A study helped by Brighton toddlers is shedding more light on the colour perception science behind the blue/black or white/gold dress puzzle.
The picture posted on Tumblr by Highlands singer Caitlin McNeill has taken the world by storm, with millions of people arguing over whether it’s blue and black or white and gold.
Writing in the Guardian today, University of Sussex researcher Marie Rogers explained one theory behind the phenomenon – which has been developed at the University of Sussex by studying local toddlers and how they perceive colour.
She explained: “In our everyday lives, there are many changes in the colour of the light illuminating our surroundings. For example, the yellow glow of an incandescent light bulb versus the blue-ish hue of a fluorescent light.
“The light that an object reflects to the eye is a combination of both the colour of the object itself and the spectrum of the light source, which may vary.
“The brain is able to disentangle these two things and decide what colour the object is. Simply put, objects appear the same colour even if the light illuminating them changes – a concept known as colour constancy.
“So, how does the brain keep colours constant? One way is by using reference points. For example, say you know your mug is white, but the light being reflected from the mug is slightly red. The brain can then discount a certain amount of red tint from the rest of the scene you are seeing.
“Other contextual knowledge may come into play, for example you are drinking coffee by the window at dawn. It makes sense for the light to be red-tinted as the illumination source is the sunrise. This is known as top-down processing.
“All of our perceptual experiences are informed by this kind of processing, resulting from context and previous knowledge.
“This is possibly something you’ve never thought about or been aware of before – you may well underestimate just how much the lighting in our world changes, because your brain compensates for it so well. This happens automatically without any conscious awareness.
“But, colour constancy is not perfect. In The Dress photo, there aren’t many cues or reference points to tell us the properties of the light source. This leads to ambiguity and the possibility of different interpretations.”
Ms Rogers works as part of the university’s Sussex Colour Group.
Amongst other things, the group works with toddlers to explore how their developing knowledge of the world and contexts might affect how they see colour.