A 10-week course at the University of Zurich resulted in the 180 participants, both men and women, feeling considerably happier by the time it was over.
"The participants were all people who saw their lives as basically in order but wanted to see whether they could nevertheless improve them," says Rene Proyer, a psychologist at the university.
The group focused on positive character traits, splitting up into three subgroups. One group was held back, while the second exercised qualities like gratitude, optimism, a sense of humour, curiosity and enthusiasm, and the third worked on appreciation of beauty, creativity, amiability, desire to learn and taking the long view.
The theory behind the study is that people who put these positive character traits into operation themselves experience more positive feelings. They enjoy life more, have better relationships with others and have more options when it comes to acting, according to the authors of the study. All of this leads to their feeling better about themselves.
The participants met every two weeks, were presented with a positive character trait and exercised it in groups.
"If the theme was gratitude they had for example to relate to the person sitting next to them how they had experienced gratitude," Proyer says.
They were then given the homework of writing a thank you letter to someone, read it aloud to them and observe the reaction.
The researchers came up with various activities to stimulate curiosity, such as finding out about another country's food and cooking a meal. "People should learn something new and observe whether they enjoy it," Proyer says.
All three groups had to fill out questionnaires at the start and end of the 10-week course on their satisfaction with life and how they felt. The result was that the men and women exercising positive qualities felt happier and had a more positive attitude.
Michael Eid, professor of psychology at Berlin's Free University, cautions that happiness is not that easy to train.
"You won't suddenly go from being an unhappy person to a happy one as a result of a course like this," he says. But there are positive results, he said, comparing it to finding a ladder to happiness and climbing it a rung at a time.
And Proyer also says that even those who exercise their positive sides regularly will not forever be on a high. "The point is not to become a happiness automaton," the psychologist says.
Being dissatisfied at times is not wrong. "Forced happiness is rubbish," Eid says, as negative feelings are also part of life.
But people who exercise their strengths are able to shift how they see the world and develop "a more positive basic attitude". And the effort is worth it, as a feeling of well-being promotes good health and longevity.