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.
وخلال فترة ستة اسابيع ،‏ لم يكن مستغربا ان يشعر هؤلاء انهم اكثر سعادة في حياتهم مما كانوا عليه من قبل .‏