutally summarises Liza's own double bind.' (286) Bea's refusal to see what is happening at Ladner's place and Liza's hopelessness are made manifest in two brief sentences in section three: 'What Bea has been sent to do, she doesn't see./ Only Liza sees.' (293). Interestingly, 'there is no object after the verbs 'sees' and 'knew' so that it up to the readers to infer what it is that the characters should see or what they keep silent about. The position of the readers mirrors Bea's since they are meant to decipher the signs of trauma. However, there are many impediments to comprehension, for instance, the confusing chronology makes it impossible to know when the abuse started or ended. The shifting viewpoints in the story -Bea is the focaliser in section two, Warren for the second and fourth sections, and Liza for the third one -prevent the readers from gaining too much information about the past. They also preclude identification with any of the characters, including Liza whose emotions are only seen through Warren in section two -the image of the girl who is locked away from everyone as she dances introduces a distances between Liza and the reader. So does the tour of Ladner's garden in section three with its constant emphasis on dissociation. This tour, as McGills argues, 'both completely identifies readers with Liza as the 'you' and utterly alienates them from her by eliding her' (McGill, 2002, p.112). There is, however, another effect of the confusing topography: the readers who, as McGill points out, are 'involved in drawing the map' (McGill, p.109), may also sympathize with Bea's confusion, since her difficulties to keep track of her direction during the first tour of Ladner's property is emphasized (Munro,. Focusing on both Liza's incomprehension and Bea's confusion, Munro manages to arise readers' empathy and to prevent over-identification with the characters. Instead, Munro aims to provoke what LaCapra calls 'emphatic unsettlement', a process which enables the outsider to be responsive to others' traumatic experience without appropriating their experience (2001, p.42; 2009, pp.65-66). She also denies her readers easy consolation and reassurance; this is achieved at the end of the story with the dialectical images which testify to the complexity of a narrative whose aim is to suggest 'what is inaccessible, unbelievable, and elusive about traumatic experience.' (Vickroy, 2002, p.8). The first image, as we have seen, is that of the scar on the tree. To see the letters as a scar, as Liza does, is also a means to evoke what Caruth calls 'the enigma of survival' (Caruth, 1996, p.58): Liza has survived her childhood abuse, she has been offered the possibility to act out her traumatic memories, yet, pain does not completely disappear. 'Vandals' is a story that resists closure, for instance, Nathalie Foy concludes that with the final image 'you could feel darkness collecting'Warren is made to feel a sense of immediate danger (Foy, 1998, p.160). However, this image also indicates that, in spite of his lack of interest or empathy, Warren has been touched by something: 'you could feel the darkness collecting' (Munro, 1994, p.294). This image resists explanation, although it echoes both Bea's depiction of her relationship with Ladner, 'I come up against blocks of solid darkness.' (274), and Liza's vision of 'dark rooms' in the garden, symbolizsing her secret life with Ladner (291). The pronoun 'you' calls on the readers who are not expected to fully understand the traumatic experience but are instead, expected to be responsive to the characters' attempts to tell their traumatic experience.

In conclusion, 'Vandals' illustrates the power of literature to offer what Caruth calls 'an enigmatic testimony not only to the nature of violent ways but to what, in trauma, resists comprehension ' (1996, p.6). Thus, Vandals' attests to the endless impact of trauma on a life' (Caruth, 1996, p.7). In 'Vandals', Munro has tried to encompass many aspects of traumatic experience, from the silence and denial that cover it, to the victim's troubled relationship with her past and her struggle with forgetting and remembering, to her ultimate attempt to survive trauma. As many trauma narratives do, 'Vandals' places readers into uncomfortable positions, a process which, as Dominic LaCapra puts it, 'poses a barrier to closure in discourse and places in jeopardy harmonizing or spiritually uplifting accounts of extreme events from which we attempt to derive reassurance' (LaCapra, 2001, pp.41-42). The story draws its power from its dialectical images, preventing reassurance, easy consolation and complacency. It is a powerful trauma narrative in that it employs reticence and indirect telling as narrative strategies to expose the silences that have often covered up child abuse and call on readers to be responsive to those who attempt to break the silence.