A researcher says having a lot of money makes you bad. Professor Paul Piff spent ten years looking at the personalities of rich people. He found their behaviour was very different to poor people's behaviour. Dr Piff said rich people break rules, do not follow the law, and do not care about others. He also said wealthy people cheat more at games and are less likely to help others. Professor Piff told the BBC that wealth makes you think more about your own interests, desires and welfare. They think their own goals and needs are the most important things in life.