Recent investigations have uncovered large, consistent deviations from the predictions of the textbook representation of Homo economicus (Roth et al, 1992, Fehr and Gächter, 2000, Camerer 2001). One problem appears to lie in economists’ canonical assumption that individuals are entirely self-interested: in addition to their own material payoffs, many experimental subjects appear to care about fairness and reciprocity, are willing to change the distribution of material outcomes at personal cost, and reward those who act in a cooperative manner while punishing (...) those who do not even when these actions are costly to the individual. These deviations from what we will term the canonical model have important consequences for a wide range of economic phenomena, including the optimal design of institutions and contracts, the allocation of property rights, the conditions for successful collective action, the analysis of incomplete contracts, and the persistence of noncompetitive wage premia. Fundamental questions remain unanswered. Are the deviations from the canonical model evidence of universal patterns of behavior, or do the individual’s economic and social environments shape behavior? If the latter, which economic and social conditions are involved? Is reciprocal behavior better explained statistically by individuals’ attributes such as their sex, age, or relative wealth, or by the attributes of the group to which the individuals belong? Are there cultures that approximate the canonical account of self-regarding behavior? Existing research cannot answer such questions because virtually all subjects have been university students, and while there are cultural differences among student populations throughout the world, these differences are small compared to the range of all social and cultural environments. To address the above questions, we and our collaborators undertook a large cross-cultural study of behavior in ultimatum, public good, and dictator games.. (shrink)
Inclusive fitness theory provides conditions for the evolutionary success of a gene. These conditions ensure that the gene is selfish in the sense of Dawkins (The selfish gene, Oxford University Press, Oxford, 1976): genes do not and cannot sacrifice their own fitness on behalf of the reproductive population. Therefore, while natural selection explains the appearance of design in the living world (Dawkins in The blind watchmaker: why the evidence of evolution reveals a universe without design, W. W. Norton, New York, (...) 1996), inclusive fitness theory does not explain how. Indeed, Hamilton’s rule is equally compatible with the evolutionary success of prosocial altruistic genes and antisocial predatory genes, whereas only the former, which account for the appearance of design, predominate in successful organisms. Inclusive fitness theory, however, permits a formulation of the central problem of sociobiology in a particularly poignant form: how do interactions among loci induce utterly selfish genes to collaborate, or to predispose their carriers to collaborate, in promoting the fitness of their carriers? Inclusive fitness theory, because it abstracts from synergistic interactions among loci, does not answer this question. Fitness-enhancing collaboration among loci in the genome of a reproductive population requires suppressing alleles that decrease, and promoting alleles that increase the fitness of its carriers. Suppression and promotion are effected by regulatory networks of genes, each of which is itself utterly selfish. This implies that genes, and a fortiori individuals in a social species, do not maximize inclusive fitness but rather interact strategically in complex ways. It is the task of sociobiology to model these complex interactions. (shrink)
The standard theories of cooperation in humans, which depend on repeated interaction and reputation effects among self-regarding agents, are inadequate. Strong reciprocity, a predisposition to participate in costly cooperation and the punishment, fosters cooperation where self-regarding behaviors fail. The effectiveness of socially coordinated punishment depends on individual motivations to participate, which are based on strong reciprocity motives. The relative infrequency of high-cost punishment is a result of the ubiquity of strong reciprocity, not its absence.
Behavioral economics has rejuvenated economic theory and deepened the bonds between economic theory and the other social sciences. Neoclassical economics does not depend on individual preferences being self-regarding. Moreover, in market contexts, laboratory experiments indicate that traditional theory works well. Behavioral economic findings thus enrich and expand neoclassical economics rather than undermining it. In particular, social norms are an emergent property of human sociality, and exist as macrosocial structures that are not reducible to the preferences of individuals. Behavioral economists are (...) not theorists, but rather experimentalists. With few exceptions, they do not provide, nor aim to provide, cogent models for the phenomena they discover. Far from downplaying “inconvenient facts,” as is the practice of traditional economic theory, behavioral economists relish finding novel forms of individual decision-making and strategic behavior. (shrink)
The various behavioral disciplines model human behavior in distinct and incompatible ways. Yet, recent theoretical and empirical developments have created the conditions for rendering coherent the areas of overlap of the various behavioral disciplines. The analytical tools deployed in this task incorporate core principles from several behavioral disciplines. The proposed framework recognizes evolutionary theory, covering both genetic and cultural evolution, as the integrating principle of behavioral science. Moreover, if decision theory and game theory are broadened to encompass other-regarding preferences, they (...) become capable of modeling all aspects of decision making, including those normally considered “psychological,” “sociological,” or “anthropological.” The mind as a decision-making organ then becomes the organizing principle of psychology. (Published Online April 27 2007) Key Words: behavioral game theory; behavioral science; evolutionary theory; experimental psychology; gene-culture coevolution; rational actor model; socialization. (shrink)
My response to commentators includes a suggestion that an additional principle be added to the list presented in the target article: the notion of human society as a complex adaptive system with emergent properties. In addition, I clear up several misunderstandings shared by several commentators, and explore some themes concerning future directions in the unification of the behavioral science. (Published Online April 27 2007).
offers an evolutionary approach to morality, in which moral rules form a cultural system that is robust and evolutionarily stable. The folk theorem is the analytical basis for his theory of justice. I argue that this is a mistake, as the equilibria described by the folk theorem lack dynamic stability in games with several players. While the dependence of Binmore's argument on the folk theorem is more tactical than strategic, this choice does have policy implications. I do not believe that (...) moral rules are solutions to the Nash bargaining problem. Rather, I believe that human beings are emotionally constituted, by virtue of their evolutionary history, to embrace prosocial and altruistic notions of in-group–out-group identification and reciprocity. These aspects of human nature are incompatible with Binmore's notion that humans are self-regarding creatures. I present empirical evidence supporting a specific form of human, other-regarding preferences known as strong reciprocity. Key Words: justice • ethics • folk theorem • evolutionary game theory. (shrink)
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. Key Words: altruism; cooperation; cross-cultural research; experimental economics; game theory; ultimatum game; public goods game; self-interest. (shrink)
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. (shrink)
Despite their distinct objects of study, the human behavioral sciences all include models of individual human behavior. Unity in the behavioral sciences requires that there be a common underlying model of individual human behavior, specialized and enriched to meet the particular needs of each discipline. Such unity does not exist, and cannot be easily attained, since the various disciplines have incompatible models and disparate research methodologies. Yet recent theoretical and empirical developments have created the conditions for unity in the behavioral (...) sciences, incorporating core principles from all fields, and based upon theoretical tools (game theory and the rational actor model) and data gathering techniques (experimental games in the laboratory and field) that transcend disciplinary boundaries. This article sketches a set of principles aimed at fostering such a unity. Key Words: behavioral science • game theory • experimental economics • rational actor model. (shrink)
Colman's critique of classical game theory is correct, but it is well known. Colman's proposed mechanisms are not plausible. Insufficient reason does what “team reasoning” is supposed to handle, and it applies to a broader set of coordination games. There is little evidence ruling out more traditional alternatives to Stackelberg reasoning, and the latter is implausible when applied to coordination games in general.
If altruism requires self-control, people must consider altruistic acts as costly, the benefits of which will only be recouped in the future. By contrast, I shall present evidence that altruism is dictated by emotions: Altruists secure an immediate payoff from performing altruistic acts, so no element of self-control is present, and no future reward is required or expected.
Methodological practices differ between economics and psychology because economists use game theory as the basis for the design and interpretation of experiments, while psychologists do not. This methodological choice explains the “four key variables” stressed by Hert-wig and Ortmann. Game theory is currently the most rigorous basis for modeling strategic choice.