Appraisals Influence Eye Pupil Size: The Effect of Goal Type and Goal Congruence

Abstract

This thesis attempted to investigate the effects of appraisal dimensions on pupillary movements. Three appraisal dimensions were under investigation: goal relevance, goal type and goal congruence. Three hypotheses were formulated. Pupil dilation a) differs in neutral and relevant events; b) depends differently on wins and losses; c) is affected by goal conduciveness and goal obstructiveness. A novel research paradigm was used to test these hypotheses. Instead of picture stimuli we relied on perceptually simple stimuli (Landolt circles) which were coupled with affective meaning. To that end we used the monetary incentive delay task (MID) where the stimuli were associated with three types of events: gains, losses, neutral. The conditioning in the experiment was successful. Pupil dilation showed a difference between neutral and relevant events. As predicted, the results confirmed that goal type has an effect on pupillary reactivity. To a degree goal conduciveness also demonstrated the pattern predicted, in that pupil reactivity changed, but only in approach conditions (conditions “you won” and “you did not win” differed significantly).