Intelligence testing is by no means foolproof

I refer to your feature 'Born to succeed' (South China Morning Post, October 29) on the controversy of relative IQ superiority between ethnic groups. Certain long-standing misconceptions need to be clarified before one can view the issue from a better perspective.

Mental ability is like money - it is distributed unequally and unfairly, and this basic fact of life has many consequences. One cannot legislate equality in all things, and trying to do so can lead to absurdity. Many controversies surrounding issues of ability arise because people do not want to face them.

A major reason is ideological. It offends egalitarian ideals, modern notions of social fairness and justice. This is especially true in the United States and Japan, where the idea that all are equal at birth, and failure to do well in society is the individual's fault, is deep rooted. Although there is no reason why the average intelligence level of all races should be the same, it is generally assumed that this difference is less significant than individual variations within a race.

Resting on false premises are the common beliefs that: intelligent people are all born possessing exceptional mental talents or genetic gifts; that they can be clearly identified and quantified by psychology tests that measure intellectual performance and are interpretable as absolute characteristics; that these psychology tests are inherently reliable and their results are objective and meaningful indicators of real-life attributes; and that superior intelligence is above all the determinant indicator and/or factor of future success in and/or contribution to society.

Psychological tests are useful, so long as their limitations are known and accounted for.

Unknown to most, the correlation of test scores to reality performance is often low. IQ tests, which mostly tap academic intelligence, correlate about 0.5 with school performance, but only about 0.2 with job performance, which is reliant on a wider range of abilities. Research into some handicapped people (whose IQ test scores may be as low as 80) who spent long hours betting at a racetrack showed that their mental feats were quite impressive. In a few cases they were so adept that they could live off their winnings.