Chapter 17: War and Peace

Sapolsky concludes the book by asking whether humans are doomed to cycles of violence or capable of building lasting peace. Sapolsky begins with stark reminders: the amygdala activates at other-race faces, poverty delays frontal development, oxytocin sharpens in-group bias, and empathy often fails to yield compassionate action. Yet he insists that optimism is justified, showing that many of humanity’s worst practices—slavery, child labor, public torture, persecution of minorities—have declined dramatically. Rates of homicide, capital punishment, and mistreatment of animals are lower, while institutions like the UN, international courts, and humanitarian organizations represent global efforts toward restraint. Sapolsky engages Steven Pinker’s The Better Angels of Our Nature, which argues violence has declined through the “civilizing process” (states monopolizing force), commerce, and a moral “Flynn effect” expanding empathy and rights. Critics counter that Pinker minimizes colonial wars, proxy conflicts, and the devastation of the 20th century. When adjusted for population and duration, atrocities from World War II, the Rwandan genocide, and Mao’s rule rank among the deadliest in history. Still, trends suggest fewer people commit violence, even if technology magnifies the reach of the violent few. The chapter explores traditional peace-promoting routes: mobility among hunter-gatherers, trade that makes war costly, and cultural diffusion spreading liberties. Religion is shown as double-edged: it reduces anxiety and boosts prosociality under punitive, moralizing gods but also fuels enduring intergroup violence. Contact theory demonstrates that under equal, cooperative conditions, sustained intergroup interaction reduces prejudice, though effects are fragile. Symbolic gestures addressing sacred values can transform conflicts, as seen in Mandela’s reconciliation or Hussein’s eulogy for Rabin. Punishment and reputation systems foster cooperation, but excessive reliance on vengeance corrodes trust. Sapolsky underscores humanity’s ambivalence toward killing. Soldiers often hesitate to fire, musket studies at Gettysburg revealed thousands of unfired weapons, and many drone pilots develop PTSD from intimate remote killings. Humans have inhibitions against close-range killing, though training and technology can override them. Despite our biology, reconciliation is possible. Truth and Reconciliation Commissions, apologies, reparations, and forgiveness—though imperfect—help societies move forward. Powerful stories illustrate this: Pumla Gobodo-Madikizela’s empathy for apartheid death squad commander Eugene de Kock, Zenji Abe’s apology at Pearl Harbor, Bouazizi’s self-immolation sparking the Arab Spring, and Hugh Thompson landing his helicopter at My Lai to stop his fellow soldiers from killing civilians. The chapter closes with Sapolsky’s decades of baboon research. A tuberculosis outbreak wiped out the most aggressive males of one troop, leaving behind a culture of low aggression and high affiliation. New males absorbed this culture, proving that primates—and by extension humans—can change. As Sapolsky notes, if baboons can transform violent hierarchies into more peaceful ones, so can we. History reveals both horror and hope: atrocities justified by metaphors and divisions, but also astonishing moments of cooperation, reconciliation, and moral courage. The task is to make these exceptions the norm, remembering that our biology does not doom us to violence but gives us the capacity to build peace.