Behave: The Biology of Humans at Our Best and Worst

by Robert M. Sapolsky

And as a third point, by the time you finish this book, you’ll see that it actually makes no sense to distinguish between aspects of a behavior that are “biological” and those that would be described as, say, “psychological” or “cultural.” Utterly intertwined.

the official intellectual goal of this book is to avoid using categorical buckets when thinking about the biology of some of our most complicated behaviors, even more complicated than chickens crossing roads.

It’s called the Wellesley effect, first shown with roommates at all-women’s Wellesley College.

sometimes the only way to understand our humanness is to consider solely humans, because the things we do are unique. While a few other species have regular nonreproductive sex, we’re the only ones to talk afterward about how it was. We construct cultures premised on beliefs concerning the nature of life and can transmit those beliefs multigenerationally, even between two individuals separated by millennia—just consider that perennial best seller, the Bible. Consonant with that, we can harm by doing things as unprecedented as and no more physically taxing than pulling a trigger, or nodding consent, or looking the other way. We can be passive-aggressive, damn with faint praise, cut with scorn, express contempt with patronizing concern. All species are unique, but we are unique in some pretty unique ways.

V. S. Naipaul, in his book Among the Believers: An Islamic Journey, describes hearing rumors while in Indonesia that when a paramilitary group would arrive to exterminate every person in some village, they would, incongruously, bring along a traditional gamelan orchestra. Eventually Naipaul encountered an unrepentant veteran of a massacre, and he asked him about the rumor. Yes, it is true. We would bring along gamelan musicians, singers, flutes, gongs, the whole shebang. Why? Why would you possibly do that? The man looked puzzled and gave what seemed to him a self-evident answer: “Well, to make it more beautiful.”

“The opposite of love is not hate; its opposite is indifference.”

The fecal hurricane concerned the involuntary lopping out of the amygdala in people without epilepsy but with a history of severe aggression. Well, doing this could be profoundly helpful. Or Orwellian. This is a long, dark story and I will save it for another time.

the frontal cortex makes you do the harder thing when it’s the right thing to do.

And throughout, the PFC imposes an overarching executive strategy for remembering these sixteen factoids.*

“Hello, I see you’ve put on some weight.” And when castigated later by their mortified spouse, they will say with calm puzzlement, “But it’s true.”

Stressed people often make hideously bad decisions, marinated in emotion;

Food evokes dopamine release in hungry individuals of all species, with an added twist in humans. Show a picture of a milkshake to someone after they’ve consumed one, and there’s rarely dopaminergic activation—there’s satiation. But with subjects who have been dieting, there’s further activation. If you’re working to restrict your food intake, a milkshake just makes you want another one.

once reward contingencies are learned, dopamine is less about reward than about its anticipation. Similarly, work by my Stanford colleague Brian Knutson has shown dopamine pathway activation in people in anticipation of a monetary reward.91 Dopamine is about mastery and expectation and confidence. It’s “I know how things work; this is going to be great.” In other words, the pleasure is in the anticipation of reward, and the reward itself is nearly an afterthought (unless, of course, the reward fails to arrive, in which case it’s the most important thing in the world). If you know your appetite will be sated, pleasure is more about the appetite than about the sating.* This

In other words, dopamine is not about the happiness of reward. It’s about the happiness of pursuit of reward that has a decent chance of occurring.*

We do something even beyond this unprecedented gratification delay: we use the dopaminergic power of the happiness of pursuit to motivate us to work for rewards that come after we are dead—depending on your culture, this can be knowing that your nation is closer to winning a war because you’ve sacrificed yourself in battle, that your kids will inherit money because of your financial sacrifices, or that you will spend eternity in paradise.

As proposed in 1990 by the superb behavioral endocrinologist John Wingfield of the University of California at Davis, and colleagues, the idea is that rising testosterone levels increase aggression only at the time of a challenge. Which is precisely how things work.

Remarkably, watching your favorite team win raises testosterone levels, showing that the rise is less about muscle activity than about the psychology of dominance, identification, and self-esteem.

In our world riddled with male violence, the problem isn’t that testosterone can increase levels of aggression. The problem is the frequency with which we reward aggression.

Oxytocin, the luv hormone, makes us more prosocial to Us and worse to everyone else. That’s not generic prosociality. That’s ethnocentrism and xenophobia. In other words, the actions of these neuropeptides depend dramatically on context—who you are, your environment, and who that person is.

Stated most broadly, sustained stress impairs risk assessment.76

There’s an additional depressing reason why stress fosters aggression—because it reduces stress.

Naturally, things are subtler than “male = fight/flight and female = tend/befriend.”

Rejection hurts adolescents more, producing that stronger need to fit in.25

But infant monkeys chose the terry-cloth mom.* “Man cannot live by milk alone. Love is an emotion that does not need to be bottle- or spoon-fed,” wrote Harlow.

The authors’ state-by-state analysis of the liberalization of abortion laws and the demographics of the crime drop showed that when abortions become readily available in an area, rates of crime by young adults decline about twenty years later. Surprise—this was highly controversial, but it makes perfect, depressing sense to me. 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?

Considerable research focuses on how poverty “gets under the skin.” Some mechanisms are human specific—if you’re poor, you’re more likely to grow up near environmental toxins,*35 in a dangerous neighborhood with more liquor stores than markets selling produce; you’re less likely to attend a good school or have parents with time to read to you. Your community is likely to have poor social capital, and you, poor self-esteem. But part of the link reflects the corrosive effects of subordination in all hierarchical species.

Pretty straightforwardly, the more categories of adversities a child suffers, the dimmer his or her chances of a happy, functional adulthood.45

In other words, when human males don’t experience the organizational prenatal effects of testosterone, you get female-typical behaviors and identification.

Thus unequal cultures make people less kind. Inequality also makes people less healthy.

inequality means more secession of the wealthy from contributing to the public good. Kaplan has shown, for example, that states with more income inequality spend proportionately less money on that key crime-fighting tool, education. As with inequality and health, the psychosocial and neomaterial routes synergize.

crowding makes unaggressive individuals more timid. In other words, it exaggerates preexisting social tendencies.

Tit for Tat drives other strategies to extinction.

It’s problematic when non–zero sum games are viewed as zero-sum (winner-take-all).18 It’s not a great mind-set to think you’ve won World War III if afterward Us have two mud huts and three fire sticks and They have only one of each.* A horrific version of this thinking occurred late during World War I, when the Allies knew they had more resources (i.e., soldiers) than Germany. Therefore, the British commander, Douglas Haig, declared a strategy of “ceaseless attrition,” where Britain went on the offensive, no matter how many of his men were killed—as long as the Germans lost at least as many.

David Berreby, in his superb book Us and Them: The Science of Identity, gives a striking example, namely that whether it was ancient Rome, medieval England, imperial China, or the antebellum South, the elite had the system-justifying stereotype of slaves as simple, childlike, and incapable of independence.

it’s not like an unwashed JFK sweater still contains his magical armpit essence, while an unwashed Madoff sweater swarms with moral-taint cooties.

Then there’s the high-warmth/low-competence categorization—the mentally disabled, people with handicaps, the elderly.*

“The Americans will leave in a year or a decade, but the Chinese will stay for a thousand years if we let them in.”

countries with more brutal socioeconomic hierarchies produce children who enforce their own hierarchies more brutally.7

contemporary studies show that the worst stress-related health typically occurs in middle management, with its killer combo of high work demands but little autonomy—responsibility without control.

(a) Subjective SES predicts health at least as accurately as objective SES, meaning that it’s not about being poor. It’s about feeling poor. (b) Independent of absolute levels of income, the more income inequality in a community—meaning the more frequently the poor have their noses rubbed in their low status—the steeper the health gradient.

More consistent has been a link between lower intelligence and a subtype of conservatism, namely right-wing authoritarianism (RWA, a fondness for hierarchy). One particularly thorough demonstration of this involved more than fifteen thousand subjects in the UK and United States; importantly, the links among low IQ, RWA, and intergroup prejudice were there after controlling for education and socioeconomic status. The standard, convincing explanation for the link is that RWA provides simple answers, ideal for people with poor abstract reasoning skills.

The other is that leftists, well, think harder, have a greater capacity for what the political scientist Philip Tetlock of the University of Pennsylvania calls “integrative complexity.” In one study conservatives and liberals, when asked about the causes of poverty, both tended toward personal attributions (“They’re poor because they’re lazy”). But only if they had to make snap judgments. Give people more time, and liberals shifted toward situational explanations (“Wait, things are stacked against the poor”). In other words, conservatives start gut and stay gut; liberals go from gut to head.34

Jonathan Haidt of NYU provides a very different view.38 He identifies six foundations of morality—care versus harm; fairness versus cheating; liberty versus oppression; loyalty versus betrayal; authority versus subversion; sanctity versus degradation. Both experimental and real-world data show that liberals preferentially value the first three goals, namely care, fairness, and liberty (and, showing an overlap with Kohlbergian formulations, undervaluing loyalty, authority, and sanctity is in many ways synonymous with postconventional thinking). In contrast, conservatives heavily value loyalty, authority, and sanctity. Obviously, this is a big difference. Is it okay to criticize your group to outsiders? Rightists: no, that’s disloyal. Leftists: yes, if justified. Should you ever disobey a law? Rightists: no, that undermines authority. Leftists: of course, if it’s a bad law. Is it okay to burn the flag? Rightists: never, it’s sacred. Leftists: come on, it’s a piece of cloth.

stated by Aleksandr Solzhenitsyn in The Gulag Archipelago, in a quote perpetually cited in this literature, “The line dividing good and evil cuts through the heart of every human being. And who is willing to destroy a piece of his own heart?”68

What about gender? Milgram-like studies have shown that women average higher rates than men of voicing resistance to the demands to obey . . . but higher rates, nonetheless, of ultimately complying.

Navigating status differences is most challenging when it comes to attaining and maintaining high rank; this requires cognitive mastery of Theory of Mind and perspective taking; of manipulation, intimidation, and deceit; and of impulse control and emotion regulation. As with so many other primates, the biographies of our most hierarchically successful members are built around what provocations are ignored during occasions where the frontal cortex kept a level head.

“Overall cheating is not limited by risk; it is limited by our ability to rationalize the cheating to ourselves.”

Then there are terms reflecting how much your resonance is about emotion versus cognition. In that sense “sympathy” means you feel sorry for someone else’s pain without understanding it. In contrast, “empathy” contains the cognitive component of understanding the cause of someone’s pain, taking his perspective, walking in his shoes.

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

The renowned cognitive linguist George Lakoff of UC Berkeley has explored the ubiquity of metaphor in language in books such as Metaphors We Live By (with philosopher Mark Johnson), and Moral Politics: How Liberals and Conservatives Think