Detecting dominance relationships, within and across species, provides a clear fitness advantage because this ability helps individuals assess their potential risk of injury before engaging in a competition. Previous research has demonstrated that 10- to 13-mo-old infants can represent the dominance relationship between two agents in terms of their physical size (larger agent = more dominant), whereas younger infants fail to do so. It is unclear whether infants younger than 10 mo fail to represent dominance relationships in general, or whether they lack sensitivity to physical size as a cue to dominance. Two studies explored whether infants, like many species across the animal kingdom, use numerical group size to assess dominance relationships and whether this capacity emerges before their sensitivity to physical size. A third study ruled out an alternative explanation for our findings. Across these studies, we report that infants 6–12 mo of age use numerical group size to infer dominance relationships. Specifically, preverbal infants expect an agent from a numerically larger group to win in a right-of-way competition against an agent from a numerically smaller group. In addition, this is, to our knowledge, the first study to demonstrate that infants 6–9 mo of age are capable of understanding social dominance relations. These results demonstrate that infants’ understanding of social dominance relations may be based on evolutionarily relevant cues and reveal infants’ early sensitivity to an important adaptive function of social groups.

No abstract

Understanding the factors that shape the social landscape is essential for living in a group, where dominant individuals often have greater control over and access to desired resources such as food and mates. Recently, researchers have demonstrated that preverbal infants, similar to their nonhuman primate relatives, already possess the cognitive schemas necessary to represent social dominance in relationships, using ecologically relevant cues such as relative physical size and group size. In this article, we discuss the phylogenetic and ontogenetic origins of infants’ and children's capacity to represent social dominance in relationships and hierarchies, and examine how these initial representations are enriched across early childhood.

Previous research has suggested that infants exhibit a preference for familiar over unfamiliar social groups (e.g., preferring individuals from their own language group over individuals from a foreign language group). However, because past studies often employ forced-choice procedures, it is not clear whether infants' intergroup preferences are driven by positivity toward members of familiar groups, negativity toward members of unfamiliar groups, or both. Across six experiments, we implemented a habituation procedure to independently measure infants' positive and negative evaluations of speakers of familiar and unfamiliar languages. We report that by 1 year of age, infants positively evaluate individuals who speak a familiar language, but do not negatively evaluate individuals who speak an unfamiliar language (Experiments 1 and 2). Several experiments rule out lower-level explanations (Experiments 3-6). Together these data suggest that children's early social group preferences may be shaped by positive evaluations of familiar group(s), rather than negative evaluations of unfamiliar groups.

During a conflict, having a greater number of allies than the opposition can improve one’s success in a conflict. However, allies must be aware that has a conflict has occurred, and this is often influenced by what they are able to see. Here, we explored whether infants’ assessment of social dominance is influenced by whether or not social allies have visual access to an episode of intergroup conflict. In Experiment 1, 9–12-month-olds only expected an agent to be socially dominant if their allies were able to witness the conflict. Experiment 2 provided further support for this finding, as infants did not expect an agent from a numerically larger group to be socially dominant when allies were unable to witness the conflict. Together, these results suggest that infants do not simply use a heuristic in which “numerically larger groups are always more dominant”. Importantly, infants are able to incorporate social allies’ ability to witness a conflict when predicting social dominance between groups.