AsianScientist (Feb. 17, 2016) – Researchers from Japan have found that infants aged between five and seven months old can categorize colors in their brains even before they acquire languages. This study was published in Proceedings of the National Academy of Sciences.
Using a near-infrared spectroscopy (NIRS) technique, the joint group of researchers from Chuo University, Japan Women’s University and Tohoku University studied the brain activity of infants to see if brain activity is different for colors in different categories.
A long-held theory called the Sapir-Whorf hypothesis claims that languages define our perceptions of the world. This theory is widely accepted in various fields of study including psychology, linguistics and anthropology.
Color perception is also considered to be subject to this theory, since colors are called by their names in daily communication. Through numerous studies on the color lexicons of languages in the world, categorical color perception is considered to be strongly affected by language.
On the other hand, the similarity of color categories across linguistic and cultural differences is also reported as strong evidence of the universality of color categories. Therefore, whether or not language affects color categories has been a central issue related to how we perceive colors.
The study found that the infants’ brain activity increased significantly when the colors 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 the occipito-temporal area in both left and right hemispheres.
Interestingly, when the researchers carried out the same experiment in adult volunteers with no significant lateralization—where some neural functions or cognitive processes tend to be more dominant in one hemisphere than the other—the results were similar. Since language-related cortical areas reside in the left hemisphere in most right-handed adults, they concluded that the observed brain activity had no direct relation to language processing.
In addition, brain activity caused by categorical color differences was not found in the occipital region, which is known to play a significant role in the early stage of visual processing.
The findings reveal that despite current beliefs, the category of colors can be independent of language, at least in the early stage of development in an infant’s visual system. This suggests that color information is processed through multiple cortical stages in infants, in a way similar to adults.
“The present study provided the first evidence, to our knowledge, that colors of different categories are represented differently in the visual cortex of prelinguistic infants, which implies that color categories may develop independently before language acquisition,” the authors wrote in their paper.
The article can be found at: Yang et al. (2016) Cortical Response to Categorical Color Perception in Infants Investigated by Near-infrared Spectroscopy.
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Source: Tohoku University; Photo: Andrew Vargas/Flickr/CC.
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