Jean-Marie Cellier

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.

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.

Depth of processing and design-assessment of ecological interfaces

Despite the cognitive vocation of a number of studies on the comparison of interfaces in sensitive industrial sectors such as the nuclear sector, and in spite of the presentation of new frameworks for both task analysis and reducing the mental load, one vital question remains: how does psychology enter into these studies? Very often the principle of depth of processing is the basis for interface design-assessment approaches in operating situations like those of nuclear reactors. This then justifies the use of a methodology based on recall. After presenting how this principle, which stems from the memory field, is the basis for the different interface designs recently proposed in the literature and the validation approach associated to these technical propositions, we present a pressurized water reactor operating situation that demonstrates the same willingness to act on reasoning through information displays. For powering up conditions, we show how integration of different representational levels has been achieved, and provide evidence for a Physical vs. a Physical and Functional display. All these features indirectly show that recent proposals on ecological interface design have some validity for real work situations, provided a context is selected. Finally, from this analysis, we define, by considering success as the limits of past experience, the conditions under which a recall technique can be used to demonstrate the efficiency of these new tools.

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.

Expertise and Strategies for the Identification of the Main Ideas in Document Indexing

This research project examined strategies used by indexers in identifying important concepts in scientific books. Indexing consists of employing a controlled terminology to express the important ideas contained in a given document. Twenty indexers of varying types and degrees of expertise indexed four books, noting, first, terms representing the main ideas, and then the indexing terms taken from a documentary language. The indexers not familiar with the content domain of the books identified fewer concepts than the indexers familiar with the domain, and based their judgements on surface-level features of the information. Prior knowledge of the experiments documentary language guided the choice of some concepts, which could be translated into controlled terms, resulting in more rapid identification. These results showed that identifying important concepts could be due to perceptual processing based on specific cues, as well as conceptual processing based on prior knowledge of the documentary language and the domain to be indexed.

Task Analysis Does Count in Making the Abstraction Hierarchy Concrete: Evidence from a Pressurized Water Reactor Situation

Proponents of the Ecological Interface Design framework have recently highlighted two important assumptions: (a) the Abstraction Hierarchy (AH) would only be a representation of the work domain, not a task representation; (b) the development of an ecological display that presents information at different levels of abstraction should be based on a full implementation of the Abstraction Hierarchy. However, as revealed by our field studies, these assumptions might dismiss the role of task analysis in making the AH concrete. First, the presentation of mass balance and energy balance in an ecological display is important because these kinds of equilibrium constitute what the operator should maintain. Second, the use of an AH and its implementation in an effective work situation will probably be state-specific. Important parameters to be monitored, mass and energy balances that should be assessed, change as a function of the overall state of the process.

Using a priming paradigm for display effectiveness assessment

Abstract In order to assess the relevance of colour coding of severity in a nuclear control board, a repetition priming measure was adapted. Fourteen operators were presented with a list of alarms taken from their display, and asked either to pay attention to their colour, or to pay attention to their severity. Then they rated the colour of studied and non-studied warnings presented without their colours. When attention was directed to severity, memory for colour was as good as when attention was directed to colour, this result indicated that colour was processed when processing severity. Repetition priming allows one to partial out memory performance into two components: that due to reconstruction based on domain knowledge, and that due to pure memory for the information presented earlier. In addition, it offers several advantages over classical measures of memory for industrial settings.