Differential Effects of Short- and Long-Term Negative Affect on Smartphone Usage: The Moderating Role of Locus of Control.

In the digital age, smartphones are often used as tools for emotion regulation. While prior research has examined affective predictors of smartphone use, few studies have considered the combined impact of short-term and long-term affective states. This study investigates how daily negative emotional states and psychological distress relate to smartphone use and whether these associations are moderated by locus of control, a core belief about perceived control. Thirty-seven participants completed a one-month daily diary study combined with objective smartphone usage tracking, which yielded 837 valid observations. Multilevel analyses showed no association between daily negative emotional state and smartphone use. However, psychological distress predicted divergent behavioral patterns based on locus of control: individuals with an internal locus of control showed reduced usage under distress, whereas those with an external locus of control exhibited increased frequency of use. These findings highlight the importance of individual control beliefs in shaping technology-mediated emotion regulation and offer implications for interventions targeting excessive smartphone use.