Stake size effects in ultimatum game and dictator game offers: A meta-analysis

Proposer's moral identity modulates fairness processing in the ultimatum game: Evidence from behavior and brain potentials

Economic decision-making is pivotal to both human private interests and the national economy. People pursue fairness in economic decision-making, but a proposer's moral identity can influence fairness processing. Previous ERP studies have revealed that moral identity has an effect on fairness considerations in the Ultimatum Game (UG), but the findings are inconsistent. To address the issue, we revised the moral-related sentences and used the ERP technique to measure the corresponding neural mechanism. We have observed that the fairness effect in UG can be mirrored in both MFN and P300 changes, whereas the moral identity effect on fairness in UG can be reflected by MFN but not P300 changes. These findings indicate that the moral identity of the proposer can modulate fairness processing in UG. The current study opens new avenues for clarifying the temporal course of the relationship between the proposer's moral identity and fairness in economic decision-making, which is beneficial for understanding the influencing mechanism of fairness processing and fair allocations in complex social contexts.

Do you really believe that? The effect of economic incentives on the acceptance of real-world data in a polarized context

Attitudes and expectations towards others are major drivers of political polarization. However, there is limited understanding of their relevance when decisions with high stakes are taken. In this study, we compare self-reported attitudes against economically incentivized estimates of data coming from official sources and offer participants financial rewards for accuracy. Our methodology yields three principal findings. (i) Extreme attitudes from a small partisan subgroup primarily account for the observed partisan divide; this subgroup diminishes when incentivized estimates are considered. (ii) There is a weak correlation between economically incentivized and unincentivized measures within individual respondents. (iii) We introduce a novel metric for assessing perceived polarization. This metric allows participants to estimate data points for those with opposing political views, rewarding accurate predictions financially. Interestingly, this measure of perceived polarization correlates with attitudes but not with incentivized data estimates. This is in line with the concept of 'false polarization', attributing polarization more to expectations towards others than to genuine differences. These findings challenge the reliability of standard attitude surveys and suggest avenues for mitigating perceived polarization in contentious issues.

Dispositional compassion shifts social preferences in systematic ways

INTRODUCTION

How people attach value to the outcomes of self and other-social preferences-is central to social behavior. Recently, how dispositional and state emotion shape such social preferences has received researchers' attention.

METHOD

The present investigation asked whether and to what extent dispositional and state compassion predict shifts in social preferences across 4 samples: two correlational samples (final ns 153 & 368, study 1a and 1b) and two experimental samples (final ns: 430 & 530, studies 2 and 3).

RESULTS

In keeping with recent accounts of compassion, dispositional compassion predicted general preference for equality, expressed as dispreference for both monetary advantage over another (interaction βs = -0.36, -0.33, -0.25, -0.22; all p < 0.001) and monetary disadvantage relative to others (βs: 0.26, 0.27, 0.28, 0.17; all p < 0.01; positive coefficients imply dispreference). This dispositional effect persisted when controlling for prosociality, positivity, agreeableness, and respectfulness. Furthermore, these dispositional compassion effects were relatively unchanged by experimental emotion inductions in studies 3 and 4. The experimental inductions of state compassion and state pride showed little evidence of systematic effects on social preferences relative to each other or a neutral condition.

DISCUSSION

Discussion focused on individual differences in emotion and social preferences.

Partner choice and cooperation in social dilemmas can increase resource inequality

Cooperation is more likely when individuals can choose their interaction partner. However, partner choice may be detrimental in unequal societies, in which individuals differ in available resources and productivity, and thus in their attractiveness as interaction partners. Here we experimentally examine this conjecture in a repeated public goods game. Individuals (n = 336), participating in groups of eight participants, are assigned a high or low endowment and a high or low productivity factor (the value that their cooperation generates), creating four unique participant types. On each round, individuals are either assigned a partner (assigned partner condition) or paired based on their self-indicated preference for a partner type (partner choice condition). Results show that under partner choice, individuals who were assigned a high endowment and high productivity almost exclusively interact with each other, forcing other individuals into less valuable pairs. Consequently, pre-existing resource differences between individuals increase. These findings show how partner choice in social dilemmas can amplify resource inequality.

Are People Generous When the Financial Stakes Are High?

How generous are people when making consequential financial decisions in the real world? We took advantage of a rare opportunity to examine generosity among a diverse sample of adults who received a gift of U.S. $10,000 from a pair of wealthy donors, with nearly no strings attached. Two-hundred participants were drawn from three low-income countries (Indonesia, Brazil, and Kenya) and four high-income countries (Australia, Canada, the United Kingdom, and the United States) as part of a preregistered study. On average, participants spent over $6,400 on purchases that benefited others, including nearly $1,700 on donations to charity, suggesting that humans exhibit remarkable generosity even when the stakes are high. To address whether generosity was driven by reputational concerns, we asked half the participants to share their spending decisions publicly on Twitter, whereas the other half were asked to keep their spending private. Generous spending was similar between the groups, in contrast to our preregistered hypothesis that enhancing reputational concerns would increase generosity.

Do mturkers collude in interactive online experiments?

One of the issues that can potentially affect the internal validity of interactive online experiments that recruit participants using crowdsourcing platforms is collusion: participants could act upon information shared through channels that are external to the experimental design. Using two experiments, I measure how prevalent collusion is among MTurk workers and whether collusion depends on experimental design choices. Despite having incentives to collude, I find no evidence that MTurk workers collude in the treatments that resembled the design of most other interactive online experiments. This suggests collusion is not a concern for data quality in typical interactive online experiments that recruit participants using crowdsourcing platforms. However, I find that approximately 3% of MTurk workers collude when the payoff of collusion is unusually high. Therefore, collusion should not be overlooked as a possible danger to data validity in interactive experiments that recruit participants using crowdsourcing platforms when participants have strong incentives to engage in such behavior.

Self-interested learning is more important than fair-minded conditional cooperation in public-goods games

Why does human cooperation often unravel in economic experiments despite a promising start? Previous studies have interpreted the decline as the reaction of disappointed altruists retaliating in response to non-altruists (Conditional Cooperators hypothesis). This interpretation has been considered evidence of a uniquely human form of cooperation, motivated by an altruistic concern for equality ('fairness') and requiring special evolutionary explanations. However, experiments have typically shown individuals not only information about the decisions of their groupmates (social information) but also information about their own payoffs. Showing both confounds explanations based on conditional cooperation with explanations based on confused individuals learning how to better play the game (Confused Learners hypothesis). Here we experimentally decouple these two forms of information, and thus these two hypotheses, in a repeated public-goods game. Analysing 616 Swiss university participants, we find that payoff information leads to a greater decline, supporting the Confused Learners hypothesis. In contrast, social information has a small or negligible effect, contradicting the Conditional Cooperators hypothesis. We also find widespread evidence of both confusion and selfish motives, suggesting that human cooperation is maybe not so unique after all.

I am entitled to it! Social power and context modulate disadvantageous inequity aversion

Previous research consistently indicated that social power influences one's fairness consideration. However, it is unclear how social power and context jointly affect inequity aversion and whether these processes would be manifested in brain activities. In this study, participants were randomly assigned into either high or low power condition and then took part in a modified ultimatum game (UG) as responders in both gain and loss contexts, with their event-related potentials (ERPs) recorded. Behavioral results showed that powerful participants were more likely to reject unfair offers in both contexts compared with powerless ones. In addition, powerful participants showed a more negative feedback-related negativity (FRN) loss-win difference wave (d-FRN) upon presentation of proposed offers compared with powerless participants only in the gain context. Interestingly, in a later time window, differences of P300 responses to proposed offers were modulated by social power in both gain and loss contexts. These results suggested that powerful people were more sensitive to fairness levels and FRN may manifest fairness consideration in a gain context, but not in a loss context. Meanwhile, P300 is sensitive to fairness considerations in both gain and loss contexts.

Multilevel Hidden Markov Models for Behavioral Data: A Hawk-and-Dove Experiment

Motivated by the analysis of behavioral data taken from an economic experiment based on the Hawk-and-Dove game, this article describes a multilevel hidden Markov model, that includes covariates, autoregression, and endogenous initial conditions under a unified framework. The data at hand are affected by multiple sources of latent heterogeneity, due to multilevel unobserved factors that operate in conjunction with observed covariates at all the levels of the data hierarchy. We fit a multilevel logistic regression model for repeated measurements of player behaviors, nested within groups of interacting players. The model integrates discrete random effects at the group level and Markovian sequences of discrete random effects at the player level. Parameters are estimated by a computationally feasible expectation-maximization algorithm. We model the probability of playing the Hawk strategy, which implies fighting aggressively for controlling an asset, and test the role played by initial possession, property, and other player-specific characteristics in driving hawkish behaviors. The results from our study suggest that crucial factors in determining hawkish behavior are both the way possession is achieved - which depends on our treatment manipulation- and possession itself. Furthermore, a clear time-dependence is observed in the data at the player level as accounted for by the Markovian random effects.

The Games We Play: Prosocial Choices Under Time Pressure Reflect Context-Sensitive Information Priorities

Time pressure is a powerful experimental manipulation frequently used to arbitrate between competing dual-process models of prosocial decision-making, which typically assume that automatic responses yield to deliberation over time. However, the use of time pressure has led to conflicting conclusions about the psychological dynamics of prosociality. Here, we proposed that flexible, context-sensitive information search, rather than automatic responses, underlies these divergent effects of time pressure on prosociality. We demonstrated in two preregistered studies (N = 304 adults from the United States and Canada; Prolific Academic) that different prosocial contexts (i.e., pure altruism vs. cooperation) have distinct effects on information search, driving people to prioritize information differently, particularly under time pressure. Furthermore, these information priorities subsequently influence prosocial choices, accounting for the different effects of time pressure in altruistic and cooperative contexts. These findings help explain existing inconsistencies in the field by emphasizing the role of dynamic context-sensitive information search during social decision-making, particularly under time pressure.

Empathy Modulates the Effect of Stress Reactivity on Generous Giving

How does acute stress influence the degree to which we cooperate with others? Research on the effects of stress on social decision-making is guided by two seemingly contrasting theories. Acute stress may trigger a Fight-or-Flight response, manifested by increased anxiety, and more egocentric or selfish behavior. Alternatively, according to the Tend-and-Befriend model, acute stress may induce affiliative behaviors, marked by increased prosociality in an effort to seek and receive social support and protection. Extant studies on the topic do not provide consistent support for either pattern of behavior, with studies showing evidence for both Fight-or-Flight or Tend-and-Befriend like responses. One possibility, may be the nature of social responses to stressful situations differ as a function of the individual. In the current study, we demonstrate an example of such a person-by-situation interaction, showing that acute stress can cause either pro-social or selfish responses, contingent on individual differences in trait empathy. One hundred and twenty three participants (60 F) were assessed for trait empathy using the Interpersonal Reactivity Index; consequently, they underwent either the Trier Social Stress Test-a well-validated paradigm for eliciting acute psychosocial stress-or a non-stress inducing control condition. Following exposure to either the stress or control condition, participants played a one-shot Dictator Game to evaluate their generosity levels. Statistical analyses revealed that acute stress by itself did not affect the amount transferred in the Dictator Game. Rather, individual differences in trait empathy moderated the effects of stress on giving. Elevations in stress-induced cortisol resulted in more generous behavior, but only in individuals high in empathy. In contrast, in individuals low in empathy, a greater rise in stress-induced cortisol resulted in more selfish behavior. Effects were more pronounced in females than males. Our findings highlight the necessity of integrating personality traits as important moderators of the link between stress and sociality.

The Role of Guilt and Empathy on Prosocial Behavior

Research on the effects of guilt on interpersonal relationships has shown that guilt frequently motivates prosocial behavior in dyadic social situations. When multiple persons are involved, however, this emotion can be disadvantageous for other people in the social environment. Two experiments were carried out to examine the effect of guilt and empathy on prosocial behavior in a context in which more than two people are involved. Experiment 1 investigates whether, in three-person situations, guilt motivates prosocial behavior with beneficial effects for the victim of one’s actions but disadvantageous effects for the third individual. Participants were faced with a social dilemma in which they could choose to take action that would benefit themselves, the victim, or the other individual. The findings show that guilt produces disadvantageous side effects for the third individual person present without negatively affecting the transgressor’s interest. In Experiment 2, participants were faced with a social dilemma in which they could act to benefit themselves, the victim, or a third person for whom they were induced to feel empathic concern. Again, the results show that guilt generates advantages for the victim but, in this case, at the expense of the transgressor and not at the expense of the third person, for whom they were induced to feel empathic concern. Therefore, guilt and empathy seem to limit the transgressor’s interest. The theoretical implications are discussed.

Distanced self-talk increases rational self-interest

Does stepping back to evaluate a situation from a distanced perspective lead us to be selfish or fair? This question has been of philosophical interest for centuries, and, more recently, the focus of extensive empirical inquiry. Yet, extant research reveals a puzzle: some studies suggest that adopting a distanced perspective will produce more rationally self-interested behavior, whereas others suggest that it will produce more impartial behavior. Here we adjudicate between these perspectives by testing the effects of adopting a third-person perspective on decision making in a task that pits rational self-interest against impartiality: the dictator game. Aggregating across three experiments (N = 774), participants who used third-person (i.e., distanced) vs. first-person (i.e., immersed) self-talk during the dictator game kept more money for themselves. We discuss these results in light of prior research showing that psychological distance can promote cooperation and fairmindedness and how the effect of psychological distance on moral decision-making may be sensitive to social context.

Generous with individuals and selfish to the masses

The seemingly rampant economic selfishness suggested by many recent corporate scandals is at odds with empirical results from behavioural economics, which demonstrate high levels of prosocial behaviour in bilateral interactions and low levels of dishonest behaviour. We design an experimental setting, the 'Big Robber' game, where a 'robber' can obtain a large personal gain by appropriating the earnings of a large group of 'victims'. In a large laboratory experiment (N = 640), more than half of all robbers took as much as possible and almost nobody declined to rob. However, the same participants simultaneously displayed standard, predominantly prosocial behaviour in Dictator, Ultimatum and Trust games. Thus, we provide direct empirical evidence showing that individual selfishness in high-impact decisions affecting a large group is compatible with prosociality in bilateral low-stakes interactions. That is, human beings can simultaneously be generous with others and selfish with large groups.

Playing with words: Do people exploit loaded language to affect others’ decisions for their own benefit?

We report on three pre-registered studies testing whether people in the position of describing a decision problem to decision-makers exploit this opportunity for their benefit, by choosing descriptions that may be potentially beneficial for themselves. In Study 1, recipients of an extreme dictator game (where dictators can either take the whole pie for themselves or give it entirely to the receiver) are asked to choose the instructions used to introduce the game to dictators, from six different instructions known from previous research to affect dictators’ decisions. The results demonstrate that some dictator game recipients tend to choose instructions that make them more likely to receive a higher payoff. Study 2 shows that people who choose descriptions that make them more likely to receive a higher payoff indeed believe that they will receive a higher payoff. Study 3 shows that receivers are more likely than dictators to choose these self-serving descriptions. In sum, our work suggests that some people choose descriptions that are beneficial to themselves; we also found some evidence that deliberative thinking and young age are associated with this tendency.

In-Organization Ethics Power-Allocation Mechanisms and Members' Decision-Making Behavior

This study examines experimental evidence showing how ethics power allocation mechanisms affect an individual's in-organization resource division and ethical behavior. We used two two-stage lab experiments to explore power seeking and usage; the experiments contained two stages of power contending and power usage. Stage one used two different power-seeking mechanisms in the honesty game. Stage two was based on the dictator game and the ultimatum game to measure an individual's power usage. The results show that the decisions taken by power-holders could influence the optimization of collective resources, and power-holders who gain power with unethical methods could result in collective resource allocation inequities. With more balanced in-organization power, members tend to be more honest. Subjects also adjust their unethical behavior to adapt to the environment, which could cause the diffusion of unethical behavior. This paper re-designed the dictator game and the ultimatum game by adding an ethically vulnerable power acquisition mechanism. For organizations to prevent the disproportionate dispersion of resources and achieve more public benefits, it is meaningful for managers to create a proper in-organization ethical power allocation mechanism.

Role of the prefrontal cortex in prosocial and self-maximization motivations: an rTMS study

More than a decade of neuroimaging and brain stimulation studies point to a crucial role for the right dorsolateral prefrontal cortex (rDLPFC) in prosocial behavior. The intuitive prosociality model postulates that the rDLPFC controls intuitive prosocial behavior, whereas the reflective model assumes that the rDLPFC controls selfish impulses during prosocial behavior. The intuitive prosociality model implies that the transient disruption of the rDLPFC should increase voluntary transfers in both dictator and generosity games. In contrast, the reflective model suggests that the transient disruption of the rDLPFC should decrease transfers in the dictator game, without affecting voluntary transfers in the generosity game, in which selfish motives are minimized. The aim of this paper was to compare predictions of the intuitive and reflective models using the classic dictator game and generosity game and continuous theta burst stimulation (cTBS). In this study, two groups of healthy participants (dictators) received either cTBS over the rDLPFC or right extrastriate visual areas. As shown by the results, the transient disruption of the rDLPFC significantly promoted prosocial motives in the dictator game only, particularly in the trials with the lowest dictator's costs. These findings partially support the notion that the rDLPFC controls intuitive prosocial behavior.

Payoff-based learning best explains the rate of decline in cooperation across 237 public-goods games

What motivates human behaviour in social dilemmas? The results of public goods games are commonly interpreted as showing that humans are altruistically motivated to benefit others. However, there is a competing 'confused learners' hypothesis: that individuals start the game either uncertain or mistaken (confused) and then learn from experience how to improve their payoff (payoff-based learning). Here we (1) show that these competing hypotheses can be differentiated by how they predict contributions should decline over time; and (2) use metadata from 237 published public goods games to test between these competing hypotheses. We found, as predicted by the confused learners hypothesis, that contributions declined faster when individuals had more influence over their own payoffs. This predicted relationship arises because more influence leads to a greater correlation between contributions and payoffs, facilitating learning. Our results suggest that humans, in general, are not altruistically motivated to benefit others but instead learn to help themselves.

Neurocomputational models of altruistic decision-making and social motives: Advances, pitfalls, and future directions

This article discusses insights from computational models and social neuroscience into motivations, precursors, and mechanisms of altruistic decision-making and other-regard. We introduce theoretical and methodological tools for researchers who wish to adopt a multilevel, computational approach to study behaviors that promote others' welfare. Using examples from recent studies, we outline multiple mental and neural processes relevant to altruism. To this end, we integrate evidence from neuroimaging, psychology, economics, and formalized mathematical models. We introduce basic mechanisms-pertinent to a broad range of value-based decisions-and social emotions and cognitions commonly recruited when our decisions involve other people. Regarding the latter, we discuss how decomposing distinct facets of social processes can advance altruistic models and the development of novel, targeted interventions. We propose that an accelerated synthesis of computational approaches and social neuroscience represents a critical step towards a more comprehensive understanding of altruistic decision-making. We discuss the utility of this approach to study lifespan differences in social preference in late adulthood, a crucial future direction in aging global populations. Finally, we review potential pitfalls and recommendations for researchers interested in applying a computational approach to their research. This article is categorized under: Economics > Interactive Decision-Making Psychology > Emotion and Motivation Neuroscience > Cognition Economics > Individual Decision-Making.

Are social desirability scales desirable? A meta-analytic test of the validity of social desirability scales in the context of prosocial behavior

Social desirability (SD) scales have been used for decades in psychology and beyond. These scales are sought to measure individuals' tendencies to present themselves overly positive in self-reports, thus allowing to control for SD biases. However, research increasingly questions the validity of SD scales, proposing that SD scales measure substantive trait characteristics rather than response bias. To provide a large-scale empirical test of the validity of SD scales, we conducted a meta-analysis (k = 41; N = 8980) on the relation between SD scale scores and prosocial behavior in economic games (where acting in a prosocial manner is highly socially desirable). If SD scales measure what they are supposed to (namely, SD bias), they should be negatively linked to prosocial behavior; if SD scales measure socially desirable traits, they should be positively linked to prosocial behavior. Unlike both possibilities, the meta-analytic correlation between SD scores and prosocial behavior was close to zero, suggesting that SD scales neither clearly measure bias nor substantive traits. This conclusion was also supported by moderation analyses considering differences in the implementation of games and the SD scales used. The results further question the validity of SD scales with the implication that scholars and practitioners should refrain from using them.

Maxims nudge equitable or efficient choices in a Trade-Off Game

The core problem in the distribution dilemma is the trade-off between equity and efficiency. With the development of socio-economic conditions, the optimal decision changes between equitable and efficient options. The methods for nudging decision-makers to make optimal decisions without changing the event are extremely important. This study used two laboratory behavior experiments to explore the impact of maxim information on the trade-off between equity and efficiency. The study explores whether stake levels and division schemes affect the nudging effect of the maxim in a Trade-Off Game (TOG). We found that participants were affected by maxim information in decision-making scenarios, and participants showed different equity preferences as the maxim information changed, without relevance of the stake level. Additionally, the nudging effect of the maxim only exists under the condition that the distributor's interests is not affected.

Gender differences in the trade-off between objective equality and efficiency

Generations of social scientists have explored whether males and females act differently in domains involving competition, risk taking, cooperation, altruism, honesty, as well as many others. Yet, little is known about gender differences in the trade-off between objective equality (i.e., equality of outcomes) and efficiency. It has been suggested that females are more equal than males, but the empirical evidence is relatively weak. This gap is particularly important, because people in power of redistributing resources often face a conflict between equality and efficiency. The recently introduced Trade-Off Game (TOG) – in which a decision-maker has to unilaterally choose between being equal or being efficient – offers a unique opportunity to fill this gap. To this end, I analyse gender differences on a large dataset including N=6,955 TOG decisions. The results show that females prefer objective equality over efficiency to a greater extent than males do. The effect turns out to be particularly strong when the TOG available options are “morally” framed in such a way to suggest that choosing the equal option is the right thing to do.

Preferences and constraints: the value of economic games for studying human behaviour

As economic games have spread from experimental economics to other social sciences, so too have critiques of their usefulness for drawing inferences about the 'real world'. What these criticisms often miss is that games can be used to reveal individuals' private preferences in ways that observational and interview data cannot; furthermore, economic games can be designed such that they do provide insights into real-world behaviour. Here, we draw on our collective experience using economic games in field contexts to illustrate how researchers can strategically alter the framing or design of economic games to draw inferences about private-world or real-world preferences. A detailed case study from coastal Colombia provides an example of the subtleties of game design and how games can be combined fruitfully with self-report data. We close with a list of concrete recommendations for how to modify economic games to better match particular research questions and research contexts.

Procedural fairness and nepotism among local traditional and democratic leaders in rural Namibia

This study tests the common conception that democratically elected leaders behave in the interest of their constituents more than traditional chiefs do. Our sample includes 64 village leaders and 384 villagers in rural Namibia, where democratically elected leaders and traditional chiefs coexist. We analyze two main attributes of local political leaders: procedural fairness preferences and preferential treatment of relatives (nepotism). We also measure personality traits and social preferences, and conduct standardized surveys on local governance practices and villagers' perceptions of their leaders' performance. Our results indicate that traditional chiefs are as likely to implement fair, democratic decision-making procedures, and are as unlikely to be nepotistic. Moreover, elected leaders and chiefs express similar social preferences and personality traits. These findings align with villagers' perceptions of most leaders in our sample as being popular and fair, and villagers' responses reveal a discrepancy between planned and de facto implementation of democratic institutions.

Influences of a Luck Game on Offers in Ultimatum and Dictator Games: Is There a Mediation of Emotions?

The ultimatum (UG) and dictator (DG) games are two tasks where a sum of money has to be divided between two players: a proposer and a receiver. Following the rational choice theory, proposers should offer the minimum in the UG and nothing in the DG, due to the presence/absence of the receivers' bargaining power. The fact that people generally make non-negligible offers in both games has suggested divergent explicative hypotheses and has generated extensive research to examine exogenous and endogenous factors underlying such decisions. Among the contextual factors affecting the proposers' offers, the sense of entitlement or of ownership has been shown to reduce offers significantly. A frequent way to induce the sense of entitlement/ownership has been to assign the role of proposer to the player who apparently has better scored in skill tasks executed before the UG or DG or has more contributed, through a previous luck game, to the amount to be shared. Such manipulations, however, could produce a possible overlapping between "ownership" and "merit," that in this study we aimed to disentangle. We manipulated the participants' initial endowment through a luck game, by increasing, decreasing or leaving it unchanged, to investigate whether winnings or losses by chance influenced offers in UG and DG in similar or different ways depending on their respective features. All participants played as proposers but this role was apparently random and disconnected from the outcomes of the luck game. Furthermore, we investigated whether the putative effect of experimental manipulation was mediated by the changes in emotions elicited by the luck game and/or by the emotions and beliefs related to decision-making. We used a non-economic version of the games, in which tokens were divided instead of money. In the study, 300 unpaid undergraduates (M = 152) from different degree programs, aged between 18 and 42 years, participated. The results revealed that the effect of outcome manipulation on offers was moderated by the specific structure of the UG and DG. Instead, emotional reactions barely mediated the effect of the experimental manipulation, suggesting that their role in those decisions is less relevant than is assumed in the literature.

Do Perceiver Effects in Interpersonal Perception Predict Cooperation in Social Dilemmas?

People’s general tendencies to view others as cold-hearted and manipulative (rather than affectionate and trustworthy) may explain defection in social dilemma situations. To capture idiosyncratic tendencies in other-perceptions, we collected mutual judgments in groups of unacquainted individuals in two studies (N1 = 83, N2 = 413) and extracted perceiver effect scores using the Social Relations Model. In both studies, participants later played a public goods game. In Study 1, perceiver effects predicted cooperation beyond self-reported and group-related control variables. However, results were not replicated in a preregistered second study with higher power and a more diverse sample. We discuss implicit group norms as a likely explanation for the inconsistent findings and suggest future directions for addressing generalized expectations in social dilemmas.

Increasing altruistic and cooperative behaviour with simple moral nudges

The conflict between pro-self and pro-social behaviour is at the core of many key problems of our time, as, for example, the reduction of air pollution and the redistribution of scarce resources. For the well-being of our societies, it is thus crucial to find mechanisms to promote pro-social choices over egoistic ones. Particularly important, because cheap and easy to implement, are those mechanisms that can change people’s behaviour without forbidding any options or significantly changing their economic incentives, the so-called “nudges”. Previous research has found that moral nudges (e.g., making norms salient) can promote pro-social behaviour. However, little is known about whether their effect persists over time and spills across context. This question is key in light of research showing that pro-social actions are often followed by selfish actions, thus suggesting that some moral manipulations may backfire. Here we present a class of simple moral nudges that have a great positive impact on pro-sociality. In Studies 1–4 (total N = 1,400), we use economic games to demonstrate that asking subjects to self-report “what they think is the morally right thing to do” does not only increase pro-sociality in the choice immediately after, but also in subsequent choices, and even when the social context changes. In Study 5, we explore whether moral nudges promote charity donations to humanitarian organisations in a large (N = 1,800) crowdfunding campaign. We find that, in this context, moral nudges increase donations by about 44 percent.

Most People Keep Their Word Rather Than Their Money

Promises are crucial for human cooperation because they allow people to enter into voluntary commitments about future behavior. Here we present a novel, fully incentivized paradigm to measure voluntary and costly promise-keeping in the absence of external sanctions. We found across three studies (N = 4,453) that the majority of participants (61%-98%) kept their promises to pay back a specified amount of a monetary endowment, and most justified their decisions by referring to obligations and norms. Varying promise elicitation methods (Study 1a) and manipulating stake sizes (Study 2a) had negligible effects. Simultaneously, when others estimated promise-keeping rates (using two different estimation methods), they systematically underestimated promise-keeping by up to 40% (Studies 1b and 2b). Additional robustness checks to reduce potential reputational concerns and possible demand effects revealed that the majority of people still kept their word (Study 3). Promises have a strong normative power and binding effect on behavior. Nevertheless, people appear to pessimistically underestimate the power of others' promises. This behavior-estimation gap may prevent efficient coordination and cooperation.

The power of moral words: Loaded language generates framing effects in the extreme dictator game

Understanding whether preferences are sensitive to the frame has been a major topic of debate in the last decades. For example, several works have explored whether the dictator game in the give frame gives rise to a different rate of pro-sociality than the same game in the take frame, leading to mixed results. Here we contribute to this debate with two experiments. In Study 1 (N=567) we implement an extreme dictator game in which the dictator either gets $0.50 and the recipient gets nothing, or the opposite (i.e., the recipient gets $0.50 and the dictator gets nothing). We experimentally manipulate the words describing the available actions using six terms, from very negative (e.g., stealing) to very positive (e.g., donating) connotations. We find that the rate of pro-sociality is affected by the words used to describe the available actions. In Study 2 (N=221) we ask brand new participants to rate each of the words used in Study 1 from “extremely wrong” to “extremely right”. We find that these moral judgments can explain the framing effect in Study 1. In sum, our studies provide evidence that framing effects in an extreme Dictator game can be generated using morally loaded language.