Billionaire investor George Soros, who pledged to donate $100m to the Human Rights Watch yesterday, must be feeling pretty cheerful. A new study claims the happier you are, the more you give away.

The Charities Aid Foundation, which has conducted a 153-country study into who gives what and why, has found happy people give more than the rich. That doesn't mean you can't be rich and happy, but the study, out today, indicates that providing you're happy, whether rich or poor, you'll give generously.