EVILICIOUS: Cruelty = Desire + Denial (14 page)

Several studies support Zahavi’s insight, including work on insects, crabs, birds, and gazelles, as well as hunter-gatherers and religious institutions. Hunter-gatherers do it by showing off and sharing their large prey capture, as well as by passing through extremely costly rites of passage from genital mutilation to body scarring. Religions do it by requiring their members to engage in elaborate, time consuming rituals: in a study of 83 utopian communities that were in operation in the 19
^th
century, those carrying out the most costly rituals survived the longest.

What this section reveals is that animals have evolved a wide variety of non-lethal strategies to compete. They use rules of thumb, and engage in assessment in order to minimize the costs of battle. What this means is that after most battles, there is either no harm done or it is minimal. This is version 1.0 of HARMING OTHERS. This version encompasses most of the behavioral routines that animals use when they fight for resources, and this includes the human animal. All of these routines are controlled by specialized hormones, brain circuits, thoughts and emotions. Some of these physiological mechanisms have remained largely unchanged over evolutionary time, whereas others have changed, guiding the thrill of victory and the agony of defeat, together with differences in the willingness to take risks. Some of these changes inched animals closer to lethal aggression, pushed some right into it, and others over the top.

HARMING OTHERS, version 1.0: raging physiology

In any competitive situation, whether it is animals working out a strategy for maximizing the odds of obtaining food or humans working out a strategy for maximizing the odds of check mating an opponent’s king, someone will walk away as the winner and someone as the loser. Winning feels good and losing feels bad. Winning fuels confidence, including the kind of overconfidence noted in the last chapter. Losing lowers self-esteem. Depending on the opponent, including what they look like and whether they are familiar or unfamiliar, it is possible to gauge the likelihood of winning or losing in advance. Depending on the individual’s prior history of wins and losses, and details of his or her personality, some individuals will embrace the challenge of a high risk-high payoff strategy whereas others will adopt a low risk-low payoff strategy. Winning, losing, and taking risks are all influenced by differences in hormone levels, neurochemicals, and patterns of brain activation. Some of these differences are set early in life by the individual’s biology, some change over the course of a year, some within a day, and some within the period of a brief glance that allows an opponent to assess the competition. These physiological processes regulate an individual’s motivation to fight or flee, as well as the sense of reward and loss that accompanies winning and losing. They adaptively regulate the capacity to harm, at least until they malfunction. Malfunctions, whatever their cause, can convert healthy, defensive, competitive, and justifiable aggression into excessive violence and in our own species, unethical violence. This teeter-tottering between normal adaptive aggression and abnormal malfunctioning aggression is at the root of my explanation of evil. Here we begin to put this part of the story together
⁴³
, looking first at testosterone — an evolutionarily ancient hormone that can loosen inhibitions, motivate fighting, and generate feelings of satisfaction when a victory is in hand.

Testosterone is a critical hormone in all social animals, guiding aggressive, sexual and social behavior. Testosterone surges when males defend their territories and when they recruit sexually receptive females. Stronger surges occur when individuals are challenged by competitors who want their territory, food, mates, or position within a hierarchy. This suggests that testosterone motivates animals to fight within the arena of competition. Conversely, testosterone drops during parental care, friendly interactions between mates, and coalitions among males. This suggests that lower levels of testosterone motivate animals to create or maintain social bonds, sometimes in the service of attacking others.

The role that testosterone plays in guiding aggressive competition is nicely seen by comparing winners and losers. Testosterone surges after an individual wins a fight, and drops following a loss. These changes are highly adaptive as they motivate winners to keep defending their resources, and motivate losers to give up and minimize future costs. Across a wide variety of species, humans included, winners are two times more likely to win the next fight whereas losers are five times less likely to win the next fight. In our own species, among male and female athletes, in sports including soccer, tennis and judo, winners have higher testosterone levels than losers because of winning. This effect even holds in competitive interactions with no physical contact, such as chess, dominoes and stock trading, as well as in cases involving audience members as opposed to those directly involved in competition. In a study of day traders on the London Stock Exchange, those making the highest profits had the highest levels of testosterone, and soccer spectators watching their team win the World Cup had higher levels than spectators on the losing side.

The ebb and flow of testosterone is thus an essential part of the story of our evolved capacity for non-lethal aggression. In humans, and all other social animals that are both closely and distantly related to us, surges in testosterone loosen restrictions on fighting, motivate resource defense, boost self-confidence following victory, and increase the odds of fighting again. These are all adaptive responses to living in a world of limited resources, and thus, a world where competition is necessary to survive. But one consequence of this adaptive system is that it can enable selfish, antisocial behavior toward others, while feeling good about it. Testosterone thus binds violence to reward. This is a connection that, if unrestricted, can lead to an appetite for cruelty. The puzzle is why we are the only species that lifts this restriction over and over again; the rest of this chapter explores this puzzle.

Testosterone is not alone when it comes to guiding individuals toward aggressive competition or away from it. The hormone cortisol regulates the stress response in fish, reptiles, birds, and mammals, including all ages of human mammals. When fear kicks in due to aggressive challenges from a dominant individual or from the appearance of a predator, cortisol rises. When individuals confront uncertainty, as occurs when they enter a novel environment or confront a stranger, cortisol rises. When cortisol levels are high, individuals are more likely to avoid costly situations or experiences, such as getting into a fight with a stranger or engaging in a social interaction with someone whose status is ambiguous as friend or foe. When cortisol levels are low, individuals are more aggressive, more reward focused, and less sensitive to punishment. Testosterone and cortisol therefore play within the bodies of animals like two children sitting on opposite ends of a see-saw. When testosterone is up and cortisol is down, individuals are primed to harm others and take risks. When testosterone is down and cortisol is up, individuals are risk averse, less likely to harm and more likely to engage in friendly social behavior.

The hormones testosterone and cortisol are joined by brain chemistry that can either dampen or heighten an individual’s aggressive reaction. Serotonin is one of the central chemical agents in this process, working on aggression through the brain systems that guide self-control. High serotonin levels are associated with behavioral inhibition, whereas low serotonin levels are associated with disinhibition or impulsivity. These changes in inhibitory control start with genetic differences between individuals (detailed in the next chapter), are affected over the course of development by particular experiences, and ebb and flow with daily experiences. The most elegant evidence for the inter-play between genes and experience comes from studies of genetically engineered mice who have had a serotonin gene altered. In these mice, those with higher levels of serotonin are much less likely to attack an intruder than those with lower levels of serotonin. Serotonin thus impacts the motivation to harm others by shifting individuals along a continuum from more impulsive to more patient.

Can the genetic differences that guide the levels of serotonin, and thus guide the levels of aggressiveness, also override an individual’s history of winning or losing? In other words, given the evidence discussed above that winners are more likely to win again and losers are more likely to lose again, can the genetic differences that determine serotonin levels cause some winners to lose and some losers to win? To answer this question, the biologist Norbert Sachser and his colleagues compared levels of aggression in genetically engineered mice with either high or low levels of serotonin, and a history as either winners or losers. Results showed that history mattered most: winners were more likely to engage in fighting an intruder than losers, whether they were engineered to have higher or lower levels of serotonin. This suggests a hierarchy of effects, with the experience of winning a fight dominant to an individual’s genetic constitution, at least in terms of genes involved in the expression of serotonin; this is a theme that we will revisit in
chapter 4
as it helps explain individual differences in our capacity to harm others, or to refrain from it.

Dopamine, as discussed in the previous chapters, is linked to the experience of reward, guiding both the individual’s sense of when it will occur while simultaneously motivating behavior that maximizes the odds of obtaining the goods. When animals reach their goals or expect to obtain them, including food, mating, or winning a fight, the brain delivers a surge of dopamine. In lizards, dominant animals have dark rings around their eyes whereas subordinates do not. The dark eye rings signal to subordinates “back off.” When animals see opponents with experimentally erased eye rings, they not only show increases in aggressive behavior but increases in dopamine, confirming the connection between this neurochemical and the anticipation of a successful and rewarding experience. As I explained in discussing the psychology of desire, when human subjects take L-dopa, a drug that increases the amount of dopamine, they feel more elated about an event in the future. In a study of stock traders on Wall Street (as opposed to London traders discussed earlier), results showed that those individuals with gene variants that cause higher levels of dopamine had longer careers as traders. To have a long career, you have to be willing to take risks and anticipate that more often than not your risky trades will pay off. Having more dopamine facilitates this risky business.

The general implication of work in humans and other animals is that individuals with heightened dopamine levels, whether naturally occurring or experimentally induced, are more likely to anticipate a rewarding experience and thus more likely to engage in risky behavior. This is true whether the risk entails finding food, competing for a mate, or fighting an opponent. What this means for our understanding of evil is that those who engage in over the top acts of gratuitous cruelty may do so in part because heightened dopamine causes them to anticipate feeling really good about it, while negating any potential risk. The conclusion is not “dopamine causes evil” but rather, “dopamine heightens the anticipated rewards of evil.” This conclusion is also not an excuse, as there are individuals with heightened levels of dopamine that do not engage in any malicious behavior. The appropriate conclusion is that certain biological changes can increase the odds of violent behavior.

Like the other physiological changes I have noted, serotonin and dopamine do not operate in isolation. Rather they both interact with each other and are directly regulated by testosterone. Thus, surges in testosterone result in lower levels of serotonin and higher levels of dopamine. This makes sense in the heat of aggressive competition: when serotonin levels are low, restrictions on aggression are lifted; when dopamine levels rise, the anticipation of reward increases as well, joining the additionally rewarding properties of testosterone. Mice will work a response lever to self-deliver testosterone, and humans become addicted to testosterone ingestion. If you inject testosterone into a mouse while it is moving about, the location associated with the injection becomes tagged as a favorite spot in the landscape, a place to revisit. Drug abusers and gamblers, two personality profiles associated with heightened experience of reward and poor self-control, have elevated levels of testosterone and dopamine.

All of these changes in hormones and brain chemistry reveal why non-lethal aggression is rewarding. These same processes and others make lethal aggression rewarding as well, but only in a small subset of animals.

HARMING OTHERS, version 1.5: upgrade to lethal aggression

I noted in the Prologue that there are three situations in which animals kill others. Two are broadly distributed across the animal kingdom — predation and infanticide — and one is extremely rare — adults killing other adults from the same species — adulticide. It is this rare form, as we will see, that is the most difficult to explain, but of greatest interest in terms of our own evolutionary history
⁴⁴
.

In virtually every taxonomic group of animals – insects, reptiles, amphibians, fish, birds, and mammals — there are predators and prey. Predators are not merely aggressive, but designed to kill prey species for the purpose of survival. When I say that predators have been designed, I mean that evolutionary processes have resulted in specialized brain areas, anatomical structures, and behavioral strategies that are highly adapted to the problem of prey capture. As noted by the psychologist Victor Nell and the neurobiologist Jan Panksepp
⁴⁵
, predatory killing is enabled by stealth-like attacks accompanied by brain circuitry that makes killing highly rewarding. These two features are important as they distinguish predatory killing from most other forms of aggression. In particular, when predators kill, it is not a reactive response to a victim, but rather, one that is planned, including the initiation of a hunt when the victim is out of sight. When predators seek out their prey, the dopamine systems of the brain are highly engaged. Recall from the last section, that dopamine is linked to reward, and especially the anticipation of reward. For predators, the anticipation of killing is the opposite of aversive — there are no internal brakes at all. Once a predator kills its prey, the brain’s opioid system kicks in, a system that I discussed in
chapter 1
. The opioids deliver pleasure. For a predator, killing and consuming its prey is like smoking opium in humans — deeply rewarding.