Economists testing the idea that happy employees work harder found that doses of chocolate or laughter made people 12% more productive at their jobs.

The study, conducted by researchers at the University of Warwick, included four different experiments with more than 700 participants.

"Under scientifically controlled conditions, making workers happier really pays off," said Professor Andrew Oswald, who led the research team with Dr. Eugenio Proto and Dr. Daniel Sgroi from the Department of Economics.

"We have shown that happier subjects are more productive, the same pattern appears in four different experiments," said Pronto. "This research will provide some guidance for management in all kinds of organizations, they should strive to make their workplaces emotionally healthy for their workforce."

Showing the first such causal evidence using randomized trials, it will be published in the Journal of Labor Economics.