What counts as human rationality: reasoning processes that embody content-independent formal theories, such as propositional logic, or reasoning processes that are well designed for solving important adaptive problems? Most theories of human reasoning have been based on content-independent formal rationality, whereas adaptive reasoning, ecological or evolutionary, has been little explored. We elaborate and test an evolutionary approach, Cosmides’ (1989) social contract theory, using the Wason selection task. In the first part, we disentangle the theoretical concept of a “social contract” from that of a “cheater-detection algorithm.” We demonstrate that the fact that a rule is perceived as a social contract—or a conditional permission or obligation, as Cheng and Holyoak (1985) proposed—is not sufficient to elicit Cosmides’ striking results, which we replicated. The crucial issue is not semantic (the meaning of the rule), but pragmatic: whether a person is cued into the perspective of a party who can be cheated. In the second part, we distinguish between social contracts with bilateral and unilateral cheating options. Perspective change in contracts with bilateral cheating options turns P & not-Q responses into not-P & Q responses. The results strongly support social contract theory, contradict availability theory, and cannot be accounted for by pragmatic reasoning schema theory, which lacks the pragmatic concepts of perspectives and cheating detection.

Present conditions and selection pressures are irrelevant to the present design of orga-nisms and do not explain how or why organisms behave adaptively, when they do. To whatever non-chance extent organisms are behaving adaptively, it is 1) because of the operation of underlying adaptations whose present design is the product of selection in the past, and 2) because present conditions resemble past conditions in those specific ways made developmentally and functionally important by the design of those adap-tations. All adaptations evolved in response to the repeating elements of past environ-ments, and their structure reflects in detail the recurrent structure of ancestral envi-ronments. Even planning mechanisms (such as “consciousness”), which supposedly deal with novel situations, depend on ancestrally shaped categorization processes and are therefore not free of the past. In fact, the categorization of each new situation into evolutionarily repeating classes involves another kind of adaptation, the emotions, which match specialized modes of organismic operation to evolutionarily recurrent situations. The detailed statistical structure of these iterated systems of events is re-flected in the detailed structure of the algorithms that govern emotional state. For this

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Evolutionary approaches to judgment under uncertainty have led to new data showing that untutored subject reliably produce judgments that conform to may principles of probability theory when (a) they are asked to compute a frequency instead of the probability of a single event, and (b) the relevant information is expressed as frequencies. But are the frequencycomputation systems implicated in these experiments better at operating over some kinds of input than others? Principles of object perception and principles of adaptive design led us to propose the individuation hypothesis: that these systems are designed to produce wellcalibrated statistical inferences when they operate over representations of “whole ” objects, events, and locations. In a series of experiments on Bayesian reasoning, we show that human performance can be systematically improved or degraded by varying whether a correct solution requires one to compute hit and false-alarm rates over “natural ” units, such as whole objects, as opposed to inseparable aspects, views, and other parsings that violate evolved principles of object construal. The ability to make well-calibrated probability judgments depends, at a very basic level, on the ability to count. The

Humans, like all other organisms, were created through the process of evolution. Consequently, all innate human characteristics are the products of the evolutionary process. Although the implications of this were quickly grasped in investigating human physiology, until recently there has been a marked resistance to applying this knowledge to human behavior. But evolution and the innate algorithms that regulate human behavior are related as cause and consequence: lawful relations are being discovered between the evolutionary process and the innate psychology it has shaped. These lawful relations constitute the basis for a new discipline, evolutionary psychology, which involves the exploration of the naturally selected "design" features of the mechanisms that control behavior. This synthesis between evolution and psychology has been slow in coming(see DeVore, this volume). The delay can be partly accounted for by two formidable barriers to the integration of these two fields: the initial imprecision of evolutionary theory, and the continuing imprecision in the social sciences, including psychology. The revolution in evolutionary theory began two decades ago and, gathering force, has subsequently come to dominate behavioral inquiry. Vague and intuitive notions of adaptation, frequently involving (either tacitly or explicitly) group selection, were replaced by increasingly refined and precise characterizations of

Abstract: “Ought ” cannot be derived from “is, ” so why should facts about human nature be of interest to business ethicists? In this article, we discuss why the nature of human nature is relevant to anyone wishing to create a more just and humane workplace and society. We begin by presenting evolutionary psychology as a research framework, and then present three examples of research that illuminate various evolved cognitive programs. The first involves the cognitive foundations of trade, including a neurocognitive mechanism specialized for a form of moral reasoning: cheater detection. The second involves the moral sentiments triggered by participating in collective actions, which are relevant to organizational behavior. The third involves the evolved programs whereby our minds socially construct groups, and how these can be harnessed to reduce racism and foster true diversity in the workplace. In each case, we discuss how what has been learned about these evolved programs might inform the

difficulties in schizophrenia

THE THEORY OF evolution by natural selection has revolutionary implications for understanding the design of the human mind and brain, as Darwin himself was the first to recognize (Darwin, 1859). Indeed, a principled understanding of the network of causation that built the functional architecture of the human species offers the possibility of transforming the study of humanity into a natural science capable of precision and rapid progress. Yet, nearly a century and a half after The Origin of Species was published, the psychological, social, and behavioral sciences remain largely untouched by these implications, and many of these disciplines continue to be founded on assumptions evolutionarily informed researchers know to be false (Pinker, 2002; Tooby & Cosmides, 1992). Evolutionary psychology is the long-forestalled scientific attempt to assemble out of the disjointed, fragmentary, and mutually contradictory human disciplines a single, logically integrated research framework for the psychological, social, and behavioral sciences—a framework that not only incorporates the evolutionary sciences on a full and equal basis, but that systematically works out all of the revisions in existing belief and research practice that such a synthesis requires (Tooby & Cosmides, 1992). The long-term scientific goal toward which evolutionary psychologists are working is the mapping of our universal human nature. By this, we mean the construction of a set of empirically validated, high-resolution models of the evolved mechanisms that collectively constitute universal human nature. Because the evolved function of a psychological mechanism is computational—to regulate behavior and the body adaptively in response to informational inputs—such a model consists of a description of the functional circuit logic or information

Coalitional aggression evolved because it allowed participants in such coalitions to promote their fitness by gaining access to disputed reproduction enhancing resources that would otherwise be denied to them. Far fewer species manifest coalitional aggression than would be expected on the basis of the actual distribution of social conditions that would favor its evolution. The exploitation of such opportunities depends on the solution by individuals of highly complex and specialized information processing problems of cooperation and social exchange, and the difficulty of evolving cognitive mechanisms capable of solving such complex computational tasks may account for the phylogenetic rarity of such multi-individual coalitions. We propose that humans and a few other cognitively pre-adapted species have evolved specialized cognitive programs, that govern coalitional behavior, and constitute a distinctive coalitional psychology. An adaptive task analysis of what such algorithms need to accomplish, in the decisions regulating coalition formation, participation, cost and benefit allocation, allows the preliminary mapping of this coalitional psychology. Scrutinization of the adaptive features of coalitional aggression reveals some surprising characteristics, including that, under certain conditions, mortality rates do not negatively impact the fitness of males in the coalition, suggesting why warfare is so favored an activity, despite its risks to participating individuals ' welfare.

Culture is the ongoing--. oroduct of the evolved osvches.. of individual humans living in e groups. Progress in our understanding of culture as a phenomenon depends an progress in uncovering the nature of the evolved mechanisms that comprise the human psyche, including but not limited to those responsible for learning. Actual attempts to specify information processing mechanisms that could, in fact, perform tasks hr~mans routinely perform have demonstrated that the human psyche cannot, even in principle, be eomprised only of a general purpose learning mechanism or any other general purpose mechanism, such as an inclusive kitness maximizer. Instead, the human psyche appears to cansist of a large number ofmechanirms, many or most of which are special purpose and domain-specific. The output of these mechanisms taken together constitutes the "private culture " of each individual, and the interactions of these private cultures lead to the cross-individual patterns of similarity that have led anthropologists to think typologically of social groups as having "a " culture. The construction of a scientific theory of culture requires as its building blocks specific models of these psychological mechanisms, and so evolutionary anthro~olow.-. deoends. on the foreine- of an evolutionary psychology. The most productive application of evolutionary biology is, therefore, in the study of the. psychological. mechanisms that generate and shave culture. rather than in the attempt to impos; on cultural change tooclosea parallel tabopuiatiod genetics and organic evolution.