The world's rich are holding an ever-increasing share of global resources, and there's a lot of evidence to suggest rich people behave selfishly. So, if it's true that the rich don't care about others, then we really need to worry, says Nikos Nikiforakis, professor of economics at NYU Abu Dhabi.

His research questions the widespread belief that the rich are actually more selfish than others, by testing people's willingness to return money that doesn't belong to them.

