Proceedings of The Physiological Society

Physiology 2016 (Dublin, Ireland) (2016) Proc Physiol Soc 37, PCB251

Poster Communications

Investigating relative genetic and environmental contributions to subjective perceptions of the colour of "the dress" in a classic twin study

I. T. Hossain1, E. Yonova-Doing2, D. Kozareva2, C. J. Hammond1,2, O. A. Mahroo1,2

1. Ophthalmology, King's College London, London, United Kingdom. 2. Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom.

Human colour vision is enabled by the existence within cone photoreceptors of photopigments with differing spectral sensitivities. However, subjective perceptions of colour are the consequence of several layers of retinal and higher cortical processing, and objects may be perceived to have the same or different colours based on intrinsic and extrinsic properties such as type of illumination, and prior experience. The widely reported phenomenon of starkly differing colour perceptions between subjects viewing a particular photograph of a dress raises intriguing questions and avenues for exploring visual neurophysiology (Schlaffke et al., 2015; Winkley et al., 2015). Are the differences determined by prior environmental experience in terms of how subjects have learned to name colours in different contexts or is there a genetic component to how the dress is perceived? The twin study design permits a relative quantification of the importance of genetic and environmental factors by examining concordance within monozygotic (MZ) and dizygotic (DZ) twin pairs. As part of a wider twin study (which had local ethics committee approval), participants were recruited from the TwinsUK cohort, which comprises adult twins, who are mostly female and of European ancestry. Participants were shown a standard image of the dress, and asked to name the colours, and then were forced to make a choice between the two common alternatives "white and gold" (WG) or "blue and black" (BB). Case-wise concordance was calculated for MZ and DZ pairs as 2C/(2C+D) where C is the number of pairs concordant, and D the number of pairs discordant for seeing the dress as blue and black (which is the less common choice). One hundred and seventy-three participants were recruited: of these 118 chose WG, and 55 chose BB. After exclusion of unpaired twins or pairs whose zygosity was unknown, responses were included from 128 twins (43 MZ and 21 DZ pairs). Concordances were 0.67 and 0.18 for MZ and DZ pairs respectively. The findings of a markedly higher concordance in MZ pairs suggests that genetic factors are important in determining the colours perceived. These genetic factors are likely to be multiple, and future studies exploring the contribution of variants in retinal photopigments or proteins involved in higher neuronal processing would be informative.

Where applicable, experiments conform with Society ethical requirements