Behave the biology of humans at our best and worst by robert m sapolsky Behave the biology of humans at our best and worst by robert m sapolsky Behave the biology of humans at our best and worst by robert m sapolsky Behave the biology of humans at our best and worst by robert m sapolsky Behave the biology of humans at our best and worst by robert m sapolsky Behave the biology of humans at our best and worst by robert m sapolsky Behave the biology of humans at our best and worst by robert m sapolsky
ALSO BY ROBERT M SAPOLSKY Monkeyluv and Other Essays on Our Lives as Animals A Primate’s Memoir The Trouble with Testosterone and Other Essays on the Biology of the Human Predicament Why Zebras Don’t Get Ulcers: A Guide to Stress, Stress-Related Diseases, and Coping Stress, the Aging Brain, and the Mechanisms of Neuron Death PENGUIN PRESS An imprint of Penguin Random House LLC 375 Hudson Street New York, New York 10014 penguin.com Copyright © 2017 by Robert M Sapolsky Penguin supports copyright Copyright fuels creativity, encourages diverse voices, promotes free speech, and creates a vibrant culture Thank you for buying an authorized edition of this book and for complying with copyright laws by not reproducing, scanning, or distributing any part of it in any form without permission You are supporting writers and allowing Penguin to continue to publish books for every reader Illustration credits appear here Library of Congress Cataloging-in-Publication Data Names: Sapolsky, Robert M., author Title: Behave: the biology of humans at our best and worst / Robert M Sapolsky Description: New York: Penguin Press, 2017 Identifiers: LCCN 2016056755 (print) | LCCN 2017006806 (ebook) | ISBN 9781594205071 (hardback) | ISBN 9780735222786 (ebook) Subjects: LCSH: Neurophysiology | Neurobiology | Animal behavior | BISAC: SCIENCE / Life Sciences / Biology / General | SOCIAL SCIENCE / Criminology | SCIENCE / Life Sciences / Neuroscience Classification: LCC QP351 S27 2017 (print) | LCC QP351 (ebook) | DDC 612.8–dc23 LC record available at https://lccn.loc.gov/2016056755 Interior Illustrations by Tanya Maiboroda here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here Version_1 To Mel Konner, who taught me To John Newton, who inspired me To Lisa, who saved me Contents Also by Robert M Sapolsky Title Page Copyright Dedication INTRODUCTION One THE BEHAVIOR Two ONE SECOND BEFORE Three SECONDS Four HOURS Five DAYS TO MINUTES BEFORE TO DAYS BEFORE TO MONTHS BEFORE Six ADOLESCENCE; OR, DUDE, WHERE’S MY FRONTAL CORTEX? Seven BACK TO THE CRIB, BACK TO THE WOMB Eight BACK TO WHEN YOU WERE JUST A FERTILIZED EGG Nine CENTURIES Ten THE TO MILLENNIA BEFORE EVOLUTION OF BEHAVIOR Eleven US VERSUS THEM Twelve HIERARCHY, Thirteen MORALITY THAT IS OBEDIENCE, AND RESISTANCE AND DOING THE RIGHT THING, ONCE YOU’VE FIGURED OUT WHAT Fourteen FEELING SOMEONE’S PAIN, UNDERSTANDING SOMEONE’S PAIN, ALLEVIATING SOMEONE’S PAIN Fifteen METAPHORS Sixteen BIOLOGY, Seventeen WAR WE KILL BY THE CRIMINAL JUSTICE SYSTEM, AND (OH, WHY NOT?) FREE WILL AND PEACE EPILOGUE Acknowledgments Appendix 1: Neuroscience 101 Appendix 2: The Basics of Endocrinology Appendix 3: Protein Basics Glossary of Abbreviations Notes Illustration Credits Index About the Author Introduction T he fantasy always runs like this: A team of us has fought our way into his secret bunker Okay, it’s a fantasy, let’s go whole hog I’ve single-handedly neutralized his elite guard and have burst into his bunker, my Browning machine gun at the ready He lunges for his Luger; I knock it out of his hand He lunges for the cyanide pill he keeps to commit suicide rather than be captured I knock that out of his hand as well He snarls in rage, attacks with otherworldly strength We grapple; I manage to gain the upper hand and pin him down and handcuff him “Adolf Hitler,” I announce, “I arrest you for crimes against humanity.” And this is where the medal-of-honor version of the fantasy ends and the imagery darkens What would I with Hitler? The viscera become so raw that I switch to passive voice in my mind, to get some distance What should be done with Hitler? It’s easy to imagine, once I allow myself Sever his spine at the neck, leave him paralyzed but with sensation Take out his eyes with a blunt instrument Puncture his eardrums, rip out his tongue Keep him alive, tube-fed, on a respirator Immobile, unable to speak, to see, to hear, only able to feel Then inject him with something that will give him a cancer that festers and pustulates in every corner of his body, that will grow and grow until every one of his cells shrieks with agony, till every moment feels like an infinity spent in the fires of hell That’s what should be done with Hitler That’s what I would want done to Hitler That’s what I would to Hitler — I’ve had versions of this fantasy since I was a kid Still at times And when I really immerse myself in it, my heart rate quickens, I flush, my fists clench All those plans for Hitler, the most evil person in history, the soul most deserving of punishment But there is a big problem I don’t believe in souls or evil, think that the word “wicked” is most pertinent to a musical, and doubt that punishment should be relevant to criminal justice But there’s a problem with that, in turn—I sure feel like some people should be put to death, yet I oppose the death penalty I’ve enjoyed plenty of violent, schlocky movies, despite being in favor of strict gun control And I sure had fun when, at some kid’s birthday party and against various unformed principles in my mind, I played laser tag, shooting at strangers from hiding places (fun, that is, until some pimply kid zapped me, like, a million times and then snickered at me, which made me feel insecure and unmanly) Yet at the same time, I know most of the lyrics to “Down by the Riverside” (“ain’t gonna study war no more”) plus when you’re supposed to clap your hands In other words, I have a confused array of feelings and thoughts about violence, aggression, and competition Just like most humans To preach from an obvious soapbox, our species has problems with violence We have the means to create thousands of mushroom clouds; shower heads and subway ventilation systems have carried poison gas, letters have carried anthrax, passenger planes have become weapons; mass rapes can constitute a military strategy; bombs go off in markets, schoolchildren with guns massacre other children; there are neighborhoods where everyone from pizza delivery guys to firefighters fears for their safety And there are the subtler versions of violence—say, a childhood of growing up abused, or the effects on a minority people when the symbols of the majority shout domination and menace We are always shadowed by the threat of other humans harming us If that were solely the way things are, violence would be an easy problem to approach intellectually AIDS—unambiguously bad news—eradicate Alzheimer’s disease—same thing Schizophrenia, cancer, malnutrition, flesh-eating bacteria, global warming, comets hitting earth— ditto The problem, though, is that violence doesn’t go on that list Sometimes we have no problem with it at all This is a central point of this book—we don’t hate violence We hate and fear the wrong kind of violence, violence in the wrong context Because violence in the right context is different We pay good money to watch it in a stadium, we teach our kids to fight back, we feel proud when, in creaky middle age, we manage a dirty hip-check in a weekend basketball game Our conversations are filled with military metaphors—we rally the troops after our ideas get shot down Our sports teams’ names celebrate violence—Warriors, Vikings, Lions, Tigers, and Bears We even think this way about something as cerebral as chess—“Kasparov kept pressing for a murderous attack Toward the end, Kasparov had to oppose threats of violence with more of the same.”1 We build theologies around violence, elect leaders who excel at it, and in the case of so many women, preferentially mate with champions of human combat When it’s the “right” type of aggression, we love it It is the ambiguity of violence, that we can pull a trigger as an act of hideous aggression or of selfsacrificing love, that is so challenging As a result, violence will always be a part of the human experience that is profoundly hard to understand This book explores the biology of violence, aggression, and competition—the behaviors and the impulses behind them, the acts of individuals, groups, and states, and when these are bad or good things It is a book about the ways in which humans harm one another But it is also a book about the ways in which people the opposite What does biology teach us about cooperation, affiliation, reconciliation, empathy, and altruism? The book has a number of personal roots One is that, having had blessedly little personal exposure to violence in my life, the entire phenomenon scares the crap out of me I think like an academic egghead, believing that if I write enough paragraphs about a scary subject, give enough lectures about it, it will give up and go away quietly And if everyone took enough classes about the biology of violence and studied hard, we’d all be able to take a nap between the snoozing lion and lamb Such is the delusional sense of efficacy of a professor Then there’s the other personal root for this book I am by nature majorly pessimistic Give me any topic and I’ll find a way in which things will fall apart Or turn out wonderfully and somehow, because of that, be poignant and sad It’s a pain in the butt, especially to people stuck around me And when I had kids, I realized that I needed to get ahold of this tendency big time So I looked for evidence that things weren’t quite that bad I started small, practicing on them—don’t cry, a T rex would never come and eat you; of course Nemo’s daddy will find him And as I’ve learned more about the subject of this book, there’s been an unexpected realization—the realms of humans harming one another are neither universal nor inevitable, and we’re getting some scientific insights into how to avoid them My pessimistic self has a hard time admitting this, but there is room for optimism * Similar circuitry is also seen in the olfactory system, which has always puzzled me What’s just to the side of the smell of an orange? A tangerine? * As an aside, there has been incredibly interesting work concerning emergent properties of the brain that helps explain how the different regions wire up in the developing brain in an optimal way that minimizes the amount (and thus “cost”) of axonal projections needed For aficionados, the things the developing brain does bear some resemblance to some approaches used for the Traveling Salesman Problem * An implication of these definitions is that the same molecule can serve as either a neurotransmitter or a hormone in different parts of the body Also (minutia warning), sometimes hormones have “paracrine” effects, influencing cells in the gland in which they were secreted * Just to make sure we have this sorted out, here’s a second example, namely the hypothalamic/pituitary/ovarian axis: the hypothalamus releases GnRH (gonadotropin-releasing hormone), which triggers the pituitary to release LH (luteinizing hormone), which triggers the ovaries to release estrogen * And just to head off a potential misunderstanding at the pass, a zillionth of a percent of the cholesterol in your body is used for hormone synthesis, so changes in levels of cholesterol in the diet won’t impact the amount of such steroids made—the body synthesizes enough cholesterol on its own for steroid synthesis * Actually typically more than one, but let’s not go there * Naturally, the picture is more complicated than this, as is the case for most everything in this primer Not all enzymes are made of proteins * And as a clarification, there are millions of copies of a particular hormone molecule (e.g., insulin) in the circulation, all sharing that same shape * Actually, I haven’t a clue how many atoms there are in the universe, but you’re required to say stuff like this * The names of which I’m omitting, to avoid inundating the newcomer * The central dogma of “information flows from DNA to RNA to protein” can be wrong There are circumstances where RNA can determine the sequence of DNA This has lots to with how some viruses work but isn’t relevant to us Another bit of revisionism, one that garnered two Nobel Prizes in 2006, is that a huge percentage of RNA does not then specify the construction of some protein Instead it can target and destroy other sequences of RNA, a phenomenon known as “RNA interference.” Still other RNAs are created simply to render some segments of DNA itself “unreadable.” * There are other, rarer types of mutations One class of them, for example, involves the codon coding for an amino acid called glutamine being repeated over and over in the gene, even dozens of times, producing what are called “polyglutamine expansion diseases,” the most famous being Huntington’s disease They are extremely rare mutations, though * As a parent and child, while half siblings share 25 percent of their genes, as grandparents and grandchildren, and so on What’s next on your reading list? Discover your next great read! Get personalized book picks and up-to-date news about this author Sign up now ... Illustration credits appear here Library of Congress Cataloging-in-Publication Data Names: Sapolsky, Robert M. , author Title: Behave: the biology of humans at our best and worst / Robert M Sapolsky. ..ALSO BY ROBERT M SAPOLSKY Monkeyluv and Other Essays on Our Lives as Animals A Primate’s Memoir The Trouble with Testosterone and Other Essays on the Biology of the Human Predicament Why... basis of our state has already accomplished much in this respect We must and should—rely on the healthy feelings of our Best and charge them with the extermination of elements of the population