The Effect of Ambiguous Image on Pupil Response of Sun and Moon Perception

This study investigates the influence of ambiguous sun and moon images on stimuli perception based on pupillometry. A random stimulus was presented in a few seconds, and another few seconds, as feedback, observers reported the stimulus was perceived as the moon or the sun. To overcome the lack of previous studies that have not been able to segregate the physical (Glare effect) and cognition factors of image stimulus, the data were grouped into two categories, i.e., as the actual image (the ground truth, “GT”) and observers’ perception (“PR”) responses. As a result, the pupil constricted significantly when the stimulus is perceived as the sun. Furthermore, this pupillary response is unassociated with the average physical luminance of images. This result indicates that high- level cognition influences perception pupillary response.