Inside the Brains of Smart Kids - Yahoo! News: "Smart kids don't necessarily have bigger brains than their peers, but the parts of their brains involved in thinking change more during adolescence.

As children grow up, the outer mantle, or cortex, of their brains thicken and thin as new neural connections are being made and then pruned to become more efficient. Using brain scans, researchers have found that the cortices of kids with high IQ scores thickened faster and for a longer period of time than children of average intelligence. "