Think it's laws or governments that keep people honest? Not according to a new study in Psychological Science. Two psychologists examined the psychological impact of genetic determinism, free will, and ethical behavior and found that people who felt like they were in control of their destiny acted more ethically than people who felt like they were not.

It is well established that changing people’s sense of responsibility can change their behavior. But what would happen if people came to believe that their behavior was the inevitable product of a causal chain beyond their control – a predetermined fate beyond the reach of free will?

Surprisingly, the link between fatalistic beliefs and unethical behavior has never been examined scientifically — until now. In their recent experiments, psychologists Kathleen Vohs of the University of Minnesota and Jonathan Schooler of the University of British Columbia decided to explore this knotty philosophical issue in the lab, and they figured out an innovative way to do it.

Vohs and Schooler set out to see if otherwise honest people would cheat and lie if their beliefs in free will were manipulated.

The psychologists gave college students a mathematics exam. The math problems appeared on a computer screen, and the subjects were told that a computer glitch would cause the answers to appear on the screen as well. To prevent the answers from showing up, the students had to hit the space bar as soon as the problems appeared.

In fact, the scientists were observing to see if the participants surreptitiously used the answers instead of solving the problems honestly on their own. Prior to the math test, Vohs and Schooler used a well-established method to prime the subjects' beliefs regarding free will: some of the students were taught that science disproves the notion of free will and that the illusion of free will was a mere artifact of the brain's biochemistry whereas others got no such indoctrination.

The results were clear: those with weaker convictions about their power to control their own destiny were more apt to cheat when given the opportunity as compared to those whose beliefs about controlling their own lives were left untouched.

Vohs and Schooler then went a step further to see if they could get people to cheat with unmistakable intention and effort. In a second study, the experimenters set up a different deception: they had the subjects take a very difficult cognitive test. Then, the subjects solved a series of problems without supervision and scored themselves. They also "rewarded" themselves $1 for each correct answer; in order to collect, they had to walk across the room and help themselves to money in a manila envelope.

The psychologists had previously primed the participants to have their beliefs in free will bolstered or reduced by having them read statements supporting a deterministic stance of human behavior. And the results were just as robust. As reported in the January issue of Psychological Science, a journal of the Association for Psychological Science, this study shows that those with a stronger belief in their own free will were less apt to steal money than were those with a weakened belief.