Is measurable IQ important? This month’s Discourse is on IQ. Welcome to the conversation. If you are already subscribed you will see the full conversation in your Inbox. Tuesdays are dedicated to ways we study IQ. Fridays are materials for you to explore - longer reads, researchers of interest, specialized deep dives, and Sundays are for pithier expositions usually in the form of OpEds or brief essays. If you are not yet subscribed:
My starting point - we are all in discovery on this Discourse - is simple. Some is plenty; enough is good, more is not necessarily better, but extraordinary might be extraordinary. Thinking about IQ like a gas tank (and for sake of argument same car, same engine, same miles/gallon just different tank sizes), if you only have a 3-gallon tank things are gonna be more difficult when you drive across country, but you can still get from Maine to Arizona. You’ll be happier and spend less time in frustration though if you stick the the town around you. The 3-gallon tank is not great, but it is functional.
If you have a 15-gallon tank, that's much more normal, and you're fine driving across country. You still have to make several pitstops, but the number of pitstops is more in line with our socialized expectation of driving across country. Additionally, you have more “room for error” in terms of your gas tank running out. One wrong turn is much less likely to get you abandoned in the wilderness unlike your 3-gallon brother.
But is it much better to have a 30-gallon tank? Twice the size of the norm and ten times the size of your 3-gallon brother - is it actually any better?
In our example of cross country driving, the smallest tank needs to stop each hour to fill up, approximately ten times a day in a 10-hour driving day. Our normal tank stops twice a day and the larger tank only needs to stop once a day. The small tank clearly bears an extra burden but with focus can make it. The difference between the normal and extra capacity tank is nominal.
In terms of our Maine to Arizona trek, a 30-gallon tank will get there a bit faster, but the real constraint changes once the tank is large enough. Once the tank is large enough to let you drive for multiple hours without stopping, the constraint becomes the rest of the system, aka the driver’s willingness to keep driving. In a 10-hour driving day, the 30-gallon tank saves 20-minutes over the 15-gallon tank, hardly earth shattering. Certainly not worth bragging about.
But what if you have 150-gallon tank? That’s an order of magnitude greater than the normal 15-gallon tank.
Again, on the surface, even an order of magnitude larger tank won’t really save you much time in the cross country trek - maybe 1-2 total hours over the entire multi-day journey.
But the difference in the Substantially Larger Tank is that now you can solve a different problem. With 3, 15, and 30-gallon tanks, there is no need to change the vehicle. With 150-gallons at your disposal . . . now you can consider a totally different kind of vehicle and very different paths.
Most of our measures for IQ trifle with the excessive precision of distinctions between the 15 and 30-gallon tanks, 126 versus 132 for example. I’ve had plenty of parents complain that my assessment of their son can’t be right, because he is “near” genius. Ability to manipulate fractions does not require genius (I promise) nor does being a genius preclude one from screwing up with fractions. Therefore, screwing up with fractions (as SO MANY of my students do), does not indicate anything about the student’s IQ. Fractions are learned. Even the 3-gallon tank kid can learn how to work with fractions. It is the other constraints that kick in during the learning process such as interest in learning the fractions (aka driver’s willingness to drive) that determine the ultimate success. The tank size isn’t what determines the success, it just makes the journey easier for some than others.
The most common measures we discuss when considering IQ are representative of essential capacity. These models fall apart when we find something exponential. This month we will look at both the models you are most likely familiar with and the extremes in order to get to the nugget of what - if anything - is important about IQ.
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