Testing the longitudinal and causal effect of social media rewards on mood and mental health in young adults

As social media platforms have increasingly pervaded our lives, societal concern about their potential detrimental effects on users’ mental health has surged. However, mechanistic evidence for this impact is still lacking. Recent work has identified a link between depression and heightened sensitivity to social media rewards. These rewards (i.e. likes, comments, followers, direct messages) are known to impact mood and affective states in the lab, yet little is known about their effect in daily-life situations. Moreover, it remains unclear how these rewards impact different aspects of social media behavior, such as logging onto the app vs. posting. Here, we take advantage of detailed behavioral data – the timing of various behaviors and social rewards on Instagram – to study the effects of social rewards on behavior as well as mood and mental health. Instagram posters (target N = 400 for this initial study) will complete five weekly surveys about their mood and mental health, as well as share their Instagram data for 3 months. Using both direct statistical analyses and computational modeling, we will quantify the reinforcing effects of social rewards on posting as well as the ‘approach’ motivation effect of these rewards on drawing users onto the app, enhanced by notifications. We will test whether these different forms of social-reward sensitivity 1) are associated with symptoms of depression and anxiety and 2) moderate the impact of social rewards on mood and symptoms. In a randomized controlled design, we will ask a random subset of the participants to turn off their notifications, and test 3) whether turning off notifications leads to fewer log-ins, less time spent on Instagram, and better mood and mental health. Our study will comprehensively test the effect of social rewards on Instagram behavior and users’ mental health using both observational and experimental approaches. We will also develop a novel model of social media behavior, with a temporal resolution that has not been feasible in prior studies. Based on our results, future studies will be able to investigate other user populations (e.g., adolescents) to determine the specificity and variability of the effects of social media rewards on Instagram users.