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What Is Intelligence?


  • 5 tables
  • Page extent: 274 pages
  • Size: 228 x 152 mm
  • Weight: 0.44 kg
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 (ISBN-13: 9780521741477)

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What Is Intelligence?
Cambridge University Press
9780521880077 - What Is Intelligence? - Beyond the Flynn Effect - By James R. Flynn

1    A bombshell in a letter box

The special function of scientific explanation is . . . to turn the unexpected, as far as possible, into the expected.

(Stephen Toulmin, Reason in ethics, p. 88)
I am a teacher and rarely write for specialists alone. I have tried to avoid the dead-stick prose so beloved by journal editors. Anyone with a good education or a major in psychology should be able to read this book and the former is more important than the latter. It assumes that everyone is interested in intelligence and would like something exciting to provide a reason to learn more about it. Specialists will find that much has been omitted but will also, I hope, find something new in the argument and something worth pursuing in the research designs recommended.

A warning for everyone: there are problems that can simply be settled by evidence, for example, whether some swans are black. But there are deeper problems that pose paradoxes. Sometimes the evidence that would solve them lies in an inaccessible past. That means we have to retreat from the scientific level of explanation to the historical level where we demand only a plausibility that conforms to the known facts. I believe that my efforts to resolve the historical paradoxes we will discuss should be judged by whether someone has a more satisfactory resolution to offer. The reader should be wary throughout to distinguish the contentions I evidence from the contentions to which I lend only plausibility.

“The Flynn effect” is the name that has become attached to an exciting development, namely, that the twentieth century saw

massive IQ gains from one generation to another. To forestall a diagnosis of megalomania, the label was coined by Herrnstein and Murray, the authors of  The bell curve, and not by myself. I have never done any studies of IQ trends over time in the sense of actually administering tests. Of those who had measured IQ gains here or there, Reed Tuddenham was the first to present convincing evidence using nationwide samples: he compared the mental test scores of US soldiers in World Wars I and II and found huge gains. Had I thought of attaching a name to the phenomenon, I would have offered his.

About 1981, it struck me that if IQ gains over time had occurred anywhere, they might have occurred everywhere and that a phenomenon of great significance was being overlooked. Therefore, I began a survey to see what data existed throughout the developed world. It was on a rather dull Saturday in November 1984 that I found a bombshell in my letter box.

It was data from the distinguished Dutch psychologist P. A. Vroon and some things were evident at a glance. Although Vroon had not developed the techniques to measure them, young Dutch males had made enormous gains in a single generation on an IQ test of forty items selected from Raven’s Progressive Matrices. The sample was exhaustive. Raven’s was supposed to be the exemplar of a culturally reduced test, one that should have shown no gains over time as culture evolved. These 18-year-olds had reached the age at which performance on Raven’s peaks. Therefore, their gains could not be dismissed as early maturation, that is, it was not just a matter that children today were about two years ahead of the children of yesterday. Current people would have a much higher IQ than the last generation even after both had reached maturity.

Over a period of twelve months, I was bombarded with data from another thirteen nations all of which showed huge gains. Today the total is almost thirty and includes data from developing nations as well. Our advantage over our ancestors is

relatively uniform at all ages from the cradle to the grave. Whether these gains will persist into the twenty-first century is problematic, at least for developed nations. But there is no doubt that they dominated the twentieth century and that their existence and size were quite unexpected. The very fact they occurred creates a crisis of confidence: how could such huge gains be intelligence gains? Either the children of today were far brighter than their parents or, at least in some circumstances, IQ tests were not good measures of intelligence. Paradoxes started to multiply. Now read on.

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