From Screen Time to Daily Rhythms

A Mixed Methods Study of Smartphone Use Among German Adults

Abstract

Understanding typical smartphone behavior increasingly relies on device-enabled fine-grained data sources that go beyond retrospective self-reports. This study contributes to this knowledge by studying how, when, and under what conditions people engage with their smartphones, using a rich mixed-method dataset that combines Android logging, iOS data donation, and mobile experience sampling. The dataset captures both the quantity and quality of smartphone use among a large, quota-targeted sample of German adults (n = 1,797). The descriptive findings indicate that smartphone engagement is characterized by frequent interactions. Most sessions last under seven minutes, and app use rarely exceeds two minutes. Usage rhythms vary throughout the day: shorter glances dominate during constrained periods, while longer sessions cluster around mornings and evenings. Younger users display more fragmented usage patterns, whereas older adults tend to engage in fewer but longer sessions. These patterns reflect the situational affordances and gratifications of different types of mobile interactions and highlight the temporal structure of smartphone use. By mapping these rhythms and use types, our findings offer a foundation for theorizing about the cognitive, behavioral, and emotional consequences of smartphone use and provide practical guidance for researchers employing intensive longitudinal and real-time measurement approaches.