Thursday, March 30, 2006

Brainy Kids' Brains Grow Slowly

That's the news from Nature, the scientific journal, in a new study out today. The cortex of all children's brains thickens as they get older, and then thins during the adolescent years. The cortexes (I'm stumped on the plural) of children with IQs of 121-149 thicken more slowly than those of children with average intelligence, reaching peak thickness at age 11, instead of age 6. Nature requires a subscription, but you can read an AP article about the research here.

No one knows quite what the implications of this are. One of the study authors suggested that a slower-thickening cortex could promote high intelligence, because the child is experiencing more complex things as his brain is growing. By this theory, gifted children would get a longer learning time than others; they'd still be learning rapidly into the late childhood years, where as other children would end that stage around age 6. But I'm not sure if that works, logically. Highly gifted children show their giftedness from infancy. They don't just outpace other children after age 6. Perhaps bright children seek out more stimulation, and this somehow slows the thickening of their cerebral cortexes (Again, what is the plural?).

Regardless, the research shows that there is a physical difference between children with gifted-level IQs and children of average intelligence. IQ tests get a bad rap, and certainly they can't show what a child will accomplish in life. Maybe they can be coached, and environment certainly plays a role. But these physical differences indicate that the tests are on to something, whatever that is.


Anonymous said...

Either "cortexes" or "cortices" is an acceptable plural.

Jenny Kalfut said...

Perhaps I'm in error, but the results seem to suggest that the growth occurs later, but is actually faster, not slower, in the children with higher IQs...

Laura Vanderkam said...

That could be, Jenny. The AP article wasn't clear, especially given the headline (that brainy kids brains grew slowly)

Anonymous said...

It's not clear from the article if we're seeing the cortices growing more slowly, or continuing to grow after the normal cortices have reached their own maximum thinkness.

Since no what knows how to interpret this information, perhaps, for now, we can just sit a little more comfortably with the idea that there are real physical differences that correlate to the real eucational-need differences and let that be that for now.

Anonymous said...

I'll try one last time:

Jason Smith said...

Hi Laura

I read the original paper and the online material. I am concerned about the validity of their initial comparison point where they show reduced cortex thickness for the highly gifted. At the subsequent two points their data was statistically indistinguishable from the moderately gifted children.

High resolution MRI of very young children is notoriously difficult due to motion. It is not given anywhere in the paper how many children they imaged at each time point, leaving open the possibility of an error due to insufficient subject number. Further more if the highly gifted children (IQ above 120 so we are not talking about highly gifted as defined on the blog) just simply held still better on their initial (5 year old) scan their data would be more accurate leading to a false difference determination.