A note to employers - keeping your staff happy will result in them working harder for you.

UK economists carried out four different experiments to test the theory that happy people work harder.

The experiments were carried out on over 700 people. Each participant was randomly selected to be shown a clip of a comedy film, be treated to free fruit, drinks and chocolate, or were questioned about recent family tragedies, such as the death of a loved one.

The study found that happy employees were 12% more productive.

According to the economists from the University of Warwick, ‘the driving force seems to be that happier workers use the time they have more effectively, increasing the pace at which they can work without sacrificing quality'.

"Companies like Google have invested more in employee support, and employee satisfaction has risen as a result. For Google, it rose by 37%. They know what they are talking about. Under scientifically controlled conditions, making workers happier really pays off," the team said.

The economists insisted that these findings have implications for employers and workplaces in general.

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

Details of these findings are published in the Journal of Labor Economics.