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What Actually Is Evil? And What Makes People Carry Out Evil Acts?

The myth of “Pure Evil,” and the real reasons why people do “evil” things.

Key points

  • "Evil people" and "evil acts" are common, but much less common than is generally believed. Most people are moral and self-controlled.
  • Most people who intentionally harm others don't think of themselves as evil, tending to minimize or justify their actions—in crime and in war.
  • Some of the worst atrocities have been motivated by Utopian ideals, especially coupled with irrational conspiratorial belief and dehumanization.
  • Biological and cultural evolution have favored cooperation and compassion in humans. Violence has in fact been declining in human societies.
On Wikimedia Commons / Bundesarchiv, Bild 183-1987-0703-507 / Unbekannt / CC-BY-SA 3.0
Adolf Hitler speaking at the Kroll Opera House to Reichstag members about war in the Pacific, December 11, 1941
Source: On Wikimedia Commons / Bundesarchiv, Bild 183-1987-0703-507 / Unbekannt / CC-BY-SA 3.0

From genocide to malware and everything in between, it’s easy to feel demoralized about the moral fiber and caring of our fellow humans. It can certainly seem that malice is endemic to humans. The default state, perhaps.

And yet, as the highly cited social psychology researcher Roy Baumeister noted in his seminal work Evil: Inside Human Violence and Cruelty:1 "One starts a work like this wondering, ‘Why is there evil?’ But after reviewing what is known about the causes of aggression, violence, oppression, and other forms of evil, one is led to the opposite question: Why isn't there more evil than there is?"

For starters, Baumeister debunks the very notion of evil, “the myth of pure evil,” making the point that the factors driving people to do bad things to each other are highly complex. The notion of evil is a simplistic one. Nevertheless, for practical purposes, he uses the term in his analysis:2

"There are four major root causes of evil or reasons that people act in ways that others will perceive as evil. Ordinary, well-intentioned people may perform evil acts when under the influence of these factors, singly or in combination."

  1. The simple desire for material gain
  2. Threatened egotism
  3. Idealism: "Noble ends are often seen as justifying violent means."2
  4. The pursuit of sadistic pleasure: "only 5 or 6 percent of perpetrators actually get enjoyment out of inflicting harm."2

Why is “evil” not more prevalent than it is?

Bad people or bad actions?

A disproportionate amount of violence and crime in ordinary societies is perpetrated by the small minority of people with antisocial personality traits. And an even smaller percentage are psychopaths, at the extreme end of the spectrum of antisocial traits—the ones most likely to commit sadistic acts of violence.3

But aside from the disproportionate contribution of nasty personality types, a lot of other violence is simply committed impulsively rather than premeditated, and many of those kinds of perpetrators do actually feel regret or shame for their actions afterward. Human interpersonal violence is often carried out by people acting impulsively, fearfully, insecurely, passionately, vengefully, or misguidedly. A lot of this is reactive aggression. Only some violence is premeditated, calculated, or predatory (proactive aggression). And when violence and crime are committed by groups, there is also the huge factor of peer pressure and influence.4

So far, we have mostly been talking about “ordinary” violence and crime, not war or government tyranny.

People who do evil things generally don’t consider themselves evil

People often tend to minimize the harmful impact of what they are doing or rationalize their reasons (even if motivated primarily by the simple desire for material gain or by threatened egotism), often seeing their action as much less of a big deal than the impact experienced from the victim’s point of view, or feeling that the victim threatened or provoked them or deserved what was done to them. Baumeister suggests that while the victims’ motto is “Never forget,” the perpetrators’ motto is “Let bygones be bygones,”5

Evil villains in Hollywood movies aside, Baumeister notes that “most people who do evil do not think of themselves as doing evil […], most of them regard themselves as good people who are trying to defend themselves as the good guys fighting against the forces of evil. The world breaks down into us against them, and it almost invariably turns out that evil lies on the side of ‘them’”6 (referring more to violence between groups, nations, ideologies, etc., than to individual criminal acts).

Even Hitler considered himself and the German people to be victims—principally of the Jews, whom (together with the leftists) he blamed for Germany’s defeat in the First World War and its subsequent crushing economic conditions and humiliation.7 He portrayed the Jews as a greedy amoral race living parasitically off the German people and set on destroying Germany. He viewed the Nazi persecution of, and subsequent mass murder of, the Jews as self-defense. An anxious man with a nervous digestive system, neurotic contamination obsessions, volatile temper, lack of formal education (not having completed his secondary schooling), and a strong tendency to externalize blame for his personal failures, Hitler was just the sort of person to believe and propagate bizarre paranoid conspiracy theories.8-12

[Note: This blog post is a bare-bones summary of a vast and complex topic. It warrants elaboration, which I’ve provided in the footnotes, with additional illuminating material, for readers who want to understand more about the motivations of evil-doers. The footnotes include, for example, quotes by Heinrich Himmler—a foremost architect of the Holocaust, explaining and justifying his own motivations.]

Societal control and self-control

Baumeister states: "All told, the four root causes of evil are pervasive, which leads one to wonder why violence and oppression are not even more common than they are. The answer is that violent impulses are typically restrained by inner inhibitions; people exercise self-control to avoid lashing out at others every time they might feel like it."13 Violence is often the result of reduced self-control or a breakdown of societal control.14

Inhibitory control or self-control is largely a function of the frontal lobes of our brains (especially the prefrontal cortex). As the neuroscientist and biological anthropologist Robert Sapolsky pithily puts it: The frontal lobe helps us do the harder thing when it's the right thing to do.15

There is very wide variability in frontal lobe functioning across individuals—probably best described by a bell curve, like most traits. A great many people have relatively lower frontal cortical brain activity and consequently lower self-control (and, more generally, weaker executive functioning). The most common clinically defined “disorder” associated with these characteristics is ADHD.16 ADHD plays an outsized role in human aggressive and criminal behavior. A recent meta-analysis of the prevalence of ADHD in incarcerated populations found that compared with published general population prevalence, there is a fivefold increase in the prevalence of ADHD in youth prison populations (30.1 percent) and a 10-fold increase in adult prison populations (26.2 percent).17

Context, context, context

The biological and social-cultural determinants of human behavior are vastly complex, as Sapolsky lucidly demonstrates in Behave: The Biology of Humans at Our Best and Worst—his richly complex multilayered explanation of the many biological and cultural factors influencing human behavior including aggression. He repeats a cautionary statement several times throughout the book, whenever we might be tempted to conclude that we have arrived at a complete explanation and understanding of what makes humans do the things they do: “It’s complicated.” Genes and the environment interact inextricably, all the time. And he reminds us of the importance of “context, context, context,” in influencing the basic biological factors that underlie human behavior.18

How a person will behave is strongly influenced by genetic predisposition, past experience (especially early childhood experience), socio-economic and cultural factors, the presence of an intact society with prosocial norms, specific interpersonal dynamics between individuals, and the particularities of the immediate circumstances.

Innate tendencies and long-term trends

There is a larger philosophical debate about whether humans in their natural uncivilized state are innately “bad” or “good,” often referred to as “Hobbes” vs. “Rousseau” views. Sapolsky helps us see why, unsurprisingly, it’s “a mixture of both.”19, 20

Steven Pinker’s magisterial work, The Better Angels of Our Nature: Why Violence Has Declined,21 provided mountains of data demonstrating that violence has actually been substantially declining in the last few centuries. Among the very many factors contributing to this, a major one was the establishment of centralized societal control in the form of the state (initially religious and authoritarian, and later democratic in many countries). There has also been an increase in norms of (and possibly even capacity for) self-control in modern societies. Improving standards of living, literacy, education, employment, and health have of course all contributed hugely too. Economic interdependence, cosmopolitanism, the resultant expanding notion of within-group (“us”), and the generally increased ability of people to understand the points of view of others very different from themselves, have also contributed greatly. The empowerment of women has also been enormously influential.

The internet and social media have amplified both the best and worst aspects of human nature, increasing the availability of both high- and low-quality information, equalizing the ability of individuals and groups to disseminate information far and wide, breaking down traditional group boundaries while also fostering new “tribal” affiliations.22

In summary

People who do bad things often tend to believe that their actions are on the side of the good, or they rationalize that their actions are justified or not such a big deal. Biological and cultural evolution have conferred many brakes on violence and malice, and have favored cooperation and even compassion. In the long view of history, there has been an uneven but unmistakable trend toward less violence and more interdependent cooperation within and between human societies.

Being a victim of an evil act is utterly devastating, demoralizing, and disillusioning, and telling victims that evil is not as common as it seems does nothing to reduce their trauma. But it might help a little to know that the world is not a pervasively bad place, that most people are not innately “evil,” and that the world is steadily becoming a less violent place.23


1. Roy F. Baumeister, Evil - Inside Human Violence and Cruelty (New York: W. H. Freeman, 1997), p. 13. See also: Baumeister, R. F. (2012). Human evil: The myth of pure evil and the true causes of violence. In M. Mikulincer & P. R. Shaver (Eds.), Herzliya series on personality and social psychology. The social psychology of morality: Exploring the causes of good and evil (p. 367–380). American Psychological Association.

We will refer in this article only to intentional acts committed by people, not to accidents, illnesses, natural disasters, or attacks by non-human animals. We will take it as self-evident that such events don't happen for an intentional "reason" (apart from the mostly instinct-driven agency of animals).

2. Baumeister, Evil - Inside Human Violence and Cruelty, p.376-7.

3. An especially malevolent combination of overlapping traits that has gained recognition in the psychological literature in the last couple of decades is the so-called dark triad, marked by narcissism (characterized by egocentrism), Machiavellianism (exploitativeness) and psychopathy (lack of empathy). Milder versions of these traits are not uncommon. People with such traits may even have many positive traits too. The really malevolent and potentially dangerous people are the small minority of the population with more marked versions of these traits.

[Click 'more' to view footnotes 4-23, below.]

[The footnotes below contain illuminating material for readers who want to understand more about the motivations of evil-doers, with a particular emphasis on the nazis. The footnotes include, for example, quotes by Heinrich Himmler—a foremost architect of the holocaust, explaining and justifying his own motivations. There are also evolutionary psychology perspectives on evil, and other insights.]

4. A few of the obvious factors contributing to violence and crime:

-- countries with weak or corrupt systems of government and law enforcement, where criminals are seen to act with impunity.

-- communities / neighborhoods lower in socio-economic status, disadvantaged, under-educated or under-employed.

-- communities whose social fabric has been badly damaged by long histories of collective trauma, oppression and discrimination.

-- high rates of alcohol and drug use.

-- low intelligence (applicable more to crime than to aggression; and probably applicable more to criminals from communities where sociological factors like those listed above are not the main cause).

-- brain disorders, brain injuries, mental illnesses, and developmental disorders (applicable more to aggression than to crime; while rates of aggression are higher in these groups than in the general population, people with such disorders tend generally to be at greater risk for self-harm and harm from others than harm to others).

-- regardless of culture or background, most violence is committed by young men (this is a simple fact of biology and evolutionary psychology).

5. Baumeister, p.43

6. Baumeister, p.62

7. The stab-in-the-back myth

8. The point of understanding Hitler’s deluded beliefs is not in any way to exonerate him and the Nazis—the fanatical and callous ruthlessness with which he and his inner circle implemented their murderous agenda constituted crimes against humanity of the highest degree, and probably required no small measure of psychopathic traits. The point here is to illustrate how deeply irrational was their obsession with the Jews—irrational to the point of diverting resources from their war effort to the program of systematic persecution and genocide.

There has been debate among historians, psychiatrists and psychologists as to whether Hitler’s beliefs were full delusions in the clinical sense of meaning that he suffered from a psychotic illness. It is important to understand that irrational beliefs exist on a continuum, with psychosis existing at one end of that continuum. The vast majority of people with irrational beliefs running counter to reality are merely credulous and lacking critical thinking; most people who believe weird things are not delusional in the clinical sense. Belief in implausible conspiracy theories is simply a more extreme manifestation of the tendency of most of us to hold implausible beliefs that are totally contradicted by evidence. The prevalence and dangerousness of irrational beliefs and human credulity in contributing to violence and war underscores the enormous importance of extensively teaching rigorous critical thinking.

9. A great many violent conflicts are driven by irrational ideologies, religious and secular. Utopian ideologies are among the worst offenders, since practically any means can come to be “rationally” seen as a regrettable but justifiable action toward achieving an imagined utopian end. Particularly when coupled with dehumanization of a group of people who are believed to be an obstacle to achieving the perfect society. As the Harvard psychologist Steven Pinker has noted, utopian ends are seen as infinitely good, and the extermination of a group of people who are believed to be preventing the achievement of a perfect, pure society appears to be justifiable [Steven Pinker, The Better Angels of Our Nature: Why Violence Has Declined (New York: Viking, 2011), pp. 320–43]. Racist nationalistic political regimes exploit this lack of identification with, and dehumanization of, other racial groups through xenophobic propaganda and indoctrination. Nazi propaganda dehumanized Jews by labeling them as subhuman vermin, pollution, a pathogen, or a malignant presence. Joseph Goebbels, the Nazi propaganda minister, wrote in his diary in March 1942: “A judgment is being carried out on the Jews which is barbaric but thoroughly deserved." Similar political strategies of dehumanization have been used prior to other orchestrated genocides, such as in Rwanda in 1994 (in which the Tutsis were referred to as “cockroaches”). Dehumanization provokes disgust and blocks the natural human inclination toward empathy. David Livingston Smith in his books Less Than Human: Why We Demean, Enslave, and Exterminate Others (New York: St. Martin's Press, 2011) and On Inhumanity: Dehumanization and How to Resist It (Oxford: Oxford University Press, 2020), provides an in-depth analysis of dehumanization.

10. Hitler seems to have been a true believer in his crazy theories about a global Jewish conspiracy and about the Jews having been responsible for Germany’s defeat in WWI and economic woes. Many of his followers bought into these theories too. But it must also no doubt have been the case that many high-ranking Nazis did not truly believe these implausible theories yet simply considered it expedient to have a political scapegoat to blame for Germany’s problems. Many Nazi officials were simply opportunists who put their own career advancement ahead of any reservations they may have had about being a cog in the vast killing machine, and they likely found ways to rationalize and mentally compartmentalize what they were doing. Nevertheless, many were probably highly motivated by what they regarded as the idealistic “noble ends” referred to by Baumeister (i.e. utopianism), in justifying their violent means. Certainly, there were also many psychopaths, thugs and opportunists who jumped on the bandwagon for reasons of self-interest, and people with personal feelings of inadequacy seduced by the prospect of power. And undoubtedly there were a great many people who were “just following orders”. Most people, of course, were more simply either inactive bystanders or complicit in small ways—small cogs in the giant Nazi machine. But it is deeply disturbing that many Nazis who were willingly and enthusiastically complicit in the genocide, and deeply committed to the irrational ideology that drove it, were educated professionals, and even intellectuals. [For more disturbing insights into how far “ordinary” people will go in following orders, or under the influence of peer pressure or group conformity, see Christopher R. Browning's book Ordinary Men: Reserve Police Battalion 101 and the final solution in Poland (New York: HarperCollins, 1992), and the famous experiments by Stanley Milgram and Philip Zimbardo.]

We struggle to understand how these people went home at night and tenderly kissed and played with their children, loved their dogs, appreciated classical music and read philosophy. As Michael Berenbaum, project director of the United States Holocaust Memorial Museum puts it: “The killers were civilized men and women of an advanced culture. They were both ordinary and extraordinary, a cross section of the men and women of Germany, its allies, and their collaborators as well as the best and the brightest.” [Michael Berenbaum, The World Must Know: The History of the Holocaust as Told in the United States Holocaust Memorial Museum (Boston: Little, Brown, 1993), p.220]

The Holocaust was primarily an ideologically-driven phenomenon that drew in far too many otherwise ordinary people as perpetrators.

To be sure, there were certainly a great many people in the midst of all this madness who were not taken up by the Nazi ideology, and some of those people actively resisted the regime at great personal risk. There were many who secretly hid or rescued Jews and other victims. They could have been, and in many cases were, killed for doing so. Most of us cannot know if we would have had the courage to do what those people did.

11. It is important to understand as well that the Nazi leadership’s “Final Solution” to “the Jewish Question”, the plan of mass murder of all European Jewry, was developed after a number of years of Nazi rule and war (probably in 1941). There was some initial hesitation and ambivalence in the Nazi hierarchy about the plan, for pragmatic reasons. The plan had progressed to the point of systematized genocide along a slippery slope of gradually increasing persecution and marginalization of Jews from society, and after the less bureaucratically systematic and less “efficient” killings by death squads. It took time for the process to assume the infamously industrial quality of en-masse rail transportation of victims to death camps, which gassed hundreds of people to death at a time and quickly cremated their bodies. It had also followed after the secret program of systematically “euthanizing” mentally disabled and mentally ill institutionalized patients. Hitler may have felt particularly justified embarking on this “solution” after the Allied countries refused to accept as refugees the large number of Jews he wanted to expel from German occupied Europe. As is well-known, the Nazis also attempted to “cleanse” their society of other undesirables, such as Roma, homosexuals, and communists.

In the analysis of many historians, genocide of the Jews was not initially the goal of the Nazis. As summarized by the respected historian Peter Hayes in his book Why? Explaining the Holocaust (New York: W. W. Norton, 2017), p. 326:

“Why murder and with these means? Because of a process of problem-solving mission creep, a cumulative radicalization of policy, as increasingly harsh efforts to ‘remove’ Jews from German territory proved insufficient or unworkable and gave way to ever more extreme methods of ‘elimination.’”

In the conclusion to his book, Hayes writes (p. 342):

“The Holocaust was not mysterious and inscrutable; it was the work of humans acting on familiar human weaknesses and motives: wounded pride, fear, self-righteousness, prejudice, and personal ambition being among the most obvious. Once persecution gathered momentum, however, it was unstoppable without the death of millions of people, the expenditure of vast sums of money, and the near destruction of the European continent. Perhaps no event in history, therefore, better confirms that very difficult warning embedded in a German proverb that captures the meaning I hope readers will take away from this book: Webret den Anfängen, ‘Beware the beginnings.’”

12. One of the most revealing insights into the minds of actual perpetrators and architects of the Holocaust can be obtained from the speeches of Heinrich Himmler. Himmler was leader of the SS and one of the most powerful men in Nazi Germany. As "Architect of the Final Solution", he was one of the people most directly responsible for the Holocaust. In October 1943, in Posen (Poznan), Poland, Himmler delivered secret speeches to officials of the Nazi party, including SS officers—the “most secret circle”. In these speeches, Himmler spoke explicitly of the extermination of the Jews, dispensing with the more usual veiled or euphemistic terms. He framed the extermination program as a very difficult but necessary historical mission of the Nazis, the necessity for which would be more fully understood and appreciated by future generations but must remain secret at the time. In these speeches, extracts of which are quoted below, he is talking to fellow officials who are involved in the extermination program and is essentially praising them for their unflinching commitment to this difficult undertaking. He remarks about how others who are less directly involved in the program and who think of it more abstractly and theoretically, tend to underestimate its magnitude and its difficulty:

"I am now referring to the evacuation of the Jews, the extermination of the Jewish people. It's one of those things that is easily said: 'The Jewish people are being exterminated', says every party member, 'this is very obvious, it's in our program, elimination of the Jews, extermination, we're doing it, hah, a small matter.' And then they turn up, the upstanding 80 million Germans, and each one has his decent Jew. They say the others are all swines, but this particular one is a splendid Jew. But none has observed it, endured it. Most of you here know what it means when 100 corpses lie next to each other, when there are 500 or when there are 1,000. To have endured this and at the same time to have remained a decent person — with exceptions due to human weaknesses — has made us tough, and is a glorious chapter that has not and will not be spoken of. Because we know how difficult it would be for us if we still had Jews as secret saboteurs, agitators and rabble-rousers in every city, what with the bombings, with the burden and with the hardships of the war. If the Jews were still part of the German nation, we would most likely arrive now at the state we were at in 1916 and 17 [...]"

What is particularly interesting here is his point about remaining “a decent person”—what he is saying is essentially that they are doing the dirty work, the unpleasant job of eliminating this scourge (the Jews) which, if not eliminated, would ultimately bring down society. He is speaking of the psychological strain that the extermination program puts on those carrying it out. The Nazis had convinced themselves that the Jews were a conspiring and contaminating force which was responsible for Germany’s loss of World War I and for many of their and the world’s societal and economic problems. He speaks of the Jews elsewhere as a “bacillus” (bacteria), They are the main obstacle to achieving a utopian future of a pure, noble and decent super-race of pure-bred Aryans.

Himmler’s speech goes on to say:

"I ask of you that that which I say to you in this circle be really only heard and not ever discussed. We were faced with the question: what about the women and children? – I decided to find a clear solution to this problem too. I did not consider myself justified to exterminate the men – in other words, to kill them or have them killed and allow the avengers of our sons and grandsons in the form of their children to grow up. The difficult decision had to be made to have this people disappear from the earth. For the organisation which had to execute this task, it was the most difficult which we had ever had. [...] I felt obliged to you, as the most superior dignitary, as the most superior dignitary of the party, this political order, this political instrument of the Führer, to also speak about this question quite openly and to say how it has been. The Jewish question in the countries that we occupy will be solved by the end of this year. Only remainders of odd Jews that managed to find hiding places will be left over."

In other speeches given to Nazi Generals in Sonthofen, Germany in May and June, 1944, Himmler states:

"Another question which was decisive for the inner security of the Reich and Europe, was the Jewish question. It was uncompromisingly solved after orders and rational recognition. I believe, gentlemen, that you know me well enough to know that I am not a bloodthirsty person; I am not a man who takes pleasure or joy when something rough must be done. However on the other hand, I have such good nerves and such a developed sense of duty – I can say that much for myself – that when I recognise something as necessary I can implement it without compromise. I have not considered myself entitled – this concerns especially the Jewish women and children – to allow the children to grow into the avengers who will then murder our children and our grandchildren. That would have been cowardly. Consequently the question was uncompromisingly resolved."

And (in the second of these Sonthofen speeches):

"It was the most terrible task and the most terrible order which could have been given to an organisation: the order to solve the Jewish question. In this circle, I may say it frankly with a few sentences. It is good that we had the severity to exterminate the Jews in our domain."

13. Baumeister p. 377. He adds: "The four root causes of evil must therefore be augmented by an understanding of the proximal cause, which is the breakdown of these inner restraints." Baumeister states elsewhere (in his 2012 book chapter referenced in footnote 1):

"Many circumstances give rise to aggressive impulses, but people restrain themselves from acting on them. Humans are social animals, and as such, they have the same aggressive impulses that enabled their evolutionary predecessors to resolve disputes in their favor and thereby to survive and reproduce. Yet humans also have a capacity for self-regulation that is at least as strong as that of other social animals. Culture relies heavily on self-regulation because culture consists partly of a system with rules and standards, and it can function only if people alter their behavior to bring it into line with those rules and standards. More and more, that includes restraining violence, which is mostly disruptive to the smooth inner functioning of cultural systems. [...] When things are going according to a culture’s plan, individuals check their aggressive impulses. When those checks fail, the impulses lead to violent action."

14. I would add that violence can also result from excessive, obsessive, rigid self-control (“tightly wound control freaks”) and excessive societal control (as in the case of Nazism and other totalitarian societies, especially those driven by perfectionist utopian ideologies).

15. Robert M. Sapolsky, Behave: The Biology of Humans at Our Best and Worst (New York: Penguin Press, 2017).

16. As I have argued elsewhere, the ADHD diagnosis is misunderstood and too limiting. It ought to be reconceptualized as a common set of traits—traits that are fundamental to human functioning—rather than just one among many kinds of psychiatric disorders. It can be understood as one end of a normal continuum (i.e. one broad end of a bell-curve, with no exact cut-off defining it), for executive functioning and associated self-control / self-regulation. Its high prevalence in the human population can be understood as the result of an evolutionary mismatch relative to the high executive functioning demands placed on people by the modern society we have created.

17. Young S, Moss D, Sedgwick O, Fridman M, Hodgkins P. A meta-analysis of the prevalence of attention deficit hyperactivity disorder in incarcerated populations. Psychological Medicine. 2015;45(2):247-258.

18. For example, higher levels of testosterone do not inevitably cause higher levels of aggression, and the hyped hormone oxytocin only increases trust and empathy toward people with whom we identify as within our group. I would add that ADHD, or the broader traits of weaker executive functioning associated with that construct, certainly do not confer an inevitability of criminal behavior and violence. Similarly, even people with psychopathic traits do not inevitably become violent, exploitative and predatory.

19. A parallel question is the evolutionary one: Which of our two equally related “first cousin” species do we humans more closely resemble: chimpanzees or bonobos? Chimpanzees tend to be more violent, including intragroup hierarchical violence, violence against females, and extragroup murdering raids, but they are capable of being very cooperative within-group. Their groups are dominated by related males. Bonobos are generally far less violent, more sexual, and also capable of high levels of cooperative behavior. Their groups are dominated by female alliances (female social organization among bonobos does not tolerate male aggression). There are evolutionary and ecological-environmental reasons for these differences between the two species. Again, the answer for humans is a mixture of both: human characteristics are somewhere in between these two closely related species. (Similarly, human characteristics are somewhere in between several other categories that are more clear-cut and dichotomous in other species, e.g. somewhere in between classic pair-bonding species and “tournament species”— tournament species are those in which males compete to mate with the most females). It was only discovered in the last decade that humans are equally related genetically to chimps and bonobos (previously it was thought that we were more closely related to chimps). A 2012 study found that we share 98.7% of our DNA with each of the two species, which in turn share 99.6% of their DNA with each other. [Prüfer K, Munch K, Hellmann I, et al. The bonobo genome compared with the chimpanzee and human genomes. Nature. 2012;486(7404):527-531.]

20. More evolutionary psychology perspectives on aggression:

In his book The Goodness Paradox: The Strange Relationship Between Virtue and Violence in Human Evolution (New York: Pantheon, 2019), the primatologist Richard Wrangham, who has spent his career studying the ecology of primate social systems and the evolutionary history of human aggression, highlights the contrast between the relatively low levels of human aggression within-group (compared with other primates, humans are very tolerant and unreactive to provocation) versus the much higher levels of between-group human aggression. He concludes that reactive aggression (see definitions provided earlier in this article) has progressively diminished much more in humans compared with other primates, whereas proactive aggression (which is more often, though not exclusively, directed at members of another group) remains quite high in humans. He hypothesizes that the reduction of reactive aggression in humans was brought about by a process of self-domestication, analogous to the selective breeding of domesticated animals for traits of tameness (or analogous to the domesticated silver foxes experiment in Siberia). He cites bonobos as an example of self-domestication (through different means and driven by different factors, compared with humans). His hypothesis for humans is that self-domestication was achieved in large part by the acquisition of language and also by a process of what amounted to capital punishment: members of a hunter-gatherer group would conspire to kill an individual who was behaving too aggressively or tyrannically. While these would have been relatively uncommon occurrences, the cumulative effect over time would have been to remove the most aggressive men from the gene pool. Wrangham makes it clear that this theory is not an endorsement of capital punishment in modern society. The anthropologist Christopher Boehm also proposed this hypothesis in his book Moral Origins: The Evolution of Virtue, Altruism, and Shame (New York: Basic Books, 2012).

The sociologist Nicholas Christakis takes a more positive view of human nature in Blueprint: The Evolutionary Origins of a Good Society (New York: Little, Brown Spark, 2019), arguing that the evolved human proclivity for cooperativeness (and learning, love, selflessness, and other prosocial traits) outweighs our capacity for aggression and has adaptive advantages over it. Christakis provides diverse examples of historical and contemporary societies and social groups to illustrate his point.

Another very important angle on human aggression comes from evolutionary psychology theories of sexual conflict in human mating, which contributes to a sizeable proportion of all human violence. Those theories are very well articulated by David Buss in When Men Behave Badly: The Hidden Roots of Sexual Deception, Harassment, and Assault. (New York: Little, Brown Spark, 2021).

21. Steven Pinker, The Better Angels of Our Nature: Why Violence Has Declined (New York: Viking, 2011)

22. In our present information age, with every person having access to almost unlimited information and a potential megaphone to the world, and with the rampant misinformation, online idiocy and vitriol we all encounter every day on the internet, it can really seem like humans are a predominantly idiotic and vile lot. But it is important to keep sight of the fact that much of the noise is produced by a loudmouthed know-nothing minority (many of whom are convinced that they are doing society a great service in combatting what they believe are malevolent conspiracies, while greatly overestimating their simplistic understanding of highly complex issues). But the majority of people, while vulnerable to misinformation, are quite reasonable and are eager to obtain more accurate information from actual experts. The prominent Canadian science educator and debunker Timothy Caulfield has studied these challenges. He writes in the context of the pandemic, “We are living through an infodemic – an era when harmful misinformation has resulted in or contributed to an increase in deaths, hospitalizations, stigma, and poor health and science policy.” He notes: “A growing body of evidence tells us that experts play a vital role in the battle against bunk. In general, the public trusts academics, scientists and health care providers. And studies have consistently shown that efforts to counter misinformation – such as on social media, where much of the noise resides and is distributed – are both needed and can have a real impact, especially if the debunking comes from an expert.” He adds: “A recent study found that the public likes seeing online corrections of misinformation, broadly endorses the practice and sees it as a public responsibility.” But “Studies have found that battling misinformation invites trouble.” Caulfield speaks from personal experience: “In the past year, I’ve received death threats and have been sued. I’ve been lied about and constantly trolled on social media. And, of course, there is the hate mail. My experience is far from unique.”

23. Baumeister, in his 2012 book chapter referenced in footnote 1, elaborates on his earlier 1997 work: "Since writing my book about evil, I have come to look at things in more evolutionary terms, and my strong impression is that instrumental violence is in some respects a hangover from an earlier stage of evolution." By "instrumental violence," he is referring to "the simple desire for material gain," and also to a large extent "threatened egotism"—which from an evolutionary psychology point of view is mostly about protecting one's status and thereby defending one's privileged access to resources, as in the case of alpha-male primates. Instrumental violence even to some degree refers to ideologically-driven violence, as such violence is usually directed at achieving practical goals. From an evolutionary point of view, "aggression enabled the biggest and strongest to survive and hence reproduce better than their weaker rivals." Baumeister makes the point that while instrumental violence often achieves its goals in the short-term, it is very often an unsuccessful strategy in the long-term—both at the level of criminal or violent individuals and at the level of violent groups, such as terrorist organizations and (arguably) even warring nation-states. "Aggression is thus evolutionarily obsolete. We have accepted better ways of resolving our conflicts" (ways that are the product of cultural evolution, such as money / business / trade, courts of law, negotiation, compromise, voting). "Yet we remain social animals underneath the cultural veneer, and sometimes people fall back on aggression to get their way. This may occur especially among people who feel that the avenues provided by their culture do not work for them."