The influence of mental representations on eye movement patterns under uncertainty
Creators: name: Renker, Johanna
Publisher: name: Technische Universität Dortmund
Year: 2017
Subjects: subject: Mental model
subject: Decision making
subject: Visual search behavior
subject: Uncertainty
subject: 610

description: This thesis investigated eye movements (i.e. number of fixations, fixation duration) during learning in uncertain situations, i.e. when interacting with a technical system like a ticket machine and users are not aware of the functioning. It was predicted that eye movements allow insights into the process of developing a mental representation under uncertainty. In order to induce uncertainty, a visual spatial search task with likely and unlikely target locations was developed. Participants were asked to predict the appearance of stimuli at target locations as accurately as possible by learning the underlying probability concept. In quick succession, they were asked to react as quickly as possible on changes of the stimuli. In total, five eye tracking experiments were gradually developed and conducted. In a first experiment, participants performed the newly developed visual spatial search task und learned the underlying probability concept of likely and unlikely target locations accurately. Eye movements became more focused, i.e. number of fixations as well as fixation duration decreased significantly over the time course of the task with increasing learning and reduced uncertainty. The aim of the second experiment was to assess to what extent search difficulty affects the development of the mental representation. Therefore, target objects were presented at an unstructured white-gray patterned background. Results showed an overall higher number of fixations than in the first experiment, however, participants also developed an accurate mental representation of the probability concept. A third experiment was designed as a relearning experiment to study the effect of initial knowledge on the development of mental representations and thus on eye movements. Participants initially learned a probability concept and in a second phase learned a different concept of target-location associations. Thereby, eye movements indicated different phases of relearning. In a fourth experiment the prediction and the reaction task were assessed separately to elucidate which dominated the development of mental representation. Results indicated that the developed mental representation of the visual spatial search task was mainly based on the prediction of the target stimuli and not on the reaction on changes of the target stimuli. In a last experiment, the manipulation of the degree of objective uncertainty by varying the probabilities of the probability concept did not lead to different eye movements. It seemed that the degree of subjective uncertainty was not affected by varying the probabilities. In conclusion, the results of the thesis demonstrated that eye movements actually gave insights into the development of mental representations under uncertainty. Eye movements informed about the learning stage, viz. the accumulation of information, independent of the content as well as the subjective uncertainty of the participants, viz. the usage of decision strategies and strategies to cope with uncertainty.