Maartje Boer

THE COMPLEX ASSOCIATION BETWEEN SMU AND WELLBEING 249 8 Table 8.3 Summary Results of Fixed Effects Models, Life Satisfaction Not controlled for SMUproblems (M1) Controlled for SMU problems (M2) Level 1 ( n = 1,419) Model B SE p β B SE p β SNS viewing a -0.003 0.011 0.807 -0.005 0.012 0.013 0.356 0.020 SNS posting b -0.012 0.008 0.136 -0.021 -0.008 0.009 0.356 -0.014 SNS liking c -0.005 0 .007 0.499 -0.010 0.003 0 .007 0.658 0.006 SNS responding d -0.022 0.012 0.062 -0.044 -0.011 0.013 0.364 -0.023 IM viewing e -0.013 0.011 0.247 -0.021 0.007 0.011 0.552 0.011 IM sending f -0.025 0.012 0.046 -0.043 -0.011 0.013 0.385 -0.019 Level 2 ( n = 5,676) Model B SE p β B SE p β SNS viewing a -0.036* 0.018 0.048 -0.084 0.022 0.017 0.192 0.051 SNS posting b -0.040 0.026 0.127 -0.069 0.017 0.029 0.554 0.029 SNS liking c -0.015 0.013 0.258 -0.044 0.016 0.014 0.238 0.048 SNS responding d -0.013 0.016 0.420 -0.035 0.027 0.016 0.080 0.072 IM viewing e -0.046** 0.015 0.002 -0.106 0.016 0.016 0.299 0.037 IM sending f -0.036** 0.013 0.008 -0.087 0.012 0.014 0.409 0.029 Notes. SNS = social network sites; IM = instant messengers; SMU = social media use; Level 1 = yearly measurements; Level 2 = adolescents; B = unstandardized coefficient; SE = standard error, p = p- value; β = STDYX-standardized coefficient. Variables with the same letter (a-f) were included in the same model. Models 1a-f were controlled by wave (level 1) and gender, educational level, and immigrant background (level 2). Models 2a-f extended model 1a-f with SMU problems as additional control variable on the first and second level. *** p < 0.001, ** p < 0.01, * p < 0.05. Curvilinear Associations Between SMU Intensity and Life Satisfaction Table 8.4 shows the summary of the fixed effects models extended with quadratic effects (see Table A8.2 from the Appendix for all model estimates). Results showed that neither at the within-person nor at the between-person level quadratic effects were significant, regardless of whether we controlled for SMU problems (M3a-f, M4a-f). For the within-person level, this means that in years when adolescents showed very low or very high SMU intensity relative to their individual average, adolescents reported equal levels of life satisfaction as in years when their SMU intensity was around their individual average. At the between-person level, it means that adolescents who showed much less or much more SMU intensity than other adolescents, reported equally high levels of life satisfaction as adolescents who showed moderate SMU intensity. Hence, no curvilinear associations between any of the SMU activities and life satisfaction were found ( RQ2 ).