Mar 06 2025

Why are some photos memorable at first glance, while others are quickly forgotten? Niimi Ryosuke, an associate professor of cognitive psychology in the Faculty of Humanities at Niigata University, investigated people’s pupil size when they looked at photographs of landscapes, objects, and more. Even after considering the effects of differences in brightness and other factors of the photos, the pupils were found to be slightly larger when looking at memorable photos. Pupil size is known not only to change in response to brightness but also to unconsciously reflect cognitive activity in the brain. The present study revealed a difference in the cognitive activity that occurs in the brain when looking at memorable and forgettable photos, which is reflected in pupil size changes.

Key points

• When looking at memorable photos, the pupils were larger than when looking at forgettable photos.
• This effect could not be explained by other factors known to affect pupil size, such as the brightness of the photo.
• The change in pupil size may reflect how the brain processes visual information.

Publication Details

Journal: Psychophysiology
Title: Pupillary responses reflect image memorability
Authors: Ryosuke Niimi
Doi: 10.1111/psyp.70007