How to Convey Perceptual Skills by Displaying Experts’ Gaze Data

How to Convey Perceptual Skills by Displaying Experts’ Gaze Data Halszka Jarodzka (h.jarodzka@iwm-kmrc.de), Katharina Scheiter (k.scheiter@iwm-kmrc.de), and Peter Gerjets (p.gerjets@iwm-kmrc.de) Knowledge Media Research Center, Konrad-Adenauer-Str. 40, 72072 Tuebingen, Germany Tamara van Gog (tamara.vangog@ou.nl) Open University of the Netherlands, P.O. Box 2960, 6401 DL Heerlen, the Netherlands Michael Dorr (dorr@inb.uni-luebeck.de) Institute for Neuro- and Bioinformatics, University of Luebeck, Ratzeburger Allee 160, 23538 Luebeck, Germany Abstract transience imposes high cognitive demands onto learners (Lowe, 1999). Hence, the fact that complex tasks often involve the interpretation of stimuli that are both visually rich and dynamic may cause serious complications for their processing. The question arises how experts compared to novices are able to cope with these demands when processing the information required for task performance. Complex tasks with a visually rich and dynamic component, like classifying locomotion patterns in moving, colorful fish, require the acquisition not only of conceptual but also of perceptual skills. In a previous study expertise differences were examined on a performance and process level by means of eye tracking and verbal protocols. It revealed that experts attended more to relevant aspects of the stimulus compared to novices and used knowledge-based shortcuts for classifying the locomotion patterns. The current study examined a method to convey perceptual skills of a didactically behaving expert to novices by means of showing them a display of the expert’s gaze data recorded while he performed the task. Results show that this type of modeling example influences visual attention and enhances performance. Expertise Effects in Processing Complex Stimuli Keywords: eye tracking; expertise; modeling; gaze display Complex tasks with a dynamic and visually rich component require not only the acquisition of conceptual but also of perceptual skills. This paper presents studies on fostering perceptual skills in novices by displaying to them how an expert distributes his visual attention while performing such a task. First, an in-depth task analysis will be made by discussing the properties of complex visual tasks and expertise differences in performing such tasks, with a focus on a previous study by the authors (Jarodzka, Scheiter, Gerjets, & Van Gog, 2009). Then, an empirical study is reported were the possibilities of training the respective skills by means of modeling examples were investigated. Complex Tasks with a Dynamic, Visual Component Complex Tasks (Van Merrienboer, 1997), like computer programming or statistical analyses, are composed of sub- skills that all need to be used and coordinated simultaneously. In order to achieve a certain level of expertise, Van Merrienboer suggests that instruction should be based on authentic, complex learning tasks, to train learners to apply and coordinate the necessary sub-skills. In addition, many complex tasks, like the interpretation of weather maps (Canham & Hegarty, 2009) or x-rays (Lesgold et al., 1988), involve dealing with visually rich displays. In particular, these tasks require users to observe and interpret transient information, which rapidly changes over time (e.g., aircraft control panels; Ellis, 1986). This Common methods for assessing skill differences in experts and novices involve recording verbal reports and eye movements during task performance. In processing complex stimuli, novices attend to saliency rather than to those aspects that are relevant for task performance (Lowe, 1999). On the other hand, people with a higher level of expertise are able to process complex stimuli more efficiently by quickly focusing their visual attention onto the relevant aspects of the task while ignoring potentially salient, but irrelevant information (e.g., Canham & Hegarty, 2009; Jarodzka et al., 2009; Lesgold et al., 1988; Lowe, 1999). Lesgold and colleagues (1988) termed this ability of experts ‘perceptual knowledge’. To conclude, the (perceptual) processing of complex stimuli does not only depend on the mere saliency of its single features, but also on the cognitive background of the observer (Henderson, 2007). Expertise Differences in Classifying Fish Locomotion. While most of the previously mentioned studies have provided important insights on expertise differences when accomplishing complex visual tasks, only the study by Jardozka et al. (2009) investigated them in perceptual processes (i.e., eye movements) on dynamic stimuli. Moreover, the investigation of visually rich, but static stimuli has been conducted on a coarse level using single basic eye tracking parameters (e.g., number of fixations). However, performing a complex task is not necessarily well reflected in these single parameters, because the skills required are likely to be composed of multiple sub-skills that are better described by sequences of steps. Thus, for the study of complex dynamic skills, expertise differences should be investigated at a more sophisticated level including sequence analyses to get a better insight into the task and the skills required (Jarodzka et al., 2009).