Our brains exist as an adaption to allow us to survive long enough to procreate. We did not evolve a brain to work harder, smarter or faster. The fitness functi

Our brains exist as an adaption to allow us to survive long enough to procreate. We did not evolve a brain to work harder, smarter or faster. The fitness function for evolution is not intelligence, it is survival and procreation. It does not follow that evolution would maximize intelligence or performance. Human intelligence exists as a by-product of many cumulative adaptions for survival.