Culture-led gene-culture coevolution is a framework within which substantive explanations of human evolution must be located. It is not itself an explanation. Explanations depend on such concrete historical evolutionary factors such as the control of fire, collective child-rearing, lethal weapon technology, altruistic cooperation and punishment, and the mastery of complex collaboration protocols leading to an effective division of social labor.

Baumard et al. mischaracterize our model of individual and social choice behavior. We model individuals who maximize preferences given their beliefs, and subject to their informational and material constraints (Fehr & Gintis 2007). Individuals thus must make trade-offs among self-regarding, other-regarding, and character virtue goals. Two genetic predispositions are particularly crucial. The first is strong reciprocity. The second is the capacity to internalize norms through the socialization process. Our model includes the authors' model as a subset.

McCullough et al.'s target article is a psychological version of the reputation models pioneered by biologist Robert Trivers (1971) and economist Robert Frank (1988). The authors, like Trivers and Frank, offer an implausible explanation of the fact that revenge is common even when there are no possible reputational effects. I sketch a more plausible model based on recent research.

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.

Moral judgments often affect scientific judgments in real-world contexts, but Knobe's examples in the target article do not capture this phenomenon.

We consider two reasons why firms should be owned and run democratically by their workers. The first concerns accountability: Because the employment relationship involves the exercise of power, its governance should on democratic grounds be accountable to those most directly affected. The second concerns efficiency: The democratic firm uses a lower level of inputs per unit of output than the analogous capitalist firm.

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.

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.

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.

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.

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.