Ocular reactions in response to impressions of emotion-evoking pictures

Abstract

Oculomotor indicies in response to emotional stimuli were analysed chronologically in order to investigate the relationships between eye behaviour and emotional activity in human visual perception. Seven participants classified visual stimuli into two emotional groups using subjective ratings of images, such as "Pleasant" and "Unpleasant". Changes in both eye movements and pupil diameters between the two groups of images were compared. Both the mean saccade lengths and the cross power spectra of eye movements for "Unpleasant" ratings were significantly higher than for other ratings of eye movements in regards to certain the duration of certain pictures shown. Also, both mean pupil diameters and their power spectrum densities were significantly higher when the durations of pictures presented were lengthened. When comparing the response latencies, pupil reactions followed the appearance of changes in the direction of eye movements. The results suggest that at specific latencies, "Unpleasant" images activate both eye movements and pupil dilations.