Why our minds have probably evolved as far as they can go

Why our minds have probably evolved as far as they can go (io9.com):

Our brains have reached an evolutionary "sweet spot", and we can't get much smarter without making major trade-offs. That's the finding of psychologists Thomas Hills of the University of Warwick and Ralph Hertwig of the University of Basel. They have examined a number of studies, and they have come to one inescapable conclusion: there's a steep price to pay for enhanced brainpower, and it's almost certainly not a good deal from an evolutionary perspective.