Proceedings of the Annual Meeting of the Cognitive Science Society

Shared sleep arrangements, especially children's, often occur in proximity to family and other caregivers. We investigated whether sleep-sharing serves as a reliable cue to familial and caregiving relationships, even in childhood. Two preregistered studies with U.S. 5–7-year-olds (N = 168) and adults (N = 168) show people possess systematic intuitions about the social meaning of shared sleep arrangements. In Study 1, both age groups robustly expected that a child character sleep-shared with family over non-family (siblings over friends; parents over teachers), while expecting equal toy-sharing. In Study 2, both age groups predicted that a child's chosen sleep-sharing (vs. toy-sharing) partner would provide physical comfort (care) when the child became upset. Adults privileged sleep-sharing over another intimate interaction––saliva-sharing––as diagnostic of a caregiving relationship. From early childhood, people use shared sleep arrangements as a powerful signal of intimate relationships, supporting their understanding of the social landscape.