Past investigations have had mixed results. Some experiments suggested that color terms influenced people in the moment of perception. Others suggested that the language effect kicked in only after some basic perception occurred.

The consensus was that different ways to label color probably did not affect the perception of color in any systematic way.

Last year, Lera Boroditsky and colleagues published a study in The Proceedings of the National Academy of Sciences showing that language could significantly affect how quickly perceptions of color are categorized. Russian and English speakers were asked look at three blocks of color and say which two were the same.

Russian speakers must distinguish between lighter blues, or goluboy, and darker blues, siniy, while English speakers do not have to, using only “blue” for any shade. If the Russians were shown three blue squares with two goluboy and one siniy, or the other way around, they picked the two matching colors faster than if all three squares were shades from one blue group. English makes no fundamental distinction between shades of blue, and English speakers fared the same no matter the mix of shades.

In two different tests, subjects were asked to perform a nonverbal task at the same time as the color-matching task. When the Russians simultaneously carried out a nonverbal task, they kept their color-matching advantage. But when they had to perform a verbal task at the same time as color-matching, their advantage began to disappear. The slowdown suggested that the speed of their reactions did not result just from a learned difference but that language was actively involved in identifying colors as the test was happening. Two other recent studies also demonstrated an effect of language on color perception and provided a clue as to why previous experimental results have been inconclusive. In The Proceedings of the National Academy of Sciences, Dr. Paul Kay of the International Computer Science Institute at Berkeley and colleagues hypothesized that if language is dominant on the left side of the brain, it should affect color perception in the right visual field. (The right visual field is connected to the left side of the brain, and vice versa.)

English-speaking subjects were shown a ring of 12 small squares that were all the same color except an odd one on the left or the right. If the odd square was shown to the right visual field and it was from a completely different color category in English, like a green square compared to the ring of blue squares, then subjects were quick to identify it as different. If the odd square shown to the right visual field was the same basic color as the ring of squares, perhaps just being a different shade of blue, subjects were not as fast to recognize the difference. If the odd square was shown to the left visual field, it didn’t matter if it was a different color or only a different shade.

The extent to which language affected color perception depended on the side of the brain being used.