The psychology of killing

The psychology of killing
Human evolution may allow us to commit genocide, but that’s no excuse
By James E. Waller
The field of evolutionary psychology, or EP, illustrates that people are part of the natural world and, like other animals, have their own particular psychological tendencies that animate behaviors. Those behaviors can be both good and bad — responsible for both love and hate — and can both be understood by EP.

“Immediate influences” explain why a behavior occurs, such as how hunger impels people to eat or lust impels them to have sex. “Ultimate influences,” conversely, refer to deeper influences from humans’ evolutionary past — why a behavior evolved by natural selection — such as the need for nutrition and reproduction that gave us the drives of hunger and lust.

It is these ultimate influences, flowing from the deep evolutionary streams of human nature, that help us understand how ordinary people commit genocide and mass killing.

EP: Full steam ahead

EP — a marriage of cognitive psychology and evolutionary biology — is leading the charge in investigating human nature as an ultimate influence on behavior. Essentially, EP is a multidisciplinary way of applying knowledge and principles from evolutionary biology to research the structure of the human mind. In a kind of reverse-engineering, EP researchers examine the human mind today for clues as to how it evolved in the past. It’s a complicated process because human nature included hundreds, perhaps thousands, of psychological adaptations, each designed for different, domain-specific conditions. Today’s human brain can be compared to a Swiss Army knife, with its various blades and gadgets meant for different tasks.

A detailed evolutionary heritage

Humans are obligated to examine the impact of what they are and who they are in understanding the origins of genocide and mass killing. While the roots of genocide and mass killing cannot be attributed solely to the deep traces of design left in the mind by natural selection, people can no longer dismiss as an unsupportable theological or philosophical assumption that human nature has a dark side. Evil deeds are at least partially grounded in human nature. An impulse to do evil is not the defining characteristic of human nature, but the impulse is certainly within human capacity.

How does our evolutionary heritage help us comprehend the perpetration of genocide and mass killing? To begin with, humans have evolved natures with broad arrays of psychological adaptations. On the positive side, some of these adaptations affirm a capacity for goodness. These include love, friendship, cooperativeness, trustworthiness, preferential and reciprocal altruism, nurturance, friendship, compassion, communication, a sense of fairness and even self-sacrifice — in short, the things that hold society together.

EP warns, however, that self-congratulation about humanity is premature. Beneath the social surface is a seamy underside of human nature that is much less flattering. Prosocial adaptations are qualified by the reality that people reserve major doses of goodness either for close kin or for nonkin who show signs of someday returning the favor. Underlying these so-called acts of charity are selfish and aggressive traits that are part of inherently self-centered human nature. Sometimes altruism and cooperation turn out to be the most effective ways to compete.

The Swiss Army knife of adaptations includes even darker ultimate motives — such as intergroup competition for dominance, boundary definition and fear of social exclusion — which often tear society apart by providing the critical building blocks for within-group niceness and between-group nastiness.

For instance, studies worldwide show that ethnocentrism (focusing on our group as the “right” one) and xenophobia (fearing outsiders or strangers) are not only universal in people, but also that these tendencies start in infancy. We have an evolved capacity to see our group as superior to all others and even to be reluctant to recognize members of other groups as deserving of equal respect. Some even suggest that our tendency to divide the world into “us” and “them” is one of the few true human universals.

A group of the !Kung San of the Kalahari Desert, for instance, call themselves by a name that literally means “the real people.” In their language, the words for “bad” and “foreign” are one and the same. Similarly, the cannibal inhabitants of the delta area of Irian in Indonesian New Guinea call themselves the Asmat, which means “the people — the human beings.” All outsiders are known very simply as Manowe — “the edible ones.” It is these types of “darker” universal adaptations that can be evoked by governments, propaganda and militaries in the recruitment of genocidal killers.

As William James, the first great American psychologist, opined more than a century ago, “We, the lineal representatives of the successful enactors of one scene of slaughter after another, must, whatever more pacific virtues we may also possess, still carry about with us, ready at any moment to burst into flame, the smoldering and sinister traits of character by means of which they lived through so many massacres, harming others, but themselves unharmed.”

EP vs. the social fabric of life

Understanding the powerful, innate, ultimate, “animal” influences lying at the core of human nature is only the first step, however, in understanding how ordinary people commit genocide and mass killing.

Natural selection may have designed certain adaptations that provide the capacity for extraordinary evil, but no other species shows the degree of premeditated mass killings of its own that humans have shown over the centuries. Indeed, it is quite unfair to other species to compare them with humankind.

EP describes the ultimate evolutionary capacities common to everyone. But this understanding must be couched in the context of the more proximate and immediate cultural, psychological and social constructions that activate these capacities.

Taming the animal instincts within

While it is not reasonable to hope for dramatic or quick evolution of humanity, the dark side of human nature is not behaviorally inevitable.

People can and should identify the psychological adaptations that can most usefully serve cooperative and peaceful goals and build on them. There are certainly innate tendencies for cooperative, caring and nonviolent relations that enhanced human ancestors’ survival rates and reproductive success in a world of limited resources. Such pro-social tendencies would have been favored by natural selection and would still be retained at some level as long-term adaptations. Fostering cultural practices and resources that activate these adaptations can be done to produce mutually beneficial outcomes for formerly antagonistic groups. As biologist Lyall Watson reminds us, “The roots of war lie deep in nature, it seems, but then so too do the roots of peace.”

Humans are not slaves to an unyielding genetic leash. The mentally ill aside, people are not forced by some internal monster of the mind to commit such atrocities as genocide or mass killing. Evolutionary adaptations are best understood not as immutable genetic programs, but simply as predispositions to learn. Genes endow a capacity to learn and to adapt to life in a variety of environments, and as a result, people are not constrained by innate psychological adaptations.

As a matter of fact, the more psychological adaptations humans have, the more capabilities they have. It’s the large number of psychological adaptations — and their infinite range of combined interactions — that make human behavior more flexible and intelligent than other animals.

James E. Waller is a professor of psychology and Edward B. Lindaman Chair at Whitworth College in Spokane, Wash.