Book review

Why intelligence-testing is a dumb idea

The Globe and Mail, September 15, 2007

A Smart History of a Failed Idea

IQ: A Smart History of a Failed Idea
By Stephen Murdoch
Wiley, 269 pages, $29.99

If you're like me, you don't like IQ tests. For one thing, you find it objectionable that someone thinks they can quantify your smarts that way, especially with the kinds of inane questions typically found on these exams. For another, the tests never seem to yield a score quite high enough, the way a cheap set of bathroom scales never produce a weight quite low enough, so you don't want to put too much faith in it. And according to U.S. writer Stephen Murdoch's intelligent new book on the subject, you're right to be skeptical.

IQ: A Smart History of a Failed Idea explores how we've become obsessed with trying to measure innate intelligence, and all the many ways that quest has gone wrong. The history kicks off with Francis Galton, the famous British eugenicist. He put together a booth for the London International Health Exhibition of 1884, where he measured people's physical attributes, things like height, hearing and the speed of your punch. He believed that physical superiorities were linked to mental ones (the latter revealed by a person's place in society) and he wanted to prove it. No correlation was ever found, but the enthusiasm for measuring mental acuity caught on.

The first tests were used to try to distinguish between different grades of mental retardation in French and U.S. institutions. It was important to know, because people increasingly believed that there was a single gene for "feeble-mindedness," and if you could prevent the stupidest people from reproducing, they argued, the world would be a better place.

A 1912 bestseller, The Kallikak Family: A Study in the Heredity of Feeble-mindedness, which centred on one supposedly feeble-minded woman and her family, provided compelling support. That is, until you consider how the evidence was gathered: Author Henry Herbert Goddard "based his research for the book largely on the work of a zealous and imaginative fieldworker he employed for years named Elizabeth Kite, a woman who rather dubiously managed to ascertain the intelligence of 480 of the girl's relatives, most of whom were dead.

Kite's methods were indirect in the extreme: She often couldn't administer IQ tests to Kallikak's relations directly, so she ascertained and defined intelligence by their behaviour. If even this were not possible, she relied on mere reputation for behaviour and ability. To gather this information, Kite zigzagged across New Jersey interviewing living Kallikaks and, to gauge the intelligence of the dead, she relied on families' memories, written records of occupation, marital status, health and even, in one instance, on the condition of heirloom furniture."

Despite the lack of rigour in the field, intelligence tests became popular. They were used to help decide not just whom to sterilize, but also who among the immigrants arriving at Ellis Island to send home. It was the First World War, however, that catapulted intelligence testing into the mainstream. Psychologists persuaded the army that it needed a way to assess incoming recruits and to decide which ones should become officers.

Almost overnight, a test meant for individuals was transformed into a test for a large groups. Since so many recruits couldn't read, there was both an "alpha," or written test, and a "beta," or picture-based version.

If that's all beginning to sound a little familiar - all those weird pictures, of rabbits missing ears that you're supposed to draw in, and forms that need to be matched up - yes, you're right, they hail from the day when illiterate conscripts had to be graded as they entered the army.

The truth is, the IQ test hasn't changed very much since it was first invented way back when by the eugenicists. In fact, one of the most popular IQ tests these days, the WAIS-III (for Wechsler Adult Intelligence Scale III; David Wechsler was a young test administrator during the First World War), comes almost entirely from that era. Of its seven verbal subtests, Murdoch tells us, no fewer than six are derived from either a 1916 test or one developed during the war. Four of seven non-verbal tests are from wartime. Jigsaw puzzles, picture arrangements, picture completions, you name it - all from long, long ago.

We all know what happened next: The tests made their way into schools. They have been - and continue to be - used to funnel kids into or away from Ivy League universities, private schools and even elite kindergartens. But despite the fact that one psychologist proclaimed that "the limits of a child's educability can be accurately predicted by mental tests in the first year," there appears to be no evidence that such is the case.

If you were to suggest that foot size at the age of three predicts height at adulthood, you'd have a way to confirm that. But how do we verify if IQ tests accurately predict anything? Because, although psychologists believe they're measuring "intelligence," there's never been any real consensus on what that is. None of the original formulators of the tests even had a clear theory about it. Historically, IQ tests have been pronounced accurate simply by turning up the same results as other IQ tests, or having matched up with teacher assessments or with "officer opinion." There are other reasons to be suspicious. For one thing, it seems that our "innate" intelligence is growing by leaps and bounds with each generation. Could it be that IQ tests aren't, as psychologists claim, measuring some basic brain power, but rather learned knowledge? Hmm. And then there's the fact that a person's own score can change quite dramatically, depending on everything from your socioeconomic situation to how much you slept the night before.

This becomes especially egregious when you consider how these tests are used by the law. Murdoch details the case of a man convicted of murder and who, with a low enough score, could be spared the death penalty. As the man learns more about the workings of the legal system, however, in order to defend himself, his IQ improves, rendering him eligible to die.

Murdoch relays the history artfully, with relevant case studies and details. I do wish he had included an appendix with entire tests as examples, though. And there was a chapter missing that would have explained what scores supposedly mean.

But read this book, and when you're done, mail it to someone who needs it more than you: a local registrar, a school administrator or anyone who's ever boasted about an IQ test score.