14 DAY TRIAL // While the issue of where intelligence is located has been a matter of dispute among academics, many studies seem to point to the fact that there are areas in the frontal cortex that seem to “house” this important trait. But other investigations have proven that other parts of the brain play a role in intelligence as well, so the issue has remained up for grabs. The problem with all these studies is that they have only looked at the brains of small numbers of children, so the results have not exactly been representative of the majority of the population.
In a new research, a team of experts from the Montreal Neurological Institute, led by neuroscientist and psychiatrist Sherif Karama, has used Magnetic resonance Imaging (MRI) scans to look at the brains of 216 individuals, all aged between 6 and 18, of both genders, and of all ethnic and sociocultural backgrounds. “It was hard to understand why something as complex as intelligence was restricted to just a few places in the brain,” the expert explains why he began the new set of studies.
In addition, he really wanted the experiments to unfold on more people, so as to get a clearer and more representative result. All the children and teens in the study also received intelligence tests, aimed at measuring their visual-spatial, reasoning, vocabulary and analogy skills. What they found, while trying to mirror older studies, was surprising even to them. The team learned that it was in fact that thickness of one's “grey matter” that weighed the most when assessing that particular individual's intelligence.
“It's not just a few regions. It's dispersed all throughout, in the areas associated with integrating information coming from diverse areas of the brain, which makes sense,” Karama says. The cerebral cortex, which is the “home” of the grey matter, is also responsible for integrating memory, language, thought and consciousness in every person. However, the expert emphasizes the fact that the differences recorded between the children with the largest and the smallest IQs were generated by variable cortex thicknesses of only half a millimeter.
“Perhaps those with [a] higher IQ have better white matter that allows for faster or better connections through disparate areas. We can also look at gender differences – if men have different regions of the brain associated with intelligence than women. The possibilities are endless,” Karama tells LiveScience, adding that future studies are required in order to further investigate this matter. The results of the latest research are published in the March-April issue of the scientific journal Intelligence.