Behave: The Biology of Humans at our Best and Worst

Why do human beings behave as they do?

We are capable of savage acts of violence but also spectacular feats of kindness: is one side of our nature destined to win out over the other?

Every act of human behaviour has multiple layers of causation, spiralling back seconds, minutes, hours, days, months, years, even centuries, right back to the dawn of time and the origins of our species. In the epic sweep of history, how does our biology affect the arc of war and peace, justice and persecution? How have our brains evolved alongside our cultures?

This is the exhilarating story of human morality and the science underpinning the biggest question of all: what makes us human?

"It's no exaggeration to say that Behave is one of the best non-fiction books I've ever read."
Wall Street Journal

“Behave” by Robert Sapolsky is a groundbreaking exploration of human behavior, examining why we do the things we do—from moments of compassion to acts of aggression. Sapolsky, a renowned neuroscientist and primatologist, combines insights from neuroscience, psychology, genetics, endocrinology, and anthropology to explain the biological and environmental influences that shape our actions.

The book takes a unique multilayered perspective, analyzing behavior from different time scales. Sapolsky begins with what happens in the brain seconds before an action, then moves backward to consider hormones, neural development, childhood experiences, culture, and evolutionary history. This approach shows how every decision is influenced by a vast web of factors, both immediate and long-term.

At its heart, “Behave” argues that human morality, empathy, aggression, and cooperation cannot be understood in isolation. Instead, they emerge from the intricate interaction of biology and environment. Sapolsky challenges simplistic views of free will and responsibility, suggesting that understanding the true roots of behavior is essential for building a more compassionate and just society.

The book is both scientifically rigorous and deeply humane, offering readers not only knowledge about the science of behavior but also insight into how to live more thoughtfully in a complex world.

CONTENT

Introduction
The Behavior
One Second Before
Seconds to Minutes Before
Hours to Days Before
Days to Months Before
Adolesccence; or, dude, where's my frontal cortex?
Back to the crib, back to the womb
Back to when you were just a fertilized egg
Centuries to millennia before
The evolution of behavior
Us Versus them
Hierarchy, obedience, and resistance
Mortality and doing the right thing, once you've figured out what that is
Feeling someone's pain, understanding someone's pain, alleviating someone's pain
Metaphors we kill by
Biology, the criminal justice system, and (oh, why not?) free will
War and peace
Epilogue
Acknowledgments
Appendix 1: Neuroscience
Appendix 2: The Basics of Endocrinology
Appendix 3: Protein Basics
Glossary of Abbreviations
Notes
Illustration Credits
Index