Hélène Eyrolle

Interference between switched tasks

Interference between tasks in a task-switching situation was interpreted in terms of theoretical models of time-sharing. Controlled processing of two separate tasks in a time-sharing situation was hypothesized to require a strategy of management whose ease of execution depends on the complexity of the task involved. Switching from one task to the other requires activation • of the resources required for performance of the new task and inhibition of the resources engaged in the first task. Failures in either of these two processes will interfere with the performance of the second task. This hypothesis was tested in a situation in which subjects had to switch from one detection task to another. Interruption of one task to carry out another task increased both processing time and error rate in the second task. The types of error (intrusions, confusions and omissions) were considered to be specific to timesharing.

Expertise in dynamic environments

This paper reviews results of comparisons between novice and expert operators in the supervision of dynamic environments. Firstly, the characteristics of expertise and its operational definitions are discussed. Secondly, the main dimensions of the complexity of these environments are described and the difficulties operators have in coping with complexity are examined. Research work carried out in field studies is then overviewed in order to assess the role of expertise in the three components of process control: monitoring, diagnosis and decision-making and executive control. The discussion stresses the convergent results of various studies. In spite of the diversity of task domains and of novice-expert definitions, results converge on three points: experts are better at producing inference, in anticipating, and have a more functional view of the process. Divergent results on directionality of reasoning, depth of knowledge in relation to performance and synchronization of actions are also discussed. Final...

Pertinence generation in radiological diagnosis: Spreading activation and the nature of expertise

An empirical study of human expert reasoning processes is presented. Its purpose is to test a model of how a human expert’s cognitive system learns to detect, and does detect, pertinent data and hypotheses. This process is called pertinence generation. The model is based on the phenomenon of spreading activation within semantic networks. Twenty-two radiologists were asked to produce diagnoses from two very difficult X-ray films. As the model predicted, pertinence increased with experience and with semantic network integration. However, the experts whose daily work involved explicit reasoning were able, in addition, to go beyond and to generate more pertinence. The results suggest that two qualitatively different kinds of expertise, basic and super, should be distinguished. A reinterpretation of the results of Lesgold et al. (1988) is proposed, suggesting that apparent nonmonotonicities in performance ore not representative of common radiological expertise acquisition but result from the inclusion of basic and super expertise on the same curve.

Effects of age and level of work experience on occurrence of accidents.

Results of a research study on the effects of age and work experience and their interaction on the occurrence of accidents in an agro-food sector are described. Three different levels of experience and six age groups were examined. Age and work experience significantly affected frequency and seriousness of accidents. A study of these two factors jointly shows that considerably higher rates of frequency and seriousness are found for the youngest and oldest subjects with low work experience. These analyses enable us to put forward several hypotheses concerning the mechanisms in the occurrence of accidents.

Visual signals in text comprehension: How to restore them when oralizing a text via a speech synthesis?

Abstract It has been assumed theoretically and established empirically that text signals exert an influence on text memorization and comprehension. The study investigates whether the restoration of the text visual signals improve text memorization and comprehension when automatically converting a text into speech. Participants listened to a restaurant menu oralized by a text-to-speech synthesis. The visual signals used in the menu were restored either with discursive segments, with prosodic cues, or with a picture of text, displayed before or during the listening. Participants had to perform tasks assessing their text memorization and comprehension. The restoration of text visual signals exerts an influence on the participants’ recall but these effects vary according to the restoration mean used and to the task. When visual signals are not restored, individuals construct an erroneous representation of the situation described in the text leading to a misinterpretation of the text meaning, whereas the discursive and prosodic restorations involve the construction of an adequate representation.

The segmented presentation of visually structured texts: Effects on text comprehension

The effects of a segmented presentation applied to a visually structured text were examined in the context of the explosion of small-screen devices. Empirical research investigating the influence of text signaling on text processing suggests that the text visual structure may influence comprehension by facilitating the construction of a coherent text representation. Undergraduate students were asked to read a text under different segmented conditions varying on the type of information provided about the text visual structure and on the segmentation unit. When the segmented presentation did not supply any information or when it only offered local information about the text visual structure, text comprehension depended on the segmentation unit. When the segmentation unit did not fit the text visual structure, an erroneous text representation was constructed, whereas the compatible segmentation unit led to a correct text comprehension. When the segmented presentation rendered the global text visual structure, the segmentation unit had no effect on comprehension and more readers constructed a correct and close text representation. Thus, the text visual structure seems to play a role in text comprehension and this role has to be taken into account for text segmented presentation.

Vertical perceptual span and the processing of visual signals in reading

A previous study by Pollatsek et al. ( 1993 ) claims that the perceptual span in reading is restricted to the fixated line, i.e. readers typically focus their visual attention on the line of text being read. The present study investigated whether readers make use of content structure signals (paragraph indentations and topic headings) present several lines away from the currently fixated line. We reasoned that as these signals are low-resolution visual objects (as opposed to letter and word identity), readers may attend to them even if they are located some distance away from the fixated line. Participants read a hierarchically organized multi-topic expository text containing structure signals in either a normal condition or a window condition, where the text disappeared above and below a vertical 3° gaze-contingent region. After reading, participants were asked to produce a written recall of the text. The results showed that the overall reading rate was not affected by the window. Nevertheless, the headings were reread more in the normal condition than in the window one. In addition, more topics were recalled in the normal than in the window condition. We interpret the results as indicating that the readers visually attend to useful text layout features while considering bigger units than single text lines. The perception of topic headings located away from the fixated line may favour long-range regressions towards them, which in turn may favour text comprehension. This claim is consistent with previous studies that showed that look-back fixations to headings are performed with an integrative intent.

Visual Signals Vertically Extend the Perceptual Span in Searching a Text: A Gaze-Contingent Window Study

This study investigated the effect of visual signals on perceptual span in text search and the kinds of signal information that facilitate the search. Participants were asked to find answers to specific questions in chapter-length texts in either a normal or a window condition, where the text disappeared beyond a vertical 3° gaze-contingent region. The texts either contained no signals, paragraph marks, or headings that did or did not inform about the text content—that is, topic headings or fake headings. The information conveyed by paragraph marks and topic headings both proved to be very helpful to the search process. Moreover, the results revealed a larger perceptual span for the signaled texts than for the unsignaled ones. The results are taken as evidence for the existence of a text layout span in text search, which is larger than the span for letter and word processing, and includes the useful typographical information on the printed page.

The Role of Expertise in Selecting Informations from Documents in a Dynamic Environment Supervision Activity

The study reported in this paper is part of a research carried out by a pluridisciplinary team at ~the:french National Telephonic Network Supervision Center (Eyrolle, Virbel, 1997). In this dynamic situation the operators’ task is to ensure phone calls regular dispatching inside the network. Given the evolutive character of both the network as well as the supervision tools, operators’ knowledge and representations have to be continuously updated thanks notably to paper documents. The analysis was then focused on the information and communication activities in terms of computer supported cooperative work systems.

Contributions to Psychohistory: XXIV. Professional Experience and Expertise in the Area of Information Sciences

Document categorization for the elaboration of a bibliography plan differs according to the level and type of expertise.