The study, led by Nicholas A. Coles of the University of Florida and Michael E. McCullough of UC San Diego, and currently in press at the Proceedings of the National Academy of Sciences, surveyed 10,772 participants across 34 countries selected specifically to capture the widest possible range of cultural difference — from Canada to Kazakhstan, Norway to Nigeria.
Each participant completed one of six brief, browser-based gratitude exercises — including writing a gratitude letter, sending a thank-you text, or reflecting on life without a valued person or thing — and researchers compared the results against three neutral control tasks.
The headline finding: gratitude works, on average
Compared to control conditions, gratitude practices produced measurable, immediate improvements across the board: participants reported more positive affect, less negative affect, greater optimism, and higher life satisfaction, along with reduced envy and increased feelings of social indebtedness. The strongest and most universal effect was on positive mood — gratitude interventions increased positive feelings in nearly every one of the 34 countries studied.
But the size of the effect depends far more on culture than on the exercise itself
The study’s most striking discovery is methodological as much as psychological: differences between countries mattered up to four and a half times more than differences between the six gratitude exercises tested. In other words, which country a person lives in shapes the impact of gratitude far more than which specific gratitude practice they perform.
Participants in Mexico showed the strongest overall response to gratitude exercises; participants in Norway showed almost none. Writing a heartfelt letter or text produced the largest shifts in mood and outlook, while simply making a list of things to be grateful for produced the smallest.
Why the gap? Culture, hierarchy, and religion all play a role
The research team identified several cultural factors linked to how strongly gratitude interventions land. In countries with tighter social norms, effects on mood, optimism, and satisfaction were consistently weaker.
In societies with greater acceptance of hierarchy (higher “power distance”), gratitude exercises produced smaller gains in life satisfaction. Meanwhile, in wealthier countries, gratitude exercises were more likely to trigger feelings of social indebtedness — and in more religious societies, less so.
For leaders, one lesson is universal:
The emotional state you create today shapes tomorrow’s performance.
Before your next meeting, take 30 seconds.
Think of one person who helped you.
Tell them. Small action. Powerful impact.
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Why this matters beyond the lab
For organizations exporting wellness or engagement programs across borders — a trend increasingly common among global employers — the findings offer a caution: an initiative that measurably lifts morale in one market may fall flat in another. The authors are explicit that gratitude interventions “may not always generalize to newly studied populations and practices,” urging practitioners to weigh both the specific exercise and the cultural context before deployment.
The full dataset — more than 1,200 individual effect-size estimates — has been made openly available, offering researchers and organizations a rare, ready-made benchmark for testing gratitude and well-being interventions across specific markets rather than assuming a one-size-fits-all approach.
The study, “A multi-national mega-study of the effects of gratitude practices on subjective well-being,” was funded by the John Templeton Foundation and is currently under peer review.
