Biology of Color Preference

Color is funny. Anthropologists have long known that different cultures have different relationships, linguistically and in day to day practice, to the color spectrum. For example, the Efe Pygmy Hunter-Gatherers of the Ituri Forest describe things as white, black, or red, and that's it. They live in a world of green. Going with the model for "Eskimos" having a hundred words for snow because snow is so important in their environment, one would expect that the Efe would have a hundred words for green. On the other hand, the Efe Hunter-Gatherers must have a fairly primitive culture, compared, say, to those of us living in Coon Rapids Minnesota, that of course they have fewer words for different colors.

[This is a reprint from gregladen.com]

Of course, this is all a bunch of hooey. First, we don't call them "Eskimos." We call them "Inuit." "Eskimo" is a bad word. It would be like calling the Irish "Drunken Leprechauns." Second, the "fact" that Inuit have a hundred words for snow is simply not true. It is an Urban Legend. Third, the great variation in something ... any thing ... does not necessarily demand a rich lexicon to describe it. You ... yes, you ... rely heavily on computers, right? Many computer users presumably need to have a concept of "memory" and the memory their computers use ... related to the choices you make when buying or using a computer, where and how you store your documents, etc. But this concept is often appallingly simplified. I know many people who can't distinguish between storage of data on a hard drive from storage of data in RAM. And there are many kinds of hard drive and many kinds of ram. And then there is processor cache, video memory, and so on. There are probably over two dozen kinds of memory, it matters to any computer user, and most computer users have either one word for memory or two. ("Memory" or "Hard drive" and "Memory")

Finally, if the Efe are Primitive, then I'm a monkey's uncle. Indeed, both are untrue. The Efe are far from primitive and I'm a monkey's great great great .... great great nephew, not uncle. The Efe have one of the largest brain to body ratios of any people. I've never met an Efe man who knew fewer than four different languages. I've never met an Efe who was not very smart. I can't say any of these things for the population living in Coon Rapids, or even Edina, Minnesota.

So why do the Efe not seem to even have a word for the color green?

I can think of two answers to that question. One is that they do but have not bothered to teach this to us. I spent years living with them, and there were basic, day to day things that I learned right up to the last day I was with them. Sure, linguists presumably asked them about this, but that means little considering that only a handful of linguists have actually worked with them. The other explanation is that this is a stupid question. We only think that one needs a large number of words for the color green (if you are an Efe) because we mistakingly think things like the Inuit have a hundred words for snow.

Then there is the issue of gender and color. I am not color blind, but I am a man. Therefore I have only a few words for color. Let's see. There's black and white, green red and yellow, and pretty much that's it. OK, maybe purple as well. Brown is a form of lightish black. I am not color blind. I'm simply not that interested.

Boys = blue, girls = pink. We know this because these are the colors of clothing, decorations and wall paper or paint in nurseries, etc. Anthropologists will tell you that this blue/pink gender thing is cultural, and that you can find exceptions to it, even reversals, if you look around the world and across history. For instance, the color association with the emperor of Rome was some girley color like purple.

A current study in the journal Current Biology claims to have found a non-culturally generated (but nonetheless culturally modified) gender difference in color preference.

The long history of color preference studies has been described as "bewildering, confused and contradictory". Although recent studies ... tend to agree on a universal preference for 'blue', the variety and lack of control in measurement methods have made it difficult to extract a systematic, quantitative description of preference. Furthermore, despite abundant evidence for sex differences in other visual domains, and specifically in other tasks of color perception ... there is no conclusive evidence for the existence of sex differences in color preference. This fact is perhaps surprising, given the prevalence and longevity of the notion that little girls differ from boys in preferring 'pink'. Here we report a robust, cross-cultural sex difference in color preference, revealed by a rapid paired-comparison task. Individual color preference patterns are summarized by weights on the two fundamental neural dimensions that underlie color coding in the human visual system. We find a consistent sex difference in these weights, which, we suggest, may be linked to the evolution of sex-specific behavioral uses of trichromacy.

Anya C. Hurlberta and Yazhu Linga. "Biological components of sex differences in color preference." Current Biology. Volume 17, Issue 16, 21 August 2007, Pages R623-R625.

I think the study design is good and the results convincing, that there is a sex difference in color preference along one aspect of the way color is perceived. Here is what the difference looks like in the figure the researchers provide:

As implied in the summary, this difference corresponds to male-female differences in visual processing. This is believable.

The ultimate (evolutionary) explanation that the researchers give is weaker. It is a fairly typical post-hoc Environment of Evolutionary Adaptedness argument. Females prefer or are more perceptive of red because they are gathering berries found in a background of green leafy stuff. Or, alternatively, females evolved to be sensitive to social signals (blushing).

We speculate that this sex difference arose from sex-specific functional specializations in the evolutionary division of labour. The hunter-gatherer theory proposes that female brains should be specialized for gathering-related tasks and is supported by studies of visual spatial abilities. Trichromacy and the L-M opponent channel are 'modern' adaptations in primate evolution thought to have evolved to facilitate the identification of ripe, yellow fruit or edible red leaves embedded in green foliage. It is therefore plausible that, in specializing for gathering, the female brain honed the trichromatic adaptations, and these underpin the female preference for objects 'redder' than the background. As a gatherer, the female would also need to be more aware of color information than the hunter. This requirement would emerge as greater certainty and more stability in female color preference, which we find. An alternative explanation for the evolution of trichromacy is the need to discriminate subtle changes in skin color due to emotional states and social-sexual signals; again, females may have honed these adaptations for their roles as care-givers and 'empathizers' .

Why do I say this is a weak post-hoc argument? For the simple reason that a reversal of their findings could be equally well explained. The game sought by hunter-gatherers is distinguished from a green foliage-rich background by its reddish-brown hue. Most meat actually collected by male hunter-gatherers is not from shooting an animal dead with an arrow, but by wounding it and following an often very subtle blood (red) trail. And so on. Regarding the blushing: Since white skin against which blushing is most obvious is a recent mutation (and a rather harmful one at that), I think this argument can be rejected out of hand.

Nonetheless, this is a good piece of research, well done, and of great interest.

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HURLBERT, A., LING, Y. (2007). Biological components of sex differences in color preference. Current Biology, 17(16), R623-R625. DOI: 10.1016/j.cub.2007.06.022