Developmental Differences in Infants' Fairness Expectations From 6 to 15 Months of Age

Core Moral Concepts and the Sense of Fairness in Human Infants

We review recent experimental studies relevant to assess the proposal that human infants possess a sense of fairness that relies on sociomoral knowledge. We propose that this knowledge may include a core concept of justice with four foundational aspects: impartiality, agency, obligatoriness and conflicting claims. Infants' and toddlers' looking times, manual preferences and spontaneous actions provide some evidence for the first three features. Very early-emerging sociomoral evaluations and expectations about resource distributions show that infants process morally relevant information about distributors and recipients, suggesting that they are sensitive to the agency and impartiality constraints. Early evaluations appear to be linked to third-party expressions of praise or admonishment and to the deliverance of rewards and punishment, providing initial support for the obligatoriness constraint. More work is needed to investigate the sensitivity to conflicting claims, to assess the universality of early emerging evaluation skills and to show how core concepts relate to the development of explicit judgments and beliefs about duties and rights.

What do children value more in a collaborator-Problem-solving capacity or fair sharing?

Collaboration requires individuals to find partners who are adept at problem-solving and act fairly when sharing the spoils of joint labor. Given that individuals might vary along both dimensions, it can create a dilemma with the challenging decision of whether to prioritize a potential partner's capacity to perform a task or the partner's level of fairness in sharing obtained resources. Here we tested whether young children can solve this dilemma when two potential partners have opposing qualities: One partner is high in the capacity to solve a problem but less likely to share fairly, whereas the other partner is lower in capacity but fair. In two studies with a total of N = 188 children aged 4 to 6 years, we found that children adjust their decisions based on the social context and the perceived difficulty of the collaborative task: Children show an overall preference for fair partners when collaborating in an easy task, but they choose partners high in problem-solving capacity and low in fairness when collaborating in a more difficult task. These results show that already young children can evaluate others along two dimensions and make trade-offs between capacity and fairness when deciding what is more relevant for a given situation.

Moral Learning and Decision-Making Across the Lifespan

Moral learning and decision-making are crucial throughout our lives, from infancy to old age. Emerging evidence suggests that there are important differences in learning and decision-making in moral situations across the lifespan, and these are underpinned by co-occurring changes in the use of model-based values and theory of mind. Here, we review the decision neuroscience literature on moral choices and moral learning considering four key concepts. We show how in the earliest years, a sense of self/other distinction is foundational. Sensitivity to intention versus outcome is crucial for several moral concepts and is most similar in our earliest and oldest years. Across all ages, basic shifts in the influence of theory of mind and model-free and model-based learning support moral decision-making. Moving forward, a computational approach to key concepts of morality can help provide a mechanistic account and generate new hypotheses to test across the whole lifespan.

Korean and American adolescents' judgments of group-based inequalities

The current study examined how adolescents from different cultural backgrounds perceive and reason about group-based inequalities. Korean (N = 84, 42 females) and American (N = 72, 36 females) adolescents, aged 12 to 17, evaluated resource distribution inequalities in school contexts among social groups differentiated by social class, race, and gender. Across both cultures, nearly all adolescents found race and gender inequalities unacceptable based on moral concerns for equality. However, judgments about inequalities based on social class were more complex; adolescents evaluated these inequalities as less wrong and coordinated equality concerns with other considerations. They further distinguished between two types of social class situations that varied in the level of inequality, judging group-level social class inequality as more unacceptable than individual-level inequality. Cultural variations were evident in the justifications for their evaluations: American adolescents coordinated moral concerns of equality and welfare with personal and conventional reasons, while Korean adolescents also considered moral concerns of merit and property rights. Different interpretations of situational contexts led to varying prioritizations of moral concerns across the two cultures.

The origins of moral sensitivities: Probing infants' expectations, evaluations, generalization, and enforcement of moral norms

Identifying the origins of moral sensitivities, and their elaboration, within infancy and early childhood is a challenging task, given inherent limitations in infants' behavior. Here, I argue for a multi-pronged, multi-method approach that involves cleaving the moral response at its joints. Specifically, I chart the emergence of infants' moral expectations, evaluations, generalization and enforcement, demonstrating that while many moral sensitivities are present in the second year of life, these sensitivities are closely aligned with, and likely driven by, infants' everyday experience. Moreover, qualitative differences exist between the moral responses that are present in infancy and those of later childhood, particularly in terms of enforcement (i.e., a lack of punishment in infancy). These findings set the stage for addressing outstanding critical questions regarding moral development, that include identifying discrete causal inputs to early moral cognition, identifying whether moral cognition is distinct from social cognition early in life, and explaining gaps that exist between moral cognition and moral behavior in development.

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.

The Cognitive Architecture of Infant Attachment

Meta-analytic evidence indicates that the quality of the attachment relationship that infants establish with their primary caregiver has enduring significance for socioemotional and cognitive outcomes. However, the mechanisms by which early attachment experiences contribute to subsequent development remain underspecified. According to attachment theory, early attachment experiences become embodied in the form of cognitive-affective representations, referred to as internal working models (IWMs), that guide future behavior. Little is known, however, about the cognitive architecture of IWMs in infancy. In this article, we discuss significant advances made in the field of infant cognitive development and propose that leveraging insights from this research has the potential to fundamentally shape our understanding of the cognitive architecture of attachment representations in infancy. We also propose that the integration of attachment research into cognitive research can shed light on the role of early experiences, individual differences, and stability and change in infant cognition, as well as open new routes of investigation in cognitive studies, which will further our understanding of human knowledge. We provide recommendations for future research throughout the article and conclude by using our collaborative research as an example.

Quantifying the emergence of moral foundational lexicon in child language development

Theorists have argued that morality builds on several core modular foundations. When do different moral foundations emerge in life? Prior work has explored the conceptual development of different aspects of morality in childhood. Here, we offer an alternative approach to investigate the developmental emergence of moral foundations through the lexicon, namely the words used to talk about moral foundations. We develop a large-scale longitudinal analysis of the linguistic mentions of five moral foundations (in both virtuous and vicious forms) in naturalistic speech between English-speaking children with ages ranging from 1 to 6 and their caretakers. Using computational methods, we collect a dataset of 1,371 human-annotated moral utterances and automatically annotate around one million utterances in child-caretaker conversations. We discover that in childhood, words for expressing the individualizing moral foundations (i.e. Care/Harm, Fairness/Cheating) tend to emerge earlier and more frequently than words for expressing the binding moral foundations (i.e. Authority/Subversion, Loyalty/Betrayal, Purity/Degradation), and words for Care/Harm are expressed substantially more often than the other foundations. We find significant differences between children and caretakers in how often they talk about Fairness, Cheating, and Degradation. Furthermore, we show that the information embedded in childhood speech allows computational models to predict moral judgment of novel scenarios beyond the scope of child-caretaker conversations. Our work provides a large-scale documentation of the moral foundational lexicon in early linguistic communication in English and forges a new link between moral language development and computational studies of morality.

Structural explanations lead young children and adults to rectify resource inequalities

Decisions about how to divide resources have profound social and practical consequences. Do explanations regarding the source of existing inequalities influence how children and adults allocate new resources? When 3- to 6-year-old children (N = 201) learned that inequalities were caused by structural forces (stable external constraints affecting access to resources) as opposed to internal forces (effort), they rectified inequalities, overriding previously documented tendencies to perpetuate inequality or divide resources equally. Adults (N = 201) were more likely than children to rectify inequality spontaneously; this was further strengthened by a structural explanation but reversed by an effort-based explanation. Allocation behaviors were mirrored in judgments of which allocation choices by others were appropriate. These findings reveal how explanations powerfully guide social reasoning and action from childhood through adulthood.

Preschoolers' retrospective and prospective judgements of immanent justice following distributive actions

Prior research provided evidence for retrospective and prospective judgements of immanent justice in adults, but the developmental origins of judgements of immanent justice remain unknown. Both retrospective and prospective judgements were investigated in preschool age, using explicit and implicit measures. In Experiment 1, 2.5- and 4-year-olds were first shown events in which one agent distributed resources fairly or unfairly, and then they saw test events in which both distributors were damaged by a misfortune. Later, they were presented with a verbal task, in which they had to respond to two questions on evaluation of the deservingness, by using explicit measures. All children were likely to approve of deserved outcomes when deeds and outcomes were congruent (i.e., unfair distributor-misfortune), and only older ones were likely to disapprove when they were incongruent (i.e., fair distributor-misfortune). In Experiment 2, 4-year-olds after seeing familiarization events of Experiment 1, were presented with two verbal questions to explore prospective judgements of immanent justice, by using explicit measures. In Experiment 3, 4-year-olds were first shown familiarization events of Experiment 1 and listened to respective narratives, then before the outcome was revealed they were assessed with a reaching task to investigate prospective judgements of immanent justice, by using implicit measures. Children reached the image depicting a bad outcome for the unfair distributor, and that illustrated a good outcome for the fair distributor. The results of the last two experiments demonstrated a fine ability to make prospective judgements at 4 years of life, and found that they were to be more prone to apply immanent justice reasoning to positive outcomes following good actions. Taken together, these results provide new evidence for preschoolers' retrospective and prospective judgements of immanent justice.

The science of justice: The neuropsychology of social punishment

The social punishment (SP) of norm violations has received much attention across multiple disciplines. However, current models of SP fail to consider the role of motivational processes, and none can explain the observed behavioral and neuropsychological differences between the two recognized forms of SP: second-party punishment (2PP) and third-party punishment (3PP). After reviewing the literature giving rise to the current models of SP, we propose a unified model of SP which integrates general psychological descriptions of decision-making as a confluence of affect, cognition, and motivation, with evidence that SP is driven by two main factors: the amount of harm (assessed primarily in the salience network) and the norm violator's intention (assessed primarily in the default-mode and central-executive networks). We posit that motivational differences between 2PP and 3PP, articulated in mesocorticolimbic pathways, impact final SP by differentially impacting the assessments of harm and intention done in these domain-general large-scale networks. This new model will lead to a better understanding of SP, which might even improve forensic, procedural, and substantive legal practices.

Toddlers' affective responses to sociomoral scenes: Insights from physiological measures

A growing literature suggests that preverbal infants are sensitive to sociomoral scenes and prefer prosocial agents over antisocial agents. It remains unclear, however, whether and how emotional processes are implicated in infants' responses to prosocial/antisocial actions. Although a recent study found that infants and toddlers showed more positive facial expressions after viewing helping (vs. hindering) events, these findings were based on naïve coder ratings of facial activity; furthermore, effect sizes were small. The current studies examined 18- and 24-month-old toddlers' real-time reactivity to helping and hindering interactions using three physiological measures of emotion-related processes. At 18 months, activity in facial musculature involved in smiling/frowning was explored via facial electromyography (EMG). At 24 months, stress (sweat) was explored via electrodermal activity (EDA). At both ages, arousal was explored via pupillometry. Behaviorally, infants showed no preferences for the helper over the hinderer across age groups. EMG analyses revealed that 18-month-olds showed higher corrugator activity (more frowning) during hindering (vs. helping) actions, followed by lower corrugator activity (less frowning) after hindering (vs. helping) actions finished. These findings suggest that antisocial actions elicited negativity, perhaps followed by brief disengagement. EDA analyses revealed no significant event-related differences. Pupillometry analyses revealed that both 18- and 24-month-olds' pupils were smaller after viewing hindering (vs. helping), replicating recent evidence with 5-month-olds and suggesting that toddlers also show less arousal following hindering than following helping. Together, these results provide new evidence with respect to whether and how arousal/affective processes are involved when infants process sociomoral scenarios.

Evaluations of pro-environmental behaviors by 7-month-old infants

Environmental morality is the foundation of a sustainable future, yet its ontogenetic origin remains unknown. In the present study, we asked whether 7-month-olds have a sense of 'environmental morality'. Infants' evaluations of two pro-environmental actions were assessed in both visual and reaching preferential tasks. In Experiment 1, the overt behavior of protecting (i.e., collecting artificial objects spread on a lawn) was compared with the action of harming the environment (i.e., by disregarding the objects). In Experiment 2, the covert behavior of protecting the environment (i.e., maintaining artificial objects inside a container) was compared with the action of harming the environment (i.e., littering the artificial objects on a lawn). The results showed infants' reaching preference for the agent who performed overt pro-environmental actions (Experiment 1), and no preference for the agent who performed covert pro-environmental actions (Experiment 2). These findings reveal a rudimentary ecological sense and suggest that infants require different abilities to evaluate overt impact-oriented and covert intend-oriented pro-environmental behaviors.

Generalizing across moral sub-domains: infants bidirectionally link fairness and unfairness to helping and hindering

Across two experiments, we investigated whether infants use prior behavior to form expectations about future behavior within the moral domain, focusing on the sub-domains of fairness and help/harm. In Experiment 1, 14- to 27-month-old infants were familiarized to an agent who either helped or hindered another agent to obtain her goal. At test, infants saw the helper or hinderer perform either a fair or unfair distribution of resources to two recipients. Infants familiarized to helping looked longer to the unfair distribution than the fair distribution at test, whereas infants familiarized to hindering looked equally at both test events, suggesting that hindering led infants to suspend baseline expectations of fairness. In Experiment 2, infants saw these events in reverse. Following familiarization to fair behavior, infants looked equally to helping and hindering; in contrast, following familiarization to unfair behavior, infants looked significantly longer to helping than hindering on test, suggesting that prior unfair behavior led infants to expect the agent to hinder another agent's goals. These results suggest that infants utilize prior information from one moral sub-domain to form expectations of how an individual will behave in another sub-domain, and that this tendency seems to manifest more strongly when infants initially see hindering and unfair distributions than when they see helping and fair distributions. Together, these findings provide evidence for consilience within the moral domain, starting by at least the second year of life.

Exploring individual differences in infants' looking preferences for impossible events: The Early Multidimensional Curiosity Scale

Infants are drawn to events that violate their expectations about the world: they look longer at physically impossible events, such as when a car passes through a wall. Here, we examined whether individual differences in infants' visual preferences for physically impossible events reflect an early form of curiosity, and asked whether caregivers' behaviors, parenting styles, and everyday routines relate to these differences. In Study 1, we presented infants (N = 47, Mage  = 16.83 months, range = 10.29-24.59 months) with events that violated physical principles and closely matched possible events. We measured infants' everyday curiosity and related experiences (i.e., caregiver curiosity-promoting activities) through a newly developed curiosity scale, The Early Multidimensional Curiosity Scale (EMCS). Infants' looking preferences for physically impossible events were positively associated with their score on the EMCS, but not their temperament, vocabulary, or caregiver trait curiosity. In Study 2A, we set out to better understand the relation between the EMCS and infants' looking preferences for physically impossible events by assessing the underlying structure of the EMCS with a larger sample of children (N = 211, Mage  = 47.63 months, range = 10.29-78.97 months). An exploratory factor analysis revealed that children's curiosity was comprised four factors: Social Curiosity, Broad Exploration, Persistence, and Information-Seeking. Relatedly, caregiver curiosity-promoting activities were composed of five factors: Flexible Problem-Solving, Cognitive Stimulation, Diverse Daily Activities, Child-Directed Play, and Awe-Inducing Activities. In Study 2B (N = 42 infants from Study 1), we examined which aspects of infant curiosity and caregiver behavior predicted infants' looking preferences using the factor structures of the EMCS. Findings revealed that infants' looking preferences were uniquely related to infants' Broad Exploration and caregivers' Awe-Inducing Activities (e.g., nature walks with infants, museum outings). These exploratory findings indicate that infants' visual preferences for physically impossible events may reflect an early form of curiosity, which is related to the curiosity-stimulating environments provided by caregivers. Moreover, this work offers a new comprehensive tool, the Early Multidimensional Curiosity Scale, that can be used to measure both curiosity and factors related to its development, starting in infancy and extending into childhood.

Intention-based evaluations of distributive actions by 4-month-olds

Four-month-olds' ability to consider the intentions of agents performing distributive actions was investigated in four experiments, using the Violation of Expectation paradigm (VoE) (Experiments 1-3) and the Preferential Looking paradigm (Experiment 4). In Experiment 1, infants were presented with two events showing two types of failed attempts to perform a distribution. In an attempt to distribute fairly, the distributor first tried to reach one of the recipients to deliver an apple, he failed, and then attempted to reach the other recipient to deliver a second apple and also failed. In an attempt to distribute unfairly, a different distributor tried unsuccessfully to bring resources always to the same recipient. Infants looked reliably longer at failed fair distribution events, suggesting that they did not just react to the actions outcomes and they attended to agents' intentions. Experiments 2 and 3 assessed alternative explanations based on perceptual factors or affiliative behaviors. In Experiment 4, during the test trials, infants were shown both distributors simultaneously and they preferred to look at the fair rather than at the unfair distributor. Overall, these findings reveal an early ability to take into account distributors' intentions and a preference for watching agents that tried to distribute resources fairly.

Preverbal infants' reactions to third-party punishments and rewards delivered toward fair and unfair agents

Rewarding individuals who distribute resources fairly and punishing those who distribute resources unfairly may be very important actions for fostering cooperation. This study investigated whether 9-month-olds have some expectations concerning punishments and rewards that follow distributive actions. Infants were shown simple animations and were tested using the violation-of-expectation paradigm. In Experiment 1, we found that infants looked longer when they saw a bystander delivering a corporal punishment to a 'fair distributor,' who distributed some windfall resources equally to the possible recipients, rather than to an 'unfair distributor,' who distributed the resources unequally. This pattern of looking times was reversed when, in Experiment 2, punishments were replaced with rewards. These findings suggest an early emergence of expectations about punishing and rewarding actions in third-party contexts, and they help to evaluate competing claims about the origins of a sense of fairness.

Understanding preferences in infancy

A preference is defined as a dispositional state that helps explain why a person chooses one option over another. Preference understanding is a significant part of interpreting and predicting others' behavior, which can also help to guide social encounters, for instance, to initiate interactions and even form relationships based on shared preferences. Cognitive developmental research in the past several decades has revealed that infants have relatively sophisticated understandings about others' preferences, as part of investigations into how young children make sense of others' behavior in terms of mental states such as intentions, dispositions including preferences, and epistemic states. In recent years, research on early psychological knowledge expands to including infant understanding of social situations. As such, infants are also found to use their preference understandings in their social life. They treat favorably others who share their own preferences, and they prefer prosocial and similar others (e.g., those who speak their language). In reviewing these results, we point out future directions for research and conclude with further suggestions and recommendations. This article is categorized under: Cognitive Biology > Cognitive Development Psychology > Development and Aging.

Investigating the detection of parent-child relationships in early childhood: The role of partiality in resource distributions

By early childhood, children possess clear expectations about how resources should be, and typically are, distributed, expecting and advocating for equal resource distributions to recipients. Moreover, recent evidence suggests that children may be able to use deviations from equality in resource distributions to make inferences about the nature of social relationships. Here, we investigated whether children use partiality in resource distributions displayed by adults toward children in third-party contexts to identify parent-child relationships, whether children anticipate preferential treatment based upon knowledge of third-party parent-child relationships, and whether children anticipate different emotional reactions to impartiality in resource distributions in parent-child interactions compared to neighbor-child interactions. Four-to seven-year-old children were presented with hypothetical vignettes about an adult character who distributed resources to two children either equally, or systematically favoring one child. By the age of 4, children used resource distribution partiality to identify an adult as a child’s parent, and also used these expectations to guide their anticipated emotional reactions to impartiality. By the age of 6, children were also more likely to anticipate partiality to be displayed in parent-child compared to neighbor-child relationships. The findings from the current study reveal that partiality in resource distributions acts as a valuable cue to aid in identifying and understanding social relationships, highlighting the integral role that resources play in children’s understanding of their social world. More broadly, our findings support the claim that children use cues that signal interpersonal investment to specify and evaluate parent-child relationships in third-party contexts.

Is Distributional Justice Equivalent to Prosocial Sharing in Children's Cognition?

Distribution and sharing are social preference behaviors supported and shaped by selection pressures, which express individuals' concern for the welfare of others. Distributive behavior results in distributive justice, which is at the core of moral justice. Sharing is a feature of the prosocial realm. The connotations of distribution and sharing are different, so the principles, research paradigms, and social functions of the two are also different. Three potential causes of confusion between the two in the current research on distribution and sharing are discussed. First, they share common factors in terms of individual cognition, situation, and social factors. Second, although they are conceptually different, prosocial sharing and distribution fairness sensitivity are mutually predictive in individual infants. Similarly, neural differences in preschoolers' perception of distribution fairness predict their subsequent sharing generosity. Finally, similar activation regions are relevant to distribution and sharing situations that need behavioral control on a neural basis.

Cross-cultural differences in early expectations about third party resource distribution

Research using non-verbal looking-time methods suggests that pre-verbal infants are able to detect inequality in third party resource allocations. However, nothing is known about the emergence of this capacity outside a very narrow Western context. We compared 12- to 20-month-old infants (N = 54) from one Western and two non-Western societies. Swedish infants confirmed the pattern from previous Western samples by looking longer at the unequal distribution, suggesting that they expected the resources to be distributed equally. Samburu infants looked longer at the equal distribution, suggesting an expectation of unequal distribution. The Kikuyu infants looked equally at both distributions, and did not show any specific exactions. These results suggest that expectations of equal distributions in third party allocations are affected by experience of cultural variations of distributive norms and social interaction early in development.

Adopted Utility Calculus: Origins of a Concept of Social Affiliation

To successfully navigate their social world, humans need to understand and map enduring relationships between people: Humans need a concept of social affiliation. Here I propose that the initial concept of social affiliation, available in infancy, is based on the extent to which one individual consistently takes on the goals and needs of another. This proposal grounds affiliation in intuitive psychology, as formalized in the naive-utility-calculus model. A concept of affiliation based on interpersonal utility adoption can account for findings from studies of infants' reasoning about imitation, similarity, helpful and fair individuals, "ritual" behaviors, and social groups without the need for additional innate mechanisms such as a coalitional psychology, moral sense, or general preference for similar others. I identify further tests of this proposal and also discuss how it is likely to be relevant to social reasoning and learning across the life span.

Infants' intention-based evaluations of distributive actions

Recent research revealed that infants attend to agents' intentions when they evaluate helping actions. The current study investigated whether infants also consider agents' intentions when they evaluate distributive actions. In Experiment 1, 9-month-old infants were first shown two failed attempts to perform a distribution. In the "failed equal distribution," the distributor first tried to reach one of the recipients to deliver an apple, failed, and then attempted to reach the other possible recipient to deliver a different apple and also failed. In the "failed unequal distribution," a different distributor always tried unsuccessfully to reach the same beneficiary. Then, in the test phase, infants were presented with the two distributors side by side, and infants' spontaneous preferential looking and reaching actions were recorded. We found a reliable preference for the equal distributor in both the visual and manual responses. Experiments 2 and 3 helped to rule out alternative explanations based on perceptual cues and affiliative biases. Overall, these findings suggest that infants' ability to evaluate distributive actions relies not only on the outcomes but also on the distributors' intentions.

Children Consider Procedures, Outcomes, and Emotions When Judging the Fairness of Inequality

Children tend to view equal resource distributions as more fair than unequal ones, but will sometimes view even unequal distributions as fair. However, less is known about how children form judgments about inequality when different procedures are used. In the present study, we investigated children's consideration of procedures (i.e., resource-distributing processes), outcomes (i.e., the distributions themselves), and emotions (i.e., the emotional reactions of those receiving the resources) when judging the fairness of unequal resource distributions. Participants (N = 130, 3- to 8-year-olds) were introduced to a Fair Coin (different color on each side) and an Unfair Coin (same color on both sides). In two between-subjects conditions, they watched a researcher flip either the Fair or Unfair Coin in order to distribute resources unequally between two child recipients. Participants then rated the fairness of this event, provided verbal justifications for their ratings (coded for references to procedures and/or outcomes), and rated the emotional state of each recipient (from which an Emotion Difference Score was computed). Results revealed that participants rated the event as more fair in the Fair Coin than the Unfair Coin condition. References to the outcome in children's justifications predicted lower fairness ratings, while references to the procedure only predicted lower ratings in the Unfair Coin condition. Greater Emotion Difference Scores predicted lower fairness ratings, and this effect increased with age. Together, these results show that children consider procedures, outcomes, and emotions when judging the fairness of inequality. Moreover, results suggest age-related increases in consideration of recipients' emotions makes inequality seem less fair, even when fair procedures are used. Implications for the development of fairness are discussed.

Kids attend to saliva sharing to infer social relationships

[Figure: see text].

Moral Reasoning Enables Developmental and Societal Change

Moral reasoning is an essential part of how humans develop and a fundamental aspect of how human societies change over time. On a developmental timescale, reasoning about interpersonal disagreements and dilemmas spurs age-related changes in moral judgments from childhood to adulthood. When asked to distribute resources among others, even young children strive to balance competing concerns with equality, merit, and need. Over the course of development, reasoning and judgments about resource distribution and other moral issues become increasingly sophisticated. From childhood to adulthood, individuals not only evaluate acts as right or wrong but also take the extra steps to rectify inequalities, protest unfair norms, and resist stereotypic expectations about others. The development of moral reasoning also enables change on a societal timescale. Across centuries and communities, ordinary individuals have called for societal change based on moral concerns with welfare, rights, fairness, and justice. Individuals have effectively employed reasoning to identify and challenge injustices. In this article, we synthesize recent insights from developmental science about the roles of moral reasoning in developmental and societal change. In the concluding section, we turn to questions for future research on moral reasoning and change.

Children strategically conceal selfishness

Can children exploit knowledge asymmetries to get away with selfishness? This question was addressed by testing 6- to 9-year-old children (N = 164; 81 girls) from the Northeastern United States in a modified Ultimatum Game. Children were assigned to the roles of proposers (who offered some proportion of an endowment) and responders (who could accept or reject offers). Both players in the Informed condition knew the endowment quantity in each trial. However, in the Uninformed condition, only proposers knew this information. In this condition, many proposers made "strategically selfish" offers that seemed fair based on the responders' incomplete knowledge but were actually highly selfish. These results indicate that even young children possess the ability to deceive others about their selfishness.

Why do children show racial biases in their resource allocation decisions?

Young children often prefer people high in status and with access to resources. Children also favor fairness and equality, especially when it comes to sharing. Two studies examined how children (N = 185; age range = 4.0-6.9 years, M_age = 5.49 years; 45% White, 12% Asian, 11% Black, 7% Hispanic, 24% other or undisclosed) reconcile these conflicting preferences by investigating the relation between children's social preferences and resource allocations to White and Black children. Race provides an important case to examine how children resolve this conflict given that children show preferences for stereotypically high-status (White) people but also show awareness of systemic racial inequality that disadvantages Black people. In a costly sharing resource allocation task (i.e., Dictator Game) where participants were asked how much of a limited resource they wanted to share with a Black child and a White child, Study 1 revealed that participants sometimes chose to share more with a White child compared with a Black child but that biased giving was unrelated to children's biased feelings of warmth toward White children. Study 2 confirmed that biased giving was unrelated to children's feelings of warmth and instead implicated children's beliefs about race and wealth; children who expected White people to have more wealth showed more pro-White bias in their giving behavior. Together, these results suggest that cultural stereotypes about wealth might shape children's economic decision making in a way that perpetuates disadvantage, but they also indicate that the processes underlying resource allocation decisions warrant further study.

The Development of Giving in Forms of Object Exchange: Exploring the Roots of Communication and Morality in Early Interaction around Objects

Giving is an act of great social importance across cultures, with communicative as well as moral dimensions because it is linked to sharing and fairness. We critically evaluate various explanations for how this social process develops in infancy and take a process-relational approach, using naturalistic observations to illustrate forms of interaction involving the exchange of objects and possible developmental trajectories for the emergence of different forms of giving. Based on our data, we propose that the object becomes a pivot point for interaction, and through the process of such interaction the social actions of showing and giving emerge and take on diverse social meanings within the relations between infants and caregivers.

Toddlers' interventions toward fair and unfair individuals

Cooperative societies rely on reward and punishment for norm enforcement. We examined the developmental origin of these interventions in the context of distributive fairness: past research has shown that infants expect resources to be distributed fairly, prefer to interact with fair distributors, and evaluate others based on their fair and unfair resource allocations. In order to determine whether infants would intervene in third-party resource distributions by use of reward and punishment we developed a novel task. Sixteen-month-old infants were taught that one side of a touch screen produces reward (vocal statements expressing praise; giving a cookie), whereas the other side produces punishment when touched (vocal statements expressing admonishment; taking away a cookie). After watching videos in which one actor distributed resources fairly and another actor distributed resources unfairly, participants' screen touches on the reward and punishment panels while the fair and unfair distributors appeared on screen were recorded. Infants touched the reward side significantly more than the punishment side when presented with the fair distributor but touched the screen sides equally when the unfair distributor was shown. Control experiments revealed no evidence of reward or punishment when infants saw food items they liked and disliked, or individuals uninvolved in the resource distribution events. These results provide the earliest evidence that infants are able to spontaneously intervene in socio-moral situations by rewarding positive actions.

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.

Young children share more under time pressure than after a delay

Adults under time pressure share with others generously, but with more time they act more selfishly. In the current study, we investigated whether young children already operate in this same way, and, if so, whether this changes over the preschool and early school age years. We tested 144 children in three age groups (3-, 5-, and 7-year olds) in a one-shot dictator game: Children were given nine stickers and had the possibility to share stickers with another child who was absent. Children in the Time Pressure condition were instructed to share quickly, whereas children in the Delay condition were instructed to take time and consider their decision carefully. Across ages, children in the Time Pressure condition shared significantly more stickers than children in the Delay condition. Moreover, the longer children waited, the less they shared. Thus, children, like adults, are more prosocial when acting spontaneously than after considering their decision more carefully.

The neurodevelopment of social preferences in early childhood

Human social preferences are the product of gene-culture coevolution, and rely on predispositions that emerge early in development. These social preferences encompasse distinct motivations, mechanisms, and behaviors, that facilitate social cohesion and cooperation. Developmental social neuroscience critically contributes in elucidating the proximate mechanisms involved in social decision-making and prosociality, and their gradual maturation in interaction with the social and cultural environment.

Infants Consider the Distributor's Intentions in Resource Allocation

Recent experimental studies suggest that preverbal infants are able to evaluate agents on the basis of their distributive actions. Here we asked whether such evaluations are based on infants' understanding of the distributors' intentions, or only the outcome of their actions. Ten-month-old infants observed animated movies of unequal resource allocations by distributors who attempted but failed to distribute resources equally or unequally between two individuals. We found that infants attended longer to the test event showing a third agent approaching a distributor who was unable to make an unequal distribution, compared to the test event where the third agent approached a distributor who was unable to make an equal distribution of resources. Our results suggest that infants' ability to encode distributive actions goes beyond an analysis of the outcome of these actions, by including the intentions of the distributors whose actions lead to these outcomes.

The moral, or the story? Changing children's distributive justice preferences through social communication

Can social communication alter children's preexisting inclinations toward equality-based or merit-based forms of resource distribution? Six- to eight-year-old children's (N = 248) fairness preferences were evaluated with third-party distribution tasks before and after an intervention. Study 1 indicated that stories about beavers dividing wood had no impact on children's fairness preferences, while Study 2 indicated that brief, direct testimony was highly influential. Study 3 matched storybooks and testimony in content, with each discussing a situation resembling the distribution task, and both formats exerted a significant impact on children's fairness preferences that persisted across several weeks. There were some indications that interventions preaching the superiority of equality-based fairness were particularly effective, but there were no differences between reason-based and emotion-based interventions. Overall, storybooks and testimony can powerfully and enduringly change children's existing distributive justice preferences, as long as the moral lessons that are conveyed are easily transferable to children's real-world contexts.

Me first: Neural representations of fairness during three-party interactions

One hallmark of human morality is a deep sense of fairness. People are motivated by both self-interest and a concern for the welfare of others. However, it remains unclear whether these motivations rely on similar neural computations, and the extent to which such computations influence social decision-making when self-fairness and other-fairness motivations compete. In this study, two groups of participants engaged in the role of responder in a three-party Ultimatum Game while being scanned with functional MRI (N = 32) or while undergoing high-density electroencephalography (N = 40). In both studies, participants accepted more OtherFair offers when they themselves received fair offers. Though SelfFairness was reliably decoded from scalp voltages by 170 ms, and from hemodynamic responses in right insula and dorsolateral prefrontal cortex, there was no overlap between neural representations of fairness for self and for other. Distinct neural computations and mechanisms seem to be involved when making decisions about fairness in three-party contexts, which are anchored in an egocentric, self-serving bias.

The importance of using multiple outcome measures in infant research

Collecting data with infants is notoriously difficult. As a result, many of our studies consist of small samples, with only a single measure, in a single age group, at a single time point. With renewed calls for greater academic rigor in data collection practices, using multiple outcome measures in infant research is one way to increase rigor, and, at the same time, enable us to more accurately interpret our data. Here, we illustrate the importance of using multiple measures in psychological research with examples from our own work on rapid threat detection and from the broader infancy literature. First, we describe our initial studies using a single outcome measure, and how this strategy caused us to nearly miss a rich and complex story about attention biases for threat and their development. We demonstrate how using converging measures can help researchers make inferences about infant behavior, and how using additional measures allows us to more deeply examine the mechanisms that drive developmental change. Finally, we provide practical and statistical recommendations for how researchers can use multiple measures in future work.

First steps toward an understanding of procedural fairness

In four experiments, we tested whether 20-month-old infants are sensitive to violations of procedural impartiality. Participants were shown videos in which help was provided in two different ways. A main character provided help to two other agents either impartially, by helping them at the same time, or in a biased way, by helping one agent almost immediately while the other after a longer delay. Infants looked reliably longer at the biased than at the unbiased help scenarios despite the fact that in both scenarios help was provided to each beneficiary. This suggests that human infants can attend to departures from impartiality and, in their second year, they already show an initial understanding of procedural fairness.

The developmental origins of social hierarchy: how infants and young children mentally represent and respond to power and status

The learnability problem of social life suggests that innate mental representations and motives to navigate adaptive relationships have evolved. Like other species, preverbal human infants form dominance hierarchies where some systematically supplant others in zero-sum conflict, and use the formidability cues of body and coalition size, as well as previous win-lose history, to predict who will prevail. Like other primates, human toddlers also seek to affiliate with allies of high rank, but unlike bonobos they pay unique attention whether others voluntarily defer to their precedence, reflecting the importance of consensual authority in cooperative human society. However, young children appear not to readily infer authority from benevolence, and expectations for inequality correlate with unwillingness to share resources even among infants.