Evolutionary psychology is based on the ideas that our behaviour is influenced by our instincts left over from our evolutionary past. These behaviours were adaptive to increase the chances of survival and reproduction.
Natural selection is the idea that the individual who is best adapted to the environment will survive and pass on their genes.
Sexual selection is the idea that species have developed specific behaviours and physical characteristics because these features allowed their ancestors to be more successful in attracting a mate. Sexual selection can explain why in some species such as human males and females look and behave differently.
Evolutionary claims that gender differences through a model of hunters and gatherers with males and females taking on different roles in the group. Females would take on the role of nurturing and gathering and this would explain behaviours such as women being more empathic and better communicators. Males would take on the hunter/protector role and thus they have evolved to be more aggressive. This links into the biological model which demonstrates the role of testosterone in males in increasing aggression. The theory is that testosterone levels have evolved to be higher in males due to their role of hunters and that this is what causes their increased levels of aggression. For example evidence by Beeman showed that castrated male rats became passive but when injected with testosterone they reverted to high levels of territorial aggression.
However much of the research on testosterone is based on animal studies such as that by Beeman. The research is comparative and thus may not be generalisable to humans. Humans are not only capable of rational thought but also it can be seen that mouse behaviour is driven much more by instinct than humans, who seem to be more dependent on social learning. This suggests that although testosterone may still play a role with