Infants Infer Social Relationships Between Individuals Who Engage in Imitative Social Interactions.

Infants are born into rich social networks and are faced with the challenge of learning about them. When infants observe social interactions, they make predictions about future behavior, but it is not clear whether these predictions are based on social dispositions, social relationships, or both. The current studies (N = 188, N = 90 males) address this question in 12-month-old infants and 16- to 18-month-old toddlers who observe social interactions involving imitation. In Studies 1 and 3, infants and toddlers expected that imitators, compared to non-imitators, would respond to their social partners' distress. Likewise, they expected the targets of imitation, compared to non-targets, to respond to their partner's distress. In Study 2, these expectations did not generalize to interactions with a new partner, providing evidence that infants learned about the relationships between individuals as opposed to their dispositions. In Study 3, infants did not make predictions about responses to laughter, suggesting that infants see imitation as indicative of a specific kind of social relationship. Together, these results provide evidence that imitative interactions support infants' and toddlers' learning about the social relationships connecting unknown individuals.

Intuitive Sociology: Children Recognize Decision-Making Structures and Prefer Groups With Less-Concentrated Power.

From an early age, children recognize that people belong to social groups. However, not all groups are structured in the same way. The current study asked whether children recognize and distinguish among different decision-making structures. If so, do they prefer some decision-making structures over others? In these studies, children were told stories about two groups that went camping. In the hierarchical group, one character made all the decisions; in the egalitarian group, each group member made one decision. Without being given explicit information about the group's structures, 6- to 8-year-old children, but not 4- and 5-year-old children, recognized that the two groups had different decision-making structures and preferred to interact with the group where decision-making was shared. Children also inferred that a new member of the egalitarian group would be more generous than a new member of the hierarchical group. Thus, from an early age, children's social reasoning includes the ability to compare social structures, which may be foundational for later complex political and moral reasoning.

Non-instrumental actions can communicate roles and relationships, not just rituals.

Actions that do not have instrumental goals can communicate social goals that are not rituals. Many non-instrumental actions such as bowing or kissing communicate a commitment to or roles in dyadic relationships. What is unclear is when people understand such actions in terms of ritual and when they understand them in terms of relationships.

Advantages and limitations of representing groups in terms of recursive utilities.

Group representations based on recursive utilities can be used to derive the same predictions as Pietraszewski in conflict situations. Additionally, these representations generalize to non-conflict situations, asymmetric relationships, and represent the stakes in a conflict. However, both proposals fail to represent asymmetries of power and responsibility and to account for generalizations from specific observed individuals to collections of non-observed individuals.

Infants infer potential social partners by observing the interactions of their parent with unknown others.

Infants are born into networks of individuals who are socially connected. How do infants begin learning which individuals are their own potential social partners? Using digitally edited videos, we showed 12-mo-old infants' social interactions between unknown individuals and their own parents. In studies 1 to 4, after their parent showed affiliation toward one puppet, infants expected that puppet to engage with them. In study 5, infants made the reverse inference; after a puppet engaged with them, the infants expected that puppet to respond to their parent. In each study, infants' inferences were specific to social interactions that involved their own parent as opposed to another infant's parent. Thus, infants combine observation of social interactions with knowledge of their preexisting relationship with their parent to discover which newly encountered individuals are potential social partners for themselves and their families.

Early concepts of intimacy: Young humans use saliva sharing to infer close relationships.

Across human societies, people form "thick" relationships characterized by strong attachments, obligations, and mutual responsiveness. People in thick relationships share food utensils, kiss, or engage in other distinctive interactions that involve sharing saliva. We found that children, toddlers, and infants infer that dyads who share saliva (as opposed to other positive social interactions) have a distinct relationship. Children expect saliva sharing to happen in nuclear families. Toddlers and infants expect that people who share saliva will respond to one another in distress. Parents confirm that saliva sharing is a valid cue of relationship thickness in their children's social environments. The ability to use distinctive interactions to infer categories of relationships thus emerges early in life, without explicit teaching; this enables young humans to rapidly identify close relationships, both within and beyond families.

Rationalization may improve predictability rather than accuracy.

We present a theoretical and an empirical challenge to Cushman's claim that rationalization is adaptive because it allows humans to extract more accurate beliefs from our non-rational motivations for behavior. Rationalization sometimes generates more adaptive decisions by making our beliefs about the world less accurate. We suggest that the most important adaptive advantage of rationalization is instead that it increases our predictability (and therefore attractiveness) as potential partners in cooperative social interactions.

Infants Choose Those Who Defer in Conflicts.

For humans and other social species, social status matters: it determines who wins access to contested resources, territory, and mates [1-11]. Human infants are sensitive to dominance status cues [12, 13]. They expect conflicts to be won by larger individuals [14], those with more allies [15], and those with a history of winning [16-18]. But being sensitive to status cues is not enough; individuals must also use status information when deciding whom to approach and whom to avoid [19]. In many non-human species, low-status individuals avoid high-status individuals and in so doing avoid the threat of aggression [20-23]. In these species, high-status individuals commit random acts of aggression toward subordinates [23] and even commit infanticide [24-26]. However, for less reactively aggressive species [27, 28], high-status individuals may be good coalition partners. This is especially true for humans, where high-status individuals can provide guidance, protection, and knowledge to subordinates [2, 29, 30]. Indeed, human adults [31-33], human toddlers [34], and adult bonobos [35] prefer high-status individuals to low-status ones. Here, we present 6 experiments testing whether 10- to 16-month-old human infants choose high- or low-status individuals-specifically, winners or yielders in zero-sum conflicts-and find that infants choose puppets who yield. Intriguingly, toddlers just 6 months older choose the winners of such conflicts [34]. This suggests that, although humans start out like many other species, avoiding high-status others, we shift in toddlerhood to approaching high-status individuals, consistent with the idea that, for humans, high-status individuals can provide benefits to low-status ones.

Toddlers prefer those who win but not when they win by force.

Social hierarchies occur across human societies, so all humans must navigate them. Infants can detect when one individual outranks another1-3, but it is unknown whether they approach others based on their social status. This paper presents a series of seven experiments investigating whether toddlers prefer high- or low-ranking individuals. Toddlers aged 21-31 months watched a zero-sum, right-of-way conflict between two puppets, in which one puppet 'won' because the other yielded the way. Of the 23 toddlers who participated, 20 reached for the puppet that 'won'. However, when one puppet used force and knocked the other puppet down in order to win, 18 out of 22 toddlers reached for the puppet that 'lost'. Five follow-up experiments ruled out alternative explanations for these results. The findings suggest that humans, from a very early age, not only recognize relative status but also incorporate status into their decisions about whether to approach or avoid others, in a way that differs from our nearest primate relatives4.

Exploring the relation between people's theories of intelligence and beliefs about brain development.

A person's belief about whether intelligence can change (called their implicit theory of intelligence) predicts something about that person's thinking and behavior. People who believe intelligence is fixed (called entity theorists) attribute failure to traits (i.e., "I failed the test because I'm not smart.") and tend to be less motivated in school; those who believe intelligence is malleable (called incremental theorists) tend to attribute failure to behavior (i.e., "I failed the test because I didn't study.") and are more motivated in school. In previous studies, researchers have characterized participants as either entity or incremental theorists based on their agreement or disagreement with three statements. The present study further explored the theories-of-intelligence (TOI) construct in two ways: first, we asked whether these theories are coherent, in the sense that they show up not only in participants' responses to the three standard assessment items, but on a broad range of questions about intelligence and the brain. Second, we asked whether these theories are discrete or continuous. In other words, we asked whether people believe one thing or the other (i.e., that intelligence is malleable or fixed), or if there is a continuous range of beliefs (i.e., people believe in malleability to a greater or lesser degree). Study (1) asked participants a range of general questions about the malleability of intelligence and the brain. Study (2) asked participants more specific questions about the brains of a pair of identical twins who were separated at birth. Results showed that TOI are coherent: participants' responses to the three standard survey items are correlated with their responses to questions about the brain. But the theories are not discrete: although responses to the three standard survey items fell into a bimodal distribution, responses to the broader range of questions fell into a normal distribution suggesting the theories are continuous.