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A comprehensive tome explores the biology of our behavior

Behave: The Biology of Humans at Our Best and Worst

Robert M. Sapolsky
Penguin Press
796 pp
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What makes our species unique is only the tip of the iceberg, while underneath sits a vast reservoir of continuity with other organisms. In Behave, Robert Sapolsky, a well-known neurobiologist and primatologist at Stanford University, ambitiously tackles the whole iceberg rather than obsessing over its little tip.

Rarely does an almost 800-page book keep my attention from start to finish, but Behave is exceptional in its scale, scope, detail, and writing style. It is a fun and informative read, diving with gusto and deep knowledge into nearly every academic controversy related to human behavior. It is also most refreshing after scores of recent books by psychologists and anthropologists that extol the human distinction.

Sapolsky places what makes us special in the wider context of humans as animals with brains that are fundamentally similar to those of other species. It is the first book that does so comprehensively enough to qualify as a guide to human behavior to be adopted as a textbook in courses not just in neuroscience but in the social and behavioral sciences in general.

Behave begins with the brain, examining the role of everything from the frontal cortex to the limbic system in human decision-making. Subsequent sections describe the influence of testosterone and other hormones, as well as neurotransmitters. This basic knowledge, which provides an essential background for the chapters that follow, is interspersed with notes about moral development, the role of mothers, and aggressive behavior.

Subsequent chapters delve into the genetics of behavioral evolution, the in-group/out-group distinction, social hierarchies, moral reasoning, and war and peace. Sapolsky moves smoothly from the latest social science studies by psychologists and anthropologists to the neural underpinnings of each phenomenon.

Emphasizing basic, unconscious processes, the focus is far less on cognition than typical of texts on human behavior, although it does get its fair share of attention. There is, for example, an entire chapter on the power of metaphors and their role in branding the enemy.


Arbitrarily assigning people to separate groups is often enough to evoke a sense of “us” versus “them.”

Sapolsky writes in a breezy, irreverent style that few authors can pull off. “Enough. Don’t get me started!” he writes at one point about the folly of intelligent design. In another instance, after discussing classic papers with thousands of citations, he adds, “The number of times your average science paper is cited can be counted on one hand, with most of the citations by the scientist’s mother.” His gentle humor emphasizes that science is fun, that controversies are to be savored, and that we move forward based on how well the data fit the ideas.

The book often veers off into little history lessons, always with intimate knowledge of the topic at hand. Given that the topics are wide-ranging—from basic neuroscience to the evolution of morality, and from twins reared apart to the comeback of Lamarck—readers will find these diversions eye-opening.

Sapolsky remains mercifully brief about B. F. Skinner and his followers, who dominated behavioral science with strikingly unbiological approaches for most of last century. We clearly have left these ideas behind.

What is perhaps most invigorating about Behave is not only that it treats academic controversies in a most colorful way but also that Sapolsky is not shy about taking a stance himself. For example, he argues against the position that warfare is in our DNA and that indigenous tribal people are “brutal savages,” which is still being promoted in both scholarly and popular accounts.

Sapolsky also believes that the notion of mirror neurons as mediators of imitation and empathy is an oversold idea. He presents these neurons as a puzzle rather than an answer.

Given how impassioned Sapolsky defends his positions, there inevitably were occasions where I disagreed, such as when the despotic alpha male baboons he knows so well are presented as typical of all nonhuman primates. But his enthusiasm makes the book far more lively than a traditional tome on human behavior, drawing the reader into the debates.

All in all, Sapolsky conveys the joy of doing behavioral science and of navigating its many controversies to get at the truth—the latter of which, he would undoubtedly agree, we have thus far only scratched the surface.

About the author

The reviewer is at the Department of Psychology, Emory University, Atlanta, GA 30322, USA.