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

Do infants use cues of saliva-sharing to infer close relationships? A replication of Thomas et al. (2022)

Thomas and colleagues found in 2022 that the observation of saliva-sharing between individuals serves as an indicator of relationship thickness for children, toddlers and infants. Our study sought to replicate their crucial experiment (2B), which was conducted online and reported that 8.5- to 10-month-old infants anticipated that a crying individual would be more likely to be comforted by a person who had been observed to share saliva with her than another person who simply had played with her. With the exception of changing the testing environment from online to laboratory, and using an eye-tracker supplemented by manual video coding, we closely followed the methodology of the original study. Our replication resulted in partial success: we replicated looking-time preference for the saliva-sharer but did not replicate the tendency to look first to the saliva-sharer upon observing the puppet's distress. These findings confirm that infants rely on certain behavioural cues for mapping social relationships among third-party individuals.

Origins of food selectivity in human visual cortex

Several recent studies, enabled by advances in neuroimaging methods and large-scale datasets, have identified areas in human ventral visual cortex that respond more strongly to food images than to images of many other categories, adding to our knowledge about the broad network of regions that are responsive to food. This finding raises important questions about the evolutionary and developmental origins of a possible food-selective neural population, as well as larger questions about the origins of category-selective neural populations more generally. Here, we propose a framework for how visual properties of food (particularly color) and nonvisual signals associated with multimodal reward processing, social cognition, and physical interactions with food may, in combination, contribute to the emergence of food selectivity. We discuss recent research that sheds light on each of these factors, alongside a broader account of category selectivity that incorporates both visual feature statistics and behavioral relevance.

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.

Wired for society? From ego-logy to eco-logy

Somewhat questioning Elizabeth Spelke's attempt to account for infants' social knowledge, our commentary argues that social cognition might be divided into several specialized systems. In addition to the core system dedicated to the intersubjective dimension of close relationships, infants could be prewired to process social relationships, such as dominance, characterized by their impersonal, normative dimension.

The Representation of Giving Actions: Event Construction in the Service of Monitoring Social Relationships

Giving is a unique attribute of human sharing. In this review, we discuss evidence attesting to our species' preparedness to recognize interactions based on this behavior. We show that infants and adults require minimal cues of resource transfer to relate the participants of a giving event in an interactive unit (A gives X to B) and that such an interpretation does not systematically generalize to superficially similar taking events, which may be interpreted in nonsocial terms (A takes X). We argue that this asymmetry, echoed in language, reveals the operations of a mechanism of event construction where participant roles are encoded only when they are crucial to rendering an action teleologically well-formed. We show that such a representation of giving allows people to monitor the direction (who gave to whom) and kind (what was given) of resource transfer within a dyad, suggesting that giving may be interpreted as indicative of a relationship based on long-term balance. As this research suggests, advancing the study of the prelinguistic representation of giving has implications for cognitive linguistics, by clarifying the relation between event participants and syntactic arguments, as well as social cognition, by identifying which kinds of relational inferences people draw from attending to acts of sharing.

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.

Infants' understanding of the causal power of agents and tools

Tools are objects that are manipulated by agents with the intention to cause an effect in the world. We show that the cognitive capacity to understand tools is present in young infants, even if these tools produce arbitrary, causally opaque effects. In experiments 1-2, we used pupillometry to show that 8-mo-old infants infer an invisible causal contact to account for the-otherwise unexplained-motion of a ball. In experiments 3, we probed 8-mo-old infants' account of a state change event (flickering of a cube) that lies outside of the explanatory power of intuitive physics. Infants repeatedly watched an intentional agent launch a ball behind an occluder. After a short delay, a cube, positioned at the other end of the occluder began flickering. Rare unoccluded events served to probe infants' representation of what happened behind the occluder. Infants exhibited larger pupil dilation, signaling more surprise, when the ball stopped before touching the cube, than when it contacted the cube, suggesting that infants inferred that the cause of the state change was contact between the ball and the cube. This effect was canceled in experiment 4, when an inanimate sphere replaced the intentional agent. Altogether, results suggest that, in the infants' eyes, a ball (an inanimate object) has the power to cause an arbitrary state change, but only if it inherits this power from an intentional agent. Eight-month-olds are thus capable of representing complex event structures, involving an intentional agent causing a change with a tool.

Shared social groups or shared experiences? The effect of shared knowledge on children's perspective-taking

Although the ability to consider others' visual perspectives to interpret ambiguous communication emerges during childhood, people sometimes fail to attend to their partner's perspective. Two studies investigated whether 4- to 6-year-olds show a "closeness-communication bias" in their consideration of a partner's perspective in a communication task. Participants played a game that required them to take their partner's visual perspective in order to interpret an ambiguous instruction. If children, like adults, perform worse when they overestimate the extent to which their perspective is aligned with that of a partner, then they should make more perspective-taking errors when interacting with a socially close partner compared with a more socially distant partner. In Study 1, social closeness was based on belonging to the same social group. In Study 2, social closeness was based on caregiving, a long-standing social relationship with a close kinship bond. Although social group membership did not affect children's consideration of their partner's perspective, children did make more perspective-taking errors when interacting with a close caregiver compared with a novel experimenter. These findings suggest that close personal relationships may be more likely to lead children to overestimate perspective alignment and hinder children's perspective-taking than shared social group membership, and they highlight important questions about the mechanisms underlying the effects of partner characteristics in perspective-taking tasks.

Human and animal dominance hierarchies show a pyramidal structure guiding adult and infant social inferences

This study investigates the structure of social hierarchies. We hypothesized that if social dominance relations serve to regulate conflicts over resources, then hierarchies should converge towards pyramidal shapes. Structural analyses and simulations confirmed this hypothesis, revealing a triadic-pyramidal motif across human and non-human hierarchies (114 species). Phylogenetic analyses showed that this pyramidal motif is widespread, with little influence of group size or phylogeny. Furthermore, nine experiments conducted in France found that human adults (N = 120) and infants (N = 120) draw inferences about dominance relations that are consistent with hierarchies' pyramidal motif. By contrast, human participants do not draw equivalent inferences based on a tree-shaped pattern with a similar complexity to pyramids. In short, social hierarchies exhibit a pyramidal motif across a wide range of species and environments. From infancy, humans exploit this regularity to draw systematic inferences about unobserved dominance relations, using processes akin to formal reasoning.

The Development of Feeding Competence in Rehabilitant Orphaned Orangutans and How to Measure It

For critically endangered species, restorative conservation becomes increasingly important. Successful re-introduction of rescued wild orangutan orphans requires rehabilitation mimicking maternal rearing in the wild. Feeding competence-what to eat, where and when to find food-needs to be learned before re-introduction. We observed seven orphans (2-10 years old) for a period of 3 years during their rehabilitation at the Yayasan Jejak Pulang forest school. Of the 111 plant genera eaten by the orphans, 92 percent were known orangutan food plants. Five plant genera were eaten by all orphans in over 90 percent of the months within the observation period. The Fruit Availability Index (FAI) was used to predict which parts of a plant were consumed by the orphans. We found that the orphans ate primarily fruit when the FAI was high, but consumed more young leaves, cambium, and pith when FAI was low. Thus, the orphans exhibited food choices very similar to mature wild orangutans and appropriate to forest productivity. The orphans' acquisition of feeding competence was facilitated by their immersion into a natural forest environment in combination with possibilities for observational learning from conspecifics as well as caregivers modelling food processing and consumption.

Précis of What Babies Know

Where does human knowledge begin? Research on human infants, children, adults, and nonhuman animals, using diverse methods from the cognitive, brain, and computational sciences, provides evidence for six early emerging, domain-specific systems of core knowledge. These automatic, unconscious systems are situated between perceptual systems and systems of explicit concepts and beliefs. They emerge early in infancy, guide children's learning, and function throughout life.

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.

Eye-tracking as a window into primate social cognition

Over the past decade, noninvasive, restraint-free eye-tracking research with primates has transformed our understanding of primate social cognition. The use of this technology with many primate species allows for the exploration and comparison of how these species attend to and understand social agents and interactions. The ability to compare and contrast the cognitive capacities of various primate species, including humans, provides insight into the evolutionary mechanisms and selective pressures that have likely shaped social cognition in similar and divergent ways across the primate order. In this review, we begin by discussing noninvasive behavioral methods used to measure primate gaze and attention before the introduction of noninvasive, restraint-free eye-tracking methodologies. Next, we focus on findings from recent eye-tracking research on primate social cognition, beginning with simple visual and search mechanisms. We then discuss the results that have built on this basic understanding of how primates view images and videos, exploring discrimination and knowledge of social agents, following social cues, tracking perspectives and predicting behavior, and the combination of eye-tracking and other behavioral and physiological methods. Finally, we discuss some future directions of noninvasive eye-tracking research on primate social cognition and current eye-tracking work-in-progress that builds on these previous studies, investigating underexplored socio-cognitive capacities and utilizing new methodologies.

Kids attend to saliva sharing to infer social relationships

[Figure: see text].

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.