Human brain evolution not only involved changes in over 900 conserved noncoding sequences , but involved various networks of genes and changes within cerebral specific gene sequences:
"If you view the brain as the body's engine, our findings suggest that the human brain fires like a 12-cylinder engine, while the chimp brain works more like a 6-cylinder engine," explained Geschwind. "It's possible that our genes adapted to allow our brains to increase in size, operate at different speeds, metabolize energy faster and enhance connections between brain cells across different brain regions." "“ Here
So what might be the cause of all these human-specific selection pressures?