ABSTRACT
This chapter explains the influence of biology on theories of aggression has been twofold. Besides the direct investigation of physical processes in the determination of behaviour, biology has also developed its own approach to the study of behaviour, known as ethology. The essence of ethology is the study of behaviour in its natural setting. Ethological studies have contributed greatly to our understanding of aggression and violence in both human and animal societies. Before considering this particular perspective, however, it is appropriate to look at some of the ways in which physical, as well as behavioural, biology has added to the understanding of aggressive behaviour. A great deal of biological research on aggression has been concerned with identifying ways in which such behaviour may be affected by the body's hormone levels. This research has centred mainly around the influence of male sex hormones or androgens, although other hormones have also been studied.
