Infants can `sense` colours even before they can speak

Tokyo: Infants aged between five and seven months are able to categorise colours in their brain, even before the acquisition of language, according to Japanese researchers.

A long-held theory called Sapir-Wharf hypothesis claims that languages define our perceptions. Colour perception is also considered to be subject to this theory since colours are called by their names in daily communications.

However, according to the new study, the category of colours can be independent of language, at least in the early stage of development in an infant's visual system.

The researchers from Chuo University, Japan Women's University and Tohoku University tested 5-7 months old infants to see if brain activity is different for colours in different categories. 

The brain activity was measured by a near infrared specrtoscopy technique which realises comfortable measurement of brain activity in infants.

The study, published in the journal of Proceedings of the National Academy of Sciences, found that the brain activity increased significantly when the colours of blue and green were alternated, while there was no significant reaction to the alternation of different shades of green. 

The difference was observed in both left and right hemispheres of the brain.

A similar difference was found in adult participants with no significant lateralisation. Since language related cortical areas reside in the left hemisphere in most right-handed adults, the observed brain activity had no direct relation to language processing. 

In addition, brain activity caused by categorical colour differences was not found in the occipital region, which is known to play a significant role in the early stage of visual processing.