Should I post my very best self? The within-person reciprocal associations between social media literacy, positivity-biased behaviors and adolescents’ self-esteem

• Social media positivity-biased behaviors may be inauthentic practices. • The relations between positivity-biased behaviors and self-esteem were studied. • Social media literacy may inform positivity-biased behaviors. • We did not find support for the hypothesized within-person relations. • We did find promising between-person results for affective social media literacy. Unauthentic social media self-presentation practices relate to lower self-esteem, yet research replicating these findings at the within-person level is lacking. By means of a three-wave longitudinal survey ( N = 1032), the present study addresses this gap by examining the reciprocal within-person relations between social media positivity-biased behaviors and self-esteem over a four-month time interval among adolescents. Furthermore, the role of social media literacy was explored in informing adolescents’ positivity-biased behaviors and thus, in turn, their self-esteem. We found no support for within-person associations between positivity-biased behaviors and self-esteem. Positive within-person associations did occur between cognitive social media literacy and positivity-biased behaviors, which was in the opposite direction of what was expected. Interestingly, on the between-person level, affective social media literacy related negatively to positivity-biased behaviors and positively to self-esteem. The results are discussed in light of peer dynamics characterizing social media behaviors.