05 Mar 2018, Catherine Gaunt
How do babies see colour?
Our visual experience is partly shaped by biology (e.g. the neurons in our visual system) but also by our experience in the world. So, what happens while these two things are developing?
There is a lot of research which shows that, even before babies know any words, they can categorise things in their environment. We ran the Rainbow Project at the Sussex Baby Lab (funded by a European Research Council grant to Professor Anna Franklin, who leads the lab) to try tounderstand how babies were making their colour categories without the words to do it with.
Our experiment used a method called ‘novelty preference’. In this method, researchers take advantage of the fact that babies prefer to look at things they are less familiar with than something they’ve seen a lot of.
In our study, babies were first shown one colour repeatedly until they lost interest in it (a process called ‘habituation’), and then this familiar colour was paired with a colour adjacent to it in the colour spectrum which they hadn’t been shown before. If they think it’s from the same group as what they’ve just been shown, they’ll look equally at both colours, but if they think it’s from a different group, they’ll look for longer at the new colour.
What were the findings?
Babies divide the colour spectrum into at least five categories: red, yellow, green, blue and purple. We compared these colour categories with how the signals from the eye combine to give us colour vision and found there was a relationship between the two; the biology behind our colour vision provides ‘fault lines’ for babies to categorise the colour spectrum. In the absence of language, babies still have a way to categorise the colours in their world, which is based on biology.
The road from having these biologically determined colour groups to knowing the words is a long one. We don’t yet fully understand how our cultural experience interacts with biology to help shape the way we see the world. There are lots of languages which don’t distinguish between green and blue, while the four- to six-month-old babies we studied do.
What other research are you doing?
Our lab and Sussex Colour Group are investigating different aspects of how and why colour perception develops. We’re working with schools and nurseries to develop an app to help diagnose colour vision deficiencies (colour ‘blindness’) in young children.