He knew he was wrong — Daniel Kahneman interview

When I was 13, my school cricket team received a visit from a top professional cricket coach, an intoxicating visit from the big leagues. I tried to hear what the great man was saying as he watched us, how he advised our teacher. ‘Never praise kids — they only mess it up next time,’ I overheard him say. After pausing to berate me for a below-average cover drive, he whispered to the teacher, ‘It’s different with criticism — that really works.’

Like a typical cocky teenager, I longed for a clever riposte. Perhaps fortunately, I didn’t have the intellectual insight to deliver one. But last week I met up with the man who did — Daniel Kahneman, professor of psychology, winner of the Nobel prize for economics and author of the newly published Thinking, Fast and Slow.

In the late 1970s, he was teaching flight instructors in the Israeli Air Force about the psychology of effective training. He told the instructors that praise rather than criticism was the best way to help the cadets improve. An experienced instructor disagreed with him: ‘On many occasions I have praised cadets… the next time they usually do worse. On the other hand, I have often screamed into a cadet’s earphone for bad execution, and in general he does better on his next try.’

Kahneman realised that the instructor was making a mistake. If a cadet did something better than normal, his next attempt at the task would in all likelihood not be as good, whether or not he was praised. In the same way, if he performed unusually badly, his next attempt would probably be better, whether or not he was criticised. The trainer was attaching a causal interpretation to the fluctuations of a random process; simple regression to the mean.