Loss of dance and infant-directed song among the Northern Aché

Dance and infant-directed song are often considered universal behaviors, a view that has been supported by considerable cross-cultural research.¹^,² The conclusion that humans in every documented society engage in these behaviors has, in turn, influenced evolutionary theories of music, which often treat human musicality as an adaptation, with benefits stemming from moving in synchrony and/or singing to infants.³^,⁴ Drawing on 122 months of fieldwork conducted between 1977 and 2020, we here report no evidence of either dance or infant-directed song among the Northern Aché of Paraguay. Excluding church singing introduced by missionaries, Northern Aché adults sing alone and in a very limited number of styles. Several lines of evidence suggest that dance and infant-directed song were lost following reductions in population size that curtailed cultural complexity among the ancestors of the Northern Aché. Although our observations are consistent with a universal psychological capacity for dance and infant-directed song, they indicate a critical role of cultural transmission in supporting these behaviors while demonstrating the value of testing claims of cultural universality in remote and minimally acculturated populations.