Characteristics of Pupil Diameter Variation during Paying Attention to a Specific Image

The severely disabled people have difficulties in communication with other people because they can hardly move their body. To understand the intention of disabled people, communication devices using eye movement have been developed. In these systems, the user can click by keeping the stationary gaze during the predetermined time. However, the gaze stationarily induced by discursive looking may cause the unintended clicking. To solve this problem, we focused on the pupil diameter variation caused by attention. The pupil diameter variation has possibility of judging whether the user pays attention or not. In this paper, we investigate the characteristics of the pupil diameter variation during paying attention by using the visual stimuli. In the experiment, four images were randomly presented to subjects. The subjects counted the frequency of a specific image which subjects previously selected among four images. As a result, the pupil diameter during the presentation of the specific image is significantly larger than that of other 3 images from 1 to 2 s after visual stimulus presentation.