This suggests that while rewards could change behaviour, it depended on the size of the reward being offered, while punishments of any size seemed to have a greater effect.
It seems disciplinarians may have been right after all – the stick really is more effective than the carrot.
Psychologists have found that people are more likely to alter their behaviour if they think they are going to be punished rather than being offered rewards.
The study found that the effect of punishing students for making incorrect choices was up to three times greater than if they were given enticements.
The researchers claim their findings could have implications for helping teachers in schools and for parents struggling to get their unruly children to behave.
It suggests that our response to punishment may be hardwired into our brains.
Dr Jan Kubanek, a neurobiologist at Washington University’s school of medicine who led the study, said: ‘Regarding teaching strategies, our study suggests that negative feedback may be more effective than positive feedback at modifying behaviour.
‘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.’
The researchers, whose work is published in the journal Cognition, devised a simple experiment that required students to listen as series of clicking noises and indicate whether they heard more clicks in their left or right ear.
Every time a participant made a choice, the researchers randomly displayed a token worth between 5 US cents and 25 US cents.
The student was given the token as a reward for every correct answer or taken away as a punishment for an incorrect response.
They also conducted a similar experiment with a second group of students who were asked to watch for flashes on either the left or right side of a computer screen.
The researchers found that if a student was given a reward, they tended to repeat the previous choice and that grew stronger as the award increased.
However, if the student was punished then they tended to avoid the previous choice.
The students also showed a strong tendency to avoid the previous choice regardless of how large a sum was lost.
This suggests that while rewards could change behaviour it depended on the size of the reward being offered, while punishments of any size seemed to have a greater effect.
Dr Kubanek said: ‘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.’
The researchers now hope to examine how the brain itself responds to rewards and punishments.
Professor Richard Abrams, a psychologist at Washington University who was also involved in the research, added: ‘The question of how rewards and punishments influence behaviour has occupied psychologists for over 100 years.
‘The difficulty has been devising effective tasks to probe that question.
‘We used a simple approach that reveals dramatic differences in the way people respond to different types of feedback.’
