When the fittest are struggling to survive, with whom are they competing? With other members of their species, or with members of other species? A gazelle on the African savannah is trying not to be eaten by cheetahs, but it is also trying to outrun other gazelles when a cheetah attacks. What matters to the gazelle is being faster than other gazelles, not being faster than cheetahs. In the same way, psychologists sometimes wonder why people are endowed with the ability to learn the part of Hamlet, or understand calculus, when neither skill was of much use to mankind in the primitive conditions where his intellect was shaped. Einstein would probably have been as hopeless as anybody in working out how to catch a woolly rhinoceros. We use out intellects not to solve practical problems, but to outwit each other. Deceiving people, detecting deceit, understanding people's motives, manipulating people - these are what the intellect is used for. Selection within the species is always going to be more important than selection between the species.
-- Matt Ridley, The Red Queen