The research behind Three Good Things

In 2005, Martin Seligman, Tracy Steen, Nansook Park, and Christopher Peterson published a study in American Psychologist testing several positive psychology exercises. One of them asked participants to write down three things that went well each day, along with why they happened, for one week.

People who did the exercise reported greater happiness and fewer depressive symptoms. The notable part was the duration: the effects were still measurable at one month, three months, and six months, after just one week of practice.

Seligman, Steen, Park & Peterson (2005). Positive Psychology Progress: Empirical Validation of Interventions. American Psychologist, 60(5), 410–421.

In 2019, J. Bryan Sexton and Kathryn C. Adair at the Duke Center for Healthcare Safety and Quality ran a pilot study of the same exercise with healthcare workers, a group with high rates of burnout. Participants recorded three good things each day for fifteen days.

The study reported improvements in emotional exhaustion, depressive symptoms, work-life balance, and happiness. It was a pilot study rather than a large randomized trial, and the authors describe it as such.

Sexton & Adair (2019). Forty-five good things. BMJ Open, 9:e022695.

It does not say this replaces treatment for depression or anxiety. It does not say everyone responds, or that the effect is large for everyone who tries it. It is a small, low-cost habit with reasonable evidence behind it, not a cure.

If you are struggling, a journaling habit is a fine thing to have alongside real support. It is not a substitute for it.

Part of what makes the exercise work is that it is small enough to repeat. Three short entries is a low enough bar to clear on an ordinary evening, which is the only way a daily habit survives a bad week.