>>11213790http://www.cell.com/current-biology/abstract/S0960-9822%2811%2901267-XThe posterior hippocampi of average-IQ adult subjects who passed the difficult Knowledge exam for London taxicab drivers showed significant enlargement as opposed to before they began studying for it. The posterior hippocampus is associated with memory and spatial reasoning, both of which are strongly correlated with IQ. Similar effects not observed in the control group or in those who failed. Pic related.
This was actually a repeat experiment with a larger sample size (n=88), i.e. the results are predictable and reproducible. Pilot study in the citations. All subjects were fully-grown adults age 30+, so "normal" brain development had already run its course.
Thus we have hard, reproducible, undeniable evidence that the brain is capable of PHYSICALLY restructuring itself in response to focused training, much like a muscle.
