The desire for achievement is one of lifes great mysteries. Social scientists have devote

The desire for achievement is one of life"s great mysteries. Social scientists have devoted lifetimes to studying the drives that spur us out of bed in the morning, compel us to work or study hard and spark all manner of human endeavor. Indeed, a textbook actually documents 32 distinct theories of human motivation.

Given this diversity of thought, it"s easy to forget that for a half century, American society has been dominated by the psychological school known as behaviorism, or Skinnerian psychology. Although behaviorism and its fundamental principle of "positive reinforcement" have long since lost their way in academic circles, the Skinnerian legacy remains powerful in every field of daily life, from the home and classroom to the workplace. Don"t want to take the trash out？ Do it, and you can go to the movies on Friday night. Not in the mood for work？ Keep plugging away, and you might get a bonus. Not interested in calculus？ Strive for an A in the class, and you"ll make the honor roll. The theory may be bankrupt, but incentives and rewards are so much a part of American culture that it"s hard to imagine life without them.

Yet that"s exactly what a growing group of researchers are advocating against today. A steady stream of research has found that rather than encouraging motivation and productivity, rewards actually can undermine genuine interest and diminish performance. "Our society is caught in a whopping paradox," asserts Alfie Kohn, author of the new book published by Rewards (Houghton Mifflin), which surveys recent research in the effectiveness of rewards. "We complain loudly about declining productivity, the crisis of our school and the distorted values of our children. But the very strategy we use to solve those problems — dangling rewards like incentive plans and grade and candy bars in front of people — is partly responsible for the fix we"re in."

It"s a tough argument to make in a culture that celebrates the spoils of success. Yet study after study shows that people tend to perform. worse, to give up more easily and to lose interest more quickly when a reward is involved. Children who are given treats for doing artwork, for example, lose their initial love of art within weeks. Teenagers who are promised a reward for tutoring youngsters don"t teach as enthusiastically as tutors offered nothing. And chief executive officers who have been awarded long-term incentive plans have often steered their companies toward lower returns.

According to behaviorism, all human actions ______ .

A．are of a great mystery

B．have no bearing on human drives

C．are supposed to be highly motivated

D．are based on stimulus and response