Language spoken impacts on colour seen

It is still a controversial idea

Babies and adults use opposite sides of their brains to process colours.

And the switch is due to the influence of language, a study suggests. It is well known that in adults, perception of colour is processed predominantly by the left hemisphere, which is also where most people process language.

eft hemisphere

Studies have shown that the language one speaks can have an impact on the colour one sees. Paul Kay at the University of California, Berkeley, and his colleagues wanted to know if this left-side bias was carved out by the development of language in the left hemisphere, or whether it was present even before language is acquired.

So they tested two age groups — adults and 4- to 6-month-old babies — with the same colour-perception task.

A coloured target is shown at a randomly chosen location on a different coloured background, and the researchers watch to see how long it takes the participant to shift their attention to the target’s location.

Adults reacted more quickly if the target was presented in the right side of the visual field, which is processed by the left hemisphere of the brain.

For babies, the pattern reversed: They were quicker if the target was in the left visual field, which is processed by the right hemisphere.

The results are published in Proceedings of the National Academy of Sciences. “The obvious conclusion is that language is constraining colour perception,” says Kay.

Language certainly seems a good candidate reason for the difference, says Jonathan Winawer, who studies colour perception and language at Stanford University in California.

Controversial idea

But this is still a controversial idea, he adds, and not the only possible explanation. “There are other things that separate adults from infants,” he points out.

The conclusion fits in with another report co-authored by Kay, working with a different team, in the same issue of Proceedings of the National Academy of Sciences.

Using functional magnetic resonance imaging, he and colleagues from the University of Hong Kong and Queen Mary Hospital, also in Hong Kong, looked at which brain areas are activated when people make judgments about different colours.

When subjects viewed various coloured squares, samples that were easy to name in their local language (red and green, for example) provoked stronger activation in areas of the brain related to word-finding than hues that are harder to name (such as pinky-beige or greeny-blue).

Integral part

Kay argues that this is because language is an integral part of the colour-perception process.

The study is good indirect evidence for this, Winawer agrees, but it doesn’t show directly that language is affecting perception, he says.

One might expect stronger activation in language areas when the colours are hard to name and people struggle for the words, he notes.

There is a long history to thinking that language affects how we perceive the world. In the 1930s, linguist Benjamin Lee Whorf proposed that the language a person speaks affects the way he or she thinks.

Brain imaging

A horde of experiments have since confirmed that language can shape our perception (of colour among other things). But direct evidence of this effect from brain imaging is only just starting to emerge.

Kay says his new work “gives comfort to the Whorfian ideas that language is intimately involved in the way we process the world."

Mind over language Other, more sophisticated processes have also been found to be influenced by language.

In a recent study published in the journal Social Cognitive and Affective Neuroscience, Chiyoko Kobayashi of Cornell University in Ithaca, New York, and colleagues suggest that even a concept as complex as ‘theory of mind’ — a concept that involves understanding how other people think — is influenced by the language a person speaks.

KERRI SMITH

Nature News Service