Fashion Brief
It is rare, other than on Oscars night, that the world holds its collective breath discussing dresses and their colours. But, if social media is to be believed, the optical illusion of a multicoloured dress divides us sharply into those who can only see gold-and-white and those for whom the dress is clearly black-and-blue.
We are always fascinated by optical illusions, by the tricks that the visual system plays with our perception, and this reminds us that for most of the time we unflinchingly rely on visual cues to navigate our world.
But what is colour perception actually for? Colour helps us to recognise objects, but it also has a more mysterious role in our lives. We like colour. The great value of gems and gold is their colour. Our desire for colour has driven industry, and has even propelled us to engage in some atrocious behaviour, such as the craze for indigo, which fuelled slavery.
Colour seems to have direct access to our emotions. Yet the way the brain calculates colour isn’t governed by simple rules: what looks like one colour to you can appear as a very different colour to me. It is this combination of factors – the emotional power of colour coupled with the inherent mystery in how colour is determined by the brain – that sparks our collective obsession with the colour of that dress.
Many in the two camps simply want to know which side is right. Others want to know why different groups of people, all with apparently “normal” colour vision, could disagree so vehemently. Yet the conundrum of the dress can be explained by considering how it is that the brain determines colour, and the environmental conditions in which the brain circuits that are responsible for colour have evolved.
The colours of different light sources can vary rather wildly. This means that the light from any given object also varies. The amazing thing about colour vision is that the colour of an object is constant – that is, we recognise it as the same colour, even as the light conditions change. And even more remarkable, the operations that discount the colour of the illuminant are entirely automatic. We take them for granted. Until they play games with us.
When I first saw the dress I thought it was orange and blue, and a Photoshop analysis of the colours of the pixels of the dress shows this to be the case. I am a visual artist, trained in painting. Painters generally try to be mindful of what the visual system does to colours; I always try to abstract colours from their surrounding context, where possible. This might explain why I see it differently than the two majority camps. One way or another, painters interested in capturing the colour of the natural world must learn how to do something rather unnatural: they have to learn to see the colour of light.
We evolved in a natural world where we were exposed to the colour of daylight. As the sun rises and sets, the colour of the illuminant varies from orange to blue. This colour isn’t “useful” because it doesn’t tell us anything about the colours of objects. So our brains have learned to get rid of this information.
By accident or design, the dress is a carefully created composition of orange and blue that confounds our visual systems. The brain tries to figure out what this ambiguous colour combination means, attempting to remove either the blue side of the daylight axis or the red side. Why some see the dress as gold-white and others as blue-black has to do with which side of this daylight chromatic axis is discounted. And for some, the colour can spontaneously flip. But importantly, at any given time, the colour is stable, because the brain doesn’t like ambiguity.
My hunch is that the more common perception is gold-white, because this is what one would expect in the day part of the daylight viewing, when the world is illuminated by the sun and shadows are illuminated by the blue sky. Just as in Monet’s paintings of haystacks in the snow, the colour of the shadow is discounted and we typically see it as gold (where the sun hits the haystack) and black (for the darker shadow). The minority, blue-black, folk are probably night owls.
Our strong desire to have visual images resolve unambiguously, coupled with our irrational passion for colour, is, I think, at the heart of why we find the dress so compelling. And why the two camps will probably keep fighting to try to prove that they are right.
