A red by any other name
Is the way we classify colour physiologically hardwired or culturally shaped? As a new analysis comes out in favour of the former, Heidi Ledford takes a hard look at the decades-old debate.
What's the fuss about?
It is essentially a 'nature versus nurture' argument about how different languages divide colours into categories. For instance, in English, there is a word for red and a word for purple, but is that the case in every language?
Some say that the underlying biological basis for how we perceive and categorize colour rules all. These are the 'universalists'. In the other corner, a handful of anthropologists believe that cultural needs shape how we define colours. These are the 'relativists'.
Throughout the 1940s to 1960s, the textbook view was that every language chops up the colour spectrum in a different way, says Paul Kay, a linguistics professor emeritus at the University of California, Berkeley. When Kay and his colleagues published a 20-language survey of residents of the San Francisco Bay area in 1969, that predominant view changed.
"Since then, there has been a continuing parade of papers that show that the ways people cut up colour space in different languages is not random," says Kay. But as is the case in nearly any debate, many researchers fall somewhere in between, and the argument rages on.
Isn't there a way to work this out?
In 1976, Kay and his collaborators embarked on a World Colour Survey. Fieldworkers roamed the globe for four years, carting kits containing 320 coloured chips and asking participants to categorize each as a colour. Responses were collected from 2,616 informants in 110 different languages.
The goal of the survey was to identify basic colour terms and how they are used. To be counted as a 'basic' term, it needed to be simple, frequently used, and only one word. As the instructions to the fieldworkers explicitly state: "We are interested in responses like 'red' and not in responses like 'the colour of the blood of a toucan that has been dead for a few hours'."
Although these data have been around since 1980, it was only in 2002 that they were converted into a publicly accessible database.
So what's new?
Delwin Lindsey and Angela Brown of Ohio State University in Columbus have reanalysed the data1 using more sophisticated statistics than had been used before, looking at every individual response separately. Their analysis yields eight categories from which all the languages select their basic colours: red, yellow-or-orange, green, blue, purple, brown, pink and grue.
Most languages of the world do not distinguish between green and blue, says Kay. Instead, they lump the two colours together into one category that linguists have labelled 'grue'.
Lindsey notes that failure to distinguish between green and blue is most common near the equator. He argues that exposure to sunlight and ultraviolet radiation may have yellowed the lenses of the people who live there, altering their ability to sense colour.
Kay disputes this explanation, noting that this yellowing is seen in cataract patients, who don't typically become blue/green colour blind. Both Lindsey and Kay are actively working to find out why some populations don't make this distinction.
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- Lindsey D. T., et al. PNAS, doi/10.1073/pnas.0607708103