Research

Punishment Trumps Rewards in Learning Behavior Experiment

• By Michael Hart
• 05/12/15

Punishing students for poor performance may be more effective than rewarding them for doing well, according to a recent study conducted by researchers at Washington University in St. Louis.

In an experiment conducted with Washington University college students, the results appeared to suggest that punishment influences behavior more than rewards do. In fact, the measured impact of losing money tokens in the experiment was two or three times greater than winning money tokens.

In the experiment, one group of students was asked to listen to a series of clicking noises and indicate whether they heard more in the left or right ear. Likewise, another group was asked to watch for flashes of light and indicate whether they saw more on the right or left side.

The clicks and flashes were randomized and came with varying frequencies, making it difficult to ever guess the correct response.

Nevertheless, also at random, students were rewarded 5, 10, 15, 20 or 25 cents whenever they got a "right" answer. They were also penalized whenever they got a "wrong" answer.

When students got what they thought was a "right" answer, they were more likely to make the same choice the next time. However, much more frequently, they were less likely to make the same choice if they were told they had gotten the "wrong" answer.

Also, while the likelihood of making the same choice again after a "right" answer was greater when the reward was larger, the likelihood of not making the same choice for the "wrong" answer remained about the same, suggesting the students took more seriously the punishment than the reward.

This particular Washington University study, funded by the National Institutes of Health, was less complex than previous studies of effects of rewards and punishments on behavior. In this study, because the stimulus — the clicks and flashes — were random, researchers were more easily able to pinpoint the effects of behavior.

"The question of how rewards and punishments influence behavior has occupied psychologists for over 100 years," said the lead researcher, Jan Kubanek, a postdoctoral research associate in anatomy and neurobiology. "The difficulty has been devising effective tasks to probe the question. We used a simple approach that reveals dramatic differences in the way people respond."

Kubanek said the results suggest that negative feedback may be more effective than positive feedback at affecting behavior, adding "such feedback does not have to be harsh, since it appears that we tend to react in the same manner to any amount of negative feedback."