Study title

This proof-of-principle study extends the novel experimental approach of Neuroadaptive Bayesian Optimisation (NBO) to infant EEG data to study individual infants' engagement with social stimuli. In particular, the Negative central event-related potential component was optimised across a range of familiar and nonfamiliar faces. Previous group-level research suggested an initial attentional preference for parent’s vs. stranger’s face around 6 months with a subsequent change towards enhanced attention to the stranger’s face. The present individualised NBO study included n=62 infants aged 5-12 months who were presented with faces linearly varying in similarity to parent’s face. Results showed lower-than-usual attrition rate, and an equal proportion of infants preferably attending to parent and stranger, with the individual’s probability of preferably attending to parent’s face increasing between 5 and 12 months but being unrelated to parent-reported social behaviour. This study proves the feasibility of the NBO approach with infant neurophysiological data to identify among a range of cues the one that maximally triggers social brain activity in the individual infant. Further, this study suggests that on the individual level, infants differ in whether they preferably attend to parent or stranger in the second half of the first year of life.Babies are born with a drive to interact with other people. Within a year, this drive takes them from a passive newborn to a smiling, talking toddler. Our goals shape how sociable we are and who we socialise with across the lifespan, and are thus fundamental to social psychology (Over, 2016). However, the reasons why babies choose to interact remains a mystery. Measuring motivation is difficult because it is generated by the child, whilst traditional experimental methods measure passive responses to stimuli produced by the experimenter. Our transformative approach to studying infant social motivation is inspired by innovations in...