"If it's more important to have self-motivation it might be good to have reminders of money," Vohs said. "If group harmony is important, it might be a good idea to keep the idea of money down. People will have to decide what goals are in the best interest."Update: Another article about the same studies: Mere Thought of Money Makes People Selfish. A quote:
"In a series of nine experiments, researchers found that money enhanced people's motivation to achieve their own goals and degraded their behavior toward others. The concept of money, they suggest, makes a person feel more self-sufficient and thus more apt to stand alone.
The scientists said the study had nothing to do with making a person feel wealthy. When real or fake money, or even a photo of cash, was placed in sight of participants, they became selfish."