Infants expect friends, but not rivals, to be happy for each other when they succeed.

A friend telling you good news earns them a smile while witnessing a rival win an award may make you wrinkle your nose. Emotions arise not just from people's own circumstances, but also from the experiences of friends and rivals. Across three moderated, online looking time studies, we asked if human infants hold expectations about others' vicarious emotions and if they expect those emotions to be guided by social relationships. Ten- and 11-month-old infants (N = 154) expected an observer to be happy rather than sad when the observer watched a friend successfully jump over a wall; infants looked longer at the sad response compared to the happy response. In contrast, infants did not expect the observer to be happy when the friend failed, nor when a different, rival jumper succeeded; infants' looking times to the two emotion responses in these conditions were not reliably different. These results suggest that infants are able to integrate knowledge across social contexts to guide expectations about vicarious emotional responses. Here infants connected an understanding of agents' goals and their outcomes with knowledge of social relationships to infer an emotion response. Biased concern for friends but not adversaries is not just a descriptive feature of human relationships, but an expectation about the social world present from early in development. Further, the successful integration of these information types welcomes the possibility that infants can jointly reason about goals, emotions, and social relationships under an intuitive theory of psychology. RESEARCH HIGHLIGHTS: 11-month-old infants use knowledge of relationships to make inferences about others' vicarious emotions. In Experiment 1 infants expected an observer to respond happily to a friend's success but not their failure. Experiments 2 and 3 varied the relationship between the observer and actor and found that infants' expectation of vicarious happiness is strongest for positive relationships and absent for negative relationships. The results may reflect an intuitive psychology in which infants expect friends to adopt concern for one another's goals and to thus experience one another's successes as rewarding.

Triadic conflict "primitives" can be reduced to welfare trade-off ratios.

Pietraszewski proposes four triadic "primitives" for representing social groups. We argue that, despite surface differences, these triads can all be reduced to similar underlying welfare trade-off ratios, which are a better candidate for social group primitives. Welfare trade-off ratios also have limitations, however, and we suggest there are multiple computational strategies by which people recognize and reason about social groups.

Imitation: Neither instinct nor gadget, but a cultural starting point?

Heyes asks whether cultural learning mechanisms are cognitive instincts or cognitive gadgets. I argue that imitation does not fall into either category. Instead, its acquisition is promoted by its value in social interactions, which is evident across phylogeny and ontogeny and does not depend on the role of imitation in cultural learning.

Using individual functional channels of interest to study cortical development with fNIRS.

Functional near-infrared spectroscopy (fNIRS) is a noninvasive neuroimaging technique that could be uniquely effective for investigating cortical function in human infants. However, prior efforts have been hampered by the difficulty of aligning arrays of fNIRS optodes placed on the scalp to anatomical or functional regions of underlying cortex. This challenge can be addressed by identifying channels of interest in individual participants, and then testing the reliability of those channels' response profiles in independent data. Using this approach, cortical regions with preferential responses to faces versus scenes, and to scenes versus faces, were observed reliably in both adults and infants. By contrast, standard analysis techniques did not reliably identify significant responses to both categories in either age group. These results reveal scene-responsive regions, and confirm face-responsive regions, in preverbal infants. More generally, the analysis approach will be a robust and sensitive tool for future characterization of the early functional development of the human brain.

Preverbal infants expect members of social groups to act alike.

The short ontogenetic time courses of conformity and stereotyping, both evident in the preschool years, point to the possibility that a central component of human social cognition is an early developing expectation that social group members will engage in common behaviors. Across a series of experiments, we show that by 7 months of age preverbal infants differentiate between actions by individuals that are and are not consistent with the actions of their social group members. Infants responded to group-inconsistent actions only in a social context: they failed to distinguish the same behavioral differences when presented with collections of nonsocial agents or inanimate objects. These results suggest that infants expect social group membership and behavior to covary, before extensive intergroup experience or linguistic input. This expectation is consistent with the socially motivated imitation and stereotyping evident in toddlers and preschoolers, and may play a role in the early emergence of one or both of these aspects of social behavior and cognition.

Interpersonal utility and children's social inferences from shared preferences.

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

Children's Reasoning About Empathy and Social Relationships.

Across the lifespan, empathic and counter-empathic emotions are shaped by social relationships. Here we test the hypothesis that this connection is encoded in children's intuitive theory of psychology, allowing them to predict when others will feel empathy versus counter-empathy and to use vicarious emotion information to infer relationships. We asked 4- to 7-year-old children (N = 79) to make emotion predictions or relationship inferences in response to stories featuring two characters, an experiencer and an observer, and either a positive or negative outcome for the experiencer. In the context of positive outcomes, we found that children engaged in robust joint reasoning about relationships and vicarious emotions. When given information about the characters' relationship, children predicted empathy from a friendly observer and counter-empathy from a rival observer. When given information about the observer's response to the experiencer, children inferred positive and negative relationships from empathic and counter-empathic responses, respectively. In the context of negative outcomes, children predicted that both friendly and rival observers would feel empathy toward the experiencer, but they still used information about empathic versus counter-empathic responses to infer relationship status. Our results suggest that young children in the US have a blanket expectation of empathic concern in response to negative outcomes, but otherwise expect and infer that vicarious emotions are connected to social relationships. Future research should investigate if children use this understanding to select social partners, evaluate their own relationships, or decide when to express empathy toward others.

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.

Individual differences provide new insight into infant looking.

A recent article by Perez and Feigenson explores variability in order to better understand infant looking time. They found that individual differences in infants' interest in surprising events were consistent across months, despite changes in event type. Moreover, looking times in infancy predicted curiosity in childhood.

Dissociable neural substrates for agentic versus conceptual representations of self.

Although humans generally experience a coherent sense of selfhood, we can nevertheless articulate different aspects of self. Recent research has demonstrated that one such aspect of self--conceptual knowledge of one's own personality traits--is subserved by ventromedial prefrontal cortex (vMPFC). Here, we examined whether an alternative aspect of "self"--being an agent who acts to achieve one's own goals--relies on cognitive processes that overlap with or diverge from conceptual operationalizations of selfhood. While undergoing fMRI, participants completed tasks of both conceptual self-reference, in which they judged their own or another person's personality traits, and agentic self-reference, in which they freely chose an object or watched passively as one was chosen. The agentic task failed to modulate vMPFC, despite producing the same memory enhancement frequently observed during conceptual self-referential processing (the "self-reference" effect). Instead, agentic self-reference was associated with activation of the intraparietal sulcus (IPS), a region previously implicated in planning and executing actions. Experiment 2 further demonstrated that IPS activity correlated with later memory performance for the agentic, but not conceptual, task. These results support views of the "self" as a collection of distinct mental operations distributed throughout the brain, rather than a unitary cognitive system.

Fixed and flexible: Dynamic prefrontal activations and working memory capacity relationships vary with memory demand.

Prefrontal cortex (PFC) activation during encoding of memoranda (proactive responses) is associated with better working memory (WM) compared to reactive/retrieval-based activation. This suggests that dynamic PFC activation patterns may be fixed, based upon one's WM ability, with individuals who have greater WM ability relying more on proactive processes and individuals with lesser WM ability relying more on reactive processes. We newly tested whether this heuristic applied when challenging an individual's WM capacity. Twenty-two participants (N = 22) underwent functional near-infrared spectroscopy (fNIRS) during a modified Sternberg WM paradigm. We tested whether the relationship between dynamic PFC activation patterns and WM capacity changed, as a function of WM demands (N = 14 after quality control). Here, higher-WM capacity was associated with more proactive PFC patterns, but only when WM capacity was overloaded. Lower-WM capacity was associated with these same patterns, but only when WM demand was low. Findings are inconsistent with a purely fixed view of dynamic PFC activation patterns and suggest higher- and lower-WM-capacity individuals flexibly engage PFC processes in a fundamentally different manner, dependent upon current WM demands.

Human infants' understanding of social imitation: Inferences of affiliation from third party observations.

Imitation is ubiquitous in positive social interactions. For adult and child observers, it also supports inferences about the participants in such interactions and their social relationships, but the origins of these inferences are obscure. Do infants attach social significance to this form of interaction? Here we test 4- to 5.5-month-old infants' interpretation of imitation, asking if the imitative interactions they observe support inferences of social affiliation, across 10 experimental conditions that varied the modality of the imitation (movement vs. sound), the roles of specific characters (imitators vs. targets), the number of characters in the displays (3 vs. 5), and the number of parties initiating affiliative test events (1 vs. 2). These experiments, together with one experiment conducted with 12-month-old infants, yielded three main findings. First, infants expect that characters who engaged in imitation will approach and affiliate with the characters whom they imitated. Second, infants show no evidence of expecting that characters who were targets of imitation will approach and affiliate with their imitators. Third, analyzing imitative interactions is difficult for young infants, whose expectations vary in strength depending on the number of characters to be tracked and the number of affiliative actors to be compared. These findings have implications for our understanding of social imitation, and they provide methods for advancing understanding of other aspects of early social cognitive development.

Social Origins of Cortical Face Areas.

Recently acquired fMRI data from human and macaque infants provide novel insights into the origins of cortical networks specialized for perceiving faces. Data from both species converge: cortical regions responding preferentially to faces are present and spatially organized early in infancy, although fully selective face areas emerge much later. What explains the earliest cortical responses to faces? We review two proposed mechanisms: proto-organization for simple shapes in visual cortex, and an innate subcortical schematic face template. In addition, we propose a third mechanism: infants choose to look at faces to engage in positively valenced, contingent social interactions. Activity in medial prefrontal cortex during social interactions may, directly or indirectly, guide the organization of cortical face areas.

Executive function depletion in children and its impact on theory of mind.

The current studies provide an experimental, rather than correlational, method for testing hypotheses about the role of executive function (EF) in conceptual development. Previous research has established that adults' tendency to deploy EF can be temporarily diminished by use. Exercising self-control in one context decreases adults' performance on other EF demanding tasks immediately thereafter. Using two different depletion methods, Experiments 1 and 3 extend this finding to preschool-aged children. Experiments 2 and 4 make use of these EF depletion methods to elucidate the role of EF in children's theory of mind reasoning. Experiment 2 shows that EF depletion affects 5-year-olds' ability to predict another's behavior on the basis of that person's false belief, and Experiment 4 shows that this negative effect of depletion extends to 4- and 5-year-olds' ability to explain others' behavior on the basis of their false beliefs. These findings provide direct evidence that EF is required for the expression of an understanding of others' false beliefs across a variety of task demands, even in children who clearly have the capacity to construct such representations. We suggest ways in which depletion may be used as a tool for further investigating the role of executive function in cognitive development.

The origins of pedagogy: developmental and evolutionary perspectives.

The question of whether and how information is actively transferred from knowledgeable to ignorant individuals has received much attention in psychology and evolutionary biology. Research in these fields has proceeded largely independently, with studies of nonhuman animals focusing on knowledgeable individuals and whether or not they meet a functional definition of teaching, while studies of children focus on the learner's assumptions and inferences. We argue that a comprehensive theory of teaching will benefit from integrating perspectives and empirical phenomena from evolutionary and developmental disciplines. In this review, we identify cases of seemingly purposeful information transfer (i.e. teaching) in human and nonhuman animals, discuss what is known about the cognitive processes that support teaching in different species, and highlight ways in which each discipline might be informed by extant theories and empirical tools from the other.

It's the thought that counts: specific brain regions for one component of theory of mind.

Evidence from developmental psychology suggests that representing the contents of other people's thoughts and beliefs depends on a component of reasoning about other minds (theory of mind) that is distinct from the earlier-developing mental-state concepts for goals, perceptions, and feelings. To provide converging evidence, the current study investigated the substrate of the late-developing process in adult brains. Three regions--the right and left temporo-parietal junction and the posterior cingulate--responded selectively when subjects read about a protagonist's thoughts, but not when they read about other subjective, internal states or other socially relevant information about a person. By contrast, the medial prefrontal cortex responded equivalently in all of these story conditions, a result consistent with a broader role for medial prefrontal cortex in general social cognition. These data support the hypothesis that the early- and late-developing components of theory of mind rely on separate psychological and neural mechanisms, and that these mechanisms remain distinct into adulthood.