How Ordinary Minds Become Capable of Real Horror

Psychopathy as facultative threat management

We like to imagine evil as something inherent in an individual. We imagine it as a corruption that infects certain people and spares others. However, history is full of examples of otherwise ordinary people committing acts that we would ascribe only to the darkest of psychopaths.

The most famous case of this probably came to mind immediately: Nazi Germany. Christopher Browning’s Ordinary Men (1992) tells the story of Reserve Police Battalion 101: middle-aged, working-class men from Hamburg who, without prior inclination to violence, went on to massacre tens of thousands of Jewish civilians in Poland. Of course, many of the German soldiers were also ordinary men, drafted into a war that they may or may not have initially believed in. And yet, they took part in one of the most horrific acts of violence in memory.

Some of you may have thought of another well-known incident: the Rwandan Genocide. From April to July 1994, over 800,000 individuals were killed, mostly by neighbors, coworkers, and acquaintances wielding machetes. Many perpetrators were ordinary villagers responding to propaganda, fear, and social pressure.

These two cases alone warrant explanation, but I could go on and on with examples of how people with no prior history of violence can, in the right circumstances, be horribly violent. In fact, almost any battle, of which there have been tens of thousands throughout history, fits into this category.

How could a species so well known for its prosociality and cooperative nature also be so violent?

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It’s not as if this question hasn’t been asked before. It’s no coincidence that some of the most famous psychology experiments in history were 1) about aggression and violence, and 2) took place not long after WWII.

Most of these studies showed how easily people could descend into aggression. In the Robbers Cave Experiment, social psychologist Muzafer Sherif invited two groups of boys to what they believed was an ordinary summer camp. When the groups were introduced and placed in competition, cooperation gave way to hostility almost immediately. Taunts, raids, and full-on brawls broke out within days. Albert Bandura’s Bobo doll experiments demonstrated that aggression can be learned through observation. Children who watched an adult beat and shout at an inflatable doll later imitated the same behavior, often with creative embellishments.

Stanley Milgram’s obedience experiments at Yale showed how easily people obey authority, even when it means harming others. Believing they were administering electric shocks to a stranger, many participants continued to escalate the voltage when instructed by an experimenter in a lab coat. Though the original findings are now mired in controversy, Philip Zimbardo’s Stanford Prison Experiment also demonstrated how some people would behave aggressively when in the right context (or persuaded by the right person to do so).

The idea that evil could be situational was revolutionary. But as psychology evolved, attention turned to the people who seemed predisposed to aggression — those for whom cruelty appeared to be stable rather than situational. The most well-known example of this is psychopathy.

In modern psychology, psychopathy isn’t thought of as a single diagnosis so much as a constellation of traits aligned along two domains. One of those is emotional and interpersonal and includes traits like superficial charm, manipulativeness, lack of empathy, and shallow emotion. The other is behavioral: things like impulsivity, irresponsibility, and a tendency toward antisocial behavior.

Across multiple studies, psychopathy is strongly connected to aggressive and violent behavior. Those who score higher in psychopathy, using clinical or sub-clinical measures, are more likely to engage in violent behavior. Psychopathic traits are also highly heritable. Estimates range from 40-70%, depending on the specific measure used.

So let’s revisit our initial question: How could a species so well known for its prosociality and cooperative nature also be so violent? Is it because of relatively stable traits like psychopathy, or can anyone become violent? Maybe a bit of both.

I’d argue that like every other animal on earth, some humans are born with aggressive tendencies that make them more likely to commit violence, including violence many find immoral or reprehensible. I’d also argue that this tendency is influenced by social and contextual situations.

Most human traits work like that; that is, they are designed (genetically, via Natural Selection) to respond to specific input signals and produce certain behavioral outputs. They are facultative.

None of that is particularly controversial, but my conclusion for how humans can be so violent might be.