Schadenfreude or empathy? Children's emotional responses to the physical pain and pleasure of prosocial and antisocial others

Adults' emotional reactions to the pain and pleasure of others are influenced by the moral character of those individuals. However, it remains unclear whether children's emotional responses also show such selectivity. To investigate this, we compared 4- to 8-year-old children's emotional responses to the physical pain and pleasure of prosocial versus antisocial puppets. In Study 1, children reported unhappiness after witnessing the pain of the prosocial and antisocial puppets but reported less unhappiness after witnessing the pain of the antisocial puppet. In Study 2, children reported happiness after witnessing the pleasure of both puppets but reported being less happy for the antisocial puppet. These results suggest that children are less likely to empathize with antisocial individuals. Meanwhile, children did not display Schadenfreude (pleasure at others' pain) or Gluckschmerz (displeasure at others' pleasure) toward antisocial individuals in our studies. Moreover, the selectivity of children's emotional responses disappeared after we manipulated the physical competence rather than the moral character of the puppets in Study 3. Our findings help to reveal the moral selectivity of emotional responses to others' pleasure and pain during early childhood.

The role of social motivation in sharing and fairness: insights from Williams syndrome

BACKGROUND

Sharing and fairness are important prosocial behaviors that help us navigate the social world. However, little is known about how and whether individuals with Williams Syndrome (WS) engage in these behaviors. The unique phenotype of individuals with WS, consisting of high social motivation and limited social cognition, can also offer insight into the role of social motivation in sharing and fairness when compared to typically developing (TD) individuals. The current study used established experimental paradigms to examine sharing and fairness in individuals with WS and TD individuals.

METHODS

We compared a sample of patients with WS to TD children (6-year-olds) matched by mental age (MA) on two experimental tasks: the Dictator Game (DG, Experiment 1, N = 17 WS, 20 TD) with adults modeling giving behaviors used to test sharing and the Inequity Game (IG, Experiment 2, N = 14 WS, 17 TD) used to test fairness.

RESULTS

Results showed that the WS group behaved similarly to the TD group for baseline giving in the DG and in the IG, rejecting disadvantageous offers but accepting advantageous ones. However, after viewing an adult model giving behavior, the WS group gave more than their baseline, with many individuals giving more than half, while the TD group gave less. Combined these results suggest that social motivation is sufficient for sharing and, in particular, generous sharing, as well as the self-focused form of fairness. Further, individuals with WS appear capable of both learning to be more generous and preventing disadvantageous outcomes, a more complex profile than previously known.

CONCLUSIONS

In conclusion, the present study provides a snapshot into sharing and fairness-related behaviors in WS, contributing to our understanding of the intriguing social-behavioral phenotype associated with this developmental disorder.

Win-win or lose-lose: Children prefer the form of equality

In middle childhood, children's sense of fairness further develops, they are willing to pay a cost to maintain equality. Win-win and lose-lose are two forms of equality. Win-win equality refers to both parties maximizing benefits, while lose-lose equality means both parties incurring the maximum loss. Win-win equality allows third party upholding fairness to gain more reputational benefits without the violator being punished, embodying the principle of "benefiting oneself without harming others". On the other hand, lose-lose equality is a more deterrent form of fairness with the violator getting punished, and the third-party might experience a situation of "effort without appreciation." However, the specific form of equality which school-aged children prefer still requires further exploration. Therefore, adopting the dictator game paradigm of third-party punishment, we design two experiments to investigate the fairness preference of first to fourth-grade children when acting as a third party and to clarify patterns of age-related changes. Study 1 (N = 111) explored children's preferred form of fairness under advantageous inequity conditions. Study 2 (N = 122) further examined children's fairness preferences in disadvantageous inequity situations. The findings suggest that when confronted with inequitable distributions, whether rooted in disadvantageous or advantageous inequity, children display a notable tendency to utilize third-party punishment to achieve an equal allocation. Meanwhile, this tendency strengthens as they progress in grade levels. Notably, children consistently manifest a preference for win-win equality, highlighting their inclination towards mutually beneficial outcomes.

Trusting young children to help causes them to cheat less

Trust and honesty are essential for human interactions. Philosophers since antiquity have long posited that they are causally linked. Evidence shows that honesty elicits trust from others, but little is known about the reverse: does trust lead to honesty? Here we experimentally investigated whether trusting young children to help can cause them to become more honest (total N = 328 across five studies; 168 boys; mean age, 5.94 years; s.d., 0.28 years). We observed kindergarten children's cheating behaviour after they had been entrusted by an adult to help her with a task. Children who were trusted cheated less than children who were not trusted. Our study provides clear evidence for the causal effect of trust on honesty and contributes to understanding how social factors influence morality. This finding also points to the potential of using adult trust as an effective method to promote honesty in children.

More than one path to pragmatics? Insights from children's grasp of implicit, figurative and ironical meaning

Human communication requires impressive inferential abilities and mind-reading skills. To learn how to speak and become competent communicators children need both. The development of pragmatic abilities presents us with a puzzle. On the one hand, much evidence suggests pragmatics play a grounding role in early communication and language acquisition. On the other, preschoolers find linguistic pragmatic inferences such as implicatures, metaphor and irony difficult to grasp. Apperly and Butterfill (2009) maintain that there are two separate systems for belief reasoning: a simpler one and a more sophisticated one that develops later. Along this line of reasoning we might also expect there to be two separate kinds of pragmatic abilities: an early set using (among other things) the simpler Theory of Mind system, and a more sophisticated one appearing later in childhood and using full-blown Theory of Mind. I will argue there is no need to divide pragmatic abilities in such a way to bridge the gap between the pragmatic inferential skills found in toddlers and the difficulties observed in preschoolers. Evidence from the past two decades indicates that phenomena such as implicatures and metaphor (but not irony) can be understood earlier than previously established. Additionally, children's apparent struggle with specific pragmatic inferences might be better explained by factors independent from pragmatic competence, but which interact with it.

Enhancing Subjective Wellbeing in Older Individuals with Amnestic Mild Cognitive Impairment: A Randomized Trial of a Positive Psychology Intervention

OBJECTIVES

This pilot study aims to explore the potential of a positive psychology intervention (PPI) in enhancing the subjective well-being of older individuals with amnestic mild cognitive impairment (MCI), a precursor to dementia.

DESIGN AND SETTING

A randomized trial was conducted, initially recruiting 51 participants aged 65 and above from the Greek Association of Alzheimer's Disease and Related Disorders in Thessaloniki, Greece. The study employed a control-experimental group setup. To ensure randomization, each participant was assigned a unique number, and a random number generator was used for group allocation.

PARTICIPANTS

A total of 41 eligible participants with amnestic mild cognitive impairment (MCI) were included in the study after screening.

INTERVENTION

The intervention consisted of a 3-week positive psychology program (PPI) where the PERMA Profiler questionnaire was administered at three intervals: pre-intervention, post-intervention, and one month after completion.

MAIN OUTCOME MEASURES

The subjective well-being of participants.

RESULTS

The analysis, conducted mainly through mixed-measures ANOVAs, supported the study's hypotheses, revealing that the 3-week PPI led to increased PERMA model scores and overall well-being, which persisted even after one month. Conversely, non-participants experienced declines in most domains except for Positive Emotion and Meaning, which demonstrated improvement and recovery during follow-up.

CONCLUSIONS

These findings suggest the potential of PPI in enhancing the subjective well-being of older adults with amnestic MCI, with implications for addressing dementia-related challenges. Further investigation is warranted to pinpoint PPI effects on MCI and tailor interventions for improved subjective well-being.

Children perpetuate competence-based inequality when they help peers

Exchanges of help between children are common and often have positive consequences. But not all help is equally beneficial, for example because some help does not provide an opportunity to practice and develop skills. Here I examine whether young children might perpetuate competence-based inequality by providing incompetent peers with less opportunity to practice and improve their skills compared to competent peers. Study 1 (N = 253, 6-9 years) shows that young children understand not all help is equally beneficial: Children think that peers who receive empowerment (hints) vs. non-empowerment (correct answers) help can learn more. Study 2 (N = 80) and 3 (N = 41) then assessed children's (7-9 years) actual helping behavior in a lab-based experiment. Through a cover story, participants were introduced to two unknown, same-age children whom they later overheard were either good or not good at solving puzzles (Study 2) or math (Study 3). Subsequently, participants got to help both of them with a puzzle-quiz (Study 2) or a math-quiz (Study 3) by providing either empowerment or non-empowerment when they asked for help. Across both studies, children were more likely to provide empowerment help to competent peers, and non-empowerment help to incompetent peers. This work suggests that when young children perceive differences in competence (e.g., based on stereotypes), they contribute to maintaining the status quo by providing the most vulnerable students, that would profit the most from improving their skills, less opportunity to do so.

How "peer-fear" of others' evaluations can regulate young children's cooperation

Children's cooperation with peers undergoes substantial developmental changes between 3 and 10 years of age. Here we stipulate that young children's initial fearfulness of peers' behaviour develops into older children's fearfulness of peers' evaluations of their own behaviour. Cooperation may constitute an adaptive environment in which the expressions of fear and self-conscious emotions regulate the quality of children's peer relationships.

Children's consideration of collaboration and merit when making sharing decisions in private

Young children share equally when they acquire resources through collaboration with a partner, yet it is unclear whether they do so because in such contexts resources are encountered as common and distributed in front of the recipient or because collaboration promotes a sense of work-based fairness. In the current studies, 5- and 8-year-old children from Germany (N = 193) acquired resources either by working individually alongside or by collaborating with a peer. After finding out that the partner's container was empty, they decided in private whether they wanted to donate some resources to the peer. When both partners had worked with equal efforts (Study 1), children shared more after collaboration than after individual work. When one partner had worked with much more effort than the other (Study 2), children shared more with a harder-working partner than with a less-working partner independently of whether they had collaborated or worked individually. Younger children were more generous than older children, in particular after collaboration. These findings support the view that collaboration promotes a genuine sense of fairness in young children, but they also indicate that merit-based notions of fairness in the context of work may develop independently of collaboration, at least by the beginning of middle childhood and in Western societies.

Preschoolers selectively trust and selectively share with others based on their past accuracy and intentions

This study investigated whether preschool-age children consider both an individual's past accuracy and intentions when deciding whether to trust and share with that individual. The participants, 3- to 5-year-olds (N = 168), played a searching game with partners who varied in both accuracy (accurate or inaccurate) and intentions (prosocial or antisocial). Children received advice from partners about where to look for a hidden object, earning prizes for correct guesses. Then they were given an opportunity to share their prizes with their partner. Results indicated that children trusted sources who provided accurate advice (regardless of intentions) and shared with sources who provided accurate advice or demonstrated prosocial intentions. These findings suggest that children attend to both an individual's accuracy and intentions when deciding how to interact with social partners and may weigh this information differently to make different social decisions.

Helpers or halos: examining the evaluative mechanisms underlying selective prosociality

This research examines the proximate evaluative mechanisms underlying prosocial partner choice-based reciprocity. Across four studies we presented 855 university undergraduates (online for course credit) and 76 4- to 6-year-olds (offline at a university laboratory) with vignettes describing prosocial, social and non-social characters, and asked participants about their person preferences in prosocial, social and general contexts. Adults demonstrated sophisticated appraisals, coordinating between relevant trait and contextual cues to make selections. Adults were particularly attentive to prosocial cues in costly conditions, suggesting that they were using dispositional attributions to make their selections. By contrast, children were largely unable to integrate trait and contextual cues in determining their partner preferences, instead displaying valenced preferences for non-social cues, suggesting the use of affective tagging. Together, these studies demonstrate that the mechanisms underlying prosocial, partner choice-based reciprocity are not early emerging and stable but show considerable development over the lifespan.

Like parent, like offspring: Intergenerational association of parental scarcity mindset with offspring's cooperative behaviors

A sense of resource availability creates a scarcity mindset, leading people to behave in a more competitive way instead of in a collaborative way. This study aims to examine the relationship between scarcity mindset and cooperative behaviors among parents and offspring, and to explore whether parents' scarcity mindset is related to their offspring's scarcity mindset and cooperative behaviors. We collected 239 parent-offspring pairs from several universities in northwest China. They completed the scarcity mindset scale and a one-shot public good game (PGG). A path model analysis was conducted to examine the relationship between scarcity mindset and cooperative behaviors for offspring and their parents, respectively. The relationship between parental scarcity mindset and offspring's cooperative behaviors was also examined. The results showed that there was a high correlation of scarcity mindset between parents and their offspring. Scarcity mindset was negatively related to cooperative behaviors among both parents and offspring. In addition, both parents' cooperative behaviors and offspring's scarcity mindset mediated the relationship between the parental scarcity mindset and offspring's cooperative behaviors. Our results supported the idea that scarcity mindset triggers competitive rather than cooperative orientation. The present findings reveal an intergenerational relationship between scarcity mindset and cooperative behaviors by highlighting the impacts of parental scarcity mindset on that of their offspring's and its additional effects on offspring's cooperative behaviors.

Longitudinal development of children's sharing behaviour: Only children versus children with siblings from rural China

This study examined the development of children's sharing behaviour towards friends and strangers using dictator games with a longitudinal design in a sample of rural Chinese children (n = 589, 47.0% girls) at 3-4 years old and 2 years later (n = 453, 44.2% girls). Results showed that the willingness to share and the amount of sharing changed over time and were affected by family structure. Only children shared fewer stickers than non-only children at ages 3-4, but the amount they shared did not differ at ages 5-6. Only children may develop reciprocal friendships at an older age due to their lack of experience with siblings. Children shared more stickers with friends than strangers at ages 3-4, and such ingroup bias became stronger at ages 5-6.

Interpersonal utility and children's social inferences from shared preferences

Similarity of behaviors or attributes is often used to infer social affiliation and prosociality. Does this reflect reasoning using a simple expectation of homophily, or more complex reasoning about shared utility? We addressed this question by examining the inferences children make from similar choices when this similarity does or does not cause competition over a zero-sum resource. Four- to six-year-olds (N = 204) saw two vignettes, each featuring three characters (a target plus two others) choosing between two types of resources. In all stories, each character expressed a preference: one 'other' chose the same resource as the target, while a second 'other' chose the different resource. In one condition there were enough resources for all the characters; in the other condition, one type of resource was limited, with only one available (inducing potential competition between the target and the similar-choice other). Children then judged which of the two 'other' characters was being nicer (prosocial judgment) and which of the two was more preferred by the target (affiliative inference). When resources were limited (vs. unlimited), children were less likely to select the similar other as being nice. Children's initial tendency to report that the target preferred the similar other was also eliminated in the limited resource scenario. These findings show that children's reasoning about similarity is not wholly based on homophily. Instead, by reasoning about shared utility - how each person values the goals of others - children engage in flexible inferences regarding whether others' similar preferences and behaviors have positive or negative social meaning.

The profit motive: Implications for children's reasoning about merit-based resource distribution

How to distribute resources in a fair way is a fundamental source of conflict in human societies. A central dilemma that people begin to grapple with during childhood is the extent to which individuals should be rewarded based on merit at the expense of equality. The current study examined children's reasoning about this dilemma by testing whether they are sensitive to information about the motives of highly productive people when determining whether they should receive extra compensation. Across two studies, children (6- to 11-year-olds, total N = 143) judged high performers to be less deserving of extra resources when they were motivated by profit rather than being intrinsically motivated, and this pattern was more pronounced among the older children. The findings demonstrate that, with age, children increasingly consider motives when deciding whether productivity should be rewarded and that the tendency of adults to view profit motives as problematic has origins during childhood.

Evidence for a developmental shift in the motivation underlying helping in early childhood

We investigated children's positive emotions as an indicator of their underlying prosocial motivation. In Study 1, 2-, and 5-year-old children (N = 64) could either help an individual or watch as another person provided help. Following the helping event and using depth sensor imaging, we measured children's positive emotions through changes in postural elevation. For 2-year-olds, helping the individual and watching another person help was equally rewarding; 5-year-olds showed greater postural elevation after actively helping. In Study 2, 5-year-olds' (N = 59) positive emotions following helping were greater when an audience was watching. Together, these results suggest that 2-year-old children have an intrinsic concern that individuals be helped whereas 5-year-old children have an additional, strategic motivation to improve their reputation by helping.

A lineage explanation of human normative guidance: the coadaptive model of instrumental rationality and shared intentionality

This paper aims to contribute to the existing literature on normative cognition by providing a lineage explanation of human social norm psychology. This approach builds upon theories of goal-directed behavioral control in the reinforcement learning and control literature, arguing that this form of control defines an important class of intentional normative mental states that are instrumental in nature. I defend the view that great ape capacities for instrumental reasoning and our capacity (or family of capacities) for shared intentionality coadapted to each other and argue that the evolution of this capacity has allowed the representation of social norms and the emergence of our capacity for normative guidance.

Infants expect agents to minimize the collective cost of collaborative actions

This paper argues that human infants address the challenges of optimizing, recognizing, and interpreting collaborative behaviors by assessing their collective efficiency. This hypothesis was tested by using a looking-time study. Fourteen-month-olds (N = 32) were familiarized with agents performing a collaborative action in computer animations. During the test phase, the looking times were measured while the agents acted with various efficiency parameters. In the critical condition, the agents' actions were individually efficient, but their combination was either collectively efficient or inefficient. Infants looked longer at test events that violated expectations of collective efficiency (p = .006, d = 0.79). Thus, preverbal infants apply expectations of collective efficiency to actions involving multiple agents.

Human adults prefer to cooperate even when it is costly

Joint actions are cooperative activities where humans coordinate their actions to achieve individual and shared goals. While the motivation to engage in joint action is clear when a goal cannot be achieved by individuals alone, we asked whether humans are motivated to act together even when acting together is not necessary and implies incurring additional costs compared to individual goal achievement. Using a utility-based empirical approach, we investigated the extent of humans' preference for joint action over individual action, when the instrumental costs of performing joint actions outweigh the benefits. The results of five experiments showed that human adults have a stable preference for joint action, even if individual action is more effective to achieve a certain goal. We propose that such preferences can be understood as ascribing additional reward value to performing actions together.

Mini managers: Children strategically divide cognitive labor among collaborators, but with a self-serving bias

Strategic collaboration according to the law of comparative advantage involves dividing tasks based on the relative capabilities of group members. Three experiments (N = 405, primarily White and Asian, 45% female, collected 2016-2019 in Canada) examined how this strategy develops in children when dividing cognitive labor. Children divided questions about numbers between two partners. By 7 years, children allocated difficult questions to the skilled partner (Experiment 1, d = 1.42; Experiment 2, d = 0.87). However, younger children demonstrated a self-serving bias, choosing the easiest questions for themselves. Only when engaging in a third-party collaborative task did 5-year-olds assign harder questions to the more skilled individual (Experiment 3, d = 0.55). These findings demonstrate early understanding of strategic collaboration subject to a self-serving bias.

The development of prosocial behavior-from sympathy to strategy

Children act prosocially already in their first years of life. Research has shown that this early prosociality is mostly motivated by sympathy for others, but that, over the course of development, children's prosocial behaviors become more varied, more selective, and more motivationally and cognitively complex. Here, we review recent evidence showing that starting at around age 5, children become gradually capable of strategically using prosocial acts as instrumental means to achieve ulterior goals such as to improve their reputation, to be chosen as social partners, to elicit reciprocity, and to navigate interpersonal obligations. Children's sympathy-based prosociality is thus being extended and reshaped into a behavioral repertoire that enables individuals to pursue and balance altruistic, mutualistic, and selfish motives.

Competence-based helping: Children's consideration of need when providing others with help

When and how other people's needs influence children's helping is poorly understood. Here we focused on whether children use information about other people's competence in their helping. In Study 1 (N = 128 4- to 8-year-old children), children could provide help to both an incompetent target and a competent target by pushing levers. Whereas older children helped incompetent targets more than competent targets, younger children (<5 years) helped both targets equally. Two further experiments (N = 20 and N = 28) revealed that 4-year-olds understood that the incompetent person needed more help and also understood how they could help. Thus, young children do not, like older children, give more help to those who need it the most. We discuss potential developmental changes toward competence-based helping.

Modern theories of human evolution foreshadowed by Darwin's Descent of Man

Charles Darwin's The Descent of Man, published 150 years ago, laid the grounds for scientific studies into human origins and evolution. Three of his insights have been reinforced by modern science. The first is that we share many characteristics (genetic, developmental, physiological, morphological, cognitive, and psychological) with our closest relatives, the anthropoid apes. The second is that humans have a talent for high-level cooperation reinforced by morality and social norms. The third is that we have greatly expanded the social learning capacity that we see already in other primates. Darwin's emphasis on the role of culture deserves special attention because during an increasingly unstable Pleistocene environment, cultural accumulation allowed changes in life history; increased cognition; and the appearance of language, social norms, and institutions.

Waste Aversion Reduces Inequity Aversion Among Chinese Children

An underlying aspect of the development of fairness is the aversion to unequal treatment toward equally deserving parties. By middle childhood, children from Western cultures are even willing to discard resources to avoid inequity. Here, a series of four studies were conducted to assess the robustness of inequity aversion in a culture that emphasizes the value of "Thrift" (i.e., waste aversion). Seven-year-old Chinese participated in third-party (N = 83) and first-person (N = 116) distributive interactions and considered both inequity aversion and waste aversion. Our findings demonstrate that Chinese children accepted inequity (unlike Americans) in the presence of waste but avoided inequity (similar to Americans) in the absence of waste. Cultural and noncultural accounts of waste aversion are discussed.

Variation in primate decision-making under uncertainty and the roots of human economic behaviour

Uncertainty is a ubiquitous component of human economic behaviour, yet people can vary in their preferences for risk across populations, individuals and different points in time. As uncertainty also characterizes many aspects of animal decision-making, comparative research can help evaluate different potential mechanisms that generate this variation, including the role of biological differences or maturational change versus cultural learning, as well as identify human-unique components of economic decision-making. Here, we examine decision-making under risk across non-human primates, our closest relatives. We first review theoretical approaches and current methods for understanding decision-making in animals. We then assess the current evidence for variation in animal preferences between species and populations, between individuals based on personality, sex and age, and finally, between different contexts and individual states. We then use these primate data to evaluate the processes that can shape human decision-making strategies and identify the primate foundations of human economic behaviour. This article is part of the theme issue 'Existence and prevalence of economic behaviours among non-human primates'.

The Origins and Psychology of Human Cooperation

Humans are an ultrasocial species. This sociality, however, cannot be fully explained by the canonical approaches found in evolutionary biology, psychology, or economics. Understanding our unique social psychology requires accounting not only for the breadth and intensity of human cooperation but also for the variation found across societies, over history, and among behavioral domains. Here, we introduce an expanded evolutionary approach that considers how genetic and cultural evolution, and their interaction, may have shaped both the reliably developing features of our minds and the well-documented differences in cultural psychologies around the globe. We review the major evolutionary mechanisms that have been proposed to explain human cooperation, including kinship, reciprocity, reputation, signaling, and punishment; we discuss key culture-gene coevolutionary hypotheses, such as those surrounding self-domestication and norm psychology; and we consider the role of religions and marriage systems. Empirically, we synthesize experimental and observational evidence from studies of children and adults from diverse societies with research among nonhuman primates.

Why do children punish? Fair outcomes matter more than intent in children's second- and third-party punishment

Humans punish fairness violations both as victims and as impartial third parties, which can maintain cooperative behavior. However, it is unknown whether similar motivations underlie punishment of unfairness in these two contexts. Here we approached this question by focusing on how both types of punishment develop in children, asking the question: What motivates young children to punish in response to fairness norm violations? We explored two potential factors: the direct experience of unfair outcomes and a partner's fair versus unfair intentions. The participants, 5- and 7-year-olds, were given the chance to engage in both second- and third-party punishment in response to either intended or unintended fairness norm violations in a single paradigm. In both age-groups, children were more likely to punish when they were directly affected by the allocation (second-party punishment) than when they were an uninvolved third party (third-party punishment). Reliable third-party punishment was shown only in the older age-group. Moreover, children's punishment was driven by outcome rather than intent, with equal rates of punishment when unequal outcomes were either the result of chance or the intentional act of another child. These findings suggest that younger children may be mainly motivated to create equal outcomes between themselves and others, whereas older children are motivated to enforce fairness norms as a general principle.

Do 7-year-old children understand social leverage?

Individuals with an advantageous position during a negotiation possess leverage over their partners. Several studies with adults have investigated how leverage can influence the coordination strategies of individuals when conflicts of interest arise. In this study, we explored how pairs of 7-year-old children solved a coordination game (based on the Snowdrift scenario) when one child had leverage over the other child. We presented a social dilemma in the form of an unequal reward distribution on a rotating tray. The rotating tray could be accessed by both children. The child who waited longer to act received the best outcome, but if both children waited too long, they would lose the rewards. In addition, one child could forgo the access to the rotating tray for an alternative option-the leverage. Although children rarely used their leverage strategically, children with access to the alternative were less likely to play the social dilemma, especially when their leverage was larger. Furthermore, children waited longer to act as the leverage decreased. Finally, children almost never failed to coordinate. The results hint to a trade-off between maximizing benefits while maintaining long-term collaboration in complex scenarios where strategies such as turn taking are hard to implement.

Young Children's Judgments and Reasoning about Prosocial Acts: Impermissible, Suberogatory, Obligatory, or Supererogatory?

In deciding when to help, individuals reason about whether prosocial acts are impermissible, suberogatory, obligatory, or supererogatory. This research examined judgments and reasoning about prosocial actions at three to five years of age, when explicit moral judgments and reasoning are emerging. Three-to five-year-olds (N = 52) were interviewed about prosocial actions that varied in costs/benefits to agents/recipients, agent-recipient relationship, and recipient goal valence. Children were also interviewed about their own prosocial acts. Adults (N = 56) were interviewed for comparison. Children commonly judged prosocial actions as obligatory. Overall, children were more likely than adults to say that agents should help. Children's judgments and reasoning reflected concerns with welfare as well as agent and recipient intent. The findings indicate that 3-to 5-year-olds make distinct moral judgments about prosocial actions, and that judgments and reasoning about prosocial acts subsequently undergo major developments.

Children avoid inefficient but fair partners in a cooperative game

Human adults use a range of social cues to obtain information about potential partners in cooperative contexts: we prefer partners who are competent, wealthy and generous, and those who abide by moral and social rules. One factor that carries particular weight is whether a prospective partner is fair. Here we ask whether children share this preference for fair partners and, if so, whether a prospective partner’s past fair behaviour influences children’s behaviour in a cooperative dilemma. Six- to nine-year-olds chose between partners who accepted or rejected resource allocations that were either strongly advantageously unequal, strongly disadvantageously unequal, or equal. They then played a one-shot Prisoner’s Dilemma Game with their chosen partner. Children overwhelmingly preferred to play with the partner who accepted rather than rejected allocations. Regardless of their partner choice decisions, children tended to defect in the Prisoner’s Dilemma Game, yet expected that their partners would be relatively more cooperative. Finally, children were more likely to cooperate with those they believed would cooperate. Together, these findings shed new light on the links between partner choice, fairness and cooperation in child development.

When Helping Hurts: Children Think Groups That Receive Help Are Less Smart

Helping has many positive consequences for both helpers and recipients. However, in the present research, we considered a possible downside to receiving help: that it signals a deficiency. We investigated whether young children make inferences about intelligence from observing some groups of people receive help and other groups not. In a novel group paradigm, we show that children (4–6 years) think groups that receive help are less smart (n = 44) but not less nice (n = 45). Children also generalized their inferences about relative intelligence to new group members (n = 55; forced‐choice‐method). These results have implications for understanding how children develop stereotypes about intelligence as well as for educational practices that group children according to their ability.

Pay to play: Children's emerging ability to use acts of generosity for selfish ends

Adults will offer favors to advance their standing and solicit a favor in return, using ostensibly prosocial acts strategically for selfish ends. Here we assessed the developmental emergence of such strategic behaviors in which individuals are generous to elicit future reciprocation from others. In a novel experimental paradigm with children aged 3 to 7 years, we tested whether children are willing to share more valuable resources when this act could prompt subsequent reciprocation. In an Experimental condition, children could share a more attractive or less attractive resource with a person who they knew would subsequently choose to play a game with either the children or another individual. In the Control condition, children knew the person would play alone. Across two studies, we found that over repeated trials, 5- and 7-year-olds, but not 3-year-olds, learned to share more valuable resources in the Experimental condition than in the Control condition. This shows that older age groups were able to quickly learn how to influence the subsequent partner choice in a novel situation. We address theoretical questions about the various types of reciprocity as being supported by different psychological mechanisms and discuss whether the current results could be explained by children's emerging ability for future-directed thinking.

Paying Back People Who Harmed Us but Not People Who Helped Us: Direct Negative Reciprocity Precedes Direct Positive Reciprocity in Early Development

The principle of direct reciprocity, or paying back specific individuals, is assumed to be a critical component of everyday social exchange and a key mechanism for the evolution of cooperation. Young children know the norm of reciprocity, but it is unclear whether they follow the norm for both positive and negative direct reciprocity or whether reciprocity is initially generalized. Across five experiments ( N = 330), we showed that children between 4 and 8 years of age engaged in negative direct reciprocity but generalized positive reciprocity, despite recalling benefactors. Children did not endorse the norm of positive direct reciprocity as applying to them until about 7 years of age (Study 4), but a short social-norm training enhanced this behavior in younger children (Study 5). Results suggest that negative direct reciprocity develops early, whereas positive reciprocity becomes targeted to other specific individuals only as children learn and adopt social norms.

Economic trust in young children

Mutually beneficial interactions often require trust that others will reciprocate. Such interpersonal trust is foundational to evolutionarily unique aspects of human social behaviour, such as economic exchange. In adults, interpersonal trust is often assessed using the 'trust game', in which a lender invests resources in a trustee who may or may not repay the loan. This game captures two crucial elements of economic exchange: the potential for greater mutual benefits by trusting in others, and the moral hazard that others may betray that trust. While adults across cultures can trust others, little is known about the developmental origins of this crucial cooperative ability. We developed the first version of the trust game for use with young children that addresses these two components of trust. Across three experiments, we demonstrate that 4- and 6-year-olds recognize opportunities to invest in others, sharing more when reciprocation is possible than in a context measuring pure generosity. Yet, children become better with age at investing in trustworthy over untrustworthy partners, indicating that this cooperative skill emerges later in ontogeny. Together, our results indicate that young children can engage in complex economic exchanges involving judgements about interpersonal trust and show increasing sensitivity to appropriate partners over development.

The influence of intention and outcome on young children's reciprocal sharing

This study investigated the influence of underlying intentions and outcomes of a partner's sharing behavior on young children's reciprocity. We provided 3- and 5-year-old children with the opportunity to share with a partner following different treatments of a partner's intention (to share or not to share) that led to different outcomes (children got or did not get stickers from their partner). For the 3-year-olds, we found that the outcome of the previous interaction influenced how much they shared, whereas the intention of their partner affected how readily they initiated sharing in response to social cues. For the 5-year-olds, we found that both outcome and intention affected how much they shared as well as how readily they initiated sharing. This suggests that already 3-year-olds are able to take into account outcome and intention information separately in reciprocal sharing. However, only 5-year-olds can combine both to flexibly maintain social interactions without running the risk of being exploited by others.

Children, but not great apes, respect ownership

Access to and control of resources is a major source of costly conflicts. Animals, under some conditions, respect what others control and use (i.e. possession). Humans not only respect possession of resources, they also respect ownership. Ownership can be viewed as a cooperative arrangement, where individuals inhibit their tendency to take others' property on the condition that those others will do the same. We investigated to what degree great apes follow this principle, as compared to human children. We conducted two experiments, in which dyads of individuals could access the same food resources. The main test of respect for ownership was whether individuals would refrain from taking their partner's resources even when the partner could not immediately access and control them. Captive apes (N = 14 dyads) failed to respect their partner's claim on food resources and frequently monopolized the resources when given the opportunity. Human children (N = 14 dyads), tested with a similar apparatus and procedure, respected their partner's claim and made spontaneous verbal references to ownership. Such respect for the property of others highlights the uniquely cooperative nature of human ownership arrangements.

Human children but not chimpanzees make irrational decisions driven by social comparison

Human evolutionary success is often argued to be rooted in specialized social skills and motivations that result in more prosocial, rational and cooperative decisions. One manifestation of human ultra-sociality is the tendency to engage in social comparison. While social comparison studies typically focus on cooperative behaviour and emphasize concern for fairness and equality, here we investigate the competitive dimension of social comparison: a preference for getting more than others, expressed in a willingness to maximize relative payoff at the cost of absolute payoff. Chimpanzees and human children (5-6- and 9-10-year-olds) could decide between an option that maximized their absolute payoff (but put their partner at an advantage) and an option that maximized their relative payoff (but decreased their own and their partner's payoff). Results show that, in contrast to chimpanzees and young children, who consistently selected the rational and payoff-maximizing option, older children paid a cost to reduce their partner's payoff to a level below their own. This finding demonstrates that uniquely human social skills and motivations do not necessarily lead to more prosocial, rational and cooperative decision-making.

Age-related differences in judgments of reciprocal and unilateral prosocial behaviors

We examined age-related differences in evaluating reciprocal prosocial behavior (e.g., helping someone who has helped you) and unilateral prosocial behavior (e.g., helping someone who has previously refused your request for help). Participants were kindergarteners, second and fifth graders, and undergraduate students (N = 110). We examined the trait evaluations of reciprocal and unilateral prosocial protagonists, behavior predictions of the participants in reciprocal and unilateral situations, and behavior predictions of others (including reciprocal and unilateral protagonists and others known to the participants) in reciprocal and unilateral prosocial situations. Results revealed that most kindergarteners did not focus on whether help was reciprocal or unilateral, and there were no clear differences in trait evaluations or predicted reciprocal or unilateral prosocial behaviors. In contrast, older children and undergraduates tended to focus on the difference between reciprocal and unilateral help. They evaluated unilateral protagonists more positively than reciprocal protagonists, and they judged the likelihood that others would engage in unilateral prosocial behaviors as lower than the likelihood that they would engage in reciprocal behaviors. However, most participants, regardless of age, predicted that they themselves would act prosocially in both reciprocal and unilateral situations. We discuss how the current results have implications for research on age-related trends in evaluating reciprocity and morality.

How does “emporiophobia” develop?

Boyer & Petersen's (B&P's) evolutionary approach to folk-economic beliefs is insightful, with far-reaching implications. We add to their discussion by positing a complementary developmental approach to the study of “emporiophobia” – studying children whose behaviors provide insight into developmental origins. We hypothesize that emporiophobia emerges early in childhood through proximal mechanisms and propose that emporiophobia develops alongside emporiophilia.