Does IQ matter?

There are several ways of attacking the question of whether IQ scores matter. One can test whether people who have high IQs are more successful in their careers or in their marriages. My guess is it would turn out yes, up to a minimum IQ (and a different minimum for different jobs), and no.

Or one can ask whether IQ tests measure anything we care about knowing. My answer is yes but not as much as we would like. Most of what I think I know about IQ and human intelligence comes from a book by that name by Nicholas Mackintosh. It came out in 1998, so it lacks all the recent genetics information, but it has a very interesting analysis of IQ tests and the nature of intelligence.

Imagine being in a room of several dozen colleagues. It is likely that there are one or two people in that room that the other people in the room think are really smart. They know stuff and think of stuff and put things together in their minds, and they’re just smart. These people probably have a high IQ. This is the common sense idea of intelligence. There are also high IQ people who seem lost in the real world.

If I remember right, 11 years after I read the book, Mackintosh says that about half of what makes us say, wow, that person is really smart is measured by standard IQ tests. The other half comes from two abilities the tests do not measure, though I don’t know why a test couldn’t be created that did.

• The ability to think through an issue with more than one variable.
• The ability to survey a situation and know what information in it is important to know to accomplish whatever one’s purpose is.

One’s intelligence¬—the sum of one’s mental abilities—is made up of many (certainly hundreds, probably thousands) of teeny abilities, and having one of these does not make having any other ability any more or less likely. The ability to remember phone numbers has nothing to do with the ability to remember faces or names or poetry or baseball statistics. The name of a tool, its purpose, and its image are stored in different parts of the brain. A teenager who can learn Japanese as a gaijin may find it hard to learn to drive. Or a kid who is a whiz at calculus might not be able to do arithmetic in his head.

It is not just that they build on each other in a Vygotskyan way, which they do, but they are separate abilities. So there is no reason to expect any random high-IQ person to be an effective analyst or manager.