Cheng, J. T., Tracy, J. L., & Henrich, J. (2010). Pride, personality, and the evolutionary foundations of human social status. Evolution and Human Behavior , 31 (5), 334-347. PDF
Henrich, J., Heine, S. J., & Norenzayan, A. (2010). The weirdest people in the world?. Behavioral and Brain Sciences , 33 (2-3), 61-83. Audio File PDF Coverage in Science
Gervais, W., & Henrich, J. (2010). The Zeus Problem:Why Representational Content Biases Cannot Explain Faith in Gods. Journal of Cognition and Culture , 10 (3-4), 383-389. PDF
Shariff, A., Norenzayan, A., & Henrich, J. (2009). The Birth of High Gods: How the cultural evolution of supernatural policing agents influenced the emgerence of complex, cooperative human societies, paving the way for civilization. In M. Schaller, A. Norenzayan, S. Heine, T. Yamaguishi, & T. Kameda (Ed.), Evolution, Culture and the Human Mind (pp. 119-136) . Lawrence Erlbaum Associates. PDF
Brosnan, S. F., Silk, J. B., Henrich, J., Mareno, M. C., Lambeth, S. P., & Schapiro, S. J. (2009). Chimpanzees (Pan troglodytes) do not develop contingent reciprocity in an experimental task. Animal Cognition , 12 (4), 587-597.Abstract

Chimpanzees provide help to unrelated individuals in a broad range of situations. The pattern of helping within pairs suggests that contingent reciprocity may have been an important mechanism in the evolution of altruism in chimpanzees. However, correlational analyses of the cumulative pattern of interactions over time do not demonstrate that helping is contingent upon previous acts of altruism, as required by the theory of reciprocal altruism. Experimental studies provide a controlled approach to examine the importance of contingency in helping interactions. In this study, we evaluated whether chimpanzees would be more likely to provide food to a social partner from their home group if their partner had previously provided food for them. The chimpanzees manipulated a barpull apparatus in which actors could deliver rewards either to themselves and their partners or only to themselves. Our findings indicate that the chimpanzees' responses were not consistently influenced by the behavior of their partners in previous rounds. Only one of the 11 dyads that we tested demonstrated positive reciprocity. We conclude that contingent reciprocity does not spontaneously arise in experimental settings, despite the fact that patterns of behavior in the field indicate that individuals cooperate preferentially with reciprocating partners.

O'Gorman, R., Henrich, J., & Van Vugt, M. (2009). Constraining free riding in public goods games: designated solitary punishers can sustain human cooperation. Proceedings of the Royal Society B-Biological Sciences , 276 (1655), 323-329.Abstract

Much of human cooperation remains an evolutionary riddle. Unlike other animals, people frequently cooperate with non-relatives in large groups. Evolutionary models of large-scale cooperation require not just incentives for cooperation, but also a credible disincentive for free riding. Various theoretical solutions have been proposed and experimentally explored, including reputation monitoring and diffuse punishment. Here, we empirically examine an alternative theoretical proposal: responsibility for punishment can be borne by one specific individual. This experiment shows that allowing a single individual to punish increases cooperation to the same level as allowing each group member to punish and results in greater group profits. These results suggest a potential key function of leadership in human groups and provides further evidence supporting that humans will readily and knowingly behave altruistically.

Henrich, J. (2009). The evolution of costly displays, cooperation and religion: Credibility enhancing displays and their implications for cultural evolution. Evolution and Human Behavior , 30 (4), 244-260. PDF
Henrich, J. (2009). The Evolution of Innovation-Enhancing Institutions. In S. J. Shennan & M. J. O'Brien (Ed.), Innovation in Cultural Systems: Contributions in Evolution Anthropology . Cambridge, MIT. PDF
Vonk, J., Brosnan, S. F., Silk, J. B., Henrich, J., Richardson, A. S., Lambeth, S. P., Schapiro, S. J., et al. (2008). Chimpanzees do not take advantage of very low cost opportunities to deliver food to unrelated group members. Animal Behaviour , 75 (5), 1757-1770.Abstract

We conducted experiments on two populations of chimpanzees, Pan troglodytes, to determine whether they would take advantage of opportunities to provide food rewards to familiar group members at little cost to themselves. In both of the experiments described here, chimpanzees were able to deliver identical rewards to themselves and to other members of their social groups. We compared the chimpanzees' behaviour when they were paired with another chimpanzee and when they were alone. If chimpanzees are motivated to provide benefits to others, they are expected to consistently deliver rewards to others and to distinguish between the partner-present and partner-absent conditions. Results from both experiments indicate that our subjects were largely indifferent to the benefits they could provide to others. They were less likely to provide rewards to potential recipients as the experiment progressed, and all but one of the 18 subjects were as likely to deliver rewards to an empty enclosure as to an enclosure housing another chimpanzee. These results, in conjunction with similar results obtained in previous experiments, suggest that chimpanzees are not motivated by prosocial sentiments to provide food rewards to other group members. The Association for the Study of Animal Behaviour. Published by Elsevier Ltd.

Henrich, J. (2008). A cultural species. In M. Brown (Ed.), Explaining Culture Scientifically (pp. 184-210) . Seattle, University of Washington Press. PDF
Henrich, J., & Boyd, R. (2008). Division of labor, economic specialization, and the evolution of social stratification. Current Anthropology , 49 (4), 715-724. PDF
Five misunderstandings about cultural evolution
Henrich, J., Boyd, R., & Richerson, P. J. (2008). Five misunderstandings about cultural evolution. Human Nature , 19 (2), 119-137. PDF
Marlowe, F., Berbesque, J. C., Barr, A., Barrett, C., Bolyanatz, A., Cardenas, J. C., Ensminger, J., et al. (2008). More ‘altruistic’ punishment in larger societies. Proceedings of the Royal Society B: Biological Sciences , 275 (1634), 587-590.Abstract

If individuals will cooperate with cooperators, and punish non-cooperators even at a cost to themselves, then this strong reciprocity could minimize the cheating that undermines cooperation. Based upon numerous economic experiments, some have proposed that human cooperation is explained by strong reciprocity and norm enforcement. Second-party punishment is when you punish someone who defected on you; third-party punishment is when you punish someone who defected on someone else. Third-party punishment is an effective way to enforce the norms of strong reciprocity and promote cooperation. Here we present new results that expand on a previous report from a large cross-cultural project. This project has already shown that there is considerable cross-cultural variation in punishment and cooperation. Here we test the hypothesis that population size (and complexity) predicts the level of third-party punishment. Our results show that people in larger, more complex societies engage in significantly more third-party punishment than people in small-scale societies.

Gintis, H., Henrich, J., Bowles, S., Boyd, R., & Fehr, E. (2008). Strong reciprocity and the roots of human morality. Social Justice Research , 21 (2), 241-253.Abstract

Human morality is a key evolutionary adaptation on which human social behavior has been based since the Pleistocene era. Ethical behavior is constitutive of human nature, we argue, and human morality is as important an adaptation as human cognition and speech. Ethical behavior, we assert, need not be a means toward personal gain. Because of our nature as moral beings, humans take pleasure in acting ethically and are pained when acting unethically. From an evolutionary viewpoint, we argue that ethical behavior was fitness-enhancing in the years marking the emergence of Homo sapiens because human groups with many altruists fared better than groups of selfish individuals, and the fitness losses sustained by altruists were more than compensated by the superior performance of the groups in which they congregated.

Henrich, J., & McElreath, R. (2007). Dual Inheritance Theory: The Evolution of Human Cultural Capacities and Cultural Evolution. In R. Dunbar & L. Barrett (Ed.), Oxford Handbook of Evolutionary Psychology (pp. 555-570) . Oxford, Oxford University Press. PDF
McElreath, R., & J., H. (2007). Modelling cultural evolution. In R. I. M. Dunbar & L. Barrett (Ed.), The Oxford Handbook of Evolutionary Psychology (pp. 571-585) . Oxford, Oxford University Press. PDF
Why Humans Cooperate: A Cultural and Evolutionary Explanation
Henrich, N., & Henrich, J. (2007). Why Humans Cooperate: A Cultural and Evolutionary Explanation . New York, Oxford University Press. Publisher's VersionAbstract

Why Humans Cooperate takes a unique look at the evolution of human cooperation and tries to answer the question: why are people willing to help others at a cost to themselves? The book brings together evolutionary theories, economic experiments, and an anthropological case study that runs throughout the book to explain and illustrate human cooperation.

Using an evolutionary framework, Natalie and Joseph Henrich have expanded upon several diverse theories for explaining cooperative or ‘helpful’ behavior, and integrated them into a unified theory. Established concepts such as kin selection and reciprocity have been linked with theories on social learning and our evolved psychologies to explain the universality of human cooperation—as well as the distinctive ways in which cooperative behavior expresses itself in different cultures.

The theories developed in the book are brought to life by examining the Chaldeans of metropolitan Detroit. By exploring Chaldean cooperation, theoretical concepts are shown to translate into social behavior, and universal psychologies for cooperation lead to culturally-specific norms, beliefs, and practices. The book also introduces a series of economic experiments that help us understand why, when, and to what extent people are willing to help others. These experiments also highlight the variation in behaviors across cultural groups, even when all the groups rely on the same cognitive machinery and evolved psychologies. The merging of theory, experiments, and the Chaldean case study allows for an in-depth exploration of the origins and manifestations of cooperation.

Henrich, J. (2006). Cooperation, Punishment, and the Evolution of Human Institutions. Science , 312 (5770), 60-61. PDF
Henrich, J., McElreath, R., Ensminger, J., Barr, A., Barrett, C., Bolyanatz, A., Cardenas, J. C., et al. (2006). Costly Punishment Across Human Societies. Science , 312 (5781), 1767-1770. PDF Supplement News & Views in Science
Henrich, J., & Henrich, N. (2006). Culture, evolution and the puzzle of human cooperation. Cognitive Systems Research , 7 (2), 220-245.Abstract

Synthesizing existing work from diverse disciplines, this paper introduces a culture-gene coevolutionary approach to human behavior and psychology, and applies it to the evolution of cooperation. After a general discussion of cooperation in humans, this paper summarizes Dual Inheritance Theory and shows how cultural transmission can be brought under the Darwinian umbrella in order to analyze how culture and genes coevolve and jointly influence human behavior and psychology. We then present a generally applicable mathematical characterization of the problem of cooperation. From a Dual Inheritance perspective, we review and discuss work on kinship, reciprocity, reputation, social norms, and ethnicity, and their application to solving the problem of cooperation. (c) 2006 Published by Elsevier B.V.