Intelligent children do not necessarily have larger brains than their peers, but the brain regions associated with thinking change more dramatically during adolescence.
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(Photo: en.wikipedia.org) |
As children grow, their cerebral cortex thickens and then thins out as neural connections are formed and subsequently pruned for efficiency. Using brain scanning techniques, researchers have found that the cortex of children with high IQs thickens more rapidly and remains thick for a longer period than that of children with average intelligence.
A total of 307 children aged 6 to 20 participated in the experiment. Most of the children underwent brain scans at least twice, spaced two years apart. Based on their IQ test scores, the children were divided into three groups: elite (121-145), high (109-120), and average (83-108).
Brain imaging revealed that the cortex of all children thickened during adolescence before thinning out again.
For instance, the cortex of the smartest 7-year-olds in the group continued to thicken until around the age of 11 or 12, before starting to thin. In contrast, the group with average IQs reached peak cortical thickness at age 8, gradually thinning out thereafter.
This reflects that intelligent children have a longer “window” of time for brain development. Furthermore, their cortex also thins out more rapidly towards the end of adolescence, possibly to efficiently eliminate unnecessary neural connections, according to lead researcher Philip Shaw from the U.S. National Institute of Mental Health.
T. An
