Human cooperation is held to be an evolutionary puzzle because people voluntarily engage in costly cooperation, and costly punishment of non-cooperators, even among anonymous strangers they will never meet again. The costs of such cooperation cannot be recovered through kin-selection, reciprocal altruism, indirect reciprocity, or costly signaling. A number of recent authors label this behavior ‘strong reciprocity’, and argue that it is: (a) a newly documented aspect of human nature, (b) adaptive, and (c) evolved by group selection. We argue exactly (...) the opposite; that the phenomenon is: (a) not new, (b) maladaptive, and (c) evolved by individual selection. In our perspective, the apparent puzzle disappears to reveal a biological and evolutionary logic to human cooperation. Group selection may play a role in theory, but it is neither necessary nor sufficient to explain human cooperation. Our alternative solution is simpler, makes fewer assumptions, and is more parsimonious with the empirical data. (shrink)

I argue that the magnitude and nature of sex differences in aggression, their development, causation, and variability, can be better explained by sexual selection than by the alternative biosocial version of social role theory. Thus, sex differences in physical aggression increase with the degree of risk, occur early in life, peak in young adulthood, and are likely to be mediated by greater male impulsiveness, and greater female fear of physical danger. Male variability in physical aggression is consistent with an alternative (...) life history perspective, and context-dependent variability with responses to reproductive competition, although some variability follows the internal and external influences of social roles. Other sex differences, in variance in reproductive output, threat displays, size and strength, maturation rates, and mortality and conception rates, all indicate that male aggression is part of a sexually selected adaptive complex. Physical aggression between partners can be explained using different evolutionary principles, arising from the conflicts of interest between males and females entering a reproductive alliance, combined with variability following differences in societal gender roles. In this case, social roles are particularly important since they enable both the relatively equality in physical aggression between partners from Western nations, and the considerable cross-national variability, to be explained. (shrink)

An emerging class of theories concerning the functional structure of the brain takes the reuse of neural circuitry for various cognitive purposes to be a central organizational principle. According to these theories, it is quite common for neural circuits established for one purpose to be exapted (exploited, recycled, redeployed) during evolution or normal development, and be put to different uses, often without losing their original functions. Neural reuse theories thus differ from the usual understanding of the role of neural plasticity (...) (which is, after all, a kind of reuse) in brain organization along the following lines: According to neural reuse, circuits can continue to acquire new uses after an initial or original function is established; the acquisition of new uses need not involve unusual circumstances such as injury or loss of established function; and the acquisition of a new use need not involve (much) local change to circuit structure (e.g., it might involve only the establishment of functional connections to new neural partners). Thus, neural reuse theories offer a distinct perspective on several topics of general interest, such as: the evolution and development of the brain, including (for instance) the evolutionary-developmental pathway supporting primate tool use and human language; the degree of modularity in brain organization; the degree of localization of cognitive function; and the cortical parcellation problem and the prospects (and proper methods to employ) for function to structure mapping. The idea also has some practical implications in the areas of rehabilitative medicine and machine interface design. (shrink)

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Evolutionary theories of morality, beginning with Darwin, have focused on explanations for altruism. More generally, these accounts have concentrated on conscience to the neglect of condemnation. As a result, few theoretical tools are available for understanding the rapidly accumulating data surrounding third-party judgment and punishment. Here we consider the strategic interactions among actors, victims, and third-parties to help illuminate condemnation. We argue that basic differences between the adaptive problems faced by actors and third-parties indicate that actor conscience and third-party condemnation (...) are likely performed by different cognitive mechanisms. Further, we argue that current theories of conscience do not easily explain its experimentally demonstrated insensitivity to consequences. However, these results might be explicable if conscience functions, in part, as a defense system for avoiding third-party punishment. If conscience serves defensive functions, then its computational structure should be closely tailored to the details of condemnation mechanisms. This possibility underscores the need for a better understanding of condemnation, which is important not only in itself but also for explaining the nature of conscience. We outline three evolutionary mysteries of condemnation that require further attention: third-party judgment, moralistic punishment, and moral impartiality. (shrink)

Second, this collection of cognitive programs evolved in the Pleistocene to solve the adaptive problems regularly faced by our hunter-gatherer ancestors-...

To understand the human capacity for psychological altruism, one requires a proper understanding of how people actually think and feel. This paper addresses the possible relevance of recent findings in experimental economics and neuroeconomics to the philosophical controversy over altruism and egoism. After briefly sketching and contextualizing the controversy, we survey and discuss the results of various studies on behaviourally altruistic helping and punishing behaviour, which provide stimulating clues for the debate over psychological altruism. On closer analysis, these studies prove (...) less relevant than originally expected because the data obtained admit competing interpretations – such as people seeking fairness versus people seeking revenge. However, this mitigated conclusion does not preclude the possibility of more fruitful research in the area in the future. Throughout our analysis, we provide hints for the direction of future research on the question. (shrink)

Economists and biologists have proposed a distinction between two mechanisms – “strong” and “weak” reciprocity – that may explain the evolution of human sociality. Weak reciprocity theorists emphasize the benefits of long-term cooperation and the use of low-cost strategies to deter free-riders. Strong reciprocity theorists, in contrast, claim that cooperation in social dilemma games can be sustained by costly punishment mechanisms, even in one-shot and finitely repeated games. To support this claim, they have generated a large body of evidence concerning (...) the willingness of experimental subjects to punish uncooperative free-riders at a cost to themselves. In this article, I distinguish between a “narrow” and a “wide” reading of the experimental evidence. Under the narrow reading, punishment experiments are just useful devices to measure psychological propensities in controlled laboratory conditions. Under the wide reading, they replicate a mechanism that supports cooperation also in “real-world” situations outside the laboratory. I argue that the wide interpretation must be tested using a combination of laboratory data and evidence about cooperation “in the wild.” In spite of some often-repeated claims, there is no evidence that cooperation in the small egalitarian societies studied by anthropologists is enforced by means of costly punishment. Moreover, studies by economic and social historians show that social dilemmas in the wild are typically solved by institutions that coordinate punishment, reduce its cost, and extend the horizon of cooperation. The lack of field evidence for costly punishment suggests important constraints about what forms of cooperation can or cannot be sustained by means of decentralised policing. (shrink)

Many weaknesses of game theory are cured by new models that embody simple cognitive principles, while maintaining the formalism and generality that makes game theory useful. Social preference models can generate team reasoning by combining reciprocation and correlated equilibrium. Models of limited iterated thinking explain data better than equilibrium models do; and they self-repair problems of implausibility and multiplicity of equilibria.

Modularity has been the subject of intense debate in the cognitive sciences for more than 2 decades. In some cases, misunderstandings have impeded conceptual progress. Here the authors identify arguments about modularity that either have been abandoned or were never held by proponents of modular views of the mind. The authors review arguments that purport to undermine modularity, with particular attention on cognitive architecture, development, genetics, and evolution. The authors propose that modularity, cleanly defined, provides a useful framework for directing (...) research and resolving debates about individual cognitive systems and the nature of human evolved cognition. Modularity is a fundamental property of living things at every level of organization; it might prove indispensable for understanding the structure of the mind as well. (shrink)

Mind perception entails ascribing mental capacities to other entities, whereas moral judgment entails labeling entities as good or bad or actions as right or wrong. We suggest that mind perception is the essence of moral judgment. In particular, we suggest that moral judgment is rooted in a cognitive template of two perceived minds—a moral dyad of an intentional agent and a suffering moral patient. Diverse lines of research support dyadic morality. First, perceptions of mind are linked to moral judgments: dimensions (...) of mind perception (agency and experience) map onto moral types (agents and patients), and deficits of mind perception correspond to difficulties with moral judgment. Second, not only are moral judgments sensitive to perceived agency and experience, but all moral transgressions are fundamentally understood as agency plus experienced suffering—that is, interpersonal harm—even ostensibly harmless acts such as purity violations. Third, dyadic morality uniquely accounts for the phenomena of dyadic completion (seeing agents in response to patients, and vice versa), and moral typecasting (characterizing others as either moral agents or moral patients). Discussion also explores how mind perception can unify morality across explanatory levels, how a dyadic template of morality may be developmentally acquired, and future directions. (shrink)

1 Adaptationism is a research strategy that seeks to identify adaptations and the specific selective forces that drove their evolution in past environments. Since the mid-1970s, paleontologist Stephen J. Gould and geneticist Richard Lewontin have been critical of adaptationism, especially as applied toward understanding human behavior and cognition. Perhaps the most prominent criticism they made was that adaptationist explanations were analogous to Rudyard Kipling's Just So Stories. Since storytelling is an inherent part of science, the criticism refers to the acceptance (...) of stories without sufficient empirical evidence. In particular, Gould, Lewontin, and their colleagues argue that adaptationists often use inappropriate evidentiary standards for identifying adaptations and their functions, and that they often fail to consider alternative hypotheses to adaptation. Playing prominently in both of these criticisms are the concepts of constraint, spandrel, and exaptation. In this article we discuss the standards of evidence that could be used to identify adaptations and when and how they may be appropriately used. Moreover, building an empirical case that certain features of a trait are best explained by exaptation, spandrel, or constraint requires demonstrating that the trait's features cannot be better accounted for by adaptationist hypotheses. Thus, we argue that the testing of alternatives requires the consideration, testing, and systematic rejection of adaptationist hypotheses. Where possible, we illustrate our points with examples taken from human behavior and cognition. Key Words: adaptation; ADHD; brain allometry; constraint; epistemology; evolutionary psychology; exaptation; female orgasm ; optimization; special design; waist-hip ratio. Footnotes1 The authors contributed equally to this paper. Order of authorship was determined alphabetically. Correspondence may be addressed to any of the authors. (shrink)

Human nature is enigmatic. Are we cruel, selfish creatures or good merciful Samaritans? This book takes you on a journey into the complexities of human mind and kind, from altruism, sharing, and large-scale cooperation, to cheating, distrust, and warfare. What are the building blocks of morality and sociality? Featuring contributions from leading researchers, such as Christophe Boesch, Leda Cosmides and John Tooby, Azar Gat, Dennis Krebs, Ara Norenzayan, and Frans B. M. de Waal, this fascinating interdisciplinary reader draws on evolutionary (...) and comparative perspectives, and is essential reading for any students interested in the unique characteristics that define humanity and society. (shrink)