Does normal pupil diameter differences in population underlie the color selection of the #dress?

TL;DR

This study investigates whether individual differences in normal pupil size influence the perception of the #dress's color, revealing significant pupil size variations among different color perception groups.

Contribution

It provides evidence that normal pupil size differences are associated with the color perception of the #dress, a novel insight into perceptual variability.

Findings

W/G and switch groups had significantly smaller pupils than B/B group.

Significant pupil size differences were confirmed with infinity focus experiments.

Pupil dilation did not induce color perception changes in the W/G group.

Abstract

The fundamental question that arises from the color composition of the #dress is: 'What are the phenomena that underlie the individual differences in colors reported given all other conditions like light and device for display being identical?'. The main color camps are blue/black (b/b) and white/gold (w/g) and a survey of 384 participants showed near equal distribution. We looked at pupil size differences in the sample population of 53 from the two groups plus a group who switched (w/g to b/b). Our results show that w/g and switch population had significantly ( w/g <b/b, p-value = 0.0086) lower pupil size than b/b camp. A standard infinity focus experiment was then conducted on 18 participants from each group to check if there is bimodality in the population and we again found statistically significant difference (w/g < b/b , p-value = 0.0132). Six participants, half from the w/g camp, were administered dilation drops that increased the pupil size by 3-4mm to check if increase in retinal illuminance will trigger a change in color in the w/g group, but the participants did not report a switch. The results suggest a population difference in normal pupil-size in the three groups.