Are some interventions designed to induce gratitude more effectively than others? In which countries and cultures do they work best to improve mood, strengthen bonds between people and promote social reciprocity? A study aimed at answering these questions—conducted in 34 countries with more than 10,000 participants—had its results published in PNAS. In Brazil, the project received the help of researchers and 598 volunteers who responded to intervention prompts via an online tool.

“One of our main overall findings is that all the proposed interventions worked,” says Paulo Sérgio Boggio, a psychologist, professor at Mackenzie Presbyterian University and coordinator of the National Institute of Science and Technology in Social and Affective Neuroscience (INCT-Sani). Boggio and his former graduate student, Beatriz Bezerra de Souza, are the two Brazilian co-authors of the article.

Thirty-six researchers are listed as authors of the paper, including experimental psychologist Michael McCullough, a professor at the University of California, San Diego. The study was coordinated by Nicholas Coles, a researcher at the University of Florida.