The shadow of the future: 5-Year-olds, but not 3-year-olds, adjust their sharing in anticipation of reciprocation

Italian Validation of the Delaying Gratification Inventory in Adolescents

The delay of gratification (DoG) is defined as the willingness to forego immediate satisfaction to achieve greater long-term gratification. This ability is essential in adolescence, as its development is crucial against desirable versus undesirable behaviors. This study investigated the psychometric proprieties of the Delaying Gratification Inventory (DGI) in Italian adolescents. A total of 621 Italian adolescents, ranging from 14 to 17 years old (M = 15.92, SD = 1.05; 47.7% boys), participated in the study. Confirmatory factor analysis identified a four-factor structure (delay of gratification concerning Food, Social Interaction, Money, and Achievement). The reliability of the Italian DGI was acceptable. Measurement invariance across gender was supported. Boys reached a higher DoG score in the Food subscale and a lower score in the Social Interaction and Achievement subscales than girls. Moreover, the Italian DGI dimensions were all positively correlated with self-control and prosocial behavior. Except for the Social Interaction subscale, positive correlations were found between the Food, Money, and Achievement subscales and self-esteem. The present findings suggest that the Italian DGI could be used for assessing DoG ability, a key regulatory ability that promotes healthy behaviors in adolescence.

Prospection and delay of gratification support the development of calculated reciprocity

Humans frequently benefit others strategically to elicit future cooperation. While such forms of calculated reciprocity are powerful in eliciting cooperative behaviors even among self-interested agents, they depend on advanced cognitive and behavioral capacities such as prospection (representing and planning for future events) and extended delay of gratification. In fact, it has been proposed that these constraints help explain why calculated reciprocity exists in humans and is rare or even absent in other animals. The current study investigated the cognitive foundation of calculated reciprocity by examining its ontogenetic emergence in relation to key aspects of children's cognitive development. Three-to-five-year-old children from the US (N = 72, mostly White, from mixed socioeconomic backgrounds) first completed a cognitive test battery assessing the cognitive capacities hypothesized to be foundational for calculated reciprocity. In a second session, children participated in a calculated reciprocity task in which they could decide how many resources to share with a partner who later had the opportunity to reciprocate (reciprocity condition) and with a partner who could not reciprocate (control condition). Results indicated a steep developmental emergence of calculated reciprocity between 3 and 5 years of age. Further analyses showed that measures of delay of gratification and prospection were important predictors of children's rate of calculated reciprocity, even when controlling for age and after including a measure of verbal ability. By contrast, theory of mind abilities were unrelated to children's reciprocal behavior. This is the first systematic investigation of essential cognitive capacities for calculated reciprocity. We discuss prospection and delay of gratification as two domain-general capacities that are utilized for calculated reciprocity and which could explain developmental as well as species-differences in cooperation.

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.

Moral disciplining: The cognitive and evolutionary foundations of puritanical morality

Why do many societies moralize apparently harmless pleasures, such as lust, gluttony, alcohol, drugs, and even music and dance? Why do they erect temperance, asceticism, sobriety, modesty, and piety as cardinal moral virtues? According to existing theories, this puritanical morality cannot be reduced to concerns for harm and fairness: It must emerge from cognitive systems that did not evolve for cooperation (e.g., disgust-based "purity" concerns). Here, we argue that, despite appearances, puritanical morality is no exception to the cooperative function of moral cognition. It emerges in response to a key feature of cooperation, namely that cooperation is (ultimately) a long-term strategy, requiring (proximately) the self-control of appetites for immediate gratification. Puritanical moralizations condemn behaviors which, although inherently harmless, are perceived as indirectly facilitating uncooperative behaviors, by impairing the self-control required to refrain from cheating. Drinking, drugs, immodest clothing, and unruly music and dance are condemned as stimulating short-term impulses, thus facilitating uncooperative behaviors (e.g., violence, adultery, free-riding). Overindulgence in harmless bodily pleasures (e.g., masturbation, gluttony) is perceived as making people slave to their urges, thus altering abilities to resist future antisocial temptations. Daily self-discipline, ascetic temperance, and pious ritual observance are perceived as cultivating the self-control required to honor prosocial obligations. We review psychological, historical, and ethnographic evidence supporting this account. We use this theory to explain the fall of puritanism in western, educated, industrialized, rich, and democratic (WEIRD) societies, and discuss the cultural evolution of puritanical norms. Explaining puritanical norms does not require adding mechanisms unrelated to cooperation in our models of the moral mind.

How resource sharing resists scarcity: the role of cognitive empathy and its neurobiological mechanisms

Resource scarcity challenges individuals' willingness to share limited resources with other people. Still, lots of field studies and laboratory experiments have shown that sharing behaviors do not disappear under scarcity. Rather, some individuals are willing to share their scarce resources with others in a similar way as when the resource is abundant, which is crucial for the maintenance and development of human society. Here, we designed a novel paradigm in which subjects decided whether (and how much) to share an amount of "relieving resources" for counteracting unpleasant noises, which mimics real-life situations that people cost their own resources to help others escape from adversity. Overall, the robustness of resource sharing under scarcity was positively correlated with individual level of the cognitive component of empathy across two independent experiments. Resource insufficiency modulated the activations of several brain regions (including the TPJ, mPFC, and PCC) as well as the functional connection (from the rTPJ to the mPFC) within the mentalizing brain network, but the modulatory effect decreased as a function of cognitive empathy. We also applied the administration of oxytocin and found significant effects on sharing behavior among individuals with a higher level of cognitive empathy, but not their low-level counterparts. These findings highlight the importance of empathy to resource sharing under scarcity and explain the underlying neurobiological mechanisms.

The psychological foundations of reputation-based cooperation

Humans care about having a positive reputation, which may prompt them to help in scenarios where the return benefits are not obvious. Various game-theoretical models support the hypothesis that concern for reputation may stabilize cooperation beyond kin, pairs or small groups. However, such models are not explicit about the underlying psychological mechanisms that support reputation-based cooperation. These models therefore cannot account for the apparent rarity of reputation-based cooperation in other species. Here, we identify the cognitive mechanisms that may support reputation-based cooperation in the absence of language. We argue that a large working memory enhances the ability to delay gratification, to understand others' mental states (which allows for perspective-taking and attribution of intentions) and to create and follow norms, which are key building blocks for increasingly complex reputation-based cooperation. We review the existing evidence for the appearance of these processes during human ontogeny as well as their presence in non-human apes and other vertebrates. Based on this review, we predict that most non-human species are cognitively constrained to show only simple forms of reputation-based cooperation. This article is part of the theme issue 'The language of cooperation: reputation and honest signalling'.

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.

I'm not a little kid anymore! Reciprocal social influence in child-adult interaction

Human decisions are often influenced by others' opinions. This process is regulated by social norms: for instance, we tend to reciprocate the consideration received from others, independently of their reliability as information sources. Nonetheless, no study to date has investigated whether and how reciprocity modulates social influence in child-adult interaction. We tested 6-, 8- and 10-year-old children in a novel joint perceptual task. A child and an adult experimenter made perceptual estimates and then took turns in making a final decision, choosing between their own and partner's response. We manipulated the final choices of the adult partner, who in one condition chose often the child's estimates, whereas in another condition tended to confirm her own response. Results reveal that 10-year-old children reciprocated the consideration received from the partner, increasing their level of conformity to the adult's judgements when the partner had shown high consideration towards them. At the same time, 10-year-old children employed more elaborate decision criteria in choosing when trusting the adult partner compared to younger children and did not show egocentric biases in their final decisions. Our results shed light on the development of the cognitive and normative mechanisms modulating reciprocal social influence in child-adult interaction.

Friendship is more than strategic reciprocity: Preschoolers' selective sharing with friends cannot be reduced to strategic concerns

The current study investigated whether children share especially much with their friends when sharing can be reciprocated (strategic sharing) or whether friendship and strategic reciprocity are independent factors in predicting children's sharing. If the former is the case, children should prefer their friend relatively more in a situation where the friend can reciprocate than in a situation without the possibility for reciprocity. In two experiments, 3- and 5-year-old participants (N = 270) could distribute stickers between themselves and three recipients: a friend, a child who would join the kindergarten group the next day, and a stranger. Half of the children were led to believe that their generosity could be reciprocated, and the other half were not. In Experiment 1, this was implemented by anonymous and nonanonymous sharing. In Experiment 2, the possibility of reciprocity or lack thereof was explicitly mentioned. The results show that participants across both age groups shared more resources with their friend than with less familiar recipients. Potential reciprocity affected 5-year-olds' sharing but not 3-year-olds' sharing-but only if reciprocity was explicitly mentioned (Experiment 2). Importantly, the preference for the friend was independent of the possibility to be reciprocated for all children. The current study shows that friendship and strategic reciprocity are relevant but probably largely independent factors for children's sharing. That is, the preference to share with friends cannot be reduced to strategic considerations.

Comportamento Altruísta na Infância: O que a Literatura nos Mostra

Resumo Uma variedade de comportamentos altruístas diferenciados tem sido evidenciada na infância. O presente artigo objetivou sistematizar estudos empíricos produzidos nos anos de 2010 a 2015 sobre o altruísmo infantil. Após a elaboração e aplicação de um protocolo sistematizado de seleção, foram encontrados 14 artigos, os quais foram analisados na íntegra. Os estudos contemplaram o altruísmo infantil (1 a 11 anos de idade) em associação a diferentes variáveis, tais como avaliação moral, custos de resposta, renda familiar, distância social, capacidade de abster-se de prêmios imediatos, eventos adversos, representações de apego, dominância social, composição genética, entre outras. Concluiu-se que crianças ainda muito jovens em contextos variados demonstram altruísmo por meio de ações topograficamente diversas à medida que encontram oportunidades para isso.

Why do preschoolers perpetuate inequalities? Theoretical perspectives on inequity preferences in the face of emerging concerns for equality

Recent research has shown that preschool children tend to preferentially allocate resources to rich than to poor others. The findings that young children tend to perpetuate inequalities are puzzling given classical developmental theories that largely focused on the emergence of equality and equity in childhood. In this review, we first sketch the early ontogeny of fairness concerns before providing an overview on studies reporting perpetuation of inequality in young children. We review four classical theories (Piaget, Kohlberg, Damon, Social Domain Theory) and discuss how they would account for this phenomenon. We then introduce four recent theoretical models that directly speak to the underlying psychological processes; the affective preference model, the reciprocity-based strategic model, the numerical matching model, and the normative model. We highlight the key tenets of each model, their relation to other developmental processes, and the strength of the empirical evidence. From each model, we derive specific hypotheses. Finally, in an integrative section we discuss how the models might relate to each other, highlight connections to other research areas, and present avenues for future research.

Paying it back and forward: The impact of experiencing and observing others' sharing and stinginess on preschoolers' own sharing behavior and expectations

Recent research suggests that children's sharing behavior is affected by experiencing or observing others' sharing. These effects have been studied within research on the development of reciprocity and the effects of social modeling. In the current study, direct and indirect types of reciprocity and social modeling were assessed in 3- to 6-year-old children in three experiments (overall N = 382). In each experiment, we explored whether negative and positive social behavior were similarly paid back and forward in each of the different types of reciprocity. Moreover, we assessed the extent to which children reciprocated toward the protagonist who had performed the actual behavior and toward a neutral other. In Experiment 1, children experienced another's sharing behavior as recipients and could then allocate resources to this character and a neutral other. In Experiment 2, children observed another's sharing behavior and could then allocate resources to this character and a neutral other. In Experiment 3, children were asked to predict another protagonist's sharing in the same context as in Experiment 1. Overall, children treated the protagonist and the neutral other similarly and predicted others to do the same. Yet, they were more likely to reciprocate negative acts in indirect types of reciprocity. The results are interpreted with respect to the impact of observational learning and representational development on children's social behavior.

Young Children's Indiscriminate Helping Behavior Toward a Humanoid Robot

Young children help others in a range of situations, relatively indiscriminate of the characteristics of those they help. Recent results have suggested that young children's helping behavior extends even to humanoid robots. However, it has been unclear how characteristics of robots would influence children's helping behavior. Considering previous findings suggesting that certain robot features influence adults' perception of and their behavior toward robots, the question arises of whether young children's behavior and perception would follow the same principles. The current study investigated whether two key characteristics of a humanoid robot (animate autonomy and friendly expressiveness) would affect children's instrumental helping behavior and their perception of the robot as an animate being. Eighty-two 3-year-old children participated in one of four experimental conditions manipulating a robot's ostensible animate autonomy (high/low) and friendly expressiveness (friendly/neutral). Helping was assessed in an out-of-reach task and animacy ratings were assessed in a post-test interview. Results suggested that both children's helping behavior, as well as their perception of the robot as animate, were unaffected by the robot's characteristics. The findings indicate that young children's helping behavior extends largely indiscriminately across two important characteristics. These results increase our understanding of the development of children's altruistic behavior and animate-inanimate distinctions. Our findings also raise important ethical questions for the field of child-robot interaction.

Normative foundations of reciprocity in preschoolers

Reciprocity has been suggested to represent a crucial normative principle for humans. The current study aimed to investigate the normative foundations of reciprocity and the development of a reciprocity norm in young children. To this end, we presented 3- to 6-year-olds with three conditions. In one condition, a protagonist reciprocated sharing a large proportion of resources. In another condition, a protagonist reciprocated sharing a small proportion of resources. In a third condition, a protagonist did not reciprocate sharing a large proportion by giving rather few resources and, thus, violated a reciprocity norm. Results show that 5- and 6-year-olds endorse compliance with a reciprocity norm, which is reflected in their evaluations of the protagonists and their spontaneous verbal affirmation of reciprocal behavior. In contrast, 3- and 4-year-olds exclusively valued general prosociality, neglecting reciprocity. This indicates that children acquire a norm of reciprocity during the course of the preschool period.

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.

Toddlers' intrinsic motivation to return help to their benefactor

A natural reaction to receiving help from someone is to help that person in return. In two studies, we investigated the developmental origins of children's motivation to return help. In Study 1, 18- and 24-month-old toddlers were either helped or not helped by an adult, and they could subsequently provide that adult with help or else observe another person providing help. We measured children's internal arousal, via changes in pupil dilation, both before and after help was provided. At both ages, children's internal arousal was higher when they could not help the adult who had previously helped them (and was lower when they could). On the other hand, if the adult needing help had not previously helped children, their internal arousal was equally low regardless of whether they or another person provided the help. Study 2 replicated this result and also found that if children had previously been helped but the person needing help was a different adult (not their benefactor), children's internal arousal was equally low regardless of whether they or another person provided the help. Together, these results suggest that young children are intrinsically motivated to return a received favor specifically to the previous benefactor, perhaps indicating a nascent sense of gratitude.

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.

Chimpanzees monopolize and children take turns in a limited resource problem

Competition over scarce resources is common across the animal kingdom. Here we investigate the strategies of chimpanzees and children in a limited resource problem. Both species were presented with a tug-of-war apparatus in which each individual in a dyad received a tool to access a reward, but tools could not be used simultaneously. We assessed the equality of tool use as well as the frequency of turn taking. Both species managed to overcome this conflict of interest but used different strategies to do so. While there was substantial variation in chimpanzee behaviour, monopolization was the common course of action: tool use was asymmetric with individual chimpanzees monopolizing the resource. In children, turn-taking emerged as the dominant strategy: tool use was symmetric and children alternated access to the tool at a high rate. These results suggest that while both species possess strategies for solving limited resource problems, humans might have evolved species unique motivations and socio-cognitive skills for dealing with such conflicts of interest.

How children use accuracy information to infer informant intentions and to make reward decisions

The ability to assess the value of the information one receives and the intentions of the source of that information can be used to establish cooperative relationships and to identify cooperative partners. Across two experiments, 4- to 8-year-old children (N = 204) received a note with correct, incorrect, or no information that affected their efforts on a search task. Children were told that all informants had played the game before and knew the location of the hidden reward. In the no information condition, children were told that the informant needed to leave before finishing the note and, thus, was not intentionally uninformative. Children rated the note with correct information as more helpful than the note with no information; incorrect information was rated least helpful. When asked about the informant's intentions, children attributed positive intentions when the information was correct and when they received unhelpful information but knew the informant was not intentionally uninformative. Children attributed less positive intentions to the informant when they received incorrect information. When given the chance to reward the informant, children rewarded the informant who provided correct information and no information equally; the informant who provided incorrect information received fewer rewards. Combined, these results suggest that young children assume that informants have positive intentions even when they provide no useful information. However, when the information provided is clearly inaccurate, children infer more negative intentions and reward those informants at lower rates. These results suggest that children tend to reward informants more based on their presumed intentions, placing less weight on the value of the information they provide.

Explaining early moral hypocrisy: Numerical cognition promotes equal sharing behavior in preschool-aged children

Recent work has documented that despite preschool-aged children's understanding of social norms surrounding sharing, they fail to share their resources equally in many contexts. Here we explored two hypotheses for this failure: an insufficient motivation hypothesis and an insufficient cognitive resources hypothesis. With respect to the latter, we specifically explored whether children's numerical cognition-their understanding of the cardinal principle-might underpin their abilities to share equally. In Experiment 1, preschoolers' numerical cognition fully mediated age-related changes in children's fair sharing. We found little support for the insufficient motivation hypothesis-children stated that they had shared fairly, and failures in sharing fairly were a reflection of their number knowledge. Numerical cognition did not relate to children's knowledge of the norms of equality (Experiment 2). Results suggest that the knowledge-behavior gap in fairness may be partly explained by the differences in cognitive skills required for conceptual and behavioral equality.

Reciprocity Among Preschoolers in Relation to Resource Allocation Toward Siblings, Friends, and Strangers

Children at age 6 years differentially treat kin, friends, and strangers in resource allocation games by being more altruistic toward kin. However, it is unknown how previous allocation experience as a recipient influences the potential kinship effect in subsequent resource allocations. The present study investigated how 4- to 6-year-old children allocated resources between themselves and a sibling, a friend, or a stranger in three allocation tasks after the recipient had previously shared or nonshared with the participant. Results showed that, when a share would induce cost on the self, 6-year-old children were likely to share with a sibling whether the sibling had previously shared or not, but they would share only with friends or strangers who had previously shared. When a share would induce no cost, participants across ages were likely to share with a recipient who had previously shared. When the decision option was between sharing equally and sharing altruistically, participants would allow the recipient to have more only when the recipient was a sibling or friend who had previously allocated altruistically. These findings suggest that kin altruism in resource allocation emerges at around 6 years of age and that reciprocity partly overrides and partly reinforces kin altruism.

Getting What You Pay For: Children's Use of Market Norms to Regulate Exchanges

Children are sensitive to a number of considerations influencing distributions of resources, including equality, equity, and reciprocity. We tested whether children use a specific type of reciprocity norm-market norms-in which resources are distributed differentially based strictly on amount offered in return. In two studies, 195 children 5-10 years and 60 adults distributed stickers to friends offering same or different amounts of money. Overall, participants distributed more equally when offers were the same and more unequally when offers were different. Although sensitive to why friends offered different amounts of money, children increasingly incorporated market norms into their distributions with age, as the oldest children and adults distributed more to those offering more, irrespective of the reasons provided.

Psychopathy to Altruism: Neurobiology of the Selfish-Selfless Spectrum

The age-old philosophical, biological, and social debate over the basic nature of humans as being “universally selfish” or “universally good” continues today highlighting sharply divergent views of natural social order. Here we analyze advances in biology, genetics and neuroscience increasing our understanding of the evolution, features and neurocircuitry of the human brain underlying behavior in the selfish–selfless spectrum. First, we examine evolutionary pressures for selection of altruistic traits in species with protracted periods of dependence on parents and communities for subsistence and acquisition of learned behaviors. Evidence supporting the concept that altruistic potential is a common feature in human populations is developed. To go into greater depth in assessing critical features of the social brain, the two extremes of selfish–selfless behavior, callous unemotional psychopaths and zealous altruists who take extreme measures to help others, are compared on behavioral traits, structural/functional neural features, and the relative contributions of genetic inheritance versus acquired cognitive learning to their mindsets. Evidence from population groups ranging from newborns, adopted children, incarcerated juveniles, twins and mindfulness meditators point to the important role of neuroplasticity and the dopaminergic reward systems in forming and reforming neural circuitry in response to personal experience and cultural influences in determining behavior in the selfish–selfless spectrum. The underlying neural circuitry differs between psychopaths and altruists with emotional processing being profoundly muted in psychopaths and significantly enhanced in altruists. But both groups are characterized by the reward system of the brain shaping behavior. Instead of rigid assignment of human nature as being “universally selfish” or “universally good,” both characterizations are partial truths based on the segments of the selfish–selfless spectrum being examined. In addition, individuals and populations can shift in the behavioral spectrum in response to cognitive therapy and social and cultural experience, and approaches such as mindfulness training for introspection and reward-activating compassion are entering the mainstream of clinical care for managing pain, depression, and stress.

The developmental emergence of direct reciprocity and its influence on prosocial behavior

Humans are a remarkably cooperative species, and one behavior thought to play an important role is that of reciprocal altruism. By ensuring that the immediate costs associated with performing a prosocial action will be recouped in the long-run, reciprocal interactions support the emergence and maintenance of group-level cooperation. Existing developmental research suggests that a tendency toward selective prosocial behavior and an understanding of direct reciprocal interactions emerge in early childhood, but much less is known about the interplay between these two behaviors. In this paper, I review the existing literature supporting the notion that reciprocity mediates early prosocial tendencies and suggest that a greater understanding of the psychological mechanisms underlying reciprocity is needed. Finally, I propose two social cognitive capacities related to prospection that I believe may help to shed light on the psychology of strategic reciprocal interactions and their role in prosocial behavior more broadly.

The specificity of reciprocity: Young children reciprocate more generously to those who intentionally benefit them

Young children engage in direct reciprocity, but the mechanisms underlying such reciprocity remain unclear. In particular, prior work leaves unclear whether children's reciprocity is simply a response to receiving benefits (regardless of whether the benefits were intended) or driven by a mechanism of rewarding or preferring all benefactors (regardless of whom they benefited). Alternatively, perhaps children engage in genuine reciprocity such that they are particularly prosocial toward benefactors who intentionally provided them with benefits. Our findings support this third, richer possibility; the 3-year-olds who received benefits through the good intentions of a benefactor were subsequently more generous toward the benefactor than children who either (a) received the same benefits from the benefactor unintentionally or (b) observed the benefactor bestow the same benefits on another individual. Thus, young children are especially motivated to benefit those who have demonstrated goodwill toward them, suggesting, as one possible mechanism, an early sense of gratitude.

Expectations about recipients' prosociality and mental time travel relate to resource allocation in preschoolers

Previous studies have revealed that preschoolers selectively allocate their resources based on their social relationship with recipients such as friendship. In this investigation, we investigated how expectations about recipients' prosociality and the ability of future thinking relate to the selective allocation of resources. In Study 1, participants aged 3.5-6 years chose how to allocate resources from two ways (selfish allocation, where only the participants could receive stickers, and equal allocation, where the participants and recipients receive get the same number of stickers) in costly and non-costly situations with three recipients (friend, peer, and stranger). Participants were asked to state which alternatives the recipients would choose if they were given a choice. The results showed that children aged 5 and 6 years tended to choose equal allocation of resources when they expected the recipients to do the same both in costly and non-costly situations. This tendency was not observed in children aged 3.5 and 4 years. In Study 2, the relationships between selectivity in non-costly allocation and two facets of future thinking (delay of gratification and mental time travel) were investigated in children aged 5 and 6 years. The results suggested that children with a higher mental time travel ability tended to be more selective in allocating resources based on social relationships; they tended to allocate more resources to the friend and fewer to the peer. Our findings suggest that expectations about a recipient's prosociality and the ability of mental time travel affect selectivity of resource allocation in children aged 5 and 6 years.

Concern for Group Reputation Increases Prosociality in Young Children

The motivation to build and maintain a positive personal reputation promotes prosocial behavior. But individuals also identify with their groups, and so it is possible that the desire to maintain or enhance group reputation may have similar effects. Here, we show that 5-year-old children actively invest in the reputation of their group by acting more generously when their group's reputation is at stake. Children shared significantly more resources with fictitious other children not only when their individual donations were public rather than private but also when their group's donations (effacing individual donations) were public rather than private. These results provide the first experimental evidence that concern for group reputation can lead to higher levels of prosociality.

Joint Rhythmic Movement Increases 4-Year-Old Children's Prosocial Sharing and Fairness Toward Peers

The allocation of resources to a peer partner is a prosocial act that is of fundamental importance. Joint rhythmic movement, such as occurs during musical interaction, can induce positive social experiences, which may play a role in developing and enhancing young children's prosocial skills. Here, we investigated whether joint rhythmic movement, free of musical context, increases 4-year-olds' sharing and sense of fairness in a resource allocation task involving peers. We developed a precise procedure for administering joint synchronous experience, joint asynchronous experience, and a baseline control involving no treatment. Then we tested how participants allocated resources between self and peer. We found an increase in the generous allocation of resources to peers following both synchronous and asynchronous movement compared to no treatment. At a more theoretical level, this result is considered in relation to previous work testing other aspects of child prosociality, for example, peer cooperation, which can be distinguished from judgments of fairness in resource allocation tasks. We draw a conceptual distinction between two types of prosocial behavior: resource allocation (an other-directed individual behavior) and cooperation (a goal-directed collaborative endeavor). Our results highlight how rhythmic interactions, which are prominent in joint musical engagements and synchronized activity, influence prosocial behavior between preschool peers.

Young children display an increase in prosocial donating in response to an upwards shift in generosity by a same-aged peer

Adult humans frequently engage in the reciprocal exchange of resources with other individuals. However, despite the important role that reciprocity plays in maintaining co-operative exchange we know relatively little of when, and how, reciprocity develops. We first asked whether pairs of young children (M = 74 months) would engage in direct reciprocity in a ‘prosocial choice test’ where a donor could select either a higher, or a lower, value reward (1v 2) for a partner at no cost to themselves (1v 1). In a subsequent retest we asked, for the first time, whether young children increase their level of prosocial donating in response to an upwards shift in generosity from an initially selfish partner. In order to determine whether interacting with another child was fundamental to the development of reciprocity we included a novel yoked non-agent condition. The results suggest that the children were engaging in a calculated form of reciprocity where the prior behavior of their child partner influenced their subsequent level of donation days after the initial exchange. Crucially we show that the children were not influenced by the value of the rewards received per se, rather selection by a human agent was key to reciprocity.

Diverse ontogenies of reciprocal and prosocial behavior: cooperative development in Fiji and the United States

Contingent reciprocity is an important foundation of human cooperation, but we know little about how reciprocal behavior develops across diverse societies, nor about how the development of reciprocal behavior is related to the development of prosocial behavior more broadly. Three- to 16-year-old children were presented with the opportunity to control the allocation of real food rewards in a binary-choice cooperative dilemma. Within dyads children alternated making choices across multiple trials, and reciprocal behavior emerged in three diverse populations (rural Fijian villages, and urban communities in both Fiji and the United States) by age 7-8. There was more societal variation in prosocial behavior than in reciprocal behavior, and there were more substantial differences between Fijians and Americans than between rural and urban populations. This suggests that the development of prosocial behavior is not driven entirely by the development of reciprocity, and differences in prosocial behavior across rural Fijians and urban Americans may not be due only to differences across rural and urban populations.

The Development of Theory of Mind and Positive and Negative Reciprocity in Preschool Children

This study examined the relation between the acquisition of false-beliefs theory of mind (ToM) and reciprocity in preschoolers. Preschool-aged children completed a task assessing the understanding of false beliefs, and played an Ultimatum Game (UG) with another child in a face-to-face setting. Negative reciprocity was assessed by examining the rejection of unfair offers made by another child in the UG, while positive reciprocity was assessed by examining allocations made by participants in a Dictator Game (DG) following the UG. The results indicated that children who had passed a task assessing first-order false beliefs were more likely to make generous offers in a DG following a fair offer made by their partner in a proceeding UG, but that false beliefs ToM was unrelated to the rejection of unfair offers in the UG.