In a controlled experiment, a researcher at the University of California at Riverside, U.S.A., asked her subjects to keep a “gratitude journal ” ​ — a diary of things for which they were thankful.
Ühes kontrollkatses, mis korraldati California Ülikoolis Riverside’is (USA), palus teadur katseisikutel „tänupäevikut ” pidada ja panna kirja kõik, mille eest nad on tänulikud.