Wednesday, December 12, 2007

IQ Says What?

Here's an interesting read.

My students in a number of my classes are always trotting out the epic myth about how IQs have been dropping and test scores are plummeting and kids are getting stupider ever year. I love to slam back at them with, well, dudes, what about the Flynn effect, then?

Huh, what? they say.

Curious, Flynn sent out some letters. He collected intelligence-test results from Europe, from North America, from Asia, and from the developing world, until he had data for almost thirty countries. In every case, the story was pretty much the same. I.Q.s around the world appeared to be rising by 0.3 points per year, or three points per decade, for as far back as the tests had been administered. For some reason, human beings seemed to be getting smarter.

Flynn has been writing about the implications of his findings—now known as the Flynn effect—for almost twenty-five years. His books consist of a series of plainly stated statistical observations, in support of deceptively modest conclusions, and the evidence in support of his original observation is now so overwhelming that the Flynn effect has moved from theory to fact. What remains uncertain is how to make sense of the Flynn effect. If an American born in the nineteen-thirties has an I.Q. of 100, the Flynn effect says that his children will have I.Q.s of 108, and his grandchildren I.Q.s of close to 120—more than a standard deviation higher. If we work in the opposite direction, the typical teen-ager of today, with an I.Q. of 100, would have had grandparents with average I.Q.s of 82—seemingly below the threshold necessary to graduate from high school. And, if we go back even farther, the Flynn effect puts the average I.Q.s of the schoolchildren of 1900 at around 70, which is to suggest, bizarrely, that a century ago the United States was populated largely by people who today would be considered mentally retarded.

Well, as this essay (and Flynn) go on to say, nu-uh, obviously. Maybe we're getting smarter, a little, who knows. (I've read some explanations for the Flynn effect that argue that exactly.) But more likely (more likely, I mean, that we are that much smarter than our greatgrandparents) is that it's an artifact of the test.

The best way to understand why I.Q.s rise, Flynn argues, is to look at one of the most widely used I.Q. tests, the so-called WISC (for Wechsler Intelligence Scale for Children). The WISC is composed of ten subtests, each of which measures a different aspect of I.Q. Flynn points out that scores in some of the categories—those measuring general knowledge, say, or vocabulary or the ability to do basic arithmetic—have risen only modestly over time. The big gains on the WISC are largely in the category known as “similarities,” where you get questions such as “In what way are ‘dogs’ and ‘rabbits’ alike?” Today, we tend to give what, for the purposes of I.Q. tests, is the right answer: dogs and rabbits are both mammals. A nineteenth-century American would have said that “you use dogs to hunt rabbits.”

“If the everyday world is your cognitive home, it is not natural to detach abstractions and logic and the hypothetical from their concrete referents,” Flynn writes. Our great-grandparents may have been perfectly intelligent. But they would have done poorly on I.Q. tests because they did not participate in the twentieth century’s great cognitive revolution, in which we learned to sort experience according to a new set of abstract categories. In Flynn’s phrase, we have now had to put on “scientific spectacles,” which enable us to make sense of the WISC questions about similarities.

To say that Dutch I.Q. scores rose substantially between 1952 and 1982 was another way of saying that the Netherlands in 1982 was, in at least certain respects, much more cognitively demanding than the Netherlands in 1952. An I.Q., in other words, measures not so much how smart we are as how modern we are.

This is a critical distinction. When the children of Southern Italian immigrants were given I.Q. tests in the early part of the past century, for example, they recorded median scores in the high seventies and low eighties, a full standard deviation below their American and Western European counterparts. Southern Italians did as poorly on I.Q. tests as Hispanics and blacks did. As you can imagine, there was much concerned talk at the time about the genetic inferiority of Italian stock, of the inadvisability of letting so many second-class immigrants into the United States, and of the squalor that seemed endemic to Italian urban neighborhoods.

Why does this matter? Well, you can see if IQ tests don't work backwards -- if they didn't work then -- maybe they don't work now?

Maybe, then, this vaunted g folks like Charles Murray and the rest are always on about, which (oddly enough) shows rich white guys to be the smart ones in the pack and (oddly enough) poor black folk to be (geez, we can't help this, can we? it's science) irrefutably just dumb, no sense pouring dollars down that rathole, isn't really measuring anything that's actually there?

We already know tests like the SAT don't actually predict how students will do when they get to school. Some evidence exists to show that teachers will teach to how well they think a student will do -- being told a student is gifted, that is, they'll treat him as gifted, and he'll perform as such; told he's stupid, they'll treated him as stupid, and, guess what, he performs as such.

That steady decline [in black children's IQ scores as they grow older], Flynn said, did not resemble the usual pattern of genetic influence. Instead, it was exactly what you would expect, given the disparate cognitive environments that whites and blacks encounter as they grow older. Black children are more likely to be raised in single-parent homes than are white children—and single-parent homes are less cognitively complex than two-parent homes. The average I.Q. of first-grade students in schools that blacks attend is 95, which means that “kids who want to be above average don’t have to aim as high.”

So why does it matter?

It's like justice. Justice doesn't exist; but by acting as though it does, we change the world. Well, whether or not IQ exists, if we act as though it does, that changes the world as well.

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