Biology shapes violence. In a significant review of the literature, Robert Sapolsky shows that human actions are shaped by environmental stimuli and their impact on biological processes that our conscious selves know nothing about. Individuals don't simply choose how to behave. Our hearts, lungs, brains and overall biology are constantly determining our actions. We cannot will these processes to stop.
The link between biology and violence is clear when we consider that being born male means having a much greater likelihood of perpetuating violence, being injured through violence, and being incarcerated for violence, than being born female.
Also, younger brains struggle to regulate emotion and impulses, and are far more likely to stimulate risky and violent behaviour than older brains. This has great consequences for South Africa, and underpins the global 16 Days of Activism Against Gender-Based Violence campaign which began on 25 November.
The biological facts are evident in South African prison and murder data. Of the 117 869 people serving prison sentences in March 2018, 87.5% were men. Of the 20 336 murders recorded in 2017/18, 86% of victims were men. Men are significantly more likely to die as a result of violence between 20 and 39 years of age than any other period in their lives.
We must change the stories we tell our children and ourselves about what it means to be a man
But it's not only biology that guides behaviour; it's biology in environment. Environment has a huge bearing on brain and nervous system development, which in turn shapes behaviour. While across the world men are more likely than women to fill prisons and meet violent deaths, men in South Africa are far more likely than men in most other countries to meet these fates.
This is because South Africans grow up and live in contexts that prime them for violence. To break this cycle we must end violence against women and children.
For children to develop into healthy, productive, non-violent adults, they need love, warmth, stimulation and predictability. But even when these are present, childhood poverty and adversity increase the likelihood of an adult suffering depression, anxiety or substance abuse; impaired cognition or impulse control; anti-social and violent behaviour; and reproducing harmful childhood relationships.
The environments in which children spend their first years influence their potential, including their ability to rein in violent impulses. Sapolsky cites the controversial correlation between the legalisation of abortion in American states and subsequent drop in crime 20 years later.
While he doesn't claim that it explains America's crime decline, he writes that the theory makes biological sense. A generation of children was not born into settings where most may have felt unwanted and rejected. As a result, thousands of would-be angry, impulsive 20-something young men never existed.
In places where status is attained through violence, testosterone stimulates violence
While abortion is legal in South Africa, one in three girls is a mother by the age of 18. Add to this the relative poverty in which many teen mothers live and that many don't return to school after giving birth, and the odds of having a safe, successful, happy and healthy life are stacked against both them and their children.
How children are raised matters immensely. For example, research shows that testosterone alone doesn't cause aggression. Rather, it stimulates status-generating behaviour. That means that in places where status is attained through violence, testosterone stimulates violence. And in places where status is earned through acts of generosity, it stimulates generosity.
Similarly, alcohol is closely linked to violence in South Africa. But alcohol only increases aggression among people already primed for aggression. Likewise, media violence makes violent people more sensitive to violence-inducing social cues but doesn't have the same effect on others.
To shift the ways testosterone, alcohol and violent media shape South African behaviour, we must change the stories we tell our children and ourselves about what it means to be a man. But this is easier said than done. Stories about South African life are often characterised by struggle. Themes of poverty, unemployment, violence and illness are common. These generate stress, and stress marinates the brain in hormones that prime us to fight or flee.
Our brains did not evolve to sustain long-term stress. Chronic stress depletes dopamine, stimulates depression and promotes aggression. One way to reduce stress in the brain is to express aggression. Similarly, punishing others stimulates brain states of satisfaction.
When one is of low status in an unequal system where the stress of life on the margins is unending, violence and punishment can earn status and release tension.
Alcohol only increases aggression among people already primed for aggression
It is easy to see how such biology underpins violence against women and children in South Africa, where one in three young people experience sexual and physical abuse, where violence is more common in the home than anywhere else, and where an average of three women are killed each day by their intimate partners.
And while many parents and teachers employ violence against children to 'discipline' them in the hope that they become successful adults, those who experience childhood trauma are more likely to abuse intimate partners and children in later life, and to suffer other problems like alcohol and substance abuse and mental health disorders.
South Africans are not born violent; our society and context make us violent. This violence has deep roots in our social and economic inequality, and how our brains and nervous systems respond to this environment. Biological research affirms social science research that has found that violence begets violence.
To change this, we must change our expectations of ourselves, especially our boys and men. We must describe ourselves as a people who are patient, gentle and kind rather than dominant, judgemental and strong.
But we must also end the poverty and inequality that stunt neurological development, flood brains in stress hormones, and prime us for lives of jealousy, mistrust and conflict. We must use these 16 days of activism to steer South Africa in the right direction.
Andrew Faull, Consultant, Justice and Violence Prevention, ISS