Pupil role in color brightness perception in relation with "the dress" explanations

Abstract

It is well known that pupil size is determined mainly by the illumination level and that the entire pupil's reflex mechanism is controlled by the sympathetic and parasympathetic nerves, in an almost exclusively bottom up fashion. On the other hand, it is a less know issue how the pupil size affects perception, and in particular, color perception. Recent studies, triggered since "the dress" image was scientifically considered by the vision community, suggest that pupil size plays an important role in the perception of brightness of colored patches. Our research suggest the existence of two groups of observers: those who have a "big pupil" and perceive colors in a dimmer way and those who have a "small pupil" and perceive colors in a brighter way. Further analysis is needed to grasp these results in a family theoretical framework.