The Anatomy of Violence (7 page)

The simple evolutionary explanation is that women are worth fighting for. They are the valuable resource that men want to get their hands on. Women bear the children, worry about their health, and make up the bulk of the parental investment. This is also true throughout the
animal kingdom. Where one sex provides the greater parental investment, the other sex will fight to access that resource. Evolutionary theory argues that poorer people kill because they are lacking resources, an argument shared in common with sociological perspectives. And the reason men are overwhelmingly the victims of homicide is because men are in competition with other men over those resources. Men who murder are also about twice as likely to be unmarried as non-murdering men of the same age.
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They have a greater need to get in on the reproductive act, and are willing to take warrior risks. For men one of the underlying causal currents for
violence is competition for resources and
difficulties in attracting females into a long-term relationship.

Let’s also not forget warrior men in the home context. Violence can be used to dominate,
control, and deter a potentially unfaithful spouse. Just as
lions who take over a female from another male will kill the
young and inseminate the lioness,
aggression toward stepchildren is a strategic way of motivating the unwanted brood to move on and not take up resources needed for the next generation bred by the stepfather.
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Consider also that sex differences in aggression are in place as early as seventeen months of age.
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Boys are toddler
warriors. This might be expected from an evolutionary perspective that says males need to be more innately wired for physical aggression than females, to prepare them for later combat for resources. Seventeen months is a bit too young for sex differences to be explained in terms of socialization differences. Social-learning theories of why males are more aggressive run into trouble with the fact that the gender difference in aggression, which is in place very early on, does not change throughout childhood and adolescence.
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Socialization theory would instead expect sex differences to increase throughout childhood, with increased exposure to aggressive role models, the media, and parenting influences, but they do not. Consider also that
violence increases throughout the teenage years to
peak at age nineteen. This is consistent with the notion that aggression and violence are tied to sexual selection and competition for mates, processes that peak at approximately this age.
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While male warriors perpetrate most violent offending, females can be aggressive too, in a surreptitious sort of way. On balance, however,
women tend to be worriers rather than warriors for reasons that evolutionary psychology can explain.

Women have to be very careful in their use of aggression and sensitive in their perception of it because personal survival is more critical to women than to men. That’s because they bear the brunt of child care and their survival is critical to the survival of their offspring. In unison with this standpoint, laboratory studies show that women consistently rate the dangerousness of an aggressive, provocative encounter higher than men do.
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Women are also more
fearful than men of situations and contexts that can involve bodily injury.
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They are more likely to develop
phobias of animals and medical and dental procedures. While they are more averse to physically risky forms of
sensation-seeking, they are not averse to seeking forms of stimulation that do not involve physical risk—things like novel experiences through music, art, and travel.
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Women also have a much greater concern over health issues than men. They rate health as more important and also go to the doctor more often.
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Fearfulness of bodily and health injury is therefore the psychological mechanism that evolution has built into women to protect them from death, helping to ensure the
survival of their young. Thus, the fact that women are far less physically aggressive than males, in almost all arenas in life and in all cultures across the world, can be explained by an evolutionary principle.
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Women are more averse to physical aggression than men because of its reproductive impact. Yet what would happen if we lowered the risk of bodily injury from aggression?

In this case a different scenario gets played out.
John Archer, of the University of Central Lancashire, has documented that the
sex difference in aggression is highest at the most severe levels of physical aggression, is much lower when it comes to
verbal aggression, and is negligible with “
indirect aggression.”
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Essentially, females are much more likely to engage in aggression when the cost to them in terms of physical injury is minimal. Indeed,
Nicki Crick, at the University of Minnesota, has argued that females are more likely than males to engage in this “indirect” or “
relational aggression,” which takes the form of excluding others from social relationships and group activities and damaging their reputation in their peer groups—gossiping, spreading rumors, humiliating the individual. Ladies, do you recall this from your teenage days or experience it now in your current working life?

So rather than being physically violent, women take a more
passive-aggressive strategy. They compete in terms of physical
attractiveness—the quality most desired by men, who use it as a guide to fertility—and allow access to the man with the most resources.
David Buss argues that women are much more likely to call their competitors ugly, make fun of their appearance, and comment on their fat thighs.
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Women attempt to ruin their rivals’ reputation by saying they have a lot of boyfriends, sleep around a lot, and are sexually promiscuous.
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Men don’t like hearing that from an evolutionary standpoint because if they get together with such a woman, they may end up rearing some other man’s offspring. Consequently, such slanderous gossiping is an effective verbal-aggression strategy for women to use that does not run a high risk of physical harm.

We’ve seen here how violence and aggression is based partly on primeval evolutionary forces from the past. While
reciprocal altruism can rule the day, antisocial
cheating can also be a successful reproductive
strategy, especially when psychopathic cheats migrate from one population to another. I’ve tried to illustrate how stealing,
rape,
homicide,
infanticide,
spousal abuse, and
spouse killing can all be viewed from an evolutionary perspective. We’ve also seen anthropological examples of how different ecological settings could have given rise to either cheating or reciprocal altruist
reproductive strategies. Males have evolved to use physical aggression to increase
genetic fitness, while women have evolved to be concerned over their own health and that of their progeny, resorting to a safer form of
relational aggression to protect their genetic interests. While evolutionary theory cannot, by any means, explain all violence, it at least provides us with a broad conceptual base with some degree of explanatory power.

The seeds of sin are rooted in our evolutionary past, the time when hominids formed social groups that shaped norms for helping behaviors—norms that a minority could break. Genes are the name of the evolutionary game, and therein lies an important implication for us. Talk about evolution, and by necessity we invoke genes. I’ve argued that antisocial, psychopathic behavior has evolved in some of us as a stable evolutionary strategy. In this ruthless,
selfish context, rape is viewed not simply as a mechanism by which men exert power and control over women, as many feminists would argue. It is also the ultimate evolutionary cheating strategy—“love” them and leave them. Inseminate as many women as you can, then leave them to get on with the hard work of raising Cain and reproducing your bad genes. So the next step we will take in tracing the anatomy of violence is to understand the genetic basis to brutishness, and which individual genes stand out as our “usual” suspects.

Jeffrey
Landrigan never knew his father. He was born on March 17, 1962, to a mother who abandoned him at a day-care center when he was just eight months old. But little Landrigan got lucky. He was adopted into an all-American family in Oklahoma. His adoptive father was a geologist named
Nick Landrigan, whose wife, Dot, was a doting mother to both Jeffrey and their biological daughter, Shannon. Well-educated, straight-laced, and respectable, they provided a perfect new beginning for little Jeffrey.

Yet an insidious shadow from the past was cast over this baby that was to effectively seal his fate. By the age of two he was already throwing temper tantrums and displaying emotional dyscontrol that quickly escalated. He began abusing
alcohol at the age of ten. His first arrest came when he was eleven, after he
burglarized a home and attempted to break open the safe. He skipped school, abused drugs, stole cars, and spent time in detention centers. He was moving rapidly into his criminal career. When he turned twenty he had a drinking bout with a childhood friend who wanted Jeffrey to be the godfather of his soon-to-be child. Jeffrey’s response? He stabbed his friend to death outside his friend’s trailer. In 1982 he started a twenty-year sentence for second-degree murder.

Incredibly, Landrigan escaped from prison, on November 11, 1989, and headed out to Phoenix, Arizona. It could have been a new life and
a clean sheet, yet murder seemed almost
destiny for Landrigan. In a Burger King in Phoenix he struck up a conversation with
Chester Dyer. Dyer was later found stabbed and strangled to
death with an electrical cord, with lacerations on his face and back. Pornographic playing cards were strewn around the bed, with the ace of hearts propped up maliciously on the victim’s back. But Landrigan’s luck was running out. While exiting the apartment he left his footprint in sugar on the floor. He was consequently arrested, found guilty of
homicide, and sentenced to death.

This might have been the last chapter in Landrigan’s dramatic, topsy-turvy life. But the strangest twist was yet to come. While Landrigan was on death row in Arizona, another inmate told him of a man named
Darrel Hill, a con he had met while on death row in Arkansas. Darrel Hill was Jeffrey’s spitting image. Hill turned out to be the biological father that Jeffrey Landrigan had never seen. He was a dead ringer for Landrigan, and looks were not the only eerie similarity.

Darrel Hill had himself started his criminal career at an early age. He too was a
drug addict. Like Landrigan he had killed not once but twice. He too had escaped from prison. Landrigan had clearly inherited much more than his father’s looks. They could hardly have been more similar.

And that’s not all. Jeffrey Landrigan’s grandfather—Darrel Hill’s father—was also an institutionalized criminal, who was shot to death by police after he robbed a drug store in a high-speed chase in 1961. He died just feet away from his then twenty-one-year-old son Darrel.

What do we make of this? Perhaps Darrel Hill summed it up best when he said:

Is there a
“
killer gene”? Or if not one, then multiple genes that, either on their own or in an intricate conspiracy with the environment, shape killers like Hill and Landrigan? Jeffrey Landrigan was adopted and raised in a safe and nurturing environment, yet despite all the love that his parents gave him—he could not be salvaged. This fascinating natural experiment—in which a baby with a violent heritage was transferred from a life of poverty and squalor into a loving, caring, successful
family, yet still became a killer—suggests that there really is a genetic predisposition to violence.

Criminologists for decades have strongly resisted this idea. In this chapter I’m going to not just try to persuade
you
beyond a reasonable doubt, but also explain why social scientists are also opening up their minds to this fascinating and important
perspective. To begin with, we’ll delve into results from adoption studies that systematically examine cases similar to Landrigan’s. In these studies, babies whose biological fathers were criminals were adopted away into noncriminal homes. We’ll see that such babies were much more likely to become adult criminals than were babies who were also adopted but whose biological fathers were not criminals.

A second research design that uses
identical and
fraternal
twins renders the same conclusion. Identical twins, who by definition have all of their genes in common, are much more similar to each other on crime and aggression than fraternal twins, who have only 50 percent of their genes in common.

A third but more unusual study comes to the same conclusion: identical twins who were separated at birth are surprisingly similar with respect to antisocial personality, despite being
reared in very different environments.

These twin and adoption studies tell us that there is a significant genetic loading for aggression, but they do not tell us which specific genes are involved. So we’ll finally turn to research at the
molecular level that is now beginning to unmask the mean genes giving rise to aggression.

About 2 percent of us are twins. Almost all of these twins are fraternal, or dizygotic, twins, who have about 50 percent of their genetic material in common. They develop from two separate eggs that are fertilized by two separate sperm, and effectively they are just like normal brothers and sisters. Much rarer—only 8 percent of all twins—are identical, or monozygotic, twins. These twins have virtually 100 percent of their genes in common because they develop from a single egg-sperm pair-up—a
zygote—that basically malfunctions and splits into two.
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Behavioral geneticists have used this malfunctioning twist of nature to
examine genetic influences on antisocial and
aggressive behavior. It’s the perfect natural experiment for exploring the extent to which any behavioral, physical, or psychological characteristic is influenced by genetics.