7.6 Evolutionary Psychology

If individual, cognitive, medical, and trauma-informed theories look to the current state of humans to explain criminal behaviour, evolutionary psychology looks for explanations in the human genome and the influence of our ancient ancestry. The key question of evolutionary psychology as it relates to crime is: How did antisocial and violent behaviour confer a survival advantage to our ancestors? Evolutionary psychology posits that the ultimate function of all biological organisms is to increase their reproductive success. Thus, traits and psychological mechanisms that improve survival and reproductive success will be increasingly prevalent in each generation (Buss, 2016; Wright, 2010). Unlike cognitive-behavioural psychology, which looks at how criminal behaviour is rewarded or deterred in the present, evolutionary psychology looks at unconscious psychological mechanisms that would have been adaptive in the environment in which they evolved, specifically the ancestral environment of the African savanna during the Pleistocene epoch (2.6 million to 11,700 years ago).

Male sexual jealousy is an example of a psychological mechanism that would have led to greater reproductive success in the ancestral environment but leads to criminal behaviour in many modern societies. Evolutionary psychologists theorise that in early humanity, males who demonstrated sexual jealousy would be more likely to ensure their resources went towards raising their own biological children, making it more likely that the genes of sexually jealous men would move forward through generations (Buss, 1988, 2006).

Social mores change much more rapidly than genomes. Today, vastly increased reproductive control (e.g., condoms and the birth control pill) and access to divorce mean that sexual infidelity is less likely to lead to men raising other men’s genetic legacies. What might have been adaptive in the Pleistocene epoch might not work today. Evolutionary psychology may explain why extreme forms of male sexual jealousy, such as mate guarding, persist even though they are now associated with felonies such as stalking and domestic violence.

Kanazawa (2008) believes that the norms against crime might have developed in reaction to evolutionary psychological mechanisms that incline men to commit crime. Comparing primate behaviour to human behaviour classified as crime among humans shows that primates often engage in theft, rape, and violence to further their access to reproduction (de Waal, 1989, 1992).

Evolution-driven psychological mechanisms may explain why, worldwide, men commit more than 90% of all crimes (Kanazawa & Still, 2000). It may also explain the universal age-crime curve across history, society, social group, race and sex, in which criminal behaviour aligns with the emergence of sexual maturity: it increases in early adolescence, peaks in late adolescence and early adulthood, rapidly decreases throughout the 20s and 30s, and levels off during middle age (Hirschi & Gottfredson, 1983).

Critics of evolutionary psychology cite the difficulty of generating testable hypotheses about what human behaviour might have been like several million years ago (Lloyd, 1999).