The following story encourages us to think twice about what behaviour modification can achieve.

Don Bannister, a psychologist who worked at a psychiatric hospital near Leeds, told me how staff at the hospital had tried to use behaviour modification on psychiatric patients. The patients’ behaviour was very bad (too much shouting, swearing, and disagreeing with staff ’s requests). The staff decided to reward good behaviour with tokens that could be ‘spent’ in the hospital shop on sweets, newspapers, cigarettes, and other goods. The result was that all of the patients bar one behaved worse than ever. When the staff asked what was happening, they found that the one well-behaved patient (an old man) was being rewarded with all of the tokens. He was rewarding the other patients for their bad behaviour with the same tokens.

The experiment was, then, unsuccessful and gives us insight into how people may manipulate the outcomes of simple behaviorist learning experiments.