Robert Sapolsky’s Behave: The Biology of Humans at Our Best and Worst was published by Penguin Books in 2018. Roughly 700 pages excluding references, the work offers an extensive coverage of the science of human behavior from varied disciplinary lenses including evolutionary psychology, genetics and epigenetics, neurobiology and endocrinology, primatology, as well as several other subfields.

Upon publication, the book was hailed as an invaluable contribution to the field of public scholarship on human behavior, due both to the scale and scope of the work and the accessible and often humorous style of Sapolsky’s writing. Though sweeping and enjoyable, the book is also of the highest academic rigor, incorporating thousands of academic references gleaned over the span of Sapolsky’s long career as a primatologist (someone who studies monkeys and apes) and neuroscientist (someone who studies the brain and nervous system). The book offers readers an introduction to the essential functions and findings of each of the fields in the paragraph above as well as coverage of many of the seminal studies and lifeworks of individual figures in these fields.

Summary

The subtitle of the book, The Biology of Humans at Our Best and Worst details Sapolsky’s major concern throughout the text: explaining exactly how humans are capable of awe-inspiring, deeply altruistic and cognitively, aesthetically or emotionally impressive behaviors at the same time as we are capable of profound selfishness, violence, hate, and depression. To understand this great variety in human behavior, Sapolsky first works to answer the fundamental question of how behaviors can be understood to occur at all. This is a topic that concerns roughly the first half of the book, as Sapolsky moves through the science of behavior in a backward chronological and then developmental framework: What events occur in the brain and body one second before the behavior occurs? Seconds to minutes before it occurs? Hours to days before? What happens in the brain in adolescence? in fetal development? Over the last few thousand years of human history? in evolution? Each of these topics is treated as a standalone chapter. This progression though causal factors more and more distant in time from the actual behavioral event allows Sapolsky a framework to discuss and connect different biological determinants of behavior in a multifactorial analysis.

After providing this dense coverage of how human behavior occurs, Sapolsky brings his attention to specific topics in the “best and worst” in human behavior, which dominates the second half of his book. These topics include our tendency to form in-groups and out-groups, the nature of human morality, sympathy vs empathy, war, and crime. Each of these topics is explored biologically and also receives its own chapter. As these chapters progress, and Sapolsky wades into hairier and hairier topics, he consistently emphasizes that the seeming complexity of these behaviors are based on simple functions in the human brain. He also urges that understanding how these behaviors occur in a scientific framework is crucial for transforming our behaviors and cultures, and making a more peaceful world is also making a more scientific one.