The Brain is Too Expensive for Survival Purposes

My interest is in the psychological adaptations that are uniquely human, the 10 percent or so of the brain's capacities that are not shared with other apes. This is where we find puzzling abilities like creative intelligence and complex language that show these great individual differences, these ridiculously high heritabilities, and these absurd wastes of time, energy, and effort. To accept these abilities as legitimate biological adaptations worthy of study, evolutionary psychology must bro...

 Complex Brains as an Advertisement for Genetic Fitness

The healthy brain theory suggests that our brains are different from those of other apes not because extrava- gantly large brains helped us to survive or to raise offspring, but because such brains are simply better advertisements of how good our genes are. The more complicated the brain, the easier it is to mess up. The human brain's great complexity makes it vulnerable to impairment through mutations, and its great size makes it physiologically costly. By producing behaviors such as languag...