The BRITE study aims to understand how mothers and their young children respond to one another while playing in order to gain knowledge about the behavioural and neural aspects of mother-child interactions. Participants include around 150 mother-child dyads recruited from the area local to the University of Pittsburgh in the United States of America. Children were between the age of one and three years at baseline assessment, which began in 2017. Participants are followed up four to five times in person and twice over the phone over a three-year follow-up period.