/ 12 November 2022

An evolutionary theory of male violence may explain the persistence of gender violence

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Male domination: People in Durban protest against gender-based violence. (Rajesh Jantilal/AFP)

‘Men lay claim to particular women as songbirds lay claim to territories, as lions lay claim to a kill, as people of both sexes lay claim to valuables,” remarked Margo Wilson, the eminent Canadian evolutionary psychologist.

For Wilson and others of her theoretical outlook, the male drive to control female sexuality is key to understanding “intimate partner violence” — the riddle of why so many men assault and even kill the women they claim to love.

They believe that such violence grows from an evolutionary taproot, pointing to the intense sexual “proprietariness” and gender violence of monkeys, chimpanzees and other of our close primate cousins.

Male violence against women is widespread across all human cultures and highly resistant to change. In this context, the standard socioeconomic explanations — including “sex as property” in capitalism and earlier economic systems — don’t seem to touch sides.

In the United States, police field half a million complaints of male partner violence each year. 

And back home President Cyril Ramaphosa has said that a “war” is being waged against South African women — almost half the country’s femicides are committed by intimate partners.

Wilson points out that men always heavily outnumber women as perpetrators of sexual violence and that the main motives for femicide — actual or suspected infidelity and desertion — are culturally uniform.

“The ubiquitous nature of male violence across time and settings challenges the idea that it can be attributed to culture or social settings alone,” writes University of Toronto psychologist Holly Johnson.

“Evolutionary psychology can help explain why men try to control female partners in ways that women do not [and] why violence is primarily male.”

Male domination is recycled in every generation, but how did the cycle begin? Why such an elaborate repertoire of controls for the “second sex”: the harem, the convent, purdah, deprivation of employment and schooling, witch-burning, genital mutilation, honour violence, the chastity belt, foot-binding, “slut shaming”, chaperones — and murder?

The evolutionists base their approach on Charles Darwin’s idea of sexual selection, in which male competition for females influences “inclusive fitness”, refined by modern “parental investment theory”.

Parental investment theory looks at the different reproductive strategies of the sexes, depending on the time and resources they expend on their offspring. Among humans, men are limited only by the number of sexual partners in propagating their genes; women protect a much larger investment in gestation and lactation.

Hence the tendency, selected over many generations, towards male promiscuity and rivalry on the one hand, and female conservatism in mate selection on the other. 

This tension, between the male drive for quantity and female resistance based on quality, is seen as underpinning sexual coercion.

American research has shown that 75% of men would instantly agree to sex if propositioned by an attractive stranger, while not one of the female respondents would.

Research also shows that male violence is typically triggered by a loss of control. One survey found that a third of Canadian battered women are attacked by intimate partners during a break-up and others in its aftermath, many while fetching their belongings.

Men and women experience sexual jealousy and possessiveness differently, according to parental investment theory. 

Men are typically inflamed by imaginings of the sexual act and fear of a third party impregnating the female partner. For women, anxiety centres on emotional, rather than physical infidelity.

Wilson, who died in 2009, was a feminist, “though not of the ranting kind”, according to her husband and co­researcher, Martin Daly.

But her understanding of sexual violence was not popular in feminist circles. 

As Johnson puts it: “Convincing feminist social scientists to consider the importance … of evolutionary bases for male partner violence is a tough sell. 

“Many express unambiguous hostility, claiming that an evolutionary framework is ‘inherently misogynistic and provides a justification for the oppression of women’.” 

The concern, it seems, is that wife-killers will claim “genes made me do it” or that the evolutionary model will be misused to argue that gender inequality is “natural”.

Being ideologically unpalatable is not disproof. But in any case, argues American anthropologist Barbara Smuts, there is no intrinsic clash between the feminist and evolutionary perspectives. 

Smuts makes the important observation that humans have evolved highly adaptable behaviour “to maximise fitness in a wide variety of environments”, and do not run on fixed genetic tramlines. 

Evolutionary biologist Richard Dawkins makes a similar point, arguing that one should not confuse evolutionary and developmental processes. Epigenetics — gene expression — is shaped by such external influences as education, law, economics, peer pressure and moral, political and religious belief systems. 

The monastic way of life, enjoining chastity, poverty and obedience, is a practical example of how both sex and power drives can be tamed.

Ancient traits: Chimpanzees are human’s close cousins and evolutionary psychologists argue that mens’ ‘proprietariness’ over women is similar – but also say that perpetual patriarchy is not inescapable. (Marc Guitard)

Evolutionary psychology was fathered by Darwin, who held that the human mind is the product of aeons of adaptive “gradation”. Wilson believes that some modern scholars, such as Bishop Samuel Wilberforce and fellow 19th-century religious objectors, still cannot accept that his revolutionary worldview applies to human behaviour. 

As per Wilberforce’s famous jibe — “Did you descend from a monkey on your grandmother or grandfather’s side?” — the evolutionary case draws on the example of our primate cousins, underscoring their fierce male competition for females and strategies to rein in female sexual independence.

Male rhesus macaques — like most primates, the larger of the sexes — become especially aggressive when females are in oestrus, and senior monkeys often attack females when they approach “peripheral” males to mate.

Male hamadryas baboons keep females on a short leash at all times, herding them away from “bachelors” in the troop and giving them admonitory neck bites if they stray.

Mountain gorillas, which form small groups of females and a single breeding male, the “silverback”, exercise an extreme form of sexual despotism — infanticide. 

After attacking and killing the silverback, freelance males often murder nursing infants to bring the mother back into oestrus. 

Smuts notes that in nine out of 10 known cases, a silverback’s death was followed by infanticide — and that the female then mated with her offspring’s killer. Some 37% of infant deaths among gorillas are infanticides; among Colombian red howlers the estimate is 44%.

Orangutangs are human’s close cousins and evolutionary psychologists argue that mens’ ‘proprietariness’ over women is similar. (Jorge Guerrero/AFP)

Parental investment appears to influence some humans; criminologist Fiona Brookman found British parents are a hundred times more likely to kill stepchildren than their biological offspring.

Female chimpanzees get it in stereo, from the alpha male seeking to monopolise mating as oestrus approaches and from peripheral males who try to lure them to clandestine “consortships” in the deep forest.

If the female spurns these overtures, she is attacked. Primatologist Jane Goodall records the case of a female chimp called Winkle, who was assaulted six times in five hours by a would-be consort. Facing such relentless pressure, most females give way.

The most sexually coercive primates are orangutans — half the adult males subject females to forced copulation after violent struggles.

Smuts makes the intriguing point that female primates who lack the support of other females and kinfolk are more exposed to male violence. Female orangutans, who move alone, are intensely vulnerable; female chimps and gorillas show little or no gender solidarity.

Young women in many traditional human societies offer a striking parallel. Leaving their native communities for “patrilocal” marriages, they lose the support of their own kin and often suffer domestic tyranny from their husband’s female relatives, in what Wilson calls the “Cinderella effect”.

In marked contrast, bonobos — among whom male violence is rare — form strong female-female bonds, often cemented by homosexuality. Among many Old World monkeys, females protect “sisters” and their infants, sometimes driving aggressive males from the troop. 

Smuts also holds that the patriarchy was bolstered by the emergence during human evolution of ever-stronger male alliances, perhaps associated with cooperative hunting, raiding and inter-group conflict. These frequently keep women in line.

Chimps, our near-twins, also form fraternities, staying in their birth groups and forging lasting bonds with male relatives that are leveraged politically during power struggles.

Strong male bonding can divide traditional human societies along gender lines — a man may refuse to protect a battered female relative to avoid alienating her husband, for example. 

But the practice that most clearly expresses the threat posed by male solidarity to women is punitive gang rape.

According to American anthropologist Thomas Gregor, the men of the Brazilian Mehinaku and other tribes carry out secret rituals in the “men’s house”, from which women are barred on pain of collective rape. “The tradition is good,” explained one of the men. “[The women] … are afraid of the men’s penises. So they just stay in the houses.”

Rape as retribution has a long and fearful history in the modern world. It seems to actuate many serial sex killers and rears its head when legal inhibitions fall in times of war.

It is in male cronyism that Smuts sees the seeds of the male-female couple or “pair bond”, another ancient institution that, among primates, is specific to humans. Most wife-battering occurs in the privacy of this arrangement, screened from the woman’s kin and other outsiders.

She observes that dominant male chimps and baboons buttress male coalitions by tolerating some mating by lower-ranking allies. Among hominins, the pair bond may have evolved from such practices, with males coming to respect one another’s exclusive breeding rights to particular females.

Pronounced male hierarchies are bad news for women: wife-beating is more common among the poor and ill-educated, according to the World Health Organisation. Smuts suggests the rise of cities 10 000 years ago, with their nascent male elites and class divisions, gave a fillip to abuse.

Gorillas are also considered human’s close cousins and evolutionary psychologists argue that mens’ ‘proprietariness’ over women is similar. (Andrey Gudkov/AFP)

Also heightening women’s vulnerability was their loss of economic self-reliance as foragers responsible for their own subsistence. This happened, she speculates, as hominids started sharing food — another behaviour unique to human primates — and became more reliant on meat provided by male hunters. 

Evolutionary psychologists are not claiming all men are abusers or that domestic violence is a positive or necessary motor of human development. Many couples are harmonious, and most men do not rape. And there are faithful men and promiscuous women.

They are pointing to deep-rooted inclinations that, interacting with environmental cues, produce a spectrum of both violent and non-violent male behaviour that seeks to restrict female autonomy.

Also, the selection pressures that shaped our hominid forebears may be stamped on our biology without necessarily being fitness-enhancing or desirable now. An example is obesity, thought to stem from the favouring of “thrifty” genes that promoted energy storage in the famine-prone past.

“We are the product of the traits that made our ancestors good at reproducing — including many that are [now] quite abhorrent,” Australian evolutionary biologist Robert Brooks reminds us.

As outlined above, Smuts insists perpetual patriarchy is not inescapable — by moulding our sociocultural environment, we can influence how our genes express themselves.

Centrally, she believes the strong male bonding and weak female alliances typical of human groups can be reversed by mobilising women politically, in particular, to press for stricter rape and domestic abuse laws. 

In South Africa, enforcement and the police processing of cases are the crux of the matter.

She also emphasises the importance of economic independence in enhancing women’s physical safety.

The evolutionary perspective does not offer radically new solutions. But neither does it imply genetic quietism and surrender to the inevitable. 

By showing that gender violence flows from primal impulses, the theory may help explain why it is so hard to eradicate — and is likely to be rolled back only by long and determined activist endeavour.

Drew Forrest is a former political editor and deputy editor of the Mail & Guardian.

The views expressed are those of the author and do not necessarily reflect the official policy or position of the Mail & Guardian.