A number of studies, for example, have shown that children are apt to become less concerned about others’ well-being if they were rewarded earlier for helping or sharing. Students, meanwhile, become less excited about learning once they’ve been given a grade (or some other artificial inducement) for doing so. And even though the average American corporation resembles a giant Skinner box with a parking lot, no controlled study has ever, to the best of my knowledge, found a long-term enhancement in the quality of work as a result of any kind of incentive or pay-for-performance plan.

Over the years, researchers have investigated some intriguing questions that stemmed from these basic findings. For instance: What if the reward is really large and luscious? (Answer: It’s apt to do even more damage to intrinsic motivation.) Are rewards destructive because they distract people from the task? (Apparently not, because other distractions don’t have the same negative effects.) Which is worse, giving people a set reward for doing something or making it contingent on how well they do it? (The latter, by a long shot.)

Give a bunch of adults or children a puzzle to solve or, say, a poem to write. Promise half of them a reward if they’re successful — and then watch as they end up being less creative and less interested in the task than those promised nothing. Such studies have led some observers to conclude that rewards should be avoided for interesting tasks but that they may be harmless or even appropriate when people with more power want to make people with less power do boring stuff. (If there’s one thing this field has taught me, it’s that rewards, like punishments, are ultimately about power.)

But newer research finds that rewards may also backfire when they’re offered for doing things that aren’t especially interesting, particularly if you watch to see what happens after the rewards stop coming. For example, a study by Thane Pittman of Colby College and his colleagues found that when people put off doing something — which often happens when a task seems unappealing — a reward offered for finishing early either didn’t help or led to increased procrastination.

Or what about rewarding people just for showing up? In 2015, researchers at Hong Kong University and New York University studied 9-year-olds in a very low-income area of India whose school attendance was spotty. These children were promised a reward if they came to school at least 32 out of 38 days. During that period, not surprisingly, many kids’ attendance improved. Afterward, however, it promptly dropped — either back to the earlier low levels or, in the case of students on whom the reward hadn’t had even a temporary effect, to a level much lower than it had been to begin with.