Behave: The Biology of Humans at Our Best and Worst

by Robert M. Sapolsky

In chapter 16 I will argue that it is wrong to think that understanding must lead to forgiveness—mainly because I think that a term like “forgiveness,” and others related to criminal justice (e.g., “evil,” “soul,” “volition,” and “blame”), are incompatible with science and should be discarded.

There’s the ambivalence of someone who spent a long time as a scorned prophet who at least got to be completely vindicated. He’s philosophical about it—hey, I’m a Hungarian Jew who escaped from a Nazi camp; you take things in stride after that.

What about one of the greatest things about adolescents, with respect to this book’s concerns—their frenzied, agitated, incandescent ability to feel someone else’s pain, to feel everyone’s pain, to try to make everything right?

This adolescent empathy frenzy can seem a bit much for adults. But when I see my best students in that state, I have the same thought—it used to be so much easier to be like that. My adult frontal cortex may enable whatever detached good I do. The trouble, of course, is how that same detachment makes it easy to decide that something is not my problem.

As has been said, the greatest crime-fighting tool is a thirtieth birthday.

As will be covered in the screed that constitutes chapter 16, I think the science encapsulated in this book should transform every nook and cranny of the criminal justice system.

What majorly predicts a life of crime? Being born to a mother who, if she could, would have chosen that you not be. What’s the most basic thing provided by a mother? Knowing that she is happy that you exist.*26

Similarly, it shouldn’t require molecular genetics or neuroendocrinology factoids to prove that childhood matters and thus that it profoundly matters to provide childhoods filled with good health and safety, love and nurturance and opportunity. But insofar as it seems to require precisely that sort of scientific validation at times, more power to those factoids.

Criticism #2: MZ twins experience life more similarly starting as fetuses. DZ twins are “dichorionic,” meaning that they have separate placentas. In contrast, 75 percent of MZ twins share one placenta (i.e., are “monochorionic”).* Thus most MZ twin fetuses share maternal blood flow more than do DZ twins, and thus are exposed to more similar levels of maternal hormones and nutrients. If that isn’t recognized, greater similarity in MZs will be misattributed to genes.

Heritability of various aspects of cognitive development is very high (e.g., around 70 percent for IQ) in kids from high–socioeconomic status (SES) families but is only around 10 percent in low-SES kids. Thus, higher SES allows the full range of genetic influences on cognition to flourish, whereas lower-SES settings restrict them. In other words, genes are nearly irrelevant to cognitive development if you’re growing up in awful poverty—poverty’s adverse effects trump the genetics.* Similarly, heritability of alcohol use is lower among religious than nonreligious subjects—i.e., your genes don’t matter much if you’re in a religious environment that condemns drinking. Domains like these showcase the potential power of classical behavior genetics.

Thus, for our purposes, genes aren’t about inevitability. Instead they’re about context-dependent tendencies, propensities, potentials, and vulnerabilities. All embedded in the fabric of the other factors, biological and otherwise, that fill these pages.

And who were the immigrants? Those in the settled world who were cranks, malcontents, restless, heretical, black sheep, hyperactive, hypomanic, misanthropic, itchy, unconventional, yearning to be free, yearning to be rich, yearning to be out of their damn boring repressive little hamlet, yearning. Couple that with the second reason—for the majority of its colonial and independent history, America has had a moving frontier luring those whose extreme prickly optimism made merely booking passage to the New World insufficiently novel—and you’ve got America the individualistic.

Why does religion arise? Because it makes in-groups more cooperative and viable (stay tuned for more in the next chapter). Because humans need personification and to see agency and causality when facing the unknown. Or maybe inventing deities is an emergent by-product of the architecture of our social brains.54

There are some pertinent patterns amid this variation. As noted, desert cultures are prone toward monotheistic religions; rain forest dwellers, polytheistic ones. Nomadic pastoralists’ deities tend to value war and valor in battle as an entrée to a good afterlife. Agriculturalists invent gods who alter the weather. As noted, once cultures get large enough that anonymous acts are possible, they start inventing moralizing gods. Gods and religious orthodoxy dominate more in cultures with frequent threats (war, natural disasters), inequality, and high infant mortality rates.

Before turfing this subject to the final chapter, three obvious points: (a) a religion reflects the values of the culture that invented or adopted it, and very effectively transmits those values; (b) religion fosters the best and worst of our behaviors; (c) it’s complicated.

First, that evolution favors survival of the fittest. Instead evolution is about reproduction, passing on copies of genes. An organism living centuries but not reproducing is evolutionarily invisible.* The difference between survival and reproduction is shown with “antagonistic pleiotropy,” referring to traits that increase reproductive fitness early in life yet decrease life span.

Another misconception is that evolution can select for preadaptations—neutral traits that prove useful in the future. This doesn’t happen; selection is for traits pertinent to the present. Related to this is the misconception that living species are somehow better adapted than extinct species. Instead, the latter were just as well adapted, until environmental conditions changed sufficiently to do them in; the same awaits us. Finally, there’s the misconception that evolution directionally selects for greater complexity. Yes, if once there were only single-celled organisms and there are multicellular ones now, average complexity has increased. Nonetheless, evolution doesn’t necessarily select for greater complexity—just consider bacteria decimating humans with some plague.

Evolution sculpts the traits of an organism in two broad ways. “Sexual selection” selects for traits that attract members of the opposite sex, “natural selection” for traits that enhance the passing on of copies of genes through any other route—e.g., good health, foraging skills, predator avoidance.

Humans show green-beard effects. Crucially, we differ as to what counts as a green-beard trait. Define it narrowly, and we call it parochialism. Include enmity toward those without that green-beard trait and it’s xenophobia. Define the green-beard trait as being a member of your species, and you’ve described a deep sense of humanity.

Remarkably, fetus and Mom have a metabolic struggle involving insulin, the pancreatic hormone secreted when blood glucose levels rise, which triggers glucose entry into target cells. The fetus releases a hormone that makes Mom’s cells unresponsive to insulin (i.e., “insulin resistant”), as well as an enzyme that degrades Mom’s insulin. Thus Mom absorbs less glucose from her bloodstream, leaving more for the fetus.*

And then a few years back, the octogenarian E. O. Wilson did something extraordinary—he decided he was wrong. And then he published a key paper with the other Wilson—“Rethinking the Theoretical Foundation of Sociobiology.” My respect for these two, both as people and as scientists, is enormous.

Despite the combination of some of our most fervent wishes and excuses, we’re neither bonobos nor chimps.

Human irrationality in distinguishing kin from nonkin takes us to the heart of our best and worst behaviors. This is because of something crucial—we can be manipulated into feeling more or less related to someone than we actually are. When it is the former, wonderful things happen—we adopt, donate, advocate for, empathize with. We look at someone very different from us and see similarities. It is called pseudokinship. And the converse? One of the tools of the propagandist and ideologue drumming up hatred of the out-group—blacks, Jews, Muslims, Tutsis, Armenians, Roma—is to characterize them as animals, vermin, cockroaches, pathogens. So different that they hardly count as human. It’s called pseudospeciation, and as will be seen in chapter 15, it underpins many of our worst moments.

Rules, laws, treaties, penalties, social conscience, an inner voice, morals, ethics, divine retribution, kindergarten songs about sharing—all driven by the third leg of the evolution of behavior, namely that it is evolutionarily advantageous for nonrelatives to cooperate. Sometimes.

Racial differences, which have only relatively recently emerged, are of little Us/Them significance. For the hunter-gatherers of our hominin history, the most different person you’d ever encounter in your life came from perhaps a couple of dozen miles away, while the nearest person of a different race lived thousands of miles away—there is no evolutionary legacy of humans encountering people of markedly different skin color.

In the 1950s the psychologist Gordon Allport proposed “contact theory.”71 Inaccurate version: if you bring Us-es and Thems together (say, teenagers from two hostile nations brought together in a summer camp), animosities disappear, similarities become more important than differences, and everyone becomes an Us. More accurate version: put Us-es and Thems together under very narrow circumstances and something sort of resembling that happens, but you can also blow it and worsen things.

Thus, in order to lessen the adverse effects of Us/Them-ing, a shopping list would include emphasizing individuation and shared attributes, perspective taking, more benign dichotomies, lessening hierarchical differences, and bringing people together on equal terms with shared goals. All to be revisited.

I’m a fairly solitary person—after all, I’ve spent a significant amount of my life studying a different species from my own, living alone in a tent in Africa. Yet some of the most exquisitely happy moments of my life have come from feeling like an Us, feeling accepted and not alone, safe and understood, feeling part of something enveloping and larger than myself, filled with a sense of being on the right side and doing both well and good.

If we accept that there will always be sides, it’s a nontrivial to-do list item to always be on the side of angels. Distrust essentialism. Keep in mind that what seems like rationality is often just rationalization, playing catch-up with subterranean forces that we never suspect. Focus on the larger, shared goals. Practice perspective taking. Individuate, individuate, individuate. Recall the historical lessons of how often the truly malignant Thems keep themselves hidden and make third parties the fall guy.

But as we’ll see, hierarchy heads in different directions from Us/Them-ing, and in uniquely human ways: Like other hierarchical species, we have alpha individuals, but unlike most others, we occasionally get to choose them. Moreover, they often are not merely highest ranking but also “lead,” attempting to maximize this thing called the common good. Furthermore, individuals vie for leadership with differing visions of how best to attain that common good—political ideologies. And finally, we express obedience both to an authority and to the idea of Authority.

As with other species, human quality of life also varies with the consequences of rank inequalities—there’s a big difference between the powerful getting seated at a restaurant before you and the powerful getting to behead you if the fancy strikes them. Recall the study of thirty-seven countries showing that the more income inequality, the more preadolescent bullying in schools. In other words, countries with more brutal socioeconomic hierarchies produce children who enforce their own hierarchies more brutally.7

Thus, rather than a replication of the SPE, this wound up being more like a replication of the FRE and the RRE (i.e., the French Revolution and the Russian Revolution): a hierarchical regime is overthrown by wet-nosed idealists who know all the songs from Les Mis, who are then devoured by Bolsheviks or Reign of Terror–ists. Importantly, the ruling junta at the end having entered the study with the strongest predispositions toward authoritarianism certainly suggests bad apples rather than bad barrels.

Some apples, even in the worst of barrels, do not go bad.*

It certainly helps to know that you are not alone, that there are others who are willing to resist, that there are those who have done so in the past. But often something still holds us back. Eichmann’s seeming normalcy supplied us, thanks to Hannah Arendt, with the notion of the banality of evil. Zimbardo, in his recent writing, emphasizes the “banality of heroism.” As discussed in various chapters, people who heroically refuse to look the other way, who do the right thing even when it carries the ultimate cost—tend to be surprisingly normal. The stars didn’t align at their births; doves of peace did not envelop them where they strode. They put their pants on one leg at a time. This should be a huge source of strength for us.

The authors found a key correlation—the lower the social capital in a country, the higher the rates of antisocial punishment. In other words, when do people’s moral systems include the idea that being generous deserves punishment? When they live in a society where people don’t trust one another and feel as if they have no efficacy.

“Heroism feels and never reasons,” to quote Emerson.

It’s the same thing here: “Why did you never cheat? Is it because of your ability to see the long-term consequences of cheating becoming normalized, or your respect for the Golden Rule, or . . . ?” The answer is “I don’t know [shrug]. I just don’t cheat.” This isn’t a deontological or a consequentialist moment. It’s virtue ethics sneaking in the back door in that moment—“I don’t cheat; that’s not who I am.” Doing the right thing is the easier thing.

And as we will see, the more the purity of empathy is clouded with the anger, disgust, and indignation of blame, the harder it is to actually help.

Thus it’s no surprise that feeling the same degree of empathy or achieving the same level of perspective taking for a Them as for an Us requires greater frontocortical activation. This is the domain where you must suppress the automatic and implicit urges to be indifferent, if not repulsed, and do the creative, motivated work of finding the affective commonalities.*24

In other words, empathic states are most likely to produce compassionate acts when we manage a detached distance. This brings to mind the anecdote from many chapters ago about the Buddhist monk I encountered who said that, yes, sometimes he cuts short his cross-legged meditation because of his knees, but not because he feels them hurting—“I do it as an act of kindness to my knees.” And this is certainly in line with the Buddhist approach to compassion, which views it as a simple, detached, self-evident imperative rather than as requiring vicarious froth. You act compassionately toward one individual because of a globalized sense of wishing good things for the world.*

Better that our good acts be self-serving and self-aggrandizing than that they don’t occur at all; better that the myths we construct and propagate about ourselves are that we are gentle and giving, rather than that we prefer to be feared than loved, and that we aim to live well as the best revenge.

I’m not advocating that people become Buddhists in order to make the world a better place. (Nor am I advocating that people don’t become Buddhists; what is the sound of one atheist waffling?)

The key is neither a good (limbic) heart nor a frontal cortex that can reason you to the point of action. Instead it’s the case of things that have long since become implicit and automatic—being potty trained; riding a bike; telling the truth; helping someone in need.

What do Hussein, McGuinness, Robinson, Viljoen, and Mandela show? That our confusion of the literal and the metaphorical, our granting of life-threatening sanctity to the symbolic, can be used to bring about the best of our behaviors. Which prepares us for the final chapter, soon to come.

And out of the decision came the formalization of what is now the common criterion for finding someone innocent by reason of insanity, namely the “M’Naghten rule”: if, at the time of the crime, the person is so “laboring under such a defect of reason from disease of the mind,” that he cannot distinguish right from wrong.*

In 2005’s Roper v. Simmons decision, the Supreme Court ruled that you can’t execute someone for a crime committed before the age of eighteen. The appropriate reasoning was straight out of chapters 6 and 7: the brain, especially the frontal cortex, is not yet at adult levels of emotional regulation and impulse control. In other words, adolescents, with their adolescent brains, aren’t as culpable as adults.

Essentially everyone working with a model of mitigated free will accepts that if there is enough brain damage, responsibility for a criminal act goes out the window. Even Stephen Morse of the University of Pennsylvania, a strident critic of neuroscience in the courtroom (much more later), concedes, “Suppose we could show that the higher deliberative centers in the brain seem to be disabled in these cases. If these are people who cannot control episodes of gross irrationality, we’ve learned something that might be relevant to the legal ascription of responsibility.”13 In this view, mitigating biological factors are relevant if the capacity for reasoning has been grossly impaired.

The frontal immaturity of the adolescent brain is more pertinent to split-second issues of impulse control than to slow, deliberative reasoning processes.

Why do “You’re so smart” and “You work so hard” have such different effects? Because they fall on either side of one of the deepest lines drawn by believers in mitigated free will. It is the belief that one assigns aptitude and impulse to biology and effort and resisting impulse to free will.

The core of that thought is Susan Fiske’s demonstration that automatic other-race-face amygdala responses can be undone when subjects think of that face as belonging to a person, not a Them. The ability to individuate even monolithic and deindividuated monsters can be remarkable.