A new study suggests that punishments are more likely to influence behavior than rewards.
The study from researchers at Washington University in St. Louis found that losses — or punishments — had a measured impact two to three times greater than gains — or rewards.
In one study, 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 randomized and often very close together, making the task challenging and the students often uncertain of the correct response, the researchers explained.
Every time a student made a choice, the researchers randomly displayed a token for 5, 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, the researchers said. 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, the researchers discovered.
This was true in both groups among those who heard clicks and those who viewed flashes, demonstrating that the stimulus itself didn’t matter, the researchers noted.
“Objectively, you’d think that winning 25 cents would have the same magnitude of effect as losing 25 cents, but that’s not what we find,” said the study’s lead author, Jan Kubanek, Ph.D., a postdoctoral research associate in anatomy and neurobiology at the Washington University School of Medicine.
The study may help in the understanding of learning behaviors, according to the researchers. For example, would students learn more efficiently if their teachers rewarded correct answers or pointed out incorrect ones?
According to this research, in some situations it may be better to deduct points when students are wrong than to reward them for correct answers. This may help students avoid making the same mistake again.
“Our study suggests that negative feedback may be more effective than positive feedback at modifying behavior,” said Kubanek.
“Our study showed that 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. From an evolutionary perspective, people tend to avoid punishments or dangerous situations. Rewards, on the other hand, have less of a life-threatening impact.”
This could help explain why students in the study strongly avoided repeating mistakes, no matter how big the punishment was.
The researchers next plan is to look at how behavioral changes in response to rewards and punishments are encoded in the brain.
“Do the neural signals in our brain also show discrepancies between how we react to rewards and punishments?” Kubanek asked. “Studying the neural mechanism involved may help us better understand and possibly alleviate neurological disorders in which the associated processes go awry.”
The study, published in the journal Cognition, was funded by the National Institutes of Health.