  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.
