No Impact? Long-Term Effects of Applying the Best Possible Self Intervention in a Real-World Undergraduate Classroom Setting

Positive psychology interventions (PPIs) improve students' well-being in laboratory settings. Best possible self (BPS) is one of the most widely used PPIs shown in the laboratory to effectively improve participants' well-being in both the short- and long-term, but limited research has been conducted in real-world contexts. This study applied BPS in an undergraduate classroom to examine its long-term effects. Students enrolled in an undergraduate education course were assigned to treatment and control groups. Three writing activities and four tests were integrated into the course as assignments in both groups. Data were analyzed using a $2\times 3$ (group and time) mixed ANOVA. The results indicate that BPS did not significantly improve the participants' well-being over time compared with the control group. In fact, the control group performed better than treatment at one month after the intervention. This aligns with recent findings of well-being during COVID-19. Potential implications and areas for future research are discussed.