Paths of peer influence:How social connections shape learning in adolescents and adults

Across five empirical studies, I examined how learners, their social sources, and the broader social environment interact to shape social learning. The research addressed three questions: (1) how do social relationships between adolescents drive the spread of behaviours within classroom social networks; (2) how do differences in confidence and social identity between learners and social sources influence the transmission of social information in belief-updating tasks; and (3) under which environmental conditions are adolescents' social learning strategies more advantageous than those of adults? Two lab-in-the-field studies in schools (N=591) revealed that adolescents' learning depends on their relationship with the social source: they preferred using information from socially close and popular peers. Two experiments with adults (N=637) demonstrated that source confidence strongly predicted influence, particularly for uncertain learners, while social identity biases persisted even when accuracy was incentivised. A comparative study (N=294) showed that adolescents used social information more flexibly than adults and learned faster which peers provided valuable information. Together, these findings show that individuals are not passive conformists but active agents who preferentially learn from close, similar, popular, and confident others. This work offers practical applications for education and policy while contributing to a more integrated science of social influence.