A Theory Explaining Biological Correlates of Criminality

Despite major advances in understanding the biological basis of human behaviour, the most popular theories of criminal behaviour remain restricted to those that consider only learning and social environmental variables. All of these strictly environmental theories have difficulty explaining why neurological, hormonal, and other biological factors would be related to criminal behaviour, yet evidence for links between such biological factors and criminality has grown. This article puts forward a theory that takes account of biological as well as environmental factors, and predicts that variables such as age, gender and social status will be associated with offending probabilities. It is argued that male sex hormones operating on the human brain increase the probability of competitive/victimizing behaviour. This type of behaviour (or behavioural tendency) is hypothesized to exist along a continuum, with ‘crude’ (criminal) forms at one end and ‘sophisticated’ (commercial) forms at the other. Individuals with the greatest capacities to learn and plan will move rapidly after puberty from criminal to non-criminal forms of competitive/victimizing behaviour. The theory predicts among other things that serious criminality will be concentrated in adolescent and young adult males of low social status. Evidence is reviewed on links between criminality and various biological variables, including testosterone, mesomorphy, maternal smoking during pregnancy, hypoglycemia, epilepsy, altered heart rate and skin conductivity, cortisol, serotonin, monoamine oxidase, and certain brainwave patterns.