What does "domain-specific brain modules. " mean? Could you explain it to me? A common error in current Darwinian thinking is the assumption that “selfish genes” are the prime mover in evolution. In strict Darwinism the prime mover is environmental threat. In the absence of threat, natural selection tends to resist change. It is un-biological to “explain” behavioural change as resulting from genetic change or the ex vacuo emergence of domain-specific brain modules. Evolutionary psychologists surely know why brains evolved: as Cosmides and Tooby point out, brains are found only in animals that move. Brains are behavioural organs, and behavioural adaptation, being immediate and non-random, is vastly more efficient than genetic adaptation. So, in animals with brains, behavioural change is the usual first response to environmental threat. If the change is successful, genetic adaptation to the new behaviour will follow more gradually. Animals do not evolve carnivore teeth and then decide it might be a good idea to eat meat.