Humans often behave altruistically towards strangers with no chance of reciprocation. From an evolutionary perspective, this is puzzling. The evolution of altruistic cooperative behavior—in which an organism’s action reduces its fitness and increases the fitness of another organism —only makes sense when it is directed at genetically related organisms or when one can expect the favor to be returned. Therefore, evolutionary theorists such as Sober and Wilson have argued that we should revise Neo-Darwininian evolutionary theory. They argue that human altruism (...) evolved through group selection in which groups of altruists were naturally selected because they had a comparative advantage over other groups. Wilson and Sober’s hypothesis attracted followers but is rejected by most of their peers. The heated debate between advocates and critics of group selection often suffers from a lack of conceptual clarity. In response, I set out to clearly distinguish ‘genetic’ from ‘cultural’ group selection and argue that the latter does not face the potentially debilitating problems plaguing the former. I defend the claim that human altruistic dispositions evolved through cultural group selection and gene-culture coevolution and offer empirical evidence in support. I also argue that actual altruistic behavior often goes beyond the kind of behavior humans have evolved to display. Conscious and voluntary reasoning processes, I show, have an important role in altruistic behavior. This is often overlooked in the scientific literature on human altruism. (shrink)

Friendship is commonly assumed to reduce strategic uncertainty and enhance tacit coordination. However, this assumption has never been tested across two opposite poles of coordination involving either strategic complementarity or substitutability. We had participants interact with friends or strangers in two classic coordination games: the stag-hunt game, which exhibits strategic complementarity and may foster “cooperation”, and the entry game, which exhibits strategic substitutability and may foster “competition”. Both games capture a frequent trade-off between a potentially high paying but uncertain option (...) and a low paying but safe alternative. We find that, relative to strangers, friends are more likely to choose options involving uncertainty in stag-hunt games, but the opposite is true in entry games. Furthermore, in stag-hunt games, friends “tremble” less between options, coordinate better and earn more, but these advantages are largely decreased or lost in entry games. We further investigate how these effects are modulated by risk attitudes, friendship qualities, and interpersonal similarities. (shrink)

This paper defends a challenge, inspired by arguments drawn from contemporary ordinary language philosophy and grounded in experimental data, to certain forms of standard philosophical practice. The challenge is inspired by contemporary philosophers who describe themselves as practicing “ordinary language philosophy”. Contemporary ordinary language philosophy can be divided into constructive and critical approaches. The critical approach to contemporary ordinary language philosophy has been forcefully developed by Avner Baz, who attempts to show that a substantial chunk of contemporary philosophy is fundamentally (...) misguided. I describe Baz’s project and argue that while there is reason to be skeptical of its radical conclusion, it conveys an important truth about discontinuities between ordinary uses of philosophically significant expressions (“know”, e.g.) and their use in philosophical thought experiments. I discuss some evidence from experimental psychology and behavioral economics indicating that there is a risk of overlooking important aspects of meaning or misinterpreting experimental results by focusing only on abstract experimental scenarios, rather than employing more diverse and more ecologically valid experimental designs. I conclude by presenting a revised version of the critical argument from ordinary language. (shrink)

Communication and content presents a comprehensive and foundational account of meaning based on new versions of situation theory and game theory. The literal and implied meanings of an utterance are derived from first principles assuming little more than the partial rationality of interacting agents. New analyses of a number of diverse phenomena – a wide notion of ambiguity and content encompassing phonetics, syntax, semantics, pragmatics, and beyond, vagueness, convention and conventional meaning, indeterminacy, universality, the role of truth in communication, semantic (...) change, translation, Frege’s puzzle of informative identities – are developed. Communication, speaker meaning, and reference are defined. Frege’s context and compositional principles are generalized and reconciled in a fixed-point principle, and a detailed critique of Grice, several aspects of Lewis, and some aspects of the Romantic conception of meaning are offered. Connections with other branches of linguistics, especially psycholinguistics, sociolinguistics, historical linguistics, and natural language processing, are explored. -/- The book will be of interest to scholars in philosophy, linguistics, artificial intelligence, and cognitive science. It should also interest readers in related fields like literary and cultural theory and the social sciences. (shrink)

The paper focuses on the issue of compatibility of social institution and convention. At first, it introduces the modest account of conventionality building on five distinctive features – interdependence, arbitrariness, mind-independence, spontaneity, and normative-neutrality – which constitute conventional behaviour, then it presents the two major theories of social institutions that explain them in terms of rules, or equilibria. The argument is that conventions cover a wide-ranging area and cannot be identified with the category of institutions because it would be too (...) restrictive and contradictory to the initial modest account. (shrink)

This paper presents considerations on altruism and prosocial behaviour formulated on the basis of some experiments with the ultimatum game. In the first part it will discuss relations between expected utility theories, the characteristics of homo oeconomicus and a modern understanding of altruism. It will focus in particular on conceptual differences, indicating that we can find more than one definition of altruism in modern literature. The second part of the text will provide an overview of selected behavioural theories of prosocial (...) behaviour. It will also present the manner in which needs, social determinants, norms, and individual psychological features affect the propensity to behave in a prosocial fashion. (shrink)

We argue that attempts to extrapolate moral motives for non-egoistic behavior in organizational behavior often interpret results empathically or deontically, while leaving other moral motivational frames, such as the utilitarian and virtue ethical, under-examined. We encourage the creation of experimental measures to distinguish various philosophical frames.

The widespread assumption that anger is a response to wrongdoing and motivates people to sanction it, as well as the lack of distinction between resentment and indignation, obscure notable differences among these three emotions in terms of their specific beliefs, goals, and action tendencies, their nonmoral or moral character, and the kinds of moral claim implied. We provide a cognitive-motivational analysis of anger, resentment, and indignation, showing that, while sharing a common core, they are distinguishable from one another because they (...) comprise nonoverlapping belief–goal compounds. We also emphasize the usefulness of applying a belief–goal analysis to kin emotions because, by comparison, one can sharpen the analysis and identify the distinctive features of each of them. (shrink)

How do people reason about their opponent in turn-taking games? Often, people do not make the decisions that game theory would prescribe. We present a logic that can play a key role in understanding how people make their decisions, by delineating all plausible reasoning strategies in a systematic manner. This in turn makes it possible to construct a corresponding set of computational models in a cognitive architecture. These models can be run and fitted to the participants’ data in terms of (...) decisions, response times, and answers to questions. We validate these claims on the basis of an earlier game-theoretic experiment about the turn-taking game “Marble Drop with Surprising Opponent”, in which the opponent often starts with a seemingly irrational move. We explore two ways of segregating the participants into reasonable “player types”. The first way is based on latent class analysis, which divides the players into three classes according to their first decisions in the game: Random players, Learners, and Expected players, who make decisions consistent with forward induction. The second way is based on participants’ answers to a question about their opponent, classified according to levels of theory of mind: zero-order, first-order and second-order. It turns out that increasing levels of decisions and theory of mind both correspond to increasing success as measured by monetary awards and increasing decision times. Next, we use the logical language to express different kinds of strategies that people apply when reasoning about their opponent and making decisions in turn-taking games, as well as the ‘reasoning types’ reflected in their behavior. Then, we translate the logical formulas into computational cognitive models in the PRIMs architecture. Finally, we run two of the resulting models, corresponding to the strategy of only being interested in one’s own payoff and to the myopic strategy, in which one can only look ahead to a limited number of nodes. It turns out that the participant data fit to the own-payoff strategy, not the myopic one. The article closes the circle from experiments via logic and cognitive modelling back to predictions about new experiments. (shrink)

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)

The ten original studies included in this Research Topic investigate selected assumptions and predictions of parochial altruism theory in detail. We, the editors, are convinced that their highly instructive findings will help researchers interested in parochial altruism, but also in intergroup psychology more generally, to gain a much more fine-grained understanding of the interplay of altruistic and spiteful motives in human decision making in the context of intergroup relations. The broad range of disciplines represented by the authors contributing to this (...) Research Topic and the variety of methods used in their studies are representative for the current interdisciplinary interest in parochial altruism. The most important insight that, in our view, can be derived from the works collected here is that human decision making in intergroup contexts is more complex than suggested by current theory. Thus, we hope that future theorizing on parochial altruism will be stimulated by the evidence gathered in this Research Topic. In this editorial, we briefly highlight central findings reported here, which, to us, appear most informative for prospective enhancements of parochial altruism theory. (shrink)

This article takes off from Johan van Benthem’s ruminations on the interface between logic and cognitive science in his position paper “Logic and reasoning: Do the facts matter?”. When trying to answer Van Benthem’s question whether logic can be fruitfully combined with psychological experiments, this article focuses on a specific domain of reasoning, namely higher-order social cognition, including attributions such as “Bob knows that Alice knows that he wrote a novel under pseudonym”. For intelligent interaction, it is important that the (...) participants recursively model the mental states of other agents. Otherwise, an international negotiation may fail, even when it has potential for a win-win solution, and in a time-critical rescue mission, a software agent may depend on a teammate’s action that never materializes. First a survey is presented of past and current research on higher-order social cognition, from the various viewpoints of logic, artificial intelligence, and psychology. Do people actually reason about each other’s knowledge in the way proscribed by epistemic logic? And if not, how can logic and cognitive science productively work together to construct more realistic models of human reasoning about other minds? The paper ends with a delineation of possible avenues for future research, aiming to provide a better understanding of higher-order social reasoning. The methodology is based on a combination of experimental research, logic, computational cognitive models, and agent-based evolutionary models. (shrink)

A variety of theoretical approaches have been taken in an attempt to understand, explain, and promote pro-environmental behavior. The present article gives an overview, including specific applications, and identifies and discusses various strategies used by researchers to deal with the availability of different approaches. The overview includes elementary rational choice theory, the theory of planned behavior, norm-activation theory, theories of habitual behavior, and theories within a social dilemma framework. Strategies identified are ‘extending existing theories by single explanatory factors’, ‘comparing theories’ (...) in a competitive manner, and ‘combining theories’ in an integrative manner. It is argued that research would benefit from more standardization in empirical applications, from more competitive theory testing as opposed to integrative theory testing, and from an evaluation of approaches on theoretical grounds as opposed to focusing solely on empirical performance. (shrink)

We analyze the dynamics of repeated interaction of two players in the Prisoner's Dilemma under various levels of interdependency information and propose an instance-based learning cognitive model to explain how cooperation emerges over time. Six hypotheses are tested regarding how a player accounts for an opponent's outcomes: the selfish hypothesis suggests ignoring information about the opponent and utilizing only the player's own outcomes; the extreme fairness hypothesis weighs the player's own and the opponent's outcomes equally; the moderate fairness hypothesis weighs (...) the opponent's outcomes less than the player's own outcomes to various extents; the linear increasing hypothesis increasingly weighs the opponent's outcomes at a constant rate with repeated interactions; the hyperbolic discounting hypothesis increasingly and nonlinearly weighs the opponent's outcomes over time; and the dynamic expectations hypothesis dynamically adjusts the weight a player gives to the opponent's outcomes, according to the gap between the expected and the actual outcomes in each interaction. When players lack explicit feedback about their opponent's choices and outcomes, results are consistent with the selfish hypothesis; however, when this information is made explicit, the best predictions result from the dynamic expectations hypothesis. (shrink)

Nous proposons dans ce texte une hypothèse explicative de la méfiance plus grande observée entre des individus différents les uns des autres sur un aspect identitaire jugé pertinent par ceux-ci. Nous débutons par présenter une esquisse de définition de la confiance et nous plaçons les normes de rationalité et de moralité au centre de cette définition. Nous faisons confiance à autrui pour qu’il respecte certaines normes explicites ou implicites. Cette définition nous permet d’éviter deux écueils : celui de considérer qu’il (...) est immoral de ne pas faire confiance à autrui, et celui de considérer qu’il est irrationnel de ne pas faire confiance à autrui. Nous ne pouvons donc pas critiquer la tendance à ne pas faire confiance à des individus différents d’un pont de vue moral ou rationnel. Nous terminons en proposant une hypothèse permettant d’expliquer comment peut émerger la méfiance entre individus différents. (shrink)

Existing economic models of prosociality have been rather silent in terms of proximate psychological mechanisms. We nevertheless identify the psychologically most informed accounts and offer a critical discussion of their hypotheses for the proximate psychological explanations. Based on convergent evidence from several fields of research, we argue that there nevertheless is a more plausible alternative proximate account available: the social motivation hypothesis. The hypothesis represents a more basic explanation of the appeal of prosocial behavior, which is in terms of anticipated (...) social rewards. We also argue in favor of our own social motivation hypothesis over Robert Sugden’s fellow-feeling account (due originally to Adam Smith). We suggest that social motivation not only stands as a proximate account in its own right but also provides a plausible scaffold for other more sophisticated motivations (e.g., fellow-feelings). We conclude by discussing some possible implications of the social motivation hypothesis on existing modeling practice. (shrink)

The paper presents a simulation of the dynamics of impersonal trust. It shows how a “trust and reciprocate” norm can emerge and stabilize in populations of conditional cooperators. The norm, or behavioral regularity, is not to be identified with a single strategy. It is instead supported by several conditional strategies that vary in the frequency and intensity of sanctions.

I discuss the possibility that there is no intrinsic unity to the capacities which are bundled under the label "folk psychology". Cooperative skills, attributional skills, and predictive skills may be scattered as parts of other non--psychological capacities. I discuss how some forms of social life bring these different skills together. I end with some remarks on how abilities that are not unified in their essential mechanisms may still form a rough practical unity. (Remark: the paper is conjectural. It describes a (...) possibility to take seriously rather than a conclusion of which I am convinced.). (shrink)

This article examines, experimentally, whether inequality affects the social capital of trust in non-market and market settings. We consider three experimental treatments, one with equality, one with inequality but no knowledge of the income of other agents, and one with inequality and knowledge. Inequality, particularly when it is known, has a corrosive effect on trusting behaviours in this experiment. Agents appear to be less sensitive to known relative income differentials in markets than they are in the non-market settings, but trust (...) in markets appears generally more vulnerable to the introduction of inequality than in the non-market setting. (shrink)

In this paper, we study the role of fairness motivation in bargaining. We show that bargaining between two strongly fairness motivated individuals who have different views about what represents a fair division may end in disagreement. Further, by applying the Nash bargaining solution, we study the influence of fairness motivation on the bargaining outcome when an agreement is reached. In particular, we show that the bargaining outcome is sensitive to the fairness motivation of the two individuals, unless they both consider (...) an equal division fair. We argue that our results accommodate existing experimental and field data on bargaining. (shrink)

The objective of this article is to investigate the impact of agent heterogeneity (as regards their attitude towards cooperation) and payoff structure on cooperative behaviour, using an experimental setting with incomplete information. A game of chicken is played considering two types of agents: ‘unconditional cooperators’, who always cooperate, and ‘strategic cooperators’, who do not cooperate unless it is in their interest to do so. Overall, our data show a much higher propensity to cooperate than predicted by theory. They also suggest (...) that agent heterogeneity matters: the higher the proportion of ‘strategic cooperators’ in the population, the higher their probability to cooperate. Finally, our data confirm that higher rewards to cooperation (embedded in the payoff structure) tend to lower defection. Taken together, our results suggest that the subjects might be non-expected utility maximizers, dealing with both outcomes and probabilities in a non-linear manner. (shrink)

Are the recent findings of Behavioural Game Theory (BGT) on unselfish behaviours relevant for the progress of game theory? Is the methodology of BGT, centred around the attempt to study theoretically players’ utility functions in the light of the feedback that experimental evidence can produce on the theory, a satisfactory one? Or is the creation of various types of ‘social preferences’ just wasteful tinkering? This article compares BGT with the methodology of Rational Game Theory (RGT). BGT is viewed as a (...) more promising and constructive approach, with regard to the relationship between experimental data and theoretical modelling. However, I also argue that today RGT and BGT are closer to one another than often thought. (shrink)

In public goods experiments, stochastic choice, censoring and motivational heterogeneity give scope for disagreement over the extent of unselfishness, and whether it is reciprocal or altruistic. We show that these problems can be addressed econometrically, by estimating a finite mixture model to isolate types, incorporating double censoring and a tremble term. Most subjects act selfishly, but a substantial proportion are reciprocal with altruism playing only a marginal role. Isolating reciprocators enables a test of Sugden’s model of voluntary contributions. We estimate (...) that reciprocators display a self-serving bias relative to the model. (shrink)

From an evolutionary standpoint, a default presumption is that true beliefs are adaptive and misbeliefs maladaptive. But if humans are biologically engineered to appraise the world accurately and to form true beliefs, how are we to explain the routine exceptions to this rule? How can we account for mistaken beliefs, bizarre delusions, and instances of self-deception? We explore this question in some detail. We begin by articulating a distinction between two general types of misbelief: those resulting from a breakdown in (...) the normal functioning of the belief formation system (e.g., delusions) and those arising in the normal course of that system's operations (e.g., beliefs based on incomplete or inaccurate information). The former are instances of biological dysfunction or pathology, reflecting “culpable” limitations of evolutionary design. Although the latter category includes undesirable (but tolerable) by-products of “forgivably” limited design, our quarry is a contentious subclass of this category: misbeliefs best conceived as design features. Such misbeliefs, unlike occasional lucky falsehoods, would have been systematically adaptive in the evolutionary past. Such misbeliefs, furthermore, would not be reducible to judicious – but doxastically1noncommittal – action policies. Finally, such misbeliefs would have been adaptive in themselves, constituting more than mere by-products of adaptively biased misbelief-producing systems. We explore a range of potential candidates for evolved misbelief, and conclude that, of those surveyed, onlypositive illusionsmeet our criteria. (shrink)

Helen Frowe has recently offered what she calls a “practical” account of self-defense. Her account is supposed to be practical by being subjectivist about permissibility and objectivist about liability. I shall argue here that Frowe first makes up a problem that does not exist and then fails to solve it. To wit, her claim that objectivist accounts of permissibility cannot be action-guiding is wrong; and her own account of permissibility actually retains an objectivist (in the relevant sense) element. In addition, (...) her attempt to restrict subjectivism primarily to “urgent” situations like self-defense contradicts her own point of departure and is either incoherent or futile. Finally, the only actual whole-heartedly objectivist account she criticizes is an easy target; while those objectivist accounts one finds in certain Western European jurisdictions are immune to her criticisms. Those accounts are also clearly superior to hers in terms of action-guidingness. (shrink)

A survey of some game-theoretic accounts of the emergence and evolution of spontaneuous cooperation in social and public-good dilemmas.

This article examines, experimentally, whether inequality affects the social capital of trust in non-market and market settings. We consider three experimental treatments, one with equality, one with inequality but no knowledge of the income of other agents, and one with inequality and knowledge. Inequality, particularly when it is known, has a corrosive effect on trusting behaviours in this experiment. Agents appear to be less sensitive to known relative income differentials in markets than they are in the non-market settings, but trust (...) in markets appears generally more vulnerable to the introduction of inequality than in the non-market setting. (shrink)

This paper presents the results of an experiment on mutual versus common knowledge of advice in a two-player weak-link game with random matching. Our experimental subjects play in pairs for thirteen rounds. After a brief learning phase common to all treatments, we vary the knowledge levels associated with external advice given in the form of a suggestion to pick the strategy supporting the payoff-dominant equilibrium. Our results are somewhat surprising and can be summarized as follows: in all our treatments both (...) the choice of the efficiency-inducing action and the percentage of efficient equilibrium play are higher with respect to the control treatment, revealing that even a condition as weak as mutual knowledge of level 1 is sufficient to significantly increase the salience of the efficient equilibrium with respect to the absence of advice. Furthermore, and contrary to our hypothesis, mutual knowledge of level 2 induces, under suitable conditions, successful coordination more frequently than common knowledge. (shrink)

Most definitions of cooperation provide sufficient but not necessary conditions. This paper describes a form of minimal cooperation, corresponding to mass actions implying many agents, such as demonstrations. It characterizes its intentional, epistemic, strategic, and teleological aspects, mostly obtained from weakening classical concepts. The rationality of minimal cooperation turns out to be part of its definition, whereas it is usually considered as an optional though desirable feature. Game-theoretic concepts thus play an important role in its definition. The paper concludes by (...) answering concrete questions about what should and should not be called cooperation. (shrink)

Recent years have witnessed an increased number of game-theoretic approaches to social norms, which apparently share some common vocabulary and methods. We describe three major approaches of this kind (due to Binmore, Bicchieri and Gintis), before comparing them systematically on five crucial themes: generality of the solution, preference transformation, punishment, epistemic conditions and type of explanation. This allows us to show that these theories are, by and large, less compatible than they seem. We then argue that those three theories struggle (...) to account for three phenomena pertaining to social norms (namely context-dependence, conflicting norms and self-evidence), with which any complete game-theoretic account should in principle be able to deal. (shrink)

This article presents a new proposal for understanding the establishment and maintenance of cooperation: the cooperation afforder with framing hypothesis, producing what can be called cooperation from afforder-framing . Three key moves are present. First, a special variety of the Stag Hunt game, the Cooperation Afforder game, will reliably produce mutualistic cooperation through an evolutionary process. Second, cognitive framing is a credible candidate mechanism to meet the special conditions and requirements of the Cooperation Afforder game. Third, once mutualistic cooperation is (...) established in this way, it will plausibly lead to broader forms of cooperation, even to limited forms of altruism. (shrink)

To a practitioner in the social sciences, game theory primarily helps to identify situations in which interdependent decisions are somehow problematic; solutions often require venturing into the social sciences. Game theory is usually about anticipating each other's choices; it can also cope with influencing other's choices. To a social scientist the great contribution of game theory is probably the payoff matrix, an accounting device comparable to the equals sign in algebra.

Understanding more about how the brain functionsshouldhelp us understand economic behaviour. But some would have us believe that it has done this already, and that insights from neuroscience have already provided insights in economics that we would not otherwise have. Much of this is just academic marketing hype, and to get down to substantive issues we need to identify that fluff for what it is. After we clear away the distractions, what is left? The answer is that a lot is (...) left, but it is still all potential. That is not a bad thing, or a reason to stop the effort, but it does point to the need for a serious reconsideration of what neuroeconomics is and what passes for explanation in this literature. I argue that neuroeconomics can be a valuable field, but not the way it is being developed and “sold” now. The same is true more generally of behavioural economics, which shares many of the methodological flaws of neuroeconomics. (shrink)

opinionated survey paper to be published in the Blackwell’s Philosophy Compass.

We develop an analysis of discourse anaphora—the relationship between a pronoun and an antecedent earlier in the discourse —using games of partial information. The analysis is extended to include information from a variety of different sources, including lexical semantics, contrastive stress, grammatical relations, and decision theoretic aspects of the context.

This paper examines the relevance of philosophical work on consciousness to its scientific study. Of particular concern is the debate over whether consciousness can be naturalized, which is typically taken to have consequences for the prospects for its scientific investigation. It is not at all clear that philosophers of consciousness have properly identified and evaluated the assumptions about scientific activity made by both naturalization and anti- naturalization projects. I argue that there is good reason to think that some of the (...) assumptions about physicalism and explanation made by the parties to the debate are open to serious doubt. Thus this paper is an invitation for those inquiring into whether consciousness can be naturalized to more carefully consider the expected payoff of such efforts. (shrink)

This study analyses behaviour in non-zero-sum finite multi-stage games, particularly the Centipede Game. The classical Nash Equilibrium fails to explain empirical behaviour and intuitive logic and has therefore been challenged. This paper introduces the ‘Pure Collective Equilibrium’, or PCE, which describes the equilibrium reached when agents assess their utility not by their own payoffs but by the mean collective payoff of the team, as outlined by some team-reasoning hypotheses. Classical behaviour and purely collective team reasoning then both represent special cases—the (...) first in which agents and their counterparts are on the Nash Equilibrium path, and the second in which agents and their counterparts are purely collective team reasoners. It is argued that agents intentionally and consistently deviate from classical rationality in the Centipede Game, even in the absence of philanthropic altruists or error-plagued populations. (shrink)

ABSTRACT The article aims at contributing to the unification of history and psychology by studying the expressions of anger and enthusiasm in several historical contexts. These mainly include France and America in the eighteenth century, but also more recent episodes of transitional justice. In addition it aims at drawing the attention of psychologist to the understudied emotion of enthusiasm. To this end, it also considers how Hume and Kant treated this emotion.

This paper explores the role of inequity aversion as an explanation for observed behavior in experimental Cournot oligopolies. We show that inequity aversion can change the nature of the strategic interaction: quantities are strategic substitutes for sufficiently asymmetric output levels but strategic complements otherwise. We find that inequity aversion can explain why: some experiments result in higher than Cournot–Nash production levels while others result in lower, collusion often occurs with only two players whereas with three or more players market outcomes (...) are very close to Cournot–Nash, and players often achieve equal profits in asymmetric Cournot oligopoly. (shrink)

Our discussion of the commentaries begins, at the evolutionary level, with issues raised by our account of the evolution of morality in terms of partner-choice mutualism. We then turn to the cognitive level and the characterization and workings of fairness. In a final section, we discuss the degree to which our fairness-based approach to morality extends to norms that are commonly considered moral even though they are distinct from fairness.

Previous literature has demonstrated the important role that trust plays in developing and maintaining well-functioning societies. However, if we are to learn how to increase levels of trust in society, we must first understand why people choose to trust others. One potential answer to this is that people view trust as normative: there is a social norm for trusting that imposes punishment for noncompliance. To test this, we report data from a survey with salient rewards to elicit people’s attitudes regarding (...) the punishment of distrusting behavior in a trust game. Our results show that people do not behave as though trust is a norm. Our participants expected that most people would not punish untrusting investors, regardless of whether the potential trustee was a stranger or a friend. In contrast, our participants behaved as though being trustworthy is a norm. Most participants believed that most people would punish someone who failed to reciprocate a stranger’s or a friend’s trust. We conclude that, while we were able to reproduce previous results establishing that there is a norm of reciprocity, we found no evidence for a corresponding norm of trust, even among friends. (shrink)

Naive physics beliefs can be systematically mistaken. They provide a useful test-bed because they are common, and also because their existence must rely on some adaptive advantage, within a given context. In the second part of the commentary we also ask questions about when a whole family of misbeliefs should be considered together as a single phenomenon.

Guala points to a discrepancy between strong negative reciprocity observed in the lab and the way cooperation is sustained This commentary suggests that in lab experiments, strong negative reciprocity is limited when uncertainty exists regarding the players' actions and the intentions. Thus, costly punishment is indeed a limited mechanism for sustaining cooperation in an uncertain environment.

Financial and prosocial biases in favor of attractive adults have been documented in the labor market, in social transactions in everyday life, and in studies involving experimental economic games. According to the taste-based discrimination model developed by economists, attractiveness-related financial and prosocial biases are the result of preferences or prejudices similar to those displayed toward members of a particular sex, racial, ethnic, or religious group. Other explanations proposed by economists and social psychologists maintain that attractiveness is a marker of personality, (...) intelligence, trustworthiness, professional competence, or productivity. Evolutionary psychologists have argued that attractive adults are favored because they are preferred sexual partners. Evidence that stereotypes about attractive people are causally related to financial or prosocial biases toward them is weak or nonexistent. Consistent with evolutionary explanations, biases in favor of attractive women appear to be more consistent or stronger than those in favor of attractive men, and biases are more consistently reported in interactions between opposite-sex than same-sex individuals. Evolutionary explanations also account for increased prosocial behavior in situations in which attractive individuals are simply bystanders. Finally, evolutionary explanations are consistent with the psychological, physiological, and behavioral changes that occur when individuals are exposed to potential mates, which facilitate the expression of courtship behavior and increase the probability of occurrence of mating. Therefore, multiple lines of evidence suggest that mating motives play a more important role in driving financial and prosocial biases toward attractive adults than previously recognized. (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)

In this response, we address eight issues concerning our proposal that human minds contain adaptations for revenge and forgiveness. Specifically, we discuss (a) the inferences that are and are not licensed by patterns of contemporary behavioral data in the context of the adaptationist approach; (b) the theoretical pitfalls of conflating proximate and ultimate causation; (c) the role of development in the production of adaptations; (d) the implications of proposing that the brain's cognitive systems are fundamentally computational in nature; (e) our (...) preferred method for considering the role of individual differences in computational systems; (f) applications of our proposal to understanding conflicts between groups; (g) the possible implications of our views for understanding the operation of contemporary criminal justice systems; and (h) the question of whether people ever “genuinely” forgive. (shrink)