When it comes to getting stubborn donkeys to carry heavy loads, more carrots is always better--the more treats you can tempt an animal with the more likely it is that the animal will do what you ask. But when it comes to motivating people, things aren't so simple.

That's the fascinating and immediately useful takeaway of research from Amy Wrzesniewski, a Yale School of Management professor of organizational behavior, and Barry Schwartz, a Swarthmore College professor of psychology. The pair recently wrote up their findings for the New York Times Gray Matter column.

How to Motivate Top Performers

Analyzing data on the motivations of more than 10,000 West Point cadets, as well as evaluations of their eventual performance at the school and later in their military careers, the researchers looked at what sort of motivation is most effective. Is it best to have an internal motive (i.e. to serve one's country), an instrumental motivation (like having a good, solid career with the military), or a mix of both? Instinct suggests the more motivations the merrier, but that's not what the data showed.

"Remarkably, cadets with strong internal and strong instrumental motives for attending West Point performed worse on every measure than did those with strong internal motives but weak instrumental ones. They were less likely to graduate, less outstanding as military officers, and less committed to staying in the military," the researchers report.

Put simply, doing the work for its inherent rewards alone proved a surer path to success than doing it for both its more intrinsic joys and external rewards like good pay and acclaim. The implications go far beyond military academies, the scientists claim.

The Counterintuitive Conclusion for Leaders

"Our study suggests that efforts should be made to structure activities so that instrumental consequences do not become motives. Helping people focus on the meaning and impact of their work, rather than on, say, the financial returns it will bring, may be the best way to improve not only the quality of their work but also--counterintuitive though it may seem--their financial success," they state.

While the researchers concede that this goes against common sense (surely, dedicated designers or salespeople are even more motivated if they're well paid too, right?), the data just doesn't seem to line up with everyday impressions on this one.

While radically underpaying or otherwise mistreating your staff is certainly not a recipe for peak motivation, apparently neither is focusing on anything but the inherent pleasures of a job well done. "Rendering an activity more attractive by emphasizing both internal and instrumental motives to engage in it is completely understandable, but it may have the unintended effect of weakening the internal motives so essential to success," they conclude.

Are you surprised by these findings?