Washington, April 27 (IANS) Whether it's for money, marbles or chalk, the brains of reward-driven people keep their game faces on, helping them win at every step of the way. Surprisingly, they win most often when there is no reward.

That's the finding of neuroscientists at Washington University in Saint Louis (WUSL), who tested randomly selected subjects with word games, some of which had monetary rewards of either 25 or 75 cents per correct answer, others of which had no money attached.

Subjects were given a short list of five words to memorise in a matter of seconds, then a 3.5-second interval or pause, then a few seconds to respond to a solitary word that either had been on the list or had not.

Test performance had no consequence in some trials, but in others, a computer graded the responses, providing an opportunity to win either 25 cent or 75 cents for quick and accurate answers.

Even during these periods, subjects were sometimes alerted that their performance would not be rewarded on that trial.

Prior to testing, subjects were submitted to a battery of personality tests that rated their degree of competitiveness and their sensitivity to monetary rewards, said a WUSL release.

Designed to test the hypothesis that excitement in the brains of the most monetary-reward-sensitive subjects would slacken during trials that did not pay, the study is co-authored by Koji Jimura, post-doctoral researcher, and Todd Braver, professor, both based in the department of psychology.

Braver is also a member of the neuroscience programme and radiology department in the university's School of Medicine.

But the researchers found a paradoxical result: the performance of the most reward-driven individuals was actually most improved - relative to the less reward-driven - in the trials that paid nothing, not the ones in which there was money at stake.