Natural Observation of Early Social Interactions in Infants in Vanuatu

Infant-directed speech (IDS) has been shown to play a key role in language development. Previous research, however, has also shown significant variability across societies in terms of how often IDS occurs. Here, we ask whether infant-directed communication (IDC)— which includes both IDS and other non-verbal infant-directed behaviours supporting social and communicative development, has a different balance of verbal and non-verbal communication in Tanna compared to what is seen in the wider literature. We examine video observations of 22 one-year olds to identify the non-verbal features of IDC that occur across cultures. First, we will measure and analyze the proportions of the observed times for IDC dimensions— i.e., speech, action, gesture, emotion, and touch, while parents engage with infants, via a linear mixed effects model. Next, we will compare our findings on these dimensions in Vanuatu to what has been reported in Western societies. Consistent with previous studies, we expect to observe less IDS in Tanna than what is typically observed in the literature. Critically, we also expect to see more non-verbal communicative modification compared to verbal communicative modification. The present work is the first to examine the non-verbal features of IDC in a non-Western society.