Maartje Boer

CHAPTER 8 248 SMU activities except for SNS posting, higher average SMU intensity was associated with higher averages in upward social comparison, with small to moderate effect sizes. Girls reported lower averages in life satisfaction than boys. For all six SMU activities except for SNS posting, girls reported higher average SMU intensity than boys. Also, girls reported higher average levels of upward social comparison than boys. Except for SNS liking, adolescents attending pre-vocational education reported higher intensity of all SMU activities than adolescents attending intermediate or pre-university education. Adolescents attending pre-vocational education reported lower average levels of upward social comparison than adolescents attending other educational tracks. Adolescents with an immigrant background reported lower average intensity of SNS liking and IM sending than adolescents without an immigrant background. Associations Between SMU Intensity and Life Satisfaction Table 8.3 shows the summary of the results from the baseline fixed effects models (see Table A8.1 from the Appendix for all model estimates). At the within-person level, for none of the SMU activities, changes in adolescents’ SMU intensitywere associatedwithchanges in their life satisfaction, regardless of whether we controlled for SMU problems. At the between-person level, high averages in more passive SMU activities, namely SNS viewing and IM viewing, were associated with lower averages in life satisfaction, but with small effect sizes (M1a,e: β = -0.084; β = -0.106, respectively). Also, the higher adolescents’ average level of IM sending, the lower their level of life satisfaction (M1f: β = -0.087). Hence, the negative association between SMU intensity and wellbeing was not specific to either more passive or active SMU ( RQ1 ). Furthermore, the negative associations were only observed at the between-person level ( RQ5 ). However, when controlled for SMU problems, these between-person associations disappeared (M2a,e,f). These results suggest that the observed negative associations were confounded by SMU problems ( RQ4 ). In addition, a sensitivity analysis was conducted where all SMU activities were simultaneously included in one model, while controlling for SMU problems. Also in this model, on both levels, no associations between any of the SMU activities and life satisfaction were found.