Objective: Interest in online positive psychology interventions (OPPIs) continues to grow. The empirical literature has identified design factors (e.g., variety and duration of activities) and moderators (e.g., personality traits) that can influence their effectiveness. A randomized controlled trial tested an empirically informed OPPI designed to promote self-efficacy and an optimistic outlook. Pessimism was included as a trait moderator.
Method: Participants (N = 466) were English-speaking adults interested in becoming happier. They were randomly assigned to complete either an OPPI cultivating optimism or a control condition writing about daily activities for 3 weeks. Follow-up assessments occurred 1 and 2 months following the exercise period.
Results: A hierarchical linear model analysis indicated that the optimism intervention increased the pursuit of engagement-related happiness in the short term and reduced dysfunctional attitudes across follow-ups. Pessimistic individuals had more to gain and reported fewer depressive symptoms at post-test.
Conclusions: These findings support the conclusion that empirically informed online interventions can improve psychological well-being, at least in the short run, and may be particularly helpful when tailored to the needs of the individual.