Praise, like penicillin, must not be administered haphazardly. There are rules and cautions that govern the handling of potent medicines - rules about timing and dosage, cautions about possible allergic reactions. There are similar regulations about the administration of emotional medicine.” So wrote a psychologist giving advice to parents in the 1960s.

Most of us believe praise has positive effects on children: we expect our praise for their accomplishments to enhance their motivation and boost their self-esteem. Yet praising children is not common to all cultures. For example, among the Gusii of Kenya or the Zinacanteco Maya, it seems children learn and acquire important skills by observing others, and are given feedback only when their performance is inadequate. Plus, east Asian cultures in general regard too much praise as harmful to a child’s character.

Research into Japanese schools has found children to be remarkably motivated, despite the lack of reward systems. Praise is seldom public and only given for truly exceptional achievement. In such a psychological environment, the rarity value gives praise or reward a much stronger motivating effect.

One theory about why these cultures are so miserly with praise is that they are more collectivist, and motivated by a drive for self-improvement rather than self-enhancement. Children want to do well because they feel obliged to give something back, while we in the West just want to feel better.

Psychologists are not sure that unmitigated and untrammelled praise is a good thing. They suggest you need to be careful about how and when you use it to get someone motivated, and that poorly timed and ill-considered praise can be counterproductive.

For starters, there is clear evidence that excessive praise for tasks the child sees as easy is demotivating; he or she infers that the adult has a low opinion of his or her ability. There is also evidence that children may devote less time to pursuing tasks if praise is withdrawn. They are driven to perform to obtain praise, rather than for the intrinsic joy or purpose of the task itself.

Perhaps one potent reason praise can be ineffective is if the child perceives it as insincere. Children are perfectly capable of asking the same questions adults do when faced with empty flattery - why do people feel they need to make up things about me? What is wrong with me that people need to cover up? Studies show that many people believe that if you fulsomely praise a child who has performed equally well as another - who gets no praise - the first child must have started from a lower ability base. In other words, it could be psychologically damaging because it conveys a message of low ability. To summarise: praise needs to be specific, consistent and genuinely felt, and take account of varying performances rather than used to manipulate. And to be an effective motivator, it has to be seen to be credible by the child receiving it.

Indeed, it could be that praise is something we do more for ourselves than the person we are praising. It might reflect a desperate need to encourage because we are worried about a child’s performance, not pleased by it. The alternative is to stand back and observe what’s going on and give more thoughtful and useful feedback. Let the person you care for know what you really think about how they are doing in a constructive way, and use your experience on how to improve further. Isn’t that what you would prefer for yourself?

Now, what did you really think of this article?Any praise would be much appreciated... Professor Raj Persaud is a consultant psychiatrist at the Maudsley hospital and senior lecturer at the Institute of Psychiatry in London. He is this year’s visiting Gresham professor for public understanding of psychiatry and will give three free public lectures at Barnard’s Inn Hall, London EC1 on September 29, October 20 and November 29. See www.gresham.ac.uk for more details. Email: rajpersaud@tes.co.uk