What Is the Optimal Way to Deliver a Positive Activity Intervention? The Case of Writing About One’s Best Possible Selves

A 4-week-long experiment examined the effects of a positive activity intervention in which students wrote about their “best possible selves” (BPS) once a week. We manipulated two factors that might affect the success of the happiness-increasing activity—whether the positive activity was administered online versus in-person and whether the participant read a persuasive peer testimonial before completing the activity. Our results indicated that the BPS activity significantly boosted positive affect and flow and marginally increased feelings of relatedness. No differences were found between participants who completed the positive activity online versus in-person. However, students who read a testimonial extolling the virtues of the BPS activity showed larger gains in well-being than those who read neutral information or completed a control task. The results lend legitimacy to online self-administered happiness-increasing activities and highlight the importance of participants’ beliefs in the efficacy of such activities for optimum results.