The effect of exposure to eye images on various behaviors has been explained as a response to an ... more The effect of exposure to eye images on various behaviors has been explained as a response to an invalid cue of observation. This invalid cue interpretation has been supported by an experiment showing that a short exposure to eye images increased dictator game generosity, but a long exposure did not. We attempted to conceptually replicate that finding with a different dependent variable, and found no effect of short or long exposure to eye images on moral condemnation. Thus, we failed to replicate previous work showing an effect of eye images on condemnation and therefore these results do not inform the invalid cue hypothesis. We found that women condemned more strongly than men and discuss this finding in light of functional theories of moral condemnation.
People are more cooperative when explicitly observed, and simply exposing people to images of eye... more People are more cooperative when explicitly observed, and simply exposing people to images of eyes or faces has been shown to increase cooperation of various types and in various contexts, albeit with notable, if controversial, exceptions. This 'eyes effect' is important both for its potential real-world applications and for its implications regarding the role of reputation in the evolution and maintenance of human cooperation. Based on the general principle that organisms eventually cease responding to uninformative stimuli, we predicted that the eyes effect would be eliminated by prolonged exposure. A novel experiment confirmed that participants exposed briefly to an eye-like image gave more money in an economic game than those in a longer exposure condition and those in a control condition. There was no generosity difference between the long exposure and control conditions. Furthermore, a meta-analysis of 25 eyes effects experiments confirmed that the effect emerges reliably after short exposures to eye images, but not after long exposures. An understanding of the limits of false cues on behaviour helps resolve empirical discrepancies regarding the eyes effect and exonerates the importance of reputation even in anonymous, one-shot interactions.
Who takes risks, and why? Does risk-taking in one context predict risk-taking in other contexts? ... more Who takes risks, and why? Does risk-taking in one context predict risk-taking in other contexts? We seek to address these questions by considering two (non-independent) pathways to risk: need-based and ability-based. The need-based pathway suggests that risk-taking is a product of competitive disadvantage, consistent with risk-sensitivity theory. The ability-based pathway suggests that people engage in risk-taking when they possess abilities or traits that increase the probability of successful risk-taking, the expected value of the risky behavior itself, and/or have signalling value. We provide a conceptual model of decision-making under risk—the relative state model— that integrates both pathways and explicates how situational and embodied factors influence the estimated costs and benefits of risk-taking in different contexts. This model may help to reconcile longstanding disagreements and issues regarding the etiology of risk-taking, such as the domain-generality versus domain-specificity of risk or differential engagement in antisocial and non-antisocial risk-taking.
Humans reject uneven divisions of resources, even at personal cost. This is observed in countless... more Humans reject uneven divisions of resources, even at personal cost. This is observed in countless experiments using the ultimatum game, where a proposer offers to divide a resource with a responder who either accepts the division or rejects it (whereupon both earn zero). Researchers debate why humans evolved a psychology that is so averse to inequity within partnerships. We suggest that the scale of competition is crucial: under local competition with few competitors, individuals reject low offers, because they cannot afford to be disadvantaged relative to competitors. If one competes against the broader population (i.e. global competition), then it pays to accept low offers to increase one's absolute pay-off. We support this intuition with an illustrative game-theoretical model. We also conducted ultimatum games where participants received prizes based on pay-offs relative to immediate partners (local competition) versus a larger group (global competition). Participants demande...
Abstract Social organisms in many taxa cooperate to produce resources that are shared among group... more Abstract Social organisms in many taxa cooperate to produce resources that are shared among group members. Some cooperatively produced resources may be monopolized by individuals who invest in within-group competition, but these have largely been ...
Journal of Personality and Social Psychology, 2008
Cooperation among nonrelatives can be puzzling because cooperation often involves incurring costs... more Cooperation among nonrelatives can be puzzling because cooperation often involves incurring costs to confer benefits on unrelated others. Punishment of noncooperators can sustain otherwise fragile cooperation, but the provision of punishment suffers from a "second-order" free-riding problem because nonpunishers can free ride on the benefits from costly punishment provided by others. One suggested solution to this problem is second-order punishment of nonpunishers; more generally, the threat or promise of higher order sanctions might maintain the lower order sanctions that enforce cooperation in collective action problems. Here the authors report on 3 experiments testing people's willingness to provide second-order sanctions by having participants play a cooperative game with opportunities to punish and reward each other. The authors found that people supported those who rewarded cooperators either by rewarding them or by punishing nonrewarders, but people did not support those who punished noncooperators--they did not reward punishers or punish nonpunishers. Furthermore, people did not approve of punishers more than they did nonpunishers, even when nonpunishers were clearly unwilling to use sanctions to support cooperation. The results suggest that people will much more readily support positive sanctions than they will support negative sanctions.
The evolution of reciprocal altruism probably involved the evolution of mechanisms to detect chea... more The evolution of reciprocal altruism probably involved the evolution of mechanisms to detect cheating and remember cheaters. In a well-known study, observed that participants had enhanced memory for faces that had previously been associated with descriptions of acts of cheating. There were, however, problems with the descriptions that were used in that study. We sought to replicate and extend the findings of Mealey and colleagues by using more controlled descriptions and by examining the possibility of enhanced altruist recognition. We also examined whether individual differences in cheating tendencies were related to cheater and altruist recognition. In the first experiment, 164 undergraduates saw 40 faces that were paired with character descriptions representing the categories cheating, trustworthiness, altruism, or neutral, for individuals who had either low or high social status. One week later participants reported which faces they recognized from the previous week (among 80 faces). Overall, the results failed to replicate the findings of Mealey and her colleagues, as there was no enhanced memory for cheaters. In addition, there was no enhanced memory for altruists, and no effect of participants' cheating tendencies. A second experiment using a slightly different methodology produced similar results, with some evidence for enhanced memory for altruists.
Risk-sensitivity theory predicts that organisms are more likely to take risks when they are unlik... more Risk-sensitivity theory predicts that organisms are more likely to take risks when they are unlikely to achieve their goals through safer, low-risk means. Those who are competitively disadvantaged are less likely to succeed in social competition and should consequently show elevated risk taking. We experimentally tested this hypothesis by exposing participants to cues of relative competitive disadvantage or relative competitive advantage via feedback from a purported reaction time based intelligence test. Participants then made a number of high-risk or low-risk economic decisions (Experiment 1). Experiment 2 built on this design by either maintaining or ameliorating cues of relative competitive (dis)advantage. Results indicate that cues of relative competitive disadvantage leads to increased risk taking, and that risk taking can be reduced when cues of disadvantage are ameliorated. Since risk taking tends to generalize across domains, these results can potentially apply to a number of problematic risky behaviors.
Relatedness is a cornerstone of the evolution of social behavior. In the human lineage, the exist... more Relatedness is a cornerstone of the evolution of social behavior. In the human lineage, the existence of cooperative kin networks was likely a critical stepping stone in the evolution of modern social complexity. Here we report the results of the first experimental manipulation of a putative cue of human kinship (facial self-resemblance) among ostensible players in a variant of the "tragedy of the commons," the oneshot public goods game, in which group-level cooperation-via contributions made to the public good and the punishment of free riders-is supported at a personal cost. In accordance with theoretical predictions, contributions increased as a function of the "kin density" of the group. Moreover, the distribution of punishment was not contingent on kin density level. Our findings indicate that the presence of a subtle cue of genealogical relatedness facilitates group cooperation, supporting the hypothesis that the mechanisms fostering contemporary sociality took root in extended family networks.
Van de Vliert&amp... more Van de Vliert's findings may be explained by the psychology of threat and bargaining. Poor people facing extreme threats must cope by surrendering individual freedom in service of shared group needs. Wealthier people are more able to flee from threats and/or resist authoritarianism, so their leaders must concede greater freedom. Incorporating these factors (plus inequality) can sharpen researchers' predictions.
Researchers from across the social sciences have found consistent deviations from the predictions... more Researchers from across the social sciences have found consistent deviations from the predictions of the canonical model of self-interest in hundreds of experiments from around the world. This research, however, cannot determine whether the uniformity results from universal patterns of human behavior or from the limited cultural variation available among the university students used in virtually all prior experimental work. To address this, we undertook a cross-cultural study of behavior in ultimatum, public goods, and dictator games in a range of small-scale societies exhibiting a wide variety of economic and cultural conditions. We found, first, that the canonical model -based on self-interest -fails in all of the societies studied. Second, our data reveal substantially more behavioral variability across social groups than has been found in previous research. Third, group-level differences in economic organization and the structure of social interactions explain a substantial portion of the behavioral variation across societies: the higher the degree of market integration and the higher the payoffs to cooperation in everyday life, the greater the level of prosociality expressed in experimental games. Fourth, the available individual-level economic and demographic variables do not consistently explain game behavior, either within or across groups. Fifth, in many cases experimental play appears to reflect the common interactional patterns of everyday life. .
From January 2012 through December 2012, the following scholars offered their valuable time and a... more From January 2012 through December 2012, the following scholars offered their valuable time and attention to review articles submitted to Evolutionary Psychology. The Journal is grateful for their efforts. We would also like to thank all of the Editorial Board members (http://www.epjournal .net/Editorial_board/index.html) for their continued efforts. ... Joshua Ackerman Maria Agthe Alexandra Alvergne James Anderson Coren Apicella Menelaos Apostolou Jeremy Atkinson Marcella Baiz Michael Baker Pat Barclay Adrian Bell Tamas Bereczkei Robert Berwick ...
Members of social groups face a trade-off between investing selfish effort for themselves and inv... more Members of social groups face a trade-off between investing selfish effort for themselves and investing cooperative effort to produce a shared group resource. Many group resources are shared equitably: they may be intrinsically non-excludable public goods, such as vigilance against predators, or so large that there is little cost to sharing, such as cooperatively hunted big game. However, group members' personal resources, such as food hunted individually, may be monopolizable. In such cases, an individual may benefit by investing effort in taking others' personal resources, and in defending one's own resources against others. We use a game theoretic "tug-of-war" model to predict that when such competition over personal resources is possible, players will contribute more towards a group resource, and also obtain higher payoffs from doing so. We test and find support for these predictions in two laboratory economic games with humans, comparing people's investment decisions in games with and without the options to compete over personal resources or invest in a group resource. Our results help explain why people cooperatively contribute to group resources, suggest how a tragedy of the commons may be avoided, and highlight unifying features in the evolution of cooperation and competition in human and non-human societies.
The effect of exposure to eye images on various behaviors has been explained as a response to an ... more The effect of exposure to eye images on various behaviors has been explained as a response to an invalid cue of observation. This invalid cue interpretation has been supported by an experiment showing that a short exposure to eye images increased dictator game generosity, but a long exposure did not. We attempted to conceptually replicate that finding with a different dependent variable, and found no effect of short or long exposure to eye images on moral condemnation. Thus, we failed to replicate previous work showing an effect of eye images on condemnation and therefore these results do not inform the invalid cue hypothesis. We found that women condemned more strongly than men and discuss this finding in light of functional theories of moral condemnation.
People are more cooperative when explicitly observed, and simply exposing people to images of eye... more People are more cooperative when explicitly observed, and simply exposing people to images of eyes or faces has been shown to increase cooperation of various types and in various contexts, albeit with notable, if controversial, exceptions. This 'eyes effect' is important both for its potential real-world applications and for its implications regarding the role of reputation in the evolution and maintenance of human cooperation. Based on the general principle that organisms eventually cease responding to uninformative stimuli, we predicted that the eyes effect would be eliminated by prolonged exposure. A novel experiment confirmed that participants exposed briefly to an eye-like image gave more money in an economic game than those in a longer exposure condition and those in a control condition. There was no generosity difference between the long exposure and control conditions. Furthermore, a meta-analysis of 25 eyes effects experiments confirmed that the effect emerges reliably after short exposures to eye images, but not after long exposures. An understanding of the limits of false cues on behaviour helps resolve empirical discrepancies regarding the eyes effect and exonerates the importance of reputation even in anonymous, one-shot interactions.
Who takes risks, and why? Does risk-taking in one context predict risk-taking in other contexts? ... more Who takes risks, and why? Does risk-taking in one context predict risk-taking in other contexts? We seek to address these questions by considering two (non-independent) pathways to risk: need-based and ability-based. The need-based pathway suggests that risk-taking is a product of competitive disadvantage, consistent with risk-sensitivity theory. The ability-based pathway suggests that people engage in risk-taking when they possess abilities or traits that increase the probability of successful risk-taking, the expected value of the risky behavior itself, and/or have signalling value. We provide a conceptual model of decision-making under risk—the relative state model— that integrates both pathways and explicates how situational and embodied factors influence the estimated costs and benefits of risk-taking in different contexts. This model may help to reconcile longstanding disagreements and issues regarding the etiology of risk-taking, such as the domain-generality versus domain-specificity of risk or differential engagement in antisocial and non-antisocial risk-taking.
Humans reject uneven divisions of resources, even at personal cost. This is observed in countless... more Humans reject uneven divisions of resources, even at personal cost. This is observed in countless experiments using the ultimatum game, where a proposer offers to divide a resource with a responder who either accepts the division or rejects it (whereupon both earn zero). Researchers debate why humans evolved a psychology that is so averse to inequity within partnerships. We suggest that the scale of competition is crucial: under local competition with few competitors, individuals reject low offers, because they cannot afford to be disadvantaged relative to competitors. If one competes against the broader population (i.e. global competition), then it pays to accept low offers to increase one's absolute pay-off. We support this intuition with an illustrative game-theoretical model. We also conducted ultimatum games where participants received prizes based on pay-offs relative to immediate partners (local competition) versus a larger group (global competition). Participants demande...
Abstract Social organisms in many taxa cooperate to produce resources that are shared among group... more Abstract Social organisms in many taxa cooperate to produce resources that are shared among group members. Some cooperatively produced resources may be monopolized by individuals who invest in within-group competition, but these have largely been ...
Journal of Personality and Social Psychology, 2008
Cooperation among nonrelatives can be puzzling because cooperation often involves incurring costs... more Cooperation among nonrelatives can be puzzling because cooperation often involves incurring costs to confer benefits on unrelated others. Punishment of noncooperators can sustain otherwise fragile cooperation, but the provision of punishment suffers from a "second-order" free-riding problem because nonpunishers can free ride on the benefits from costly punishment provided by others. One suggested solution to this problem is second-order punishment of nonpunishers; more generally, the threat or promise of higher order sanctions might maintain the lower order sanctions that enforce cooperation in collective action problems. Here the authors report on 3 experiments testing people's willingness to provide second-order sanctions by having participants play a cooperative game with opportunities to punish and reward each other. The authors found that people supported those who rewarded cooperators either by rewarding them or by punishing nonrewarders, but people did not support those who punished noncooperators--they did not reward punishers or punish nonpunishers. Furthermore, people did not approve of punishers more than they did nonpunishers, even when nonpunishers were clearly unwilling to use sanctions to support cooperation. The results suggest that people will much more readily support positive sanctions than they will support negative sanctions.
The evolution of reciprocal altruism probably involved the evolution of mechanisms to detect chea... more The evolution of reciprocal altruism probably involved the evolution of mechanisms to detect cheating and remember cheaters. In a well-known study, observed that participants had enhanced memory for faces that had previously been associated with descriptions of acts of cheating. There were, however, problems with the descriptions that were used in that study. We sought to replicate and extend the findings of Mealey and colleagues by using more controlled descriptions and by examining the possibility of enhanced altruist recognition. We also examined whether individual differences in cheating tendencies were related to cheater and altruist recognition. In the first experiment, 164 undergraduates saw 40 faces that were paired with character descriptions representing the categories cheating, trustworthiness, altruism, or neutral, for individuals who had either low or high social status. One week later participants reported which faces they recognized from the previous week (among 80 faces). Overall, the results failed to replicate the findings of Mealey and her colleagues, as there was no enhanced memory for cheaters. In addition, there was no enhanced memory for altruists, and no effect of participants' cheating tendencies. A second experiment using a slightly different methodology produced similar results, with some evidence for enhanced memory for altruists.
Risk-sensitivity theory predicts that organisms are more likely to take risks when they are unlik... more Risk-sensitivity theory predicts that organisms are more likely to take risks when they are unlikely to achieve their goals through safer, low-risk means. Those who are competitively disadvantaged are less likely to succeed in social competition and should consequently show elevated risk taking. We experimentally tested this hypothesis by exposing participants to cues of relative competitive disadvantage or relative competitive advantage via feedback from a purported reaction time based intelligence test. Participants then made a number of high-risk or low-risk economic decisions (Experiment 1). Experiment 2 built on this design by either maintaining or ameliorating cues of relative competitive (dis)advantage. Results indicate that cues of relative competitive disadvantage leads to increased risk taking, and that risk taking can be reduced when cues of disadvantage are ameliorated. Since risk taking tends to generalize across domains, these results can potentially apply to a number of problematic risky behaviors.
Relatedness is a cornerstone of the evolution of social behavior. In the human lineage, the exist... more Relatedness is a cornerstone of the evolution of social behavior. In the human lineage, the existence of cooperative kin networks was likely a critical stepping stone in the evolution of modern social complexity. Here we report the results of the first experimental manipulation of a putative cue of human kinship (facial self-resemblance) among ostensible players in a variant of the "tragedy of the commons," the oneshot public goods game, in which group-level cooperation-via contributions made to the public good and the punishment of free riders-is supported at a personal cost. In accordance with theoretical predictions, contributions increased as a function of the "kin density" of the group. Moreover, the distribution of punishment was not contingent on kin density level. Our findings indicate that the presence of a subtle cue of genealogical relatedness facilitates group cooperation, supporting the hypothesis that the mechanisms fostering contemporary sociality took root in extended family networks.
Van de Vliert&amp... more Van de Vliert's findings may be explained by the psychology of threat and bargaining. Poor people facing extreme threats must cope by surrendering individual freedom in service of shared group needs. Wealthier people are more able to flee from threats and/or resist authoritarianism, so their leaders must concede greater freedom. Incorporating these factors (plus inequality) can sharpen researchers' predictions.
Researchers from across the social sciences have found consistent deviations from the predictions... more Researchers from across the social sciences have found consistent deviations from the predictions of the canonical model of self-interest in hundreds of experiments from around the world. This research, however, cannot determine whether the uniformity results from universal patterns of human behavior or from the limited cultural variation available among the university students used in virtually all prior experimental work. To address this, we undertook a cross-cultural study of behavior in ultimatum, public goods, and dictator games in a range of small-scale societies exhibiting a wide variety of economic and cultural conditions. We found, first, that the canonical model -based on self-interest -fails in all of the societies studied. Second, our data reveal substantially more behavioral variability across social groups than has been found in previous research. Third, group-level differences in economic organization and the structure of social interactions explain a substantial portion of the behavioral variation across societies: the higher the degree of market integration and the higher the payoffs to cooperation in everyday life, the greater the level of prosociality expressed in experimental games. Fourth, the available individual-level economic and demographic variables do not consistently explain game behavior, either within or across groups. Fifth, in many cases experimental play appears to reflect the common interactional patterns of everyday life. .
From January 2012 through December 2012, the following scholars offered their valuable time and a... more From January 2012 through December 2012, the following scholars offered their valuable time and attention to review articles submitted to Evolutionary Psychology. The Journal is grateful for their efforts. We would also like to thank all of the Editorial Board members (http://www.epjournal .net/Editorial_board/index.html) for their continued efforts. ... Joshua Ackerman Maria Agthe Alexandra Alvergne James Anderson Coren Apicella Menelaos Apostolou Jeremy Atkinson Marcella Baiz Michael Baker Pat Barclay Adrian Bell Tamas Bereczkei Robert Berwick ...
Members of social groups face a trade-off between investing selfish effort for themselves and inv... more Members of social groups face a trade-off between investing selfish effort for themselves and investing cooperative effort to produce a shared group resource. Many group resources are shared equitably: they may be intrinsically non-excludable public goods, such as vigilance against predators, or so large that there is little cost to sharing, such as cooperatively hunted big game. However, group members' personal resources, such as food hunted individually, may be monopolizable. In such cases, an individual may benefit by investing effort in taking others' personal resources, and in defending one's own resources against others. We use a game theoretic "tug-of-war" model to predict that when such competition over personal resources is possible, players will contribute more towards a group resource, and also obtain higher payoffs from doing so. We test and find support for these predictions in two laboratory economic games with humans, comparing people's investment decisions in games with and without the options to compete over personal resources or invest in a group resource. Our results help explain why people cooperatively contribute to group resources, suggest how a tragedy of the commons may be avoided, and highlight unifying features in the evolution of cooperation and competition in human and non-human societies.
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Papers by Pat Barclay