Jean Ensminger

Economic man in cross-cultural perspective: Behavioral experiments in 15 small-scale societies

Researchers from across the social sciences have found consistent deviations from the predictions of the canonical model of self-interest in hundreds of experiments from around the world. This research, however, cannot determine whether the uniformity results from universal patterns of human behavior or from the limited cultural variation available among the university students used in virtually all prior experimental work. To address this, we undertook a cross-cultural study of behavior in ultimatum, public goods, and dictator games in a range of small-scale societies exhibiting a wide variety of economic and cultural conditions. We found, first, that the canonical model - based on self-interest - fails in all of the societies studied. Second, our data reveal substantially more behavioral variability across social groups than has been found in previous research. Third, group-level differences in economic organization and the structure of social interactions explain a substantial portion of the behavioral variation across societies: the higher the degree of market integration and the higher the payoffs to cooperation in everyday life, the greater the level of prosociality expressed in experimental games. Fourth, the available individual-level economic and demographic variables do not consistently explain game behavior, either within or across groups. Fifth, in many cases experimental play appears to reflect the common interactional patterns of everyday life.

Costly punishment across human societies.

Recent behavioral experiments aimed at understanding the evolutionary foundations of human cooperation have suggested that a willingness to engage in costly punishment, even in one-shot situations, may be part of human psychology and a key element in understanding our sociality. However, because most experiments have been confined to students in industrialized societies, generalizations of these insights to the species have necessarily been tentative. Here, experimental results from 15 diverse populations show that (i) all populations demonstrate some willingness to administer costly punishment as unequal behavior increases, (ii) the magnitude of this punishment varies substantially across populations, and (iii) costly punishment positively covaries with altruistic behavior across populations. These findings are consistent with models of the gene-culture coevolution of human altruism and further sharpen what any theory of human cooperation needs to explain.

Markets, religion, community size, and the evolution of fairness and punishment

A Fair Society Many of the social interactions of everyday life, especially those involving economic exchange, take place between individuals who are unrelated to each other and often do not know each other. Countless laboratory experiments have documented the propensity of subjects to behave fairly in these interactions and to punish those participants deemed to have behaved unfairly. Henrich et al. (p. 1480, see the Perspective by Hoff) measured fairness in thousands of individuals from 15 contemporary, small-scale societies to gain an understanding of the evolution of trustworthy exchange among human societies. Fairness was quantitated using three economic games. Various societal parameters, such as the extent to which food was purchased versus produced, were also collected. Institutions, as represented by markets, community size, and adherence to a world religion all predict a greater exercise of fairness in social exchange. The origins of modern social norms and behaviors may be found in the evolution of institutions. Large-scale societies in which strangers regularly engage in mutually beneficial transactions are puzzling. The evolutionary mechanisms associated with kinship and reciprocity, which underpin much of primate sociality, do not readily extend to large unrelated groups. Theory suggests that the evolution of such societies may have required norms and institutions that sustain fairness in ephemeral exchanges. If that is true, then engagement in larger-scale institutions, such as markets and world religions, should be associated with greater fairness, and larger communities should punish unfairness more. Using three behavioral experiments administered across 15 diverse populations, we show that market integration (measured as the percentage of purchased calories) positively covaries with fairness while community size positively covaries with punishment. Participation in a world religion is associated with fairness, although not across all measures. These results suggest that modern prosociality is not solely the product of an innate psychology, but also reflects norms and institutions that have emerged over the course of human history.

Making a market : the institutional transformation of an African society

1. A proper marriage: new institutional economic anthropology 2. Transaction costs: the history of trade among the Orma 3. Distribution of the gains from trade 4. Agency theory: patron-client relations as a form of labor contracting 5. Property rights: dismantling the commons 6. Collective action: from community to state 7. Conclusion: ideology and the economy.

More ‘altruistic’ punishment in larger societies

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.

Changing Social Norms: Common Property, Bridewealth, and Clan Exogamy

Much has been written on change in social norms, but with few exceptions such efforts have failed to synthesize the growing theoretical literature with the specifics of empirical cases. Attempting such a synthesis, we develop a theoretical framework for explaining norm emergence and change that builds on Barths idea of generative models. We identify three mechanisms offered in the contemporary theoretical literature to account for the dynamic process of norm change: (I) coordination on focal points, (2) competitive selection among contracts, and (3) bargaining. We investigate three examples of norm change among the Galole Orma - common property rights, bridewealth, and clan exogamy - and show that examination of strategic decision making within the constraints presented by social context can produce adequate accounts of such change. We conclude that the primary mechanism in norm change among the Orma is bargaining and that the most important sources of such change are asymmetries in bargaining power.

Culture does account for variation in game behavior

Lamba and Maces critique (1) of our research (2–4) is based on incorrect claims about our experiments and several misunderstandings of the theory underpinning our efforts. Their findings are consistent with our previous work and lead to no unique conclusions.

Economic and political differentiation among Galole Orma women

The Orma are cattle‐herders living close to Tana River in Kenya. This paper gives an outline of Orma propertyholding and of womens contributions to production in terms of labor. The relationship between control over resources (either outright ownership, rights over use, or indirect control through childrens ownership) is discussed in relation to the influence women wield in issues considering sale of stock, decisions to shift or not, and the use of child labor. Formal and informal positions of power held by Orma women are analysed in relation to the effectiveness of womens influence over production decisions. The access that Orma women have to property varies with the degree of integration into the cash economy and to ones position on the nomadic‐sedentary continuum. With greater sedentarization and integration into cash economy women seem to lose control over economic resources in terms of outright ownership. They participate less in manual tasks of production. However, by a variety of informal and f...

Models of decision-making and the coevolution of social preferences

We would like to thank the commentators for their generous comments, valuable insights and helpful suggestions. We begin this response by discussing the selfishness axiom and the importance of the preferences, beliefs, and constraints framework as a way of modeling some of the proximate influences on human behavior. Next, we broaden the discussion to ultimate-level (that is evolutionary) explanations, where we review and clarify gene-culture coevolutionary theory, and then tackle the possibility that evolutionary approaches that exclude culture might be sufficient to explain the data. Finally, we consider various methodological and epistemological concerns expressed by our commentators.

Reply to van Hoorn: Converging lines of evidence

We agree with the comments by van Hoorn (1) on our critique (2): testing causal hypotheses about human behavior is a challenge (1, 3). Making progress requires specifying alternative hypotheses and then testing these hypotheses using diverse and converging lines of evidence. We have defended the hypothesis that social norms, which culturally coevolved with the institutions of large-scale societies including markets, influence economic decision-making. This hypothesis emerged from a larger set that we developed both at the outset of our project and as we went along. Our interdisciplinary team’s initial list of hypotheses included the idea that experimental games might spark an innate reciprocity module that would yield little variation across populations. We also considered the hypothesis that group-level differences might result from individual differences in wealth or income. Nevertheless, what emerged in the data in our first project was (i) substantial variation among 15 populations, (ii) a strong correlation with market integration, and (iii) little relation to individual-level economic or demographic variables. Not satisfied with our first effort, we sampled 10 new populations, replicated these findings with improved protocols (developed based on critiques of the Phase I), and then extended them to two additional experimental games. Along the way, we have explored alternative hypotheses using measures of genetic relatedness, social network position, anonymity manipulations, and framing tools. To our knowledge, no other existing hypotheses can better account for the observed patterns of variation.