Why tracking habits together works (what the research says)

Starting a habit is easy. Still doing it in week three is another story. The good news: it’s not just about willpower, it’s about environment — and one of the variables that weighs the most is the people around you. Three serious studies, run on thousands of participants, explain why.

Write your goal down and tell a friend: the Matthews (2007) study

Dr Gail Matthews, a psychologist at Dominican University of California, followed 267 participants split into five groups, from the most informal (just thinking about their goal) to the most structured (writing the goal down, defining concrete actions and sending a weekly progress update to a friend).

The result: 76% of participants who wrote their goals down and sent a weekly update to a friend achieved them, versus 43% for those who kept them in mind, and roughly 60–70% for the intermediate groups.

The interesting detail is that writing alone isn’t what makes the difference: it’s the weekly update sent to someone. A light but regular commitment, in front of a witness who matters to you.

The Köhler effect: pushing on next to someone whose effort you can see

In 2012, Irwin and colleagues published an experiment in Annals of Behavioral Medicine inspired by the Köhler effect, a phenomenon documented since the 1920s: when you work on a task in a pair and can see your partner’s progress, you persist roughly twice as long as when working alone.

The effect is strongest for the weaker member of the pair: seeing the other person keep going makes you want to keep going too. And it works without competition or punishment — simply because the other person’s effort is visible.

Monitoring your progress works — especially when it’s recorded or shared

The third piece of the puzzle: a meta-analysis by Harkin et al. (2016), published in Psychological Bulletin, aggregating nearly 140 studies covering about 20,000 people. The conclusion: monitoring your progress has a clear positive effect on goal attainment, and the effect is stronger when progress is physically recorded (paper, app, notebook) or shared with others.

In other words, simply checking off, writing down and watching your streak change behaviour. Sharing it amplifies it further.

How to put this into practice

1. Write the habit down with a precise name and frequency (“read 15 minutes every evening” rather than “read more”).
2. Pick one trusted person — partner, friend, relative — and share your habit with them. One person is enough.
3. Give a regular update, however small: a Sunday evening message or a shared “done ✓”.
4. Plan for missed days: motivation research is clear that guilt doesn’t help. Have a get-back-on-track plan for the next day.
5. Celebrate milestones together: encouragement received beats penance sessions.

What Habitudes Partagées takes from this

These principles are exactly what the app implements: sharing limited to the people you choose, a morning and evening Catch-up that shows who moved forward, one-tap encouragement, a Guardian Joker to save a streak after a missed day, and stats that make your progress visible.

One honest caveat: these studies look at tracking and social support in general, not at Habitudes Partagées itself, which has not been the subject of a clinical study. The app simply applies what research has documented for decades.

If you want to give it a try, create your first habit, invite someone who matters to you, and see what changes in two weeks: Habitudes Partagées, free and ad-free.