Exploring Variation in Infants' Preference for Infant‐directed Speech: Evidence From a Multi‐Site Study in Africa

Infants show a preference for infant‐directed speech (IDS) over adult‐directed speech (ADS). This preference has been linked to infants' language processing and word learning in experimental settings, and also correlates with later language outcomes. Recently, the cross‐cultural consistency of infants' IDS preference has been confirmed by large‐scale, multisite replication studies, but conclusions from these studies were primarily based on participants from North America and Europe. The current study addressed this sampling bias via a large‐scale, multisite study of infants (3–15 months) across communities in Africa. We investigated whether participants showed a preference for IDS over ADS, and if so, whether the magnitude of their preference differs from effects documented in other populations of infants. Across six sites (total N = 200), we observed a preference for IDS over ADS ( = 0.06), suggesting that infants look on average 6% longer on the IDS trials than the ADS trials. There was no significant difference between African infants in this study and a method‐matched subsample of infants from prior studies of IDS preference. This study provides new evidence on the generalizability of IDS preference and looking‐time methods more broadly, while also highlighting some of the challenges of global big team science. Summary This study demonstrates a reliable infant‐directed speech preference among African infants aged 3–15 months using a large‐scale, multisite experimental design. Our findings showed no significant difference in IDS preference magnitude between African infants and method‐matched samples from prior North American and European MB1 studies. Our study provides evidence for the cross‐cultural generalizability of IDS preference while identifying practical challenges of conducting international multisite developmental research.