Money is an incentive to work hard, but it also promotes selfish behavior. Those conclusions may not be surprising, but now researchers find that merely thinking of money makes people less likely to give help to others.

"Self-sufficient people are more diligent in their own goals," says Kathleen D. Vohs, a consumer psychologist at the University of Minnesota. "Money is cognitively and mentally linked to personal goals. It allows people to do things efficiently and not need other people."

Vohs and her colleagues performed a series of experiments to determine how money affects people's behavior. In a lab, they subconsciously reminded volunteers of money in different ways, either by showing them money-related words such as "salary," or by revealing a poster or screensaver with currency on it. The researchers primed other participants with play money or neutral stimuli, such as fish. After priming, the participants performed different tasks that were unrelated to money but that assessed their behavior in social situations.

When money is on the brain, people become disinclined to ask for help when faced with a difficult or even an impossible puzzle, Vohs and her colleagues report in this week's issue of Science. They tried to work on the task by themselves, she explains. Eventually most did ask for help--it just took them longer to come around.

People who think, even subconsciously, about money are also less helpful than others, the researchers say. After witnessing a pre-arranged accident in which someone walking through the testing area dropped a box of pencils, money-primed participants picked up fewer of the fallen pencils than the other subjects did.

Just being reminded of the concept of money "transforms people to capitalist individuals," says Drazen Prelec, a psychologist at the Massachusetts Institute of Technology who was not involved in the study. And, Vohs notes, "their behavior was not something they realized they were doing."

The U.S. and other Western societies value self-reliance, Prelec says. "This is less so in other cultures," he adds. The people in this study were from Asian-Canadian or European-Canadian backgrounds, and Vohs says country of origin had no effect on behavior, adding that many Eastern cultures are becoming more money-focused. So if you want to keep your employees fixed on their goals, keep a stack of money on their desks. Just don't expect them to help each other.