Ahh, I originally read this as evolutionary pressure, which I think goes in the opposite direction in this case. Dependence on some external stimulus can be adaptive if that stimulus is readily available and has otherwise beneficial effects. It'd be interesting to get a look at some of the game theoretic dynamics of intelligence, novel thinking, and so on - while you would expect an evolutionary pressure to entertain (at least some limited number of) novel ideas, it seems there may also be evolutionary pressure to discourage others from doing so (to maintain social cohesion, i.e., make your neighbours more predictable).