If only we could set motivation on cruise control.

Propelling teams forward is a basic leadership task. But  people's perception of their chances of success and willingness to exert energy change as they get closer to reaching their goals, research shows. Leaders who understand this are able to modify their  motivational techniques over time to carry employees across the finish line.

Go! Go! Go!

Two motivational systems operate in every human being, according to Olya Bullard, a professor at University of Winnipeg. The first system, called promotion, focuses on rewards. The second system, called prevention, focuses on punishment. Leaders tend to leverage one system or the other--by either cheering people on or stressing the consequences of failure. (In North America and some other regions, people are generally more susceptible to positive reinforcement.)

Applauding incremental success works well in the early stages of an effort with a set goal, says Bullard. That is when people assess their performance based on how far they've progressed from zero, the point at which they began. They are motivated by every step that moves them forward. Imagine you have challenged your sales team to sell $100,000 worth of product. "You say to them, 'You started with no sales. Now you have sold $1,000! Yeah!" says Bullard. "Then, 'You just sold $2,000! Pat yourself on the back.'"

Don't stop going! Don't stop going! Don't stop going!

But as people pass the midpoint toward their goals, something happens, says Bullard, who conducted her research with Rajesh V. Manchanda of the University of Manitoba. They stop focusing on how far they have come and start focusing on how far they have yet to go. The prevention system kicks in. As people contemplate their distance from the end point, they concentrate more on the chances they won't reach it and the negative consequences if they fail to do so.

At that point, Bullard says, leaders should shift their motivational approach to align with employees' changed focus. Rather than applaud doing things right, leaders should urge people not to start doing things wrong. "In the beginning you might tell the team to start cold calling people and win business," says Bullard. "Toward the end, you would say, 'Don't stop cold-calling people! Don't miss out on that sale!"

The leader's style of motivation "should not be either/or," says Bullard. "People change how they see the goal. So [the approach to motivation] should change too."

The joy of victory

Another motivation challenge emerges when employees pursue not some quantitative goal but rather triumph over a rival. In those circumstances, people assess their positions against a moving target. The danger becomes complacency.

In the early stages of competition, just believing that winning is feasible has the most important influence on motivation, says Jordan Etkin, a professor of marketing at Duke University's Fuqua School of Business. (Stanford's Szu-Chi Huang and Fudan University's Liyin Jin co-authored the study.) So staying ahead helps. Every investment or sale your company lands at the expense of a competitor is new evidence that you can actually win this thing. That validation is especially important for startup teams, who may still question the decision to leave secure employment.

The agony of complacency

Winning feels great, of course. But always winning dulls your motivation, and that can hurt you. "If you are ahead you can lose that scrappiness," says Etkin. "You may slack off a little bit." The optimal position is to be a little bit behind. "That is a highly motivating state because you want to catch up," says Etkin.

Obviously leaders don't want their teams stalled in second place just so they'll be eternally hungry. So by all means encourage outright wins and--when they occur-- give people brief periods to relish their triumph. That helps sustain high performance.

However, "it becomes a little bit of a game how long to sit back and enjoy being on top without potentially doing damage to future performance," says Etkin. So always have that next rabbit lined up and ready to chase. "Yes, we beat this company," says Etkin. "But those guys over there are a little bit better than we are."