UC Davis

Social influence is a normative phenomenon whereby individuals adjust their behaviors, thoughts, and/or feelings to meet the demands of their social context. Prior work has demonstrated that adolescents are particularly sensitive to explicit forms of social influence from their peers and parents, resulting in numerous effects on their neurobiology and behavior. Furthermore, work has found that implicit forms of social influence differentially modulate young adults’ neural response patterns. Relatively little is known, however, about whether characteristics of adolescents, as well as aspects of their relationships with socially influential agents, relate to individual differences in behavioral and neural sensitivity to implicit social influence. This dissertation reports on two studies in adolescents and young adults that collectively examined the behavioral outputs and neural underpinnings of implicit forms of social influence from peers and mothers, and considered qualities of their relationships with these social partners, as well as age and gender effects. Study 1 investigated whether conflict and perceived relationship quality with one’s mother across early to late adolescence was associated with neural responses to experimentally-manipulated, implicit peer influence later in young adulthood. Study 2 used a novel behavioral task paradigm to test whether implicit social influence of a mother’s and a friend’s preferences impacted adolescents’ own preferences, and assessed if shifts in their preferences varied based on adolescents’ sex and age, as well as quality of relationship with each social agent. Results from Study 1 indicated that higher levels of adolescent-maternal conflict experienced across multiple years of adolescence was associated with young adults’ elevated neural response to implicit peer influence cues in brain regions involved in salience detection and reward processing. Conversely, having a higher quality adolescent-maternal relationship was associated with reduced neural responses to implicit peer influence cues in the same brain regions. Results from Study 2 demonstrated that adolescent girls, compared to boys, were more likely to align their preferences with those of their friend than their mother. An age-related effect further demonstrated that older adolescents were more likely to show this pattern than were younger adolescents, however there was no significant interaction of age and gender. Quality of relationship with mother or friend did not have a significant effect on adolescents’ preference shift. Taken together, these studies revealed that adolescents and young adults differentially process and respond to implicit social influence cues from close others, as manifest in their behavioral and brain responses. A comprehensive understanding of the types of social cues adolescents and young adults attend to, from whom, and when in development has the potential to inform intervention work designed to offset potentially negative social influences and promote youths’ adaptive responses to the information conveyed from influential others in their social contexts.