Growing evidence suggests that online positive-psychological interventions effectively increase well-being, and a wealth of evidence describes cognitive-affective responses to such interventions. Few studies, however, have directly compared responses across popular exercises such as the best-possible-self intervention, the gratitude letter, or self-compassionate writing. In addition, current evidence is ambiguous regarding the effects of potential moderator variables such as trait gratitude and emotional self-awareness. To address these issues, we randomized 432 German adults to perform either optimism, gratitude, self-compassion, or control writing interventions in an online setting. Participants reported trait gratitude and trait emotional self-awareness before the interventions, as well as momentary optimism, gratitude, self-compassion, positive affect, and current thoughts immediately after the interventions. Results indicate higher momentary optimism after the best-possible-self intervention and higher momentary gratitude after the gratitude letter than after the control task. There were no differences when comparing the best-possible-self intervention with the gratitude letter. Both interventions increased the number of positive self-relevant thoughts. The self-compassion condition showed no effects. Moderation analysis results indicate that neither emotional self-awareness nor trait gratitude moderated the intervention effects. Future studies should compare responses across different positive-psychological interventions using more comprehensive exercises to ensure larger effects.
