American Scientist

Hierarchy in the Forest: The Evolution of Egalitarian Behavior. Christopher Boehm. 292 pp. Harvard University Press, 1999. $39.95.

Understanding the roles that cooperation and conflict play in shaping the political dynamics of human societies has fascinated and perplexed anthropologists, evolutionary psychologists and behavioral ecologists for quite some time. Philosophical debates on human nature—typically the division among Rousseauian and Hobbesian camps on whether humans are intrinsically altruistic or selfish—often cloud our perspective while trying to resolve human political dynamics. In Hierarchy in the Forest, Christopher Boehm certainly does not allow this seemingly endless match of wits to prevail. Rather, he integrates human dispositions toward domination and submission with the onset of human moral capacities (and thus cooperation) in tackling the issue of egalitarianism from an evolutionary perspective.

This well-written book, geared toward an audience with a background in the behavioral and evolutionary sciences but accessible to a broad readership, raises two general questions: "What is an egalitarian society?" and "How have these societies evolved?" Boehm begins by arguing that egalitarian societies, although peaceful by nature, are maintained by the subordinates' ability as a group to aggressively and vigilantly keep the would-be dominant individuals in check. To ensure that the readers do not mistake egalitarian societies for those that are devoid of competition or social order, he coins the term "reverse dominance hierarchy," which expresses the importance of subordinate coalitions in maintaining parity within the group. From here, he takes the reader on a journey from the Arctic to the Americas, from Australia to Africa, in search of hunter-gatherer and tribal societies that emanate the egalitarian ethos—one that promotes generosity, altruism and sharing but forbids upstartism, aggression and egoism. Throughout this journey, Boehm tantalizes the reader with vivid anthropological accounts of ridicule, criticism, ostracism and even execution—prevalent tactics used by subordinates in egalitarian societies to level the social playing field. The foundation of egalitarianism having been so clearly laid down, the book shifts to its evolutionary gear.Hierarchy in the Forest comes to a close with Boehm constructing an ambivalence model that reflects on human nature and its influences on egalitarianism. In essence, humans will forever experience a three-tiered "psychological tug of war" where intrinsic tendencies toward dominance do battle with altruistic cultural and moral codes and with emotional resentment of domination. It is this mindful war that triggers hierarchical societies, whether they be controlled by the dominant individuals or by subordinate coalitions, to predominate in humans. Hierarchy in the Forest is an interesting and thought-provoking book that is surely an important contribution to perspectives on human sociality and politics.—Ryan Earley, Biology, University of Louisville

At the forefront of his evolutionary discussion lies one question: How could the cooperative air of egalitarian societies evolve despite innate human dispositions toward dominance? Boehm first uses the similarities and differences among ape social systems (chimpanzees, bonobos, gorillas and humans) to reconstruct the political tendencies of a common ancestor. From this, he reasons that the common ancestor was prone to orthodox, despotic hierarchies. This leads to a walk through evolutionary time that elucidates the advent of weaponry, intelligence, language and morality as keys to the evolution of egalitarianism. Now the reader is primed for a discussion of a controversial topic: group selection. Boehm proposes that cultural influences on human behavior, specifically the social control of would-be dominants by subordinate coalitions (via ridicule, ostracism and so on) and the ability of humans to arrive at consensual decisions create an arena through which group selection can operate. These arguments are presented in a logical and convincing manner but, being the pinnacle of this book, deserve further attention and debate.