Today, in my site on Quora I received the following question from Jeremy Prusky.
Mr. Kelly- for years I have been trying to understand how so many intelligent people like yourself put faith into the concept of the IQ test- and I’m wondering if you can finally convince me of the validity and worth, of that. …I hope you will not be offended by the quesioning, but you write a lot about IQ and intelligence, and so I feel, who better to ask?
The post below is my response to Jeremy’s question.
Jeremy, thank you for your insightful question. I am never offended by such thought-provoking questions because they are the conduit to rational discussion. I agree entirely with the issues you raise regarding IQ tests. Although they are the best measure we have of intelligence, they have significant limitations, several of which you have identified and on which I will elaborate below.
First and foremost, I agree that the person who takes the test must understand the format of such tests whereby a pattern in a series of successive matrices must be identified and a correct answer selected from a group of options. To make the test valid, a person should take a few preparatory sample of IQ items to ensure that they know what they are expected to do. If a person from this or another culture took an IQ test without such preparation, the score would be meaningless.
As you say, a single IQ test taken in less than an hour, on a given day at a given age, is a snapshot and has limited validity. We have observed that the same person taking IQ tests over several different months or years can get results that differ by as much as a standard deviation, depending on mood or external influences, so the third digit in an IQ is not particularly reliable. However an average over several IQ tests would give a more accurate measure.
Furthermore, IQ tests don’t measure creativity, inventiveness or even long-term problem solving. One might ask, “Why do we use IQ tests when they have so many limitations?” The surprising thing about IQ tests is that they have an uncanny relationship to things like job performance, choice of college major and entrepreneurial success. (see https://www.intelligence-and-iq.com/what-scientific-evidence-validates-iq-tests-as-a-measure-of-intelligence/ and https://www.intelligence-and-iq.com/whats-the-difference-between-intelligence-wisdom-and-cleverness/). Those of low IQ are usually less able to do the more sophisticated jobs than those of higher IQ. Almost no one who scores below 115 on a IQ tests can become a theoretical physicist, mathematician or computer scientist. Highly successful entrepreneurs, Steve Jobs, Bill Gates, Jeff Bezos, and Elon Musk all scored extremely high on IQ tests. Often an IQ test undervalues someone, as in the case of Richard Feynman who scored only 125 on a single IQ test, but he is an exception that proves the rule.
So, while I concede that IQ tests have significant limitations and should be taken under advisement, I recognize that they serve as the best predictors we have of future intellectual achievement.
