Though teachers and parents do it every day, there’s lots of evidence paying kids to learn/read/study is a waste of time.  As Alfie Kohn, educational consultant, sums up the substantial body of research:

Rewards are no more helpful at enhancing achievement than they are at fostering good values. At least two dozen studies have shown that people expecting to receive a reward for completing a task (or for doing it successfully) simply do not perform as well as those who expect nothing (Kohn, 1993). This effect is robust for young children, older children, and adults; for males and females; for rewards of all kinds; and for tasks ranging from memorizing facts to designing collages to solving problems.

Indeed, paying people to change their behavior and opinions often backfires. In school, kids think ‘hey, studying must be a chore if they pay me to do it.’ The immense natural joy of learning, of accomplishing something and growing, is stifled by the sensation of laboring for a treat. Again, Kohn offers a particularly telling example:

In one representative study, young children were introduced to an unfamiliar beverage called kefir. Some were just asked to drink it; others were praised lavishly for doing so; a third group was promised treats if they drank enough. Those children who received either verbal or tangible rewards consumed more of the beverage than other children, as one might predict. But a week later these children found it significantly less appealing than they did before, whereas children who were offered no rewards liked it just as much as, if not more than, they had earlier (Birch et al., 1984).

Kohn applies this anti-rewards analysis to healthcare, arguing that using incentives to try to promote healthy behavior is ineffective or counterproductive.  Again, Kohn cites lots of research.  Even if it is temporarily effective, paying for healthy behavior is a band-aid that’s likely to fall off.

[Rewards] ignore the reasons we may turn to food or cigarettes for solace. “Smoking, drinking, overeating, or not exercising often represent coping strategies for some kind of underlying distress,” Dr. Jonathan Robison, a health educator, observes.  Incentive programs not only ignore those problems but may produce “a cycle of repeated failure.”

What’s the right approach? According to Kohn, “First, address people’s motives and deeper concerns rather than just trying to change their behavior. Second, help people to get some control over their lives.  Finally, build on their relationships with others to promote change. Couples and friends tend to lose weight together more effectively than do individuals.”