The resurgence of the IQ.

IQ went out of vogue for a little while, especially following the response to the Bell Curve. It looks like it's back in the most recent issue of Nature, where scientists from the NIMH correlated IQ with structural differences in the brains of developing children.

"When the researchers split the children into three groups according to their initial IQ scores, they noticed a characteristic pattern of changes in the brains of the group with the highest scores. The thickness of the cortex — the outer layer of the brain that controls high-level functions such as memory — started off thinner than that of the other groups, but rapidly gained depth until it was thicker than normal during the early teens. All three groups converged, with the children having cortexes of roughly equal thickness by age 19. The strongest effect was seen in the prefrontal cortex, which controls planning and reasoning."