Leader-follower dynamics during early social interactions matter for infant word learning

We know little about the extent to which infants’ interests shape their own language acquisition. We hypothesized that infants’ decisions to visually explore a specific object signal focal increases in attention, and that when caregivers respond to these manifestations of interest by naming the object this boosts word learning. To examine this, we invited caregivers and their 14-month-old infants to play with novel objects, before testing infants’ retention of the novel object-label mappings, while their electroencephalogram was recorded. Results show that infants’ proactive looks towards an object during play signal enhanced interest, as evidenced through greater neural signatures of endogenous attention. Furthermore, when caregivers named objects during these episodes, infants showed greater word learning, but only when caregivers also joined their focus of attention. Our findings demonstrate the feasibility of studying word learning in realistic, interactive settings, and support the idea that infants’ interests guide their acquisition of a lexicon.