To Örebro University

Introduction: The popular and scientific literature point at technology use as one of the main reasons for adolescents’ sleep deprivation. However, controlled studies into one of the most common uses of technology – online socializing – are lacking, along with the recognition of individual differences in the link between technology use and sleep. This experiment with adolescent girls aimed to 1) test whether socializing online with a friend delayed bedtimes compared to only watching Netflix, 2) investigate individual and friendship characteristics that may explain later bedtimes on the social night, 3) explore reasons for going to bed as perceived by the participants.

Method: Adolescent girls (N = 34, Mage = 16.8, range 16-18) came to the lab with a close girlfriend on two nights on two consecutive weeks and were randomly assigned to either i) Netflix + WhatsApp with the friend, ii) Netflix only, counterbalanced to minimise order effects. Self-selected bedtimes were directly observed using infrared cameras while measures of friendship quality, co-rumination, self-control, bedtime procrastination, and chronotype were self-reported at baseline, the reasons for going to bed were asked in the morning using VAS (1-10). 

Results: Participants went to sleep on average at 22:25 (0:53) on the Netflix only night and 22:35 (0:46) on the social night, thus delaying their bedtimes for an average of 10 minutes on the social night. This difference was not significant and there was large variability. The girls who delayed their bedtimes on the social night as compared to the Netflix only night were more likely to report lower self-control [F(1,31)=4.01, η2=.115] and higher friendship quality scores [F(1,31)=6.05, η2=.163], no other significant differences were found. The strongest reason for going to bed on the social night was “feeling sleepy” (M = 6.8) rather than not wanting to “let my friend down” (M = 4.0) or being “absorbed in the conversation” (M = 3.8).

Conclusion: Girls with lower self-control and higher friendship quality tended to delay their bedtimes when they were able to socialize online with a friend. Therefore, taking into account individual differences and peer dynamics may help enhance sleep interventions in adolescence.