Forming conceptually rich social categories helps people navigate the complex social world by allowing them to reason about others’ likely thoughts, beliefs, actions, and interactions as guided by group membership. Yet, social categorization often has nefarious consequences. We suggest that the foundation of the human ability to form useful social categories is in place in infancy: social categories guide infants’ inferences about peoples’ shared characteristics and social relationships. We also suggest that the ability to form abstract social categories may be separable from the eventual negative downstream consequences of social categorization, including prejudice, discrimination and stereotyping. Whereas a tendency to form inductively rich social categories appears early in ontogeny, prejudice based on each particular category dimension may not be inevitable.

Selecting appropriate foods is a complex and evolutionarily ancient problem, yet past studies have revealed little evidence of adaptations present in infancy that support sophisticated reasoning about perceptual properties of food. We propose that humans have an earlyemerging system for reasoning about the social nature of food selection. Specifically, infants' reasoning about food choice is tied to their thinking about agents' intentions and social relationships. Whereas infants do not expect people to like the same objects, infants view food preferences as meaningfully shared across individuals. Infants' reasoning about food preferences is fundamentally social: They generalize food preferences across individuals who affiliate, or who speak a common language, but not across individuals who socially disengage or who speak different languages. Importantly, infants' reasoning about food preferences is flexibly calibrated to their own experiences: Tests of bilingual babies reveal that an infant's sociolinguistic background influences whether she will constrain her generalization of food preferences to people who speak the same language. Additionally, infants' systems for reasoning about food is differentially responsive to positive and negative information. Infants generalize information about food disgust across all people, regardless of those people's social identities. Thus, whereas food preferences are seen as embedded within social groups, disgust is interpreted as socially universal, which could help infants avoid potentially dangerous foods. These studies reveal an early-emerging system for thinking about food that incorporates social reasoning about agents and their relationships, and allows infants to make abstract, flexible, adaptive inferences to interpret others' food choices.food | social cognition | infancy | cognitive development | disgust

Early language exposure is essential to developing a formal language system, but may not be sufficient for communicating effectively. To understand a speaker’s intention, one must take the speaker’s perspective. Multilingual exposure may promote effective communication by enhancing perspective taking. We tested children on a task that required perspective taking to interpret a speaker’s intended meaning. Monolingual children failed to interpret the speaker’s meaning dramatically more often than bilingual children and children who were exposed to a multilingual environment but were not bilinguals themselves. Children who were merely exposed to a second language performed as well as bilingual children, despite having lower executive function scores. Thus, communicative advantages may be social in origin, and not due to enhanced executive control. For millennia, multilingual exposure has been the norm. Our study shows that such an environment may facilitate the development of perspective-taking tools that are critical for effective communication.

Predicting others’ affiliative relationships is critical to social cognition, but there is little evidence of how this ability develops. We examined 9-month-old infants’ inferences about third-party affiliation based on shared and opposing evaluations. Infants expected two people who expressed shared evaluations to interact positively, whereas they expected two people who expressed opposing evaluations to interact negatively. A control condition revealed that infants’ expectations could not be due to mere perceptual repetition. Thus, an abstract understanding that third-party affiliation can be based on shared intentions has roots in the first year of life. These findings have implications for understanding humans’ earliest representations of the social world.

Early exposure to multiple languages can enhance children’s communication skills, even when children are effectively monolingual (Fan, Liberman, Keysar, & Kinzler, 2015). Here we report evidence that the social benefits of multilingual exposure emerge in infancy. Sixteen-month-old infants participated in a communication task that required taking a speaker’s perspective to understand her intended meaning. Infants were presented with two identical toys, such as two cars. One toy was mutually visible to both the infant and the speaker, but the other was visible only to the infant and blocked from the speaker’s view by an opaque barrier. The speaker requested the mutually visible toy and we evaluated whether infants understood the speaker’s request. Whereas monolingual infants were at chance at choosing between the two toys, infants with multilingual exposure reliably chose the toy the speaker requested. Successful performance was not related to the degree of exposure to other languages, suggesting that even minimal multilingual exposure may enhance communication skills.