The IQ Question
Recently there has been a bit of a debate in the heretical discourse space about IQ. Debates over IQ have been going on in the background for years, since the invention of IQ testing. So, this recent debate isn't a new thing -- it's just a new iteration of a perennial debate. The latest iteration was started by Nassim Taleb, who declared that IQ is bullshit. He also declared that psychology is bullshit.
https://medium.com/incerto/iq-is-largely-a-pseudoscientific-swindle-f131c101ba39
Is Taleb right? Is IQ bullshit? Is psychology bullshit?
I will briefly answer the question about psychology and then talk about IQ in more detail.
Psychology is not bullshit but there is plenty of bullshit in psychology. However, there is also plenty of bullshit in every scientific field, including the "hard" sciences such as physics and biology. To dismiss psychology as a field because of bullshit psychology would be like dismissing chemistry because of alchemy. We can and should develop theories of how the brain works and how human behavior is determined. We are making progress in that direction, in spite of bullshit psychology.
Now for the IQ question. IQ is not bullshit, but there are a lot of misconceptions about it.
What is IQ? People often say things like "My IQ is X" or "You obviously have a low IQ". (I sometimes say things like this.) Statements like this presume that intelligence can be simply measured by an IQ test in the same way that height is measured by a ruler.
When talking about traits, we need to distinguish between three things:
Some traits, such as height, are simple and one dimensional. We can measure height by putting a ruler next to a person, and there is almost no ambiguity or arbitrariness about how to measure it. The distinction between the measurement and the trait itself is not very important for a simple trait such as height. But what about a complex multi-dimensional trait such as strength?
We could measure strength with a single exercise test, such as bench press. But that would only test the strength of certain muscles, and it is arbitrary which test we use. Or, we could design a test that involves multiple exercises, such as squats, bench press, pull-ups, deadlifts, etc. But that would also be arbitrary. We could design many such tests and they would produce different results. It is likely that the results of different tests would be correlated, and we might call that correlation the "g factor" for strength. But the tests would still be arbitrary.
Then there is the question of what we are actually measuring. A strength test measures some set of complex effects (performance on different exercises) that have multiple causes. For example, one cause of performance is the strength of the muscles involved in the exercise. Another is whether the muscles are fatigued from recent activity. Another is whether the person had a good breakfast. Another is motivation to excel at the test. Another is experience doing the exercises on the test. All of those causes combine to produce an effect. Some of the causes we think of as "strength" and others we do not. No metric can measure just what we think of as "strength", assuming we could define it. A test only measures performance on the test.
There is also the difference between the innate potential for a trait and the trait itself. We might be interested in the innate potential for a trait, but we only have access to the trait itself or to some effect that is partially caused by it, such as performance on a test. For example, a person might have the innate potential to be very strong, but do poorly on a strength test because he never goes to the gym.
For a complex trait such as strength we have to distinguish between the genetic potential, the phenotypic trait, and a metric. They are related as follows:
This applies to IQ:
Why does this matter? Because people have a tendency to collapse these three things into one thing. When people say things like "My IQ is X" they mean that an IQ of X is a stable, persistent, and probably innate property of themselves. They equate their IQ score with their genetic potential for intelligence. That is a bit misleading, because X was just a test result that occurred on a specific test under specific conditions. It is just a measurement of a metric.
If you practice taking IQ tests you will almost certainly increase your IQ score on similar tests. Would such practice make you more intelligent, or just reallocate some of your intelligence to the kinds of problems that are found on IQ tests? Probably the latter.
IQ tests don't measure all the mental abilities that contribute to our intuitive concept of intelligence. IQ does not depend on long-term memory, creativity, curiosity, or the ability to learn from experience. It does not depend on the mental processing involved in physical abilities, such as throwing a ball or running around obstacles.
So, when you are using the concept of IQ you should keep all of that in mind. IQ doesn't "measure intelligence". IQ measures performance on certain tests. Performance on those tests is a partial effect of certain mental abilities. Those mental abilities are a partial effect of inherited genetic potential. Not all mental abilities are tested by IQ tests. "IQ" is not a synonym for intelligence, although it might sometimes be convenient to pretend that it is.
Having said all that, IQ is a very useful metric. Why? Because it has predictive power. IQ is correlated (positively or negatively) with many other things, such as educational attainment, income, and criminality. At the level of countries, average IQ correlates with per capita GDP. I haven't done the analysis, but I would bet that it also negatively correlates with homicide rates at a global level. IQ is useful because we can measure it with standardized tests and use those data to generate explanations and predictions.
Some people view IQ testing as immoral or unfair, typically for one of two reasons. One reason is that it selects people based on a test, rather than based on their ability to do a job. That is true, but there are good reasons for using tests. For example, we can't select heart surgeons based on letting them try heart surgery and seeing how well they do. Standardized testing is a very useful tool for selecting individuals to do jobs. The other reason people typically reject IQ testing is that it supports "immoral" policies or attitudes, such as eugenics or racial prejudice. This is an appeal to consequences fallacy. It is not only irrational, it is dangerous. Ignoring the truth is more likely to have negative consequences than accepting it and dealing with it.
To summarize, IQ is a useful metric as long as you understand what it is and what it isn't.
Someday I might write a post on the more difficult question: what is intelligence?
https://medium.com/incerto/iq-is-largely-a-pseudoscientific-swindle-f131c101ba39
Is Taleb right? Is IQ bullshit? Is psychology bullshit?
I will briefly answer the question about psychology and then talk about IQ in more detail.
Psychology is not bullshit but there is plenty of bullshit in psychology. However, there is also plenty of bullshit in every scientific field, including the "hard" sciences such as physics and biology. To dismiss psychology as a field because of bullshit psychology would be like dismissing chemistry because of alchemy. We can and should develop theories of how the brain works and how human behavior is determined. We are making progress in that direction, in spite of bullshit psychology.
Now for the IQ question. IQ is not bullshit, but there are a lot of misconceptions about it.
What is IQ? People often say things like "My IQ is X" or "You obviously have a low IQ". (I sometimes say things like this.) Statements like this presume that intelligence can be simply measured by an IQ test in the same way that height is measured by a ruler.
When talking about traits, we need to distinguish between three things:
- A phenotypic trait, such as height or strength.
- A metric that is used to "measure" the trait.
- The genetic potential for the trait.
Some traits, such as height, are simple and one dimensional. We can measure height by putting a ruler next to a person, and there is almost no ambiguity or arbitrariness about how to measure it. The distinction between the measurement and the trait itself is not very important for a simple trait such as height. But what about a complex multi-dimensional trait such as strength?
We could measure strength with a single exercise test, such as bench press. But that would only test the strength of certain muscles, and it is arbitrary which test we use. Or, we could design a test that involves multiple exercises, such as squats, bench press, pull-ups, deadlifts, etc. But that would also be arbitrary. We could design many such tests and they would produce different results. It is likely that the results of different tests would be correlated, and we might call that correlation the "g factor" for strength. But the tests would still be arbitrary.
Then there is the question of what we are actually measuring. A strength test measures some set of complex effects (performance on different exercises) that have multiple causes. For example, one cause of performance is the strength of the muscles involved in the exercise. Another is whether the muscles are fatigued from recent activity. Another is whether the person had a good breakfast. Another is motivation to excel at the test. Another is experience doing the exercises on the test. All of those causes combine to produce an effect. Some of the causes we think of as "strength" and others we do not. No metric can measure just what we think of as "strength", assuming we could define it. A test only measures performance on the test.
There is also the difference between the innate potential for a trait and the trait itself. We might be interested in the innate potential for a trait, but we only have access to the trait itself or to some effect that is partially caused by it, such as performance on a test. For example, a person might have the innate potential to be very strong, but do poorly on a strength test because he never goes to the gym.
For a complex trait such as strength we have to distinguish between the genetic potential, the phenotypic trait, and a metric. They are related as follows:
- The phenotypic trait is caused by genetic potential and other factors.
- The metric is caused by the phenotypic trait and other factors.
This applies to IQ:
- Mental abilities are caused by genetic potential and other factors.
- IQ test performance is caused by mental abilities and other factors.
Why does this matter? Because people have a tendency to collapse these three things into one thing. When people say things like "My IQ is X" they mean that an IQ of X is a stable, persistent, and probably innate property of themselves. They equate their IQ score with their genetic potential for intelligence. That is a bit misleading, because X was just a test result that occurred on a specific test under specific conditions. It is just a measurement of a metric.
If you practice taking IQ tests you will almost certainly increase your IQ score on similar tests. Would such practice make you more intelligent, or just reallocate some of your intelligence to the kinds of problems that are found on IQ tests? Probably the latter.
IQ tests don't measure all the mental abilities that contribute to our intuitive concept of intelligence. IQ does not depend on long-term memory, creativity, curiosity, or the ability to learn from experience. It does not depend on the mental processing involved in physical abilities, such as throwing a ball or running around obstacles.
So, when you are using the concept of IQ you should keep all of that in mind. IQ doesn't "measure intelligence". IQ measures performance on certain tests. Performance on those tests is a partial effect of certain mental abilities. Those mental abilities are a partial effect of inherited genetic potential. Not all mental abilities are tested by IQ tests. "IQ" is not a synonym for intelligence, although it might sometimes be convenient to pretend that it is.
Having said all that, IQ is a very useful metric. Why? Because it has predictive power. IQ is correlated (positively or negatively) with many other things, such as educational attainment, income, and criminality. At the level of countries, average IQ correlates with per capita GDP. I haven't done the analysis, but I would bet that it also negatively correlates with homicide rates at a global level. IQ is useful because we can measure it with standardized tests and use those data to generate explanations and predictions.
Some people view IQ testing as immoral or unfair, typically for one of two reasons. One reason is that it selects people based on a test, rather than based on their ability to do a job. That is true, but there are good reasons for using tests. For example, we can't select heart surgeons based on letting them try heart surgery and seeing how well they do. Standardized testing is a very useful tool for selecting individuals to do jobs. The other reason people typically reject IQ testing is that it supports "immoral" policies or attitudes, such as eugenics or racial prejudice. This is an appeal to consequences fallacy. It is not only irrational, it is dangerous. Ignoring the truth is more likely to have negative consequences than accepting it and dealing with it.
To summarize, IQ is a useful metric as long as you understand what it is and what it isn't.
Someday I might write a post on the more difficult question: what is intelligence?
The way I see it, intelligence is real, and it's also "concrete" enough so that you should be able to test it in a standarized manner. (This is just based on my experience, not on any data or science). I don't know if IQ measures this ability or not. There's a possibility that it doesn't, but it seems to at least approximate it to some degree.
ReplyDeleteThe fact that IQ correlates with things like "income" or whatever is actually irrelevant IMO.
Intelligence is the mental capacity required to understand complex topics. It matters because it's an important trait to have in order to become a doctor or engineer (well, a "good" doctor and a "good" engineer).
"Street smarts" as Taleb puts it is required a lot more in areas where there's little or no civilization. It's also not so much about intelligence as much as it is about assertiveness and forming alliances - it's a set of personality traits that are separate from the kind of intelligence required to become an engineer.
Taleb is right on one point though: your IQ score does not define you or your life destiny.
He's completely wrong on the importance of having a population with a high average IQ.
Even if IQ might not matter so much for the individual; it matters a lot for the collective.