Humans are characterized by an extreme dependence on culturally transmitted information. Such dependence requires the complex integration of social and asocial information to generate effective learning and decision making. Recent formal theory predicts that natural selection should favour adaptive learning strategies, but relevant empirical work is scarce and rarely examines multiple strategies or tasks. We tested nine hypotheses derived from theoretical models, running a series of experiments investigating factors affecting when and how humans use social information, and whether such behaviour is adaptive, across several computer-based tasks. The number of demonstrators, consensus among demonstrators, confidence of subjects, task difficulty, number of sessions, cost of asocial learning, subject performance and demonstrator performance all influenced subjects' use of social information, and did so adaptively. Our analysis provides strong support for the hypothesis that human social learning is regulated by adaptive learning rules.

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'Altruistic' and 'antisocial' punishers are one and the same AbstractIn certain economic experiments, some participants willingly pay a cost to punish peers who contribute too little to the public good. Because such punishment can lead to improved group outcomes, this costly punishment has been conceived of as altruistic. Here we provide evidence that individual variation in the propensity to punish low contributions is unrelated to altruism. First, individual use of punishment was uncorrelated with contribution to the public good, contrary to the hypothesis that punishers are proximally motivated by prosocial preferences. Second, individual use of punishment was positively correlated across situations where the use of punishment is typically group beneficial and situations where the use of punishment is typically group detrimental, as well as across situations of radically different strategic structures. These findings contrast sharply with the premise that the tendency to use punishment can fruitfully be regarded as an adaptation for solving social dilemmas.Keywords. public goods, costly punishment, cooperation, altruism 4 Economic experiments have shown that people use costly punishment in public goods games more frequently than is expected from rational optimizers of financial gain (1-3).Often, though not always, this punishment is directed at those who have made low contributions to the public good. While contributions to the public good diminish over time in the absence of punishment, the addition of costly punishment, contingent on the particular usage of that punishment, can induce and sustain cooperation. Thus punishment, in some cases, appears to solve the first order social dilemma of the public goods game. This finding has inspired an "altruistic" punishment hypothesis: human cooperation in social dilemmas is explained, in part, by the prevalence of individuals predisposed by evolution to pay the costs of punishing non-cooperators and thus sustain cooperation. Here we provide direct tests of both a motivational and an instrumental interpretation of the "altruistic" punishment hypotheses namely: i) Punishment is directly motivated by prosocial preferences. ii)Regardless of proximal motivation, individual propensity to punish is a (cultural) group level adaptation specifically for solving collective action problems.Under the motivational interpretation of the altruistic punishment hypothesis, punishment of low contributors should be correlated with other behaviors that are motivated by prosocial preferences. Although general patterns of behavior in the public goods game can be understood without invoking prosocial preferences (4), individual differences in contributions to the public good when there is no threat of punishment are related to individual differences in prosocial preferences (5). Therefore, within groups playing a public goods game the motivational interpretation of the altruistic punishment hypothesis predicts individual

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