Enhanced memory for the wolf in sheep’s clothing:: Facial trustworthiness modulates face-trait associative memory

Our decision about whether to trust and cooperate with someone is influenced by the individual’s facial appearance despite its limited predictive power. Thus, remembering trustworthy-looking cheaters is more important than remembering untrustworthy-looking cheaters because we are more likely to trust and cooperate with the former, resulting in a higher risk of unreciprocated cooperation. The present study investigated whether our mind adaptively copes with this problem by enhancing memory for trustworthy-looking cheaters. Participants played a debt game, wherein they learned to discriminate among good, neutral, and bad lenders, who respectively charged no, moderate, and high interest on the debt. Each lender had either a trustworthy- or untrustworthy-looking face. A subsequent memory test revealed that participants remembered the bad traits of trustworthy-looking lenders more accurately than those of untrustworthy-looking lenders. The results demonstrate enhanced memory for trustworthy-looking cheaters, or wolves in sheep’s clothing, implying that humans are equipped with protective mechanisms against disguised, unfaithful signs of trustworthiness.     

The spiral of distrust: (Non‐)cooperation in a repeated trust game is predicted by anger and individual differences in negative reciprocity orientation

This study investigated state anger and individual differences in negative reciprocity orientation as predictors of individuals' willingness to cooperate with strangers. In order to observe real behaviour, we used a trust game that was played over six periods. In the trust game, a first player (sender) determines how much of a certain endowment she/he wants to share with a second player (trustee), who then can give something back. We varied whether participants received feedback [feedback (yes, no)] about the trustee's behavioural decision (amount sent back). Supporting our hypotheses, the results suggest that feedback compared with no feedback about the trustee's behaviour increased anger. Specifically, information about low back transfers triggered anger and non‐cooperation in return. Importantly, participants with a strong negative reciprocity orientation reported higher levels of anger and were less willing to cooperate with the trustee compared with those with low negative reciprocity orientation. Moreover, even when anger was low, individuals with a strong negative reciprocity orientation were less willing to cooperate compared with those with a low negative reciprocity orientation. Thus, negative reciprocity orientation seems to arouse a spiral of distrust. Theoretical and practical implications of these findings are discussed.     

信任还是设防？互动博弈中社会善念对合作行为的促进效应

社会善念是个体在人际互动中充满善意地关注、尊重并保护他人选择的需要和权利的行为,通过实施社会善念有助于提升他人的合作行为。为检验这一假设,本实验设置了“施—受”双方的互动博弈情境,采用“物品选择游戏”操纵实施者的社会善念水平,分别利用信任博弈和公共物品游戏测查接受者在互动过程中的信任水平和合作行为。结果发现：相比于低社会善念组,被试在高社会善念组中表现出更高的信任水平和合作行为。进一步路径分析也发现,信任在感知社会善念与合作行为间发挥着部分中介作用。由此可见,社会善念行为的实施为互动双方建立信任关系提供了重要线索,降低了人们时时“设防”的监控动机,使合作带来的利益双赢成为可能。     

There's no “I” in team: Effects of cooperative video games on cooperative behavior

The present research tests the idea that playing a team‐player video game in which players work together as teammates and assist each other in achieving a common goal increases cooperative behavior toward a new partner. In fact, relative to a single‐player mode, cooperatively playing a video game increased cooperation in a mixed‐motive decision dilemma task. Because the players were exposed to the same video game content in both experimental conditions, the effect on cooperative behavior can only be accounted for by the different way the game was played. Mediation analyses revealed that cooperative team play promoted feelings of cohesion, which activated trust (i.e., the expectation of reciprocal cooperation), which in turn increased cooperative behavior. Copyright © 2013 John Wiley & Sons, Ltd.     

Trust recovery following voluntary or forced financial compensations in the trust game: The role of trait forgiveness

One of the major challenges that actors in economic exchange relations face today concerns dealing with defection and overcoming the erosion of trust and cooperation that may result from a transgression. As transgressions in these relations usually entail a monetary loss for the victim, a common restorative approach involves providing a financial compensation to the victim. This research examines whether compensations that were provided voluntarily (rather than forced) would promote more trust among victims. In contrast to standard economic theory, we predict that individual differences exist that determine the degree to which victims are susceptible towards information about how the financial compensation is delivered in their decision to trust and cooperate again. Experimental data from a trust game confirmed our hypotheses by showing that whereas receiving a voluntary compensation from the transgressor communicates more repentance to victims than when this compensation was imposed, particularly people with a low tendency to forgive discount this repentance in their decision to trust again.     

The smell of cooperativeness: Do human body odours advertise cooperative behaviours?

Several physical features influence the perception of how cooperative a potential partner is. While previous work focused on face and voice, it remains unknown whether body odours influence judgements of cooperativeness and if odour-based judgements are accurate. Here, we first collected axillary odours of cooperative and uncooperative male donors through a public good game and used them as olfactory stimuli in a series of tasks examining whether and how they influence cooperative decision-making in an incentivized economic game and ratings of cooperativeness. Our results show that having access to the donor's body odours provided a strategic advantage to women during economic decisions (but not to men): with age, women were more likely to cooperate with cooperative men and to avoid interacting with uncooperative men. Ratings of cooperativeness were nonetheless unrelated to the donors’ actual cooperativeness. Finally, while men with masculine and intense body odours were judged less cooperative, we found no evidence that donors’ actual cooperativeness was associated with less masculine or less intense body odour. Overall, our findings suggest that, as faces and voices, body odours influence perceived cooperativeness and might be used accurately and in a non-aware manner as olfactory cues of cooperativeness, at least by women.     

Unequal but not separate: Emergence of rich–poor cooperation in resource exchange

Addressing inequality is a critical challenge for society as a whole and requires sustained efforts to promote fairness and opportunity for all. Filling in the resource gap across social classes is essential in reducing inequality. Previous studies have revealed that ingroup favouritism hinders the rich from cooperating with the poor and expands the wealth gap. Nevertheless, how to find ways of narrowing the gap between the rich and the poor remains an open question. Inducing rich–poor cooperation could be effective in eliciting resource flow across classes. In this study, two experiments using a modified Prisoner's Dilemma game were conducted in Japan (N = 213) and China (N = 150) to examine whether highlighting partners' cooperativeness under permeable group boundaries induces rich–poor cooperation. All participants were allocated to the rich group and participated in the game with programmed rich- or poor-group partner bots, whose cooperation rates were manipulated. Despite the initial resource disparities between participants and the partner bots, participants were more likely to select and cooperate with cooperative poor-group partners than with non-cooperative rich-group partners. Generalized trust played an important role in the enhancement of rich–poor cooperation. The findings shed light on the possibility of reducing inequality and promoting social mobility in society.     

The implicit cognition of reciprocal exchange: automatic retrieval of positive and negative experiences with partners in a prisoner's dilemma game

Models of reciprocity imply that cheater detection is an important prerequisite for successful social exchange. Considering the fundamental role of memory in reciprocal exchange, these theories lead to the prediction that memory for cheaters should be preferentially enhanced. Here, we examine whether information of a partner's previous behaviour in an interaction is automatically retrieved when encountering the face of a partner who previously cheated or cooperated. In two studies, participants played a sequential prisoner's dilemma game with cheaters and cooperative partners. Alternating with the game blocks, participants were asked to classify the smiling or angry facial expressions of cooperators and cheaters. Both experiments revealed congruence effects, reflecting faster identification of the smiles of cooperators (Experiments 1 and 2) and faster identification of the angry facial expressions of cheaters (Experiment 2). Our study provides evidence for the automatic retrieval of the partner's behaviour in the game, regardless of whether partners cheated or cooperated, and thus provides further evidence against the cheater detection hypothesis.     

When to (or not to) trust intelligent machines: Insights from an evolutionary game theory analysis of trust in repeated games

The actions of intelligent agents, such as chatbots, recommender systems, and virtual assistants are typically not fully transparent to the user. Consequently, users take the risk that such agents act in ways opposed to the users’ preferences or goals. It is often argued that people use trust as a cognitive shortcut to reduce the complexity of such interactions. Here we formalise this by using the methods of evolutionary game theory to study the viability of trust-based strategies in repeated games. These are reciprocal strategies that cooperate as long as the other player is observed to be cooperating. Unlike classic reciprocal strategies, once mutual cooperation has been observed for a threshold number of rounds they stop checking their co-player’s behaviour every round, and instead only check it with some probability. By doing so, they reduce the opportunity cost of verifying whether the action of their co-player was actually cooperative. We demonstrate that these trust-based strategies can outcompete strategies that are always conditional, such as Tit-for-Tat, when the opportunity cost is non-negligible. We argue that this cost is likely to be greater when the interaction is between people and intelligent agents, because of the reduced transparency of the agent. Consequently, we expect people to use trust-based strategies more frequently in interactions with intelligent agents. Our results provide new, important insights into the design of mechanisms for facilitating interactions between humans and intelligent agents, where trust is an essential factor.     

Individual differences in game motivation as moderators of preprogrammed strategy effects in prisoner's dilemma.

The impact of three programmed strategies (tit-for-tat, 100% cooperation, and 100% defection) on cooperation level in the Prisoner's Dilemma game is examined as a function of the subject's motivational orientation (cooperative, competitive, or individualistic). Motivational orientation was assessed on the basis of each subject's choices across four classes of decomposed games. Following this assessment, subject's played 30 trials of Prisoner's dilemma in matrix form against one of the above-mentioned strategies. Results were wholly consistent with predictions, showing that (a) cooperatively oriented subjects cooperate with a tit-for-tat and a 100% cooperative strategy, but defect against a 100% defecting strategy, (b) competitive subjects defect against all three strategies; and (c) individualistic subjects defect against both 100% cooperative and 100% defective strategies, but they cooperate with a tit-for-tat strategy. It appears reasonable to conclude that the outcomes of a Prisoner's Dilemma have affectively different meaning (i.e., values) for subjects of differing orientations, and that subjects of all three orientations adopt strategies that effectively maximize their particular type of reward in the game.     

When do people cooperate? The neuroeconomics of prosocial decision making

Understanding the roots of prosocial behavior is an interdisciplinary research endeavor that has generated an abundance of empirical data across many disciplines. This review integrates research findings from different fields into a novel theoretical framework that can account for when prosocial behavior is likely to occur. Specifically, we propose that the motivation to cooperate (or not), generated by the reward system in the brain (extending from the striatum to the ventromedial prefrontal cortex), is modulated by two neural networks: a cognitive control system (centered on the lateral prefrontal cortex) that processes extrinsic cooperative incentives, and/or a social cognition system (including the temporo-parietal junction, the medial prefrontal cortex and the amygdala) that processes trust and/or threat signals. The independent modulatory influence of incentives and trust on the decision to cooperate is substantiated by a growing body of neuroimaging data and reconciles the apparent paradox between economic versus social rationality in the literature, suggesting that we are in fact wired for both. Furthermore, the theoretical framework can account for substantial behavioral heterogeneity in prosocial behavior. Based on the existing data, we postulate that self-regarding individuals (who are more likely to adopt an economically rational strategy) are more responsive to extrinsic cooperative incentives and therefore rely relatively more on cognitive control to make (un)cooperative decisions, whereas other-regarding individuals (who are more likely to adopt a socially rational strategy) are more sensitive to trust signals to avoid betrayal and recruit relatively more brain activity in the social cognition system. Several additional hypotheses with respect to the neural roots of social preferences are derived from the model and suggested for future research.     

Effects of minimal social cues on trust in the investment game

In anonymous game tasks, individuals’ prosocial behaviour was shown to increase when those individuals were provided with social cues from a third party or bystander. It has been suggested that those social cues can be presented using a configuration suggestive of a face with ‘watching eyes’. This led us to question whether it was possible to provide the watching‐eyes configuration with even weaker facial information, such as a simple dot pattern. By using a minimal social cue paradigm, such as the one described above, the present research found that individuals’ trust toward the trustee increased when they detected the watching‐eyes dot pattern as a source of social cues in two settings: a hypothetical investment game for both college students (Study 1) and customs officers (Study 2); and an actual investment game for college students (Study 3).     

Cooperation in repeated interactions: A systematic review of Centipede game experiments, 1992–2016

Cooperation is a fundamental form of social interaction, and turn-taking reciprocity one of its most familiar manifestations. The Centipede game provides a formal model of such alternating reciprocal cooperation, but a backward induction (BI) argument appears to prove logically that instrumentally rational players would never cooperate in this way. A systematic review of experimental research reveals that human decision makers cooperate frequently in this game, except under certain extreme conditions. Several game, situational, and individual difference variables have been investigated for their influence on cooperation. The most influential are aspects of the payoff function (especially the social gain from cooperation and the risk associated with a cooperative move), the number of players, repetitions of the game, group vs. individual decisions, and players’ social value orientations (SVOs). Our review of experimental evidence suggests that other-regarding preferences, including prosocial behavioural dispositions and collective rationality, provide the most powerful explanation for cooperation.     

Effects of initial choices in the prisoner's dilemma

In the two‐person prisoner's dilemma game (PDG), there is considerable evidence that the tit‐for‐tat (TFT) strategy is most effective in inducing the other person to cooperate. One of the important features of the TFT strategy is that it cooperates on the first trial. We varied the initial choices of a simulated other, and tested the effects of (a) initial choices (cooperation or defection), and (b) persistence of initial choices: unilateral cooperation (or defection) on the first trial, first two trials, or first four trials. Results showed that a cooperative strategy—one that starts with cooperative choices—induced greater cooperation than a strategy that started with defections. The results of this study clearly show that (a) a cooperative strategy—one that initiates unilateral cooperation at the outset and then adopts a TFT strategy—is very effective in inducing subsequent cooperation from the other party, (b) the effectiveness of a cooperative strategy varies directly with the cooperative orientation of the other party (a cooperative strategy is more effective against a cooperative than a competitive person), and (c) initial cooperation is more effective if it is repeated more than once. Copyright © 2002 John Wiley & Sons, Ltd.     

Friend or foe: the effect of implicit trustworthiness judgments in social decision-making

The human face appears to play a key role in signaling social intentions and usually people form reliable and strong impressions on the basis of someone's facial appearance. Therefore, facial signals could have a substantial influence on how people evaluate and behave towards another person in a social interaction, such as an interactive risky decision-making game. Indeed, there is a growing body of evidence that demonstrates that social behavior plays a crucial role in human decision-making. Although previous research has demonstrated that explicit social information about one's partner can influence decision-making behavior, such as knowledge about the partner's moral status, much less is known about how implicit facial social cues affect strategic decision-making. One particular social cue that may be especially important in assessing how to interact with a partner is facial trustworthiness, a rapid, implicit assessment of the likelihood that the partner will reciprocate a generous gesture. In this experiment, we tested the hypothesis that implicit processing of trustworthiness is related to the degree to which participants cooperate with previously unknown partners. Participants played a Trust Game with 79 hypothetical partners who were previously rated on subjective trustworthiness. In each game, participants made a decision about how much to trust their partner, as measured by how much money they invested with that partner, with no guarantee of return. As predicted, people invested more money in partners who were subjectively rated as more trustworthy, despite no objective relationship between these factors. Moreover, the relationship between the amount of money offered seemed to be stronger for trustworthy faces as compared to untrustworthy faces. Overall, these data indicate that the perceived trustworthiness is a strong and important social cue that influences decision-making.     

Understanding cooperation in the Prisoner’s Dilemma game

In the standard one-shot Prisoner’s Dilemma game, participants often choose to cooperate, when the optimal strategy is to defect. This puzzling finding has attracted considerable interest both in terms of possible computational frameworks for modeling human judgment, but also regarding the more general debate of human altruism. In this research, we ask how much of human behavior in this task can be explained by a putative bias for cooperative behavior and whether this, in turn, is influenced by personality. We compared performance on the standard task with performance on a matched neutral one; we manipulated the optimal strategy (defect or cooperate); and we manipulated the amount of payoff for responding optimally. Results revealed little evidence for a bias for cooperative behavior, but significant associations with the personality factors of Behavioural Activation System (BAS) Reward Responsivity and Agreeableness were found. These findings are discussed in terms of the attempt to explain judgment in one-shot, Prisoner’s Dilemma tasks with statistical or probabilistic models.     

同伴特点如何影响人们的合作与冲突行为?

人类的生存繁衍依赖于人们之间的相互合作,合作与冲突行为的研究近年来成为心理学的研究热点。本研究通过实验程序操纵Chicken Game中博弈同伴的特点,考察个体在社会困境中面对不同特点同伴时的合作行为。结果发现：(1)同伴道义论组和功利论组总和解率没有显著差异,同伴竞争组和合作组的总和解率也没有显著差异。(2)在与道义论以及合作型的同伴互动时,个体的行为没有明显受到上次博弈反馈的影响。(3)当同伴为功利论时,相比于上次博弈个体选择和解而同伴选择进攻,双方都选择和解时个体在当前博弈中更倾向于和解;(4)在同伴竞争组中,相比于上次博弈个体选择进攻而同伴选择和解,双方都选择和解时被试在当前博弈中会更倾向于和解。实验结果表明个体在博弈任务中会受到同伴特点的影响,并且同伴在博弈中的行为特点的影响更为显著。本研究从同伴特点来考察个体的合作行为,揭示了影响个体博弈行为的一种因素。     

面孔可信度评价调节：经验迁移假说的提出与验证

面孔可信度评价对人际信任和合作行为有重要影响。以往研究发现面部特征、背景环境等附加信息能通过自下而上、自上而下两种方式调节人们对他人面孔可信度的评价, 但具体的起效和失效机制尚不清晰。针对这一问题, 本文提出了“经验迁移假说”, 并对两类调节方式的认知机制、经验迁移的边界条件和调节过程进行探究。本研究为深化理解人际信任的调控机制提供理论和实证依据。     

社会距离与合作指数对不同年龄青少年合作行为影响的差异

本研究采用重复囚徒困境实验范式,考察了社会距离和合作指数对不同年龄青少年（初中生、高中生和大学生,且每个年龄段的被试数为40名）在博弈决策中的合作行为的影响。结果发现：（1）随着年龄的增加,青少年合作行为的总体趋势表现为下降;（2）社会距离对大学生的合作行为的正向作用显著,而中学生的合作行为却不受其影响;（3）个体合作率会受到合作指数的促进作用,但这种促进作用在大学生中表现的更为显著。即随年龄增长,个体会更少的采取合作行为,并且个体是否采取合作在更大程度上基于当前博弈中的收支情况和与博弈对象之间的社会距离。     

Why and when justice sensitivity leads to pro- and antisocial behavior

People differ in how injustice-sensitive they are either as victims or as observers. Whereas observer sensitivity is positively related to cooperative behavior, victim sensitivity promotes antisocial and egoistic behavior. The present article investigates the dynamics underlying these effects. Participants played an online-based public goods game and were informed about the number of people who violated a fairness rule in previous rounds of the game (no, some, or many violators). High victim-sensitive participants contributed less to the public good even in the “some violators” condition. High observer-sensitive participants contributed more to the public good even in the “many violators” condition. The findings correspond with the sensitivity to mean intentions model and cannot be explained by individual differences in general trust.