When it comes to intelligence, what factors distinguish the brains of exceptionally smart humans from those of average humans? As science has long suspected, overall brain size matters somewhat, accounting for about 6.7 percent of individual variation in intelligence. More recent research has pinpointed the brain’s prefrontal cortex, a region just behind the forehead, as a critical hub for high-level mental processing, with activity levels there predicting another 5 percent of variation in individual intelligence. Now, new research from Washington University in St. Louis suggests that another 10 percent of individual differences in intelligence can be explained by the strength of neural pathways connecting the left prefrontal cortex to the rest of the brain.
Control of thought and behavior is fundamental to human intelligence. Evidence suggests a frontoparietal brain network implements such cognitive control across diverse contexts. We identify a mechanism—global connectivity—by which components of this network might coordinate control of other networks. A lateral prefrontal cortex (LPFC) region’s activity was found to predict performance in a high control demand working memory task and also to exhibit high global connectivity. Critically, global connectivity in this LPFC region, involving connections both within and outside the frontoparietal network, showed a highly selective relationship with individual differences in fluid intelligence. These findings suggest LPFC is a global hub with a brainwide influence that facilitates the ability to implement control processes central to human intelligence.
Contradicts Stephen Jay Gould. I don’t know who to believe.
Update: I meant “whom”.