Self-Efficacy Predicts Differential Neuroticism Change in a Smartphone-Based Intervention

Self-guided, digital interventions can help people change their personality traits in desired directions, including becoming less neurotic. However, little is known about how and why people differ in intervention-related changes. Theoretical models state that intentional personality change must be perceived as feasible and that being motivated to change is not sufficient to elicit lasting trait changes. Here, we tested self-efficacy and growth mindset as predictors of neuroticism change in a 6-week digital intervention (N = 426), using multiple measures of neuroticism at pre-intervention, post-intervention (9 weeks), and follow-up (7 weeks later). Zooming in on temporal processes during the intervention, we also examined co-development of weekly neuroticism and self-efficacy measures as well as week-to-week temporal associations. We found more consistent evidence for self-efficacy predicting differential neuroticism change than growth mindset. Over the intervention period, participants with higher self-efficacy showed greater decreases in self-reported neuroticism and greater increases in emotional resilience than those with lower self-efficacy. Over the follow-up period, participants with higher self-efficacy continued to improve more in neuroticism and emotional resilience. Last, higher self-efficacy in one week was associated with lower neuroticism in the following week, and vice versa, even when controlling for participants’ overall trajectories. The findings support theoretical assumptions regarding perceived feasibility being an important precondition for neuroticism change and suggest that a reinforcement mechanism exists between weekly self-efficacy and neuroticism. We discuss implications for theory and future intervention studies.