Smartphone Screen Time: Inaccuracy of self-reports and influence of psychological and contextual factors

Previous research investigating associations between screen time and various undesirable consequences (e.g., poor mental health) has relied heavily on self-report measures. However, there is debate regarding whether self reports overestimate or underestimate actual screen time. We used advances in iPhone software to address this question and to investigate the influence of individual difference factors, and COVID-19 lockdown restrictions, on screen time. Participants (N = 267, 18-25 years) completed scales measuring depression, anxiety, smartphone attachment, and estimated their screen time. Thereafter, they shared screenshots of their battery use (BUS) and iPhone screen time (iOS STT) data. Some (n = 24) shared their BUS data again during the COVID-19 lockdown. Whereas the BUS data (10-day average, including two weekends) indicated that self-reports underestimated actual use, the iOS STT data (7-day average) indicated that self-reports overestimated actual use (ps < .007). Smartphone use was heavier over weekends and screen time increased significantly during the lockdown (p = .001). Finally, smartphone attachment mediated the relationship between objective screen time and depression, but not anxiety. We conclude that iPhone tracking features can reliably collect objective screen time data, and that screen time is significantly influenced by both individual difference factors and environmental context.