Language affects half of what the human eye sees, a study suggests.
The right field of vision was quicker at detecting colours than the left
University of California researchers tested the hypothesis that language plays a role in perception by carrying out a series of colour tests.
They found that people were able to identify colours faster in their right visual field than in their left.
The Proceedings of the National Academy of Sciences study said it was because the right field is processed in the brain area responsible for language.
The theory that language impacts on perception forms part of the Whorf hypothesis, which states there is a systematic relationship between the grammatical categories of the language a person speaks and how that person both understands the world and behaves in it.
For example, speakers of English judge colours that straddle the green/blue boundary as less similar than speakers of Tarahumara, a language spoken in Mexico which does not have separate words for the colours.
The researchers thought that if language was to have this affect it would only do so on the right of their visual field because of the way the brain handles language.
They asked 13 people to identify a colour on a square among a group of other squares all of which were the same colour.
In one test the squares were all shades of blue, with one square being a different shade.
In the second test there was two colours used, blue and green. The participants were quicker in the second test at identifying the different colour square when it was in their right field of vision - to the right of their head.
There was no difference in speed in the first test, suggesting because the colours had a different name in the second test the mind was able to identify the colour more quickly when it was seen in a certain field of vision.
To reinforce the findings, the team carried out the tests again but asked the participants to silently rehearse an eight-digit number in a bid to interfere with the language function of the brain.
The results showed that the differences between the two field decreased.
The researchers said the findings supported the Whorf hypothesis, but only in the right visual field.
Report co-author Aubrey Gilbert said: "Previous studies addressing the possible influence of language on perception have tended to look for a simple yes or no answer to the question.
"Our findings suggest a more complex picture, based on the functional organisation of the brain."