Punishment twice as effective in guiding behaviour than reward

Would students learn more efficiently if their teachers rewarded correct answers or doled out punishment for incorrect ones? New research says it may be better to deduct points when students are wrong than to reward them for being correct.

Punishment has greater impact on behaviour than rewards, showed the experiment devised at Washington University in St. Louis.

The study involving 88 students at the university found that losses -- or punishments -- had a measured impact two to three times greater than gains -- or rewards.

In one study group, students listened to a series of clicking noises and indicated whether they heard more clicks in the left or right ear. In another group, students watched for flashes of light on a screen and indicated whether they saw more flashes on the right or left side.

The number of clicks and flashes on each side were randomised and often very close together, making the task challenging and the students were often uncertain of the correct response.

Every time a student made a choice, the researchers randomly displayed a token for five, 10, 15, 20 or 25 cents that was given as a reward for the correct answer or taken away as a punishment for an incorrect response.

As might be expected, when a student was rewarded, he or she tended to repeat the previous choice. And that tendency grew stronger as the award increased. When a student was punished, he or she strongly avoided the previous choice.

However, unlike the response to a reward, no matter how large a sum was lost, the students showed a strong and consistent tendency to avoid the previous choice.

This was true in both groups -- among those who heard clicks and those who viewed flashes -- demonstrating that the stimulus itself did not matter.

"Objectively, you would think that winning 25 cents would have the same magnitude of effect as losing 25 cents, but that is not what we find," said the study's lead author Jan Kubanek.

The study appeared online in the journal Cognition.