In the past, a lot of people have promoted IQ tests as if they could measure intelligence. There was a time that public schools used them to recommend careers to various people. Now, we have learned that IQ tests are measuring something, but it is not clear what exactly they are measuring! It is certainly not intelligence.

IQ tests are supposed to give the same result regardless of age or circumstance. They are also supposed to measure intelligence and only intelligence. Both of these claims are unlikely at best. IQ tests were given to poor farmers in northern India. When they had plenty of food, they scored high on these tests. When they did not have as much food, they scored low. Nor is this is only example. IQ tests have increased over time. Since other things have also increased over time such as leisure activity and health -IQ tests could be measuring one of these.

The real objection to IQ tests does not come from that source though. There are three different ways that someone could be more or less intelligent. The first way is that someone could be able to think abstractly. Since all humans and only humans can do that (leave out aliens and angels), this will not measure the difference in intelligence between any two human beings. The second way is by practice and training. Someone who has gone to school and learned how to think is better at it than someone who has not. Naturally, this does separate people into different levels of ability. But it only indicates how educated someone is. There is no reason apart from time and money that anyone cannot attain the same levels of ability as anyone else. The final way that someone could be more or less intelligent is by interest or attention. The more time and effort that you spend doing something, the better you will become at it. This is especially true when you like what you are doing. So someone who likes learning math will naturally be better at it than someone who does not like it. They will spend more time doing math and more of their attention will be focused on math.

If I am correct, and those three ways are the only ways in which people are intelligent, then IQ tests are useless. IQ tests are really measuring a combination of learning, training, attention and interest with respect to a particular kind of intellectual activity. Attention depends in part on interest and in part on competing concerns. So poor people may have little attention to spend on IQ tests. Interest is partly a matter of choice and partly a matter of nature. In either case, IQ tests are not the best instrument to find out someone’ s interest. Perhaps we could use IQ tests to measure the learning and training of someone in a particular area. However, it was not designed to do that. As it currently stands, IQ tests do not measure anything useful.

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Comments on The Uselessness of IQ Tests

  1. I think the idea that an IQ test measures an underlying ability is problematic.

    Reading a few articles on how IQ tests work, I’ve found that a causal connection is posited by theorists between some underlying ability (“intelligence”, “spatial reasoning”, “cognitive ability”) and the correct or incorrect answers to an IQ test. It’s believed that by measuring the answers, the underlying ability which “causes” the answers is estimated. One author compares IQ tests to breathalyzers and white blood cell counts. They say that all three tests can measure a “concealed inner state” because the “concealed inner state” is causally connected with the data output of the instrument. The comparison doesn’t work to establish IQ tests as measures of intelligence. For one thing, a breathalyzer doesn’t measure blood alcohol content and a white blood cell test doesn’t measure infections. For another, two separate acts are involved in a breathalyzer test and a white blood cell test. First, the amount of alcohol in the breath is measured, and the quantity of white blood cells in the bloodstream is measured. Second, based upon established causal connections (between drinking alcohol and blood alcohol content, between white blood cell counts and infections) inferences can be made about the so-called “concealed inner state”. In the case of an IQ test, the quantity of correct and incorrect answers is measured, as well as the frequency at which correct and incorrect answers occur. Now, based on an established causal connection between the underlying ability and the answers to the test, it should be possible to make inferences about the underlying ability based on the score. It isn’t possible because there is no causal connection. If you equate cognition with brain activity, then brain activity is supposedly the cause of correct and incorrect answers. In that case, correctness would have to be a physical object or system independent of the brain and which is causally connected to the brain. Where is correctness located? What is its size? How much correctness exists? How does the brain cause correctness?

    Perhaps an alternative would be to interpret IQ test results in terms of “understanding”. For example, with a 120 IQ, it could be said that a person’s understanding is above average. What is it that they understand better than others? A system of signs (a semiotic or semantic system that is more basic than logic or math or any formal system). In the case of spatial reasoning, the signs would be all shapes, and the system would be the relationships between the shapes. If a person gets a spatial reasoning question wrong, one could only justify that they lack an understanding of certain spatial relationships, and not that they can’t understand or that they will never be able to understand. A system of signs is independent of the brain. When a person encounters a sign, it causes activity in their brain. Can it be concluded based on this causal connection (between signs and brain activity) that a person’s ability to understand systems of signs cannot change? No, because a person’s brain, specifically the neural pathways in which brain activity occurs, can change throughout their lifetime.

    So, I don’t think that IQ tests measure intelligence, and I don’t think IQ scores justify beliefs about what a person can or cannot do (intellectually or otherwise) throughout their life time.

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