In Norms in the Wild, distinguished philosopher Cristina Bicchieri argues that when it comes to human behavior, social scientists place too much stress on rational deliberation. In fact, she says, many choices occur without much deliberation at all. Two people passing in a corridor automatically negotiate their shared space; cars at an intersection obey traffic signals; we choose clothing based on our instincts for what is considered appropriate. Bicchieri's theory of social norms accounts for these automatic components (...) of coordination, where individuals react automatically to cues that focus their attention on what the norm is in that situation. Social norms thus act as rules for making choices in a social world where people expect others -- often unconsciously -- to follow the same rule. Some norms enable seamless social co-operation, while others are less beneficial to human flourishing.Bicchieri is famous for her interdisciplinary work on game theory and most recently her work on social norms, and Norms in the Wild represents her latest challenge to many of the fundamental assumptions of the social sciences. Bicchieri's work has broad implications not only for understanding human behavior, but for changing it for better outcomes. People have a strongly conditioned preference for following social norms, but that also means that manipulating their expectations can cause major behavioral changes. Bicchieri has been working recently with UNICEF and other NGO's to explore the applicability of her views to issues of human rights around the world. Is it possible to change social expectations around forced marriage, genital mutilations, and public health practices like vaccinations and sanitation? If so, how? What tools might we use? This short book explores how social norms work, and how changing them - changing preferences, beliefs, and especially social expectations - can potentially improve lives all around the world. It will appeal to an unusually broad range of readers including philosophers, psychologists and others in behavioral sciences, and anyone involved in public policy or at NGOs. (shrink)

In The Grammar of Society, first published in 2006, Cristina Bicchieri examines social norms, such as fairness, cooperation, and reciprocity, in an effort to understand their nature and dynamics, the expectations that they generate, and how they evolve and change. Drawing on several intellectual traditions and methods, including those of social psychology, experimental economics and evolutionary game theory, Bicchieri provides an integrated account of how social norms emerge, why and when we follow them, and the situations where (...) we are most likely to focus on relevant norms. Examining the existence and survival of inefficient norms, she demonstrates how norms evolve in ways that depend upon the psychological dispositions of the individual and how such dispositions may impair social efficiency. By contrast, she also shows how certain psychological propensities may naturally lead individuals to evolve fairness norms that closely resemble those we follow in most modern societies. (shrink)

:This essay investigates the relationships among scripts, schemata, and social norms. The authors examine how social norms are triggered by particular schemata and are grounded in scripts. Just as schemata are embedded in a network, so too are social norms, and they can be primed through spreading activation. Moreover, the expectations that allow a social norm’s existence are inherently grounded in particular scripts and schemata. Using interventions that have targeted gender norms, open defecation, female genital cutting, and other collective issues (...) as examples, the authors argue that ignoring the cognitive underpinnings of a social norm can hamper the effectiveness of behavioral interventions. (shrink)

This book explores how individual actions coordinate to produce unintended social consequences. In the past this phenomenon has been explained as the outcome of rational, self-interested individual behaviour. Professor Bicchieri shows that this is in no way a satisfying explanation. She discusses how much knowledge is needed by agents in order to coordinate successfully. If the answer is unbounded knowledge, then a whole variety of paradoxes arise. If the answer is very little knowledge, then there seems hardly any possibility (...) of attaining coordination. The solution to coordination and cooperation is for agents to learn about each other. The author concludes that rationality must be supplemented by models of learning and by an evolutionary account of how social order can persist. (shrink)

This book explores how individual actions coordinate to produce unintended social consequences. In the past this phenomenon has been explained as the outcome of rational, self-interested individual behaviour. Professor Bicchieri shows that this is in no way a satisfying explanation. She discusses how much knowledge is needed by agents in order to coordinate successfully. If the answer is unbounded knowledge, then a whole variety of paradoxes arise. If the answer is very little knowledge, then there seems hardly any possibility (...) of attaining coordination. The solution to coordination and cooperation is for agents to learn about each other. The author concludes that rationality must be supplemented by models of learning and by an evolutionary account of how social order can persist. (shrink)

During the Nineties Italian politics underwent major changes. Following the uncovering of systemic corruption, the current political establishment was wiped out. The system of representation at both the national and local level underwent a significant transformation that improved voters’ control over their elected representatives. We argue that both events were the consequence of citizens’ demand for greater accountability of public officers. We model the relationship between voters and politicians as a repeated Trust game. In such game, cooperation can be attained (...) by means of external or internal controls. Whereas judicial investigation is an external monitoring mechanism, the electoral reform provides controls internal to the political system. We explain the Italian transition between these different modes of control and show under which conditions a cooperative equilibrium can be established in which voters trust their representatives who in turn act in the public interest. (shrink)

How is one to act so as to do as well as possible according to one’s ranking of the possible outcomes? How—as it may be put—is one to act rationally? Sometimes the possible outcomes are not under one’s own control: an outcome is a combination of one’s own and another agent’s action. Often, then, one must try to work out what the other agent will do, in order to do as well as possible in one’s own lights. It is situations (...) of this sort—situations of “strategic interaction”—that most concern the game theorist. (shrink)

A descriptive norm is a behavioral rule that individuals follow when their empirical expectations of others following the same rule are met. We aim to provide an account of the emergence of descriptive norms by first looking at a simple case, that of the standing ovation. We examine the structure of a standing ovation, and show it can be generalized to describe the emergence of a wide range of descriptive norms.

What is considered to be fair depends on context-dependent expectations. Using a modified version of the Ultimatum Game, we demonstrate that both fair behavior and perceptions of fairness depend upon beliefs about what one ought to do in a situation—that is, upon normative expectations. We manipulate such expectations by creating informational asymmetries about the offer choices available to the Proposer, and find that behavior varies accordingly. Proposers and Responders show a remarkable degree of agreement in their beliefs about which choices (...) are considered fair. We discuss how these results fit into a theory of social norms. (shrink)

Often, when several norms are present and may be in conflict, individuals will display a self-serving bias, privileging the norm that best serves their interests. Xiao and Bicchieri (J Econ Psychol 31(3):456–470, 2010) tested the effects of inequality on reciprocating behavior in trust games and showed that—when inequality increases—reciprocity loses its appeal. They hypothesized that self-serving biases in choosing to privilege a particular social norm occur when the choice of that norm is publicly justifiable as reasonable, even if not (...) optimal for one of the parties. In line with the literature on motivated reasoning, this justification should find some degree of support among third parties. The results of our experimental survey of third parties support the hypothesis that biases are not always unilateral selfish assessments. Instead, they occur when the choice to favor a particular norm is supported by a shared sense that it is a reasonable and justifiable choice. (shrink)

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)

Using an economic bargaining game, we tested for the existence of two phenomena related to social norms, namely norm manipulation – the selection of an interpretation of the norm that best suits an individual – and norm evasion – the deliberate, private violation of a social norm. We found that the manipulation of a norm of fairness was characterized by a self-serving bias in beliefs about what constituted normatively acceptable behaviour, so that an individual who made an uneven bargaining offer (...) not only genuinely believed it was fair, but also believed that recipients found it fair, even though recipients of the offer considered it to be unfair. In contrast, norm evasion operated as a highly explicit process. When they could do so without the recipient's knowledge, individuals made uneven offers despite knowing that their behaviour was unfair. (shrink)

The difficulty of defining rational behavior in game situations is that the players'' strategies will depend on their expectations about other players'' strategies. These expectations are beliefs the players come to the game with. Game theorists assume these beliefs to be rational in the very special sense of beingobjectively correct but no explanation is offered of the mechanism generating this property of the belief system. In many interesting cases, however, such a rationality requirement is not enough to guarantee that an (...) equilibrium will be attained. In particular, I analyze the case of multiple equilibria, since in this case there exists a whole set of rational beliefs, so that no player can ever be certain that the others believe he has certain beliefs. In this case it becomes necessary to explicitly model the process of belief formation. This model attributes to the players a theory of counterfactuals which they use in restricting the set of possible equilibria. If it were possible to attribute to the players the same theory of counterfactuals, then the players'' beliefs would eventually converge. (shrink)

In the social sciences norms are sometimes taken to play a key explanatory role. Yet norms differ from group to group, from society to society, and from species to species. How are norms formed and how do they change? This 'state-of-the-art' collection of essays presents some of the best contemporary research into the dynamic processes underlying the formation, maintenance, metamorphosis and dissolution of norms. The volume combines formal modelling with more traditional analysis, and considers biological and cultural evolution, individual learning, (...) and rational deliberation. In filling a significant gap in the current literature this volume will be of particular interest to economists, political scientists and sociologists, in addition to philosophers of the social sciences. (shrink)

University of Pennsylvania, USA, el322{at}nyu.edu ' + u + '@' + d + ' '//--> One of the most consistent findings in experimental studies of social dilemmas is the positive influence of face-to-face communication on cooperation. The face-to-face `communication effect' has been recently explained in terms of a `focus theory of norms': successful communication focuses agents on pro-social norms, and induces preferences and expectations conducive to cooperation. 1 Many of the studies that point to a communication effect, however, do not (...) further explore whether and to what extent the communication medium affects cooperative behavior. In this article, we ask if pro-social behavior can emerge and survive in computer-mediated environments. We show that, like face-to-face communication, computer-mediated communication also positively affects cooperation in social dilemmas, but cooperation is more difficult to establish and maintain. We argue that the discrepancy between the computer-mediated and the face-to-face communication effects is a consequence of the distinct capabilities of different media to focus agents on pro-social norms and to allow them to develop mutual expectations about future behavior. Key Words: social dilemmas • laboratory experiments • communication • social norms • cooperation • computer-mediated communication. (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.

This article addresses several issues raised by Nichols, Gintis, and Skyrms and Zollman in their comments on my book, The Grammar of Society: The Nature and Dynamics of Social Norms . In particular, I explore the relation between social and personal norms, what an adequate game-theoretic representation of norms should be, and what models of norms emergence should tell us about the formation of normative expectations.

A large class of games is that of non-cooperative, extensive form games of perfect information. When the length of these games is finite, the method used to reach a solution is that of a backward induction. Working from the terminal nodes, dominated strategies are successively deleted and what remains is a unique equilibrium. Game theorists have generally assumed that the informational requirement needed to solve these games is that the players have common knowledge of rationality. This assumption, however, has given (...) rise to several problems and paradoxes. Most notably, it has been shown that the common knowledge assumption makes the theory of the game inconsistent at some information set. The present paper shows that a) no common knowledge of rationality need be assumed for the backward induction solution to hold. Rather, it is sufficient that the players have a number of levels of knowledge proportional to the length of the game, and b) it is also necessary that the number of levels of knowledge is finite and proportional to the length of the game. For a higher number of levels of knowledge, inconsistencies arise. (shrink)

:Recent behavioral economics studies have shown that third parties compensate players in Dictator, Ultimatum, and Trust games. However, there are almost no studies about what drives third parties to compensate victims in such games. It can be argued that compensation is a form of helping; and helping behavior, in a variety of forms, has been widely researched, especially with regard to motivators. Previous work on helping behavior has focused on empathic concern as a primary driver. In sharp contrast, anger is (...) often seen as an antisocial motivator resulting in aggression. However, other research has shown that moral outrage, anger evoked by the violation of a moral rule or a social norm, can lead to the punishment of a perpetrator, often described as altruistic or pro-social punishment. Some of the motivations for pro-social punishment, namely a concern for justice or the restoration of community values, can also be realized through victim compensation. We therefore propose the hypothesis that moral outrage leads to compensating behavior above and beyond what is predicted by empathic concern, but only when a social norm has been violated. We test this hypothesis in two studies, both of which use modified trust games in which the investor experiences a loss due either to a social norm violation or some other cause. Study 1 shows that trait moral outrage predicts third-party compensatory behavior above and beyond empathic concern, but only when a social norm is violated. To better understand the causal mechanism, Study 2 directly manipulated moral outrage, showing again that moral outrage leads to compensation, but only when a social norm is violated. View HTML Send article to KindleTo send this article to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle. Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply. Find out more about the Kindle Personal Document Service.I’M SO ANGRY I COULD HELP YOU: MORAL OUTRAGE AS A DRIVER OF VICTIM COMPENSATIONVolume 32, Issue 2Erik W. Thulin and Cristina Bicchieri DOI: https://doi.org/10.1017/S0265052516000145Your Kindle email address Please provide your Kindle [email protected]@kindle.com Available formats PDF Please select a format to send. By using this service, you agree that you will only keep articles for personal use, and will not openly distribute them via Dropbox, Google Drive or other file sharing services. Please confirm that you accept the terms of use. Cancel Send ×Send article to Dropbox To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about sending content to Dropbox. I’M SO ANGRY I COULD HELP YOU: MORAL OUTRAGE AS A DRIVER OF VICTIM COMPENSATIONVolume 32, Issue 2Erik W. Thulin and Cristina Bicchieri DOI: https://doi.org/10.1017/S0265052516000145Available formats PDF Please select a format to send. By using this service, you agree that you will only keep articles for personal use, and will not openly distribute them via Dropbox, Google Drive or other file sharing services. Please confirm that you accept the terms of use. Cancel Send ×Send article to Google Drive To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about sending content to Google Drive. I’M SO ANGRY I COULD HELP YOU: MORAL OUTRAGE AS A DRIVER OF VICTIM COMPENSATIONVolume 32, Issue 2Erik W. Thulin and Cristina Bicchieri DOI: https://doi.org/10.1017/S0265052516000145Available formats PDF Please select a format to send. By using this service, you agree that you will only keep articles for personal use, and will not openly distribute them via Dropbox, Google Drive or other file sharing services. Please confirm that you accept the terms of use. Cancel Send ×Export citation Request permission. (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.

Subjects communicated prior to playing trust games; the richness of the communication media and the topics of conversation were manipulated. Communication richness failed to produce significant differences in first-mover investments. However, the topics of conversation made a significant difference: the amounts sent were considerably higher in the unrestricted communication conditions than in the restricted communication and no-communication conditions. Most importantly, we find that first-movers' expectations of second-movers' reciprocation are influenced by communication and strongly predict their levels of investment.

There has been a great deal of interaction among game theorists, philosophers and logicians in certain foundational problems concerning rationality, the formalization of knowledge and practical reasoning, and models of learning and deliberation. This volume brings together the work of some of the pre-eminent figures in their respective disciplines, all of whom are engaged in research at the forefront of their fields. Together they offer a conspectus of the interaction of game theory, logic and epistemology in the formal models of (...) knowledge, belief, deliberation and learning, and in the relationship between Bayesian decision theory and game theory, as well as between bounded rationality and computational complexity. (shrink)

Experimental results in Ultimatum, Trust and Social Dilemma games have been interpreted as showing that individuals are, by and large, not driven by selfish motives. But we do not need experiments to know that. In our view, what the experiments show is that the typical economic auxiliary hypothesis of non-tuism should not be generalized to other contexts. Indeed, we know that when the experimental situation is framed as a market interaction, participants will be more inclined to keep more money, share (...) less, and disregard other participants’ welfare [Hoffman et al., 1994]. When the same game is framed as a fair division one, participants overall show a much greater concern for the other parties’ interests. The data thus indicate that the context of an interaction is of paramount importance in eliciting different motives. The challenge then is to model utility functions that are general enough to subsume a variety of motives and specific enough to allow for meaningful, interesting predictions to be made. For the sake of simplicity (and brevity), in what follows we will concentrate upon the results of experiments that show what appears to be individuals’ disposition to behave in a fair manner in a variety of circumstances [Camerer, 2003]., though what we are saying can be easily applied to other research areas. Such experimental results have been variously interpreted, each interpretation being accompanied by a specific utility function. We shall consider three such functions and the underlying interpretations that support them, and assess each one on the basis of what they claim to be able to explain and predict. (shrink)

Not so long ago, many economists and philosophers felt that their disciplines had no use for experimental methods. An experimental study was, by its nature, ‘not economics’ or ‘not philosophy’ – psychology maybe. Opinion has changed dramatically. This issue of Economics and Philosophy represents a collection of recent contributions to experimental research that explicitly deal with empirical findings or methodological questions in the intersection of the two disciplines. To the best of our knowledge, it is the first such collection dedicated (...) to addressing these common interests. (shrink)

Bicchieri's topic is the modeling of interaction between decision makers in situations in which the outcome of the interaction depends on what the parties jointly do. Examples include chess, firms competing for business, politicians competing for votes, jury members deciding on a verdict, animals fighting over prey, bidders competing in auctions, threats and punishments in long-term relationships. Rationality assumptions are a basic ingredient of game theory, but though rational choice might be unproblematic in normative decision theory, it becomes problematic (...) in interactive contexts, where the outcome of one’s choice depends on the actions of other agents. Another basic ingredient is the idea of equilibrium play: roughly, an equilibrium is a combination of strategies, one for each player, such that each player’s strategy is a best reply to the other players’ choices. Thus it is individually rational for each agent to play her equilibrium strategy; but, notoriously, such individually rational play can lead to sub-optimal outcomes, as in the well-known prisoner’s dilemma. The relationship between rationality assumptions and equilibrium play is Bicchieri’s main focus. (shrink)

Social cooperation often relies on individuals’ spontaneous norm obedience when there is no punishment for violation or reward for compliance. However, people do not consistently follow pro-social norms. Previous studies have suggested that an individual’s tendency toward norm conformity is affected by empirical information (i.e., what others did or would do in a similar situation) as well as by normative information (i.e., what others think one ought to do). Yet little is known about whether people have an intrinsic desire to (...) obtain norm-revealing information. In this paper, we use a dictator game to investigate whether dictators actively seek norm-revealing information and, if so, whether they prefer to get empirical or normative information. Our data show that although the majority of dictators choose to view free information before making decisions, they are equally likely to choose empirical or normative information. However, a large majority (more than 80%) of dictators are not willing to incur even a very small cost for getting information. Our findings help to understand why norm compliance is context-dependent, and highlight the importance of making norm-revealing information salient in order to promote conformity. (shrink)

“How social norms change” is not only a theoretical question but also an empirical one. Many organizations have implemented programs to abandon harmful social norms. These programs are standardly monitored and evaluated with a set of empirical tools. While monitoring and evaluation (M&E) of changes in objective outcomes and behaviors is well developed, we will argue that M&E of changes in the wide range of beliefs and preferences important to social norms is still problematic. In this paper, we first present (...) a theoretical framework and then show how it should guide social norms measurement. As a case study, we focus on the harmful practice of child marriage. We show how an operational theory of social norms can guide the design of surveys, experiments and vignettes. We use examples from existing research to illustrate how to study social norms change. (shrink)

It is usually assumed in game theory that agents who interact strategically with each other are rational, know the strategies open to other agents as well as their payoffs and, moreover, have common knowledge of all the above. In some games, that much information is sufficient for the players to identify a "solution" and play it. The most commonly adopted solution concept is that of Nash equilibrium. A Nash equilibrium is defined a combination of strategies, one for each player, such (...) that no player can profit from a deviation from his strategy if the opponents stick to their strategies. Nash equilibrium is taken to have predictive power, in the sense that in order to predict how rational agents will in fact behave, it is enough to identify the equilibrium patterns of actions. Barring the case in which players have dominant strategies, to play her part in a Nash equilibrium a player must believe that the other players play their part, too. But an intelligent player must immediately realize that she has no ground for this belief. Take the case of a one-shot, simultaneous game. Here all undominated strategies are possible choices, and the beliefs supporting them are possible beliefs, even if this game has a.. (shrink)

We analyze common reasoning about admissibility in the strategic and extensive form of a game. We define a notion of sequential proper admissibility in the extensive form, and show that, in finite extensive games with perfect recall, the strategies that are consistent with common reasoning about sequential proper admissibility in the extensive form are exactly those that are consistent with common reasoning about admissibility in the strategic form representation of the game. Thus in such games the solution given by common (...) reasoning about admissibility does not depend on how the strategic situation is represented. We further explore the links between iterated admissibility and backward and forward induction. (shrink)

We present an axiomatic approach for a class of finite, extensive form games of perfect information that makes use of notions like “rationality at a node” and “knowledge at a node.” We distinguish between the game theorist's and the players' own “theory of the game.” The latter is a theory that is sufficient for each player to infer a certain sequence of moves, whereas the former is intended as a justification of such a sequence of moves. While in general the (...) game theorist's theory of the game is not and need not be axiomatized, the players' theory must be an axiomatic one, since we model players as analogous to automatic theorem provers that play the game by inferring (or computing) a sequence of moves. We provide the players with an axiomatic theory sufficient to infer a solution for the game (in our case, the backwards induction equilibrium), and prove its consistency. We then inquire what happens when the theory of the game is augmented with information that a move outside the inferred solution has occurred. We show that a theory that is sufficient for the players to infer a solution and still remains consistent in the face of deviations must be modular. By this we mean that players have distributed knowledge of it. Finally, we show that whenever the theory of the game is group-knowledge (or common knowledge) among the players (i.e., it is the same at each node), a deviation from the solution gives rise to inconsistencies and therefore forces a revision of the theory at later nodes. On the contrary, whenever a theory of the game is modular, a deviation from equilibrium play does not induce a revision of the theory. (shrink)

The prelims comprise: Strategic Interaction Nash Equilibrium Normal‐form Refinements Games in Extensive Form Extensive‐form Refinements Selection by Evolution Notes.

The paper provides a framework for representing belief-contravening hypotheses in games of perfect information. The resulting t-extended information structures are used to encode the notion that a player has the disposition to behave rationally at a node. We show that there are models where the condition of all players possessing this disposition at all nodes (under their control) is both a necessary and a su cient for them to play the backward induction solution in centipede games. To obtain this result, (...) we do not need to assume that rationality is commonly known (as is done in [Aumann (1995)]) or commonly hypothesized by the players (as done in [Samet (1996)]). The proposed model is compared with the account of hypothetical knowledge presented by Samet in [Samet (1996)] and with other possible strategies for extending information structures with conditional propositions. (shrink)

How do socially imposed rules develop into internalized pro-social codes? In the article “From Bodo Ethics to Distributive Justice”, Russell Hardin discusses one of the central themes of his work: How we “export” social order from a small, insular community to a large, anonymous society. In Bodo’s small village, everyone knows everyone else, interactions are face-to-face, and people live relatively isolated from other communities. In this context, the social norms developed by the community are easily enforceable. But what about large, (...) anonymous societies, where monitoring is difficult and costly and sanctioning transgressions carries a greater risk? When unobserved, only someone with an inner motivation to behave in a socially beneficial way will continue to obey the informal rules. How such an inner motivation develops is a topic of debate in moral philosophy and psychology, especially whether pro-social decisions are a matter of rationality or are driven by emotions. Supporters of the emotional drivers of pro-social behavior argue that anger and empathy play an essential role. In this chapter, we will focus on the role of these emotions in compensatory and sanctioning behavior. (shrink)