At a glance
In a 2005 study of 577 adults, writing down three good things each night for one week was linked to higher happiness and fewer depressive symptoms for six months, compared with a placebo exercise. A 2012 replication found a "positive placebo" worked about as well, so how it works is still debated.
The instructions
Every night for a week, write down three things that went well that day. Next to each one, write why it happened. That's it, and it takes a few minutes.
Most people skip the "why," but it's the part doing the work. It connects a good moment to something you or someone else actually did, instead of chalking it up to luck.
What the study did
| Journal | American Psychologist, 60(5) |
|---|---|
| Participants | 577 adults recruited online. 411 (71%) completed every follow-up. |
| Design | Randomly assigned to one of five exercises or a placebo, which was writing about early memories each night. |
| Length | One week of exercises, with follow-ups at one week, one month, three months, and six months. |
| Measures | Steen Happiness Index and the CES-D depression scale. |
What they found
Two of the five exercises stood out. Three good things, and using one of your top strengths in a new way each day, both raised happiness and lowered depressive symptoms for six months compared with placebo. The gratitude visit, where people wrote and delivered a thank-you letter, produced big gains too, but they faded after about a month.
The researchers also noticed that people who kept doing their exercise after the week was over held onto the benefits longest. For anyone actually trying this, that's probably the most useful line in the paper.
The catch
The participants weren't a random slice of the population. They signed up online for a happiness study, and most were well educated, which makes it harder to know how far the results carry over.
In 2012, Myriam Mongrain and Tracy Anselmo-Matthews repeated the study with a stronger control group, including a "positive placebo" where people wrote about happy early memories. The real exercises did raise happiness over six months, but so did the positive placebo. Their read was that part of the benefit may come from simply spending a few minutes on positive things about yourself, whatever the exact format.
For a habit that takes five minutes and costs nothing, that's still a good deal.
How I'd do it
- Pick the same time every night and set a reminder. Right before bed works for most people.
- Write three things. Small ones are fine, and they keep the habit easy.
- Add one sentence on why each one happened.
- Keep going after the first week. That's where the lasting benefits showed up.
Some examples: finished my lab report early because I started it Monday instead of Thursday. My friend texted to thank me for the advice I gave her last week. Went to the gym even though I was tired, and felt way better after.
Where DoubtFree fits
DoubtFree is built around this kind of habit. You can log a good thing in a few seconds, set a daily reminder, and tag entries. And when you need a reminder, Resurface brings your old entries back.