Digital Distractions with Peer Influence : The Impact of Mobile App Usage on Academic and Labor Market Outcomes

Concerns over the excessive use of mobile phones, especially among youths and young adults, are growing. We present, to our knowledge, the first estimates of both behavioral spillover and contextual peer effects, as well as the first comprehensive evidence of how own and peers' mobile app usage affects academic performance, physical health, and labor market outcomes. Our analysis leverages administrative data from a Chinese university of three cohorts of students over up to four years merged with mobile phone records, random roommate assignments, and a policy shock that affects peers' peers. App usage is contagious: a one s.d. increase in roommates' in-college app usage raises own app usage by 5.8% on average, with substantial heterogeneity across students. High app usage is detrimental to all outcomes we measure. A one s.d. increase in app usage reduces GPAs by 36.2% of a within-cohort-major s.d. and lowers wages by 2.3%. Roommates' app usage exerts both direct effects (e.g., noise and disruptions) and indirect effects (via behavioral spillovers) on GPAs and wages, resulting in a total negative impact of over half the size of the own usage effect. Extending China's minors' game restriction of three hours per week to college students would boost their initial wages by 0.9%. Using high-frequency GPS data, we identify one underlying mechanism: high app usage crowds out time in study halls and increases late arrivals at and absences from lectures