Wednesday, May 02, 2007

Colour perception/discrimination/categorisation

New Scientist Magazine's Roxanne Khamsi reports on a recent study that claims to support the Whorfian hypothesis. The lead author is quoted as saying, "this is the first time that evidence has been offered to show cross-linguistic differences in colour perception in an objective task." That seemed a striking claim to me, so I tried to get a look at the original paper. Unfortunately, it's subscribers only, but here's the abstract (a good summary is here).
English and Russian color terms divide the color spectrum differently. Unlike English, Russian makes an obligatory distinction between lighter blues ("goluboy") and darker blues ("siniy"). We investigated whether this linguistic difference leads to differences in color discrimination. We tested English and Russian speakers in a speeded color discrimination task using blue stimuli that spanned the siniy/goluboy border. We found that Russian speakers were faster to discriminate two colors when they fell into different linguistic categories in Russian (one siniy and the other goluboy) than when they were from the same linguistic category (both siniy or both goluboy). Moreover, this category advantage was eliminated by a verbal, but not a spatial, dual task. These effects were stronger for difficult discriminations (i.e., when the colors were perceptually close) than for easy discriminations (i.e., when the colors were further apart). English speakers tested on the identical stimuli did not show a category advantage in any of the conditions. These results demonstrate that (i) categories in language affect performance on simple perceptual color tasks and (ii) the effect of language is online (and can be disrupted by verbal interference).
The keywords linked to the article in the Proceedings of the National Academy of Sciences, where the study is published are "categorization | cross-linguistic | Whorf".

So, is perception the same as discrimination / categorisation? When I first read this, I took perception to be sense 3a in Merriam-Webster's, "3 a : awareness of the elements of environment through physical sensation [color perception]". Given this meaning, it strikes me as quite different from discrimination. But according to A Dictionary of Psychology, "In psychology, a distinction is conventionally drawn between sensation , the subjective experience or feeling that results from excitation of sensory receptors, and perception, sensory experience that has been interpreted with reference to its presumed external stimulus object or event."

This choice of a technical sense of the word over the everyday one is probably second nature to the psychologist (just as a lawyer might go for conclusory without knowing that it would mean nothing to most of us), but it might throw off the layperson.

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