Evidence for compositional abilities in one-year-old infants

• Published in: Communications psychology Vol. 3; no. 1; pp. 37 - 9
• Main Authors: Dautriche, Isabelle, Chemla, Emmanuel
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 10.03.2025; Nature Publishing Group; Springer Nature; Nature Portfolio
• Subjects: 4014/477/2811; 631/477/2811; Behavioral Science and Psychology; Cognition & reasoning; Cognitive science; Cognitive Sciences; Health Sciences; Humanities and Social Sciences; Language; Life Sciences; Linguistics; Medicine; multidisciplinary; Neurons and Cognition; Neurosciences; Psychiatry; Psychology; Psychometrics; Science; Statistics for Life Sciences
• ISSN: 2731-9121; 2731-9121
• DOI: 10.1038/s44271-025-00222-9

Compositionality is a means of constructing complex objects through the transformation and combination of simpler elements. While it is common to view compositionality as inherently complex, and thus to assume that compositionality is a byproduct of advanced language expertise, we argue otherwise. We propose that, although compositionality produces complex outcomes, the underlying processes are simple and can often be reduced to the general mechanism of function application. Accordingly, we explore the origins of compositionality not only in compositional language but also, and at an earlier stage, in the development of compositional representations and thoughts in young infants. Infants correctly composed simple noun-verb sentences at 14 months, facial expressions with objects at 12 months, and mental physical transformations at 10 months. This offers evidence for function application, the essence of compositionality, in infancy—emerging well before and outside the development of compositional language. A series of three studies provide evidence in infants for function application, the essence of compositionality, emerging before and outside the development of compositional language.