ABSTRACT
Two types of biological explanations can be used to understand psychopathy. First, we can examine the evolutionary factors that lead to the maintenance of the condition within human populations. Second, we can consider what is going on biologically in psychopaths in order to explain their internal states and behaviour. We can think of the former explanation as a functional one and the latter as a causal one. With regard to evolutionary explanations, it is suggested that psychopaths adopt a fast-life strategy whereby they achieve success by manipulating others. The notion of frequency-dependent selection has been utilised to suggest that, when most individuals are mild altruists, psychopaths can be successful by acting as freeriders. Causal biological explanations suggest that psychopaths have specific genes associated with the disorder. These, no doubt, act via interaction with a harsh rearing environment. Findings from scanning techniques, such as MRI, suggest that there are differences in the activation of specific brain areas in psychopaths when compared with control subjects. Such areas include the amygdala and parts of the cerebral cortex. There is also evidence that psychopaths have unbalanced levels of circulating hormones including testosterone and cortisol.
