Neurobiological sensitivity to popular peers moderates daily links between social media use and affect.

Social media behaviors increase during adolescence, and quantifiable feedback metrics (e.g., likes, followers) may amplify the value of social status for teens. Social media's impact on adolescents' daily affect may be exacerbated given the neurodevelopmental changes that increase youths' sensitivity to socio-emotional information. This study examines whether neurobiological sensitivity to popularity moderates daily links between social media use and affect. Adolescents (N = 91, M(age)=13.6 years, SD(age)=0.6 years) completed an fMRI task in which they viewed faces of their high (>1 SD above the mean) and low (<1 SD below the mean) popular peers based on peer-nominated sociometric ratings from their school social networks. Two years later, adolescents reported their time spent on social media and affect daily for two weeks. Neural tracking of popularity in the ventromedial and dorsomedial prefrontal cortex moderated the association between time on social media and affect. Specifically, adolescents who tracked high popular peers in the vmPFC reported more positive affect on days when they used social media more. Adolescents who tracked low popular peers in the vmPFC and dmPFC reported more negative affect on days when they used social media more. Results suggest that links between social media and affect depend on individual differences in neural sensitivity to popularity.