Messaging, posting, and browsing: A mobile experience sampling study investigating youth's social media use, affective well-being, and loneliness.

Employing a mobile experience sampling design, we investigated in the present study how different types of mobile social media use relate to young individuals' momentary affective well-being and momentary loneliness. We differentiated between three types of social media use: Messaging, posting, and browsing. Moreover, we studied fear of missing out (FoMO) as a moderating variable. We collected data from 79 middle and late adolescents (M- age = 17.55 years, SD = 1.29; 59% girls) yielding 956 momentary assessments. The results showed that messaging and posting were positively related to affective well-being, while browsing was associated with higher levels of loneliness. Furthermore, some of the relations between social media use, affective well-being, and loneliness were also moderated by FoMO. Our results highlight the need to differentiate between different types of social media use, to include individual predispositions, and to apply methods that account for daily fluctuations in psychological well-being when studying the complex relationship between youth's mobile social media use and well-being.