Title: A Cooperative Species: Human Reciprocity and Its Evolution
Author: Samuel Bowles and Herbert Gintis
Scope: 4 stars
Readability: 3 stars
My personal rating: 5 stars
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Topic of Book

The authors examine the cultural, biological and other processes that explain how humans became an exceptionally cooperative species.

If you would like to learn more about long-term human history, read my book From Poverty to Progress: How Humans Invented Progress, and How We Can Keep It Going.

Key Take-aways

• Assumptions made by economists and other disciplines that human individuals are largely self-interested does not match with our reality.
• Cooperation is a key part of human behavior. This cooperation extends far beyond people who are genetically related to each other. Nor can pure reciprocity (tit-for-tat) explain this level of cooperation.
• Hunter Gatherer bands lived in a highly competitive environment, where any band that learned to cooperate with others within the band could gain a critical survival advantage.
• Most likely war between Hunter Gatherer bands played a key role.
• All it would take is one person within a band to be biologically predisposed to cooperate altruistically with other band members. Because this behavior increased the survival chances of the group, those genes would tend to spread throughout the group.
• Humans have also evolved a desire to punish those who undermine group norms and cooperation even when that puts the punisher at risk. Shame and ostracism are important examples.
• Finally, institutions have evolved to punish free riders who try to take advantage of cooperation within their own group by shirking.

Important Quotes from Book

In the pages that follow we advance two propositions.

First, people cooperate not only for self-interested reasons but also because they are genuinely concerned about the well-being of others, try to uphold social norms, and value behaving ethically for its own sake. People punish those who exploit the cooperative behavior of others for the same reasons. Contributing to the success of a joint project for the benefit of one’s group, even at a personal cost, evokes feelings of satisfaction, pride, even elation. Failing to do so is often a source of shame or guilt.

Second, we came to have these “moral sentiments” because our ancestors lived in environments, both natural and socially constructed, in which groups of individuals who were predisposed to cooperate and uphold ethical norms tended to survive and expand relative to other groups, thereby allowing these prosocial motivations to proliferate. The first proposition concerns proximate motivations for prosocial behavior, the second addresses the distant evolutionary origins and ongoing perpetuation of these cooperative dispositions.

While cooperation is common in many species, Homo sapiens is exceptional in that in humans cooperation extends beyond close genealogical kin to include even total strangers, and occurs on a much larger scale than other species except for the social insects.

In the pages that follow we will examine the cultural, biological and other processes that explain how humans became this exceptionally cooperative species. By cooperation we mean engaging with others in a mutually beneficial activity. Examples include the joint pursuit of political and military objectives as well as the more prosaic foundations of everyday life: collaboration among employees in a firm, exchanges between buyers and sellers, and the maintenance of local amenities among neighbors.

Cooperative behavior may confer benefits net of costs on the individual cooperator, and thus could be motivated entirely by self-interest. Market exchange is an example. In this case, cooperation is a form of mutualism, namely an activity that confers net benefits both on the actor and on others. But cooperation may also impose net costs upon individuals in the sense that not cooperating would increase their fitness or other material payoffs. In this case cooperative behavior constitutes a form of altruism.

Models of altruism toward close family members and reciprocal altruism (which really should be called “enlightened self-interest”) are popular among biologists and economists alike and explain many forms of human cooperation, particularly those occurring in families or in frequently repeated dyadic (two-person) or other very small group interactions.

But these models fail to explain two facts about human cooperation: that it takes place in groups far larger than the immediate family, and that both in real life and in laboratory experiments, it occurs in interactions that are unlikely to be repeated, and where it is impossible to obtain reputational gains from cooperating. The most parsimonious proximal explanation of cooperation, one that is supported by extensive experimental and other evidence, is that people gain pleasure from or feel morally obligated to cooperate with like-minded people. People also enjoy punishing those who exploit the cooperation of others, or feel morally obligated to do so. Free-riders frequently feel guilty, and if they are sanctioned by others, they may feel ashamed. We term these feelings social preferences.

Rather, we seek to explain why we are not purely selfish—why the social preferences that sustain altruistic cooperation are so common. Proximate answers to this question are to be found in the way that our brains process information and induce the behavioral responses that we term cooperation. But how did we come to have brains that function in this manner?

Early human environments are part of our answer. Our Late Pleistocene ancestors inhabited the large-mammal-rich African savannah and other environments in which cooperation in acquiring and sharing food yielded substantial benefits at relatively low cost. The slow human life-history with prolonged periods of dependency of the young also made the cooperation of non-kin in child rearing and provisioning beneficial. As a result, members of groups that sustained cooperative strategies for provisioning, childrearing, sanctioning non-cooperators, defending against hostile neighbors, and truthfully sharing information had significant advantages over members of non-cooperative groups.

In the course of our subsequent history we created novel social and physical environments exhibiting similar, or even greater, benefits of cooperation, among them the division of labor coordinated by market exchange and respect of rights of property, systems of production characterized by increasing returns to scale (irrigated agriculture, modern industry, information systems with network externalities), and warfare. The impressive scope of these modern forms of cooperation was facilitated by the emergence in the last seven millennia of governments capable of enforcing property rights and providing incentives for the self-interested to contribute to common projects.

In the pages that follow we will advance three reasons why these altruistic social preferences supporting cooperation outcompeted unmitigated and amoral self-interest.

First, human groups have devised ways to protect their altruistic members from exploitation by the self-interested. Prominent among these is the public-spirited shunning, ostracism, and even execution of free-riders and others who violate cooperative norms. Other group activities protecting altruists from exploitation are leveling practices that limit hierarchy and inequality, including sharing food and information.

Second, humans adopted prolonged and elaborate systems of socialization that led individuals to internalize the norms that induce cooperation, so that contributing to common projects and punishing defectors became objectives in their own right rather than constraints on behavior. Together, the internalization of norms and the protection of the altruists from exploitation served to offset, at least partially, the competitive handicaps born by those who were motivated to bear personal costs to benefit others.

Third, between-group competition for resources and survival was and remains a decisive force in human evolutionary dynamics. Groups with many cooperative members tended to survive these challenges and to encroach upon the territory of the less cooperative groups, thereby both gaining reproductive advantages and proliferating cooperative behaviors through cultural transmission. The extraordinarily high stakes of intergroup competition and the contribution of altruistic cooperators to success in these contests meant that sacrifice on behalf of others, extending beyond the immediate family and even to virtual strangers, could proliferate. Modern-day nationalism is an example. This is part of the reason why humans became extraordinarily group-minded, favoring cooperation with insiders and often expressing hostility toward outsiders. Boundary-maintenance supported within-group cooperation and exchange by limiting group size and within-group linguistic, normative and other forms of heterogeneity. Insider favoritism also sustained the between-group conflicts and differences in behavior that made group competition a powerful evolutionary force.

In short, humans became the cooperative species that we are because cooperation was highly beneficial to the members of groups that practiced it, and we were able to construct social institutions that minimized the disadvantages of those with social preferences in competition with fellow group members, while heightening the group-level advantages associated with the high levels of cooperation that these social preferences allowed. These institutions proliferated because the groups that adopted them secured high levels of within-group cooperation, which in turn favored the groups’ survival as a biological and cultural entity in the face of environmental, military and other challenges.

Humans became a cooperative species because our distinctive livelihoods made cooperation within a group highly beneficial to its members and, exceptionally among animals, we developed the cognitive, linguistic and other capacities to structure our social interactions in ways that allowed altruistic cooperators to proliferate.

Among these socially constructed environments, three were particularly important: group-structured populations with frequent and lethal intergroup competition, within-group leveling practices such as sharing food and information, and developmental institutions that internalized socially beneficial preferences. The second reason why the emergence of social preferences among early humans would be highly likely is the vast number of foraging bands during the Late Pleistocene and earlier. Even if strong reciprocity initially emerged in a very small fraction of the human population, it is highly likely that over tens of thousands of generations and something like 150,000 foraging bands, it would have occurred that the strong reciprocators or other altruistic cooperators were prevalent in one or more such groups at some point. These bands would have done very well in competition with other bands.

Related Books

• “Not by Genes Alone: How Culture Transformed Human Evolution” by Richerson and Boyd
• “The Origin and Evolution of Cultures” by Robert Boyd and Peter Richerson
• “The Secret of Our Success” by Joseph Henrich
• “Nonzero: The Logic of Human Destiny” by Robert Wright
• “The Evolution of Everything: How New Ideas Emerge” by Matt Ridley
• “Cultural Evolution: How Darwinian Theory Can Explain Human Culture” by Alex Mesoudi

If you would like to learn more about long-term human history, read my book From Poverty to Progress: How Humans Invented Progress, and How We Can Keep It Going.