(This post is mostly quotes from Cosma Shalizi’s book review of James Flynn’s What is Intelligence? Beyond the Flynn Effect.
What is the Flynn effect?
In every country where we can find records of consistent IQ tests given to large numbers of people, scores have been rising as far back as the records go, in some cases to the early 20th century, and by large amounts, sometimes (e.g., for draftees in the Netherlands) as much as twenty IQ points every thirty years.
How did the Flynn effect get unnoticed for so long?
By convention, IQ tests are designed so that the mean score is 100 points, the standard deviation is 15 points, and the scores follow a Gaussian probability distribution, the now-infamous bell-shaped curve. At least, all of this is true of a norming or reference sample of test-takers, when the test is put together; they are hoped to be representative of future test-takers. Scores on individual questions are weighted and added up, and then transformed, as the distribution of raw scores is quite skewed rather than symmetrically bell-shaped. In essence, the IQ scores of future test-takers is computed by seeing where their raw scores fall in the distribution of the original reference sample, and reading off the corresponding Gaussian value. There are wrinkles — e.g., some test-makers set the standard deviation to be 16 or even 24 points — but those are the basics.
Two test-takers who give exactly the same set of answers to the same questions can thus get different IQ scores, if they are normed against different reference samples. Test-makers periodically re-norm their tests against new samples, keeping the mean at 100, but that mean score can represent very different levels of absolute performance.
Flynn’s discovery came from intelligence tests which had been consistently given with the same sets of questions over time, and where the raw scores had been recorded. What he found is that someone who gets an IQ score of 100 today gets more questions right than did someone who got a score of 100 in 1950, who in turn answered more right than did someone with a score of 100 in 1900. The exact rate of gain depends on the country and on the test, from a high of 6–7 IQ points per decade to a low of only a few points over a half-century. A rough summary is that measured IQ has been rising at, conservatively, 3 points per decade for as far back as the data go, across the industrialized world.
This rate is enough that someone who had an IQ of 100 in 1900 would have had an IQ of only 70 in 2000 — low enough to be classified as mentally retarded, and so, in the US, exempt from capital punishment, as being incapable of fully understanding their own actions.
What are some attempted explanations for the Flynn effect which get dismissed in the book?
A number of explanations have been suggested for the Flynn effect, most of which Flynn swats down with little trouble. It is just too large, too widespread, and too steady, to be due to improved nutrition, greater familiarity with IQ tests, or (a personal favorite) hybrid vigor from mixing previously-isolated populations, all of which have been seriously proposed. Nobody seems to have bit the bullet and suggested that modern societies have natural or sexual selection for higher IQ; but the numbers wouldn’t add up in any case.
The Flynn effect seems to imply at least one of two things: either our ancestors of a century ago were astonishingly stupid, or IQ tests measure intelligence badly.
What’s Flynn’s thesis for why the Flynn effect happens? It’s the “IQ tests are culturally biased” answer, but he fleshes it out in the only way I’ve seen that’s actually substantive:
Flynn contends that our ancestors were no dumber than we are, but that most of them used their minds in different ways than we do, to which IQ tests are more or less insensitive; we have become increasingly skilled at the uses of intelligence IQ tests do catch. Though he doesn’t put it this way, he thinks that IQ tests are massively culturally biased, and that the culture they favor has been imposed on the populations of the developed countries (and, increasingly, the rest of the world) through a far-reaching, sustained and successful campaign of cultural imperialism and social engineering.
This can be seen in Flynn’s discussion of a hypothetical, but typical, test question: “How are rabbits and dogs alike?”
Answers like “both are raised on farms”, “both come in breeds with different colors”, “both are eaten by people in some parts of the world and kept as pets in others”, “both have claws”, “both can destroy gardens”, and Flynn’s example answer, “you can use dogs to hunt rabbits” are true, but not what IQ testers look for. (Even the answer “they’re not alike, in any way that matters” could be sensibly defended.)
The test-makers want you to say “both are mammals”. What the testers look for, in other words, is not knowledge of the concrete world or of functional relationships, but mastery of one set of abstract concepts, which the test-makers themselves have internalized as highly-trained scientific professionals and literate intellectuals.
To generalize (ha!) from the above illustrative example — this quote is also the reason for this blog post:
All thought involves some degree of abstraction, but IQ testers, like intellectuals in general, tend to value abstraction as such. As well as preferring answers which show familiarity with our current scientific concepts, IQ tests also reward certain kinds of problem-solving abilities, what Flynn describes as solving “problems not solvable by mechanical application of a learned method” (p. 53; I don’t think he really means to deny the possibility of AI). Prime examples, to his mind, are things like tests of similarities and analogies, and pattern-completion tests like Raven’s Progressive Matrices. In the latter, each question consists of a series of line drawings, followed by a choice of several extra drawings from which the test-taker is supposed to pick the one that completes or finishes the sequence. (See here for an example.) Raven hoped that his test would be a fairly pure measurement of ability to “educe relations”, i.e., to discover patterns, which he regarded as the essence of intelligence. Raven’s test is often said to be subject to little or no cultural bias (a claim resting on basically no evidence whatsoever). Yet it is on tests of this type that the Flynn effect is strongest, 5 points per decade at the least. Below them come similarities and analogies tests of the rabbit/dog kind. Scores on vocabulary, arithmetic and general-information tests, on the other hand, show the lowest rates of improvement, and even some small declines.
Flynn refers to these transformations in how we think as “liberation from the concrete” and “putting on scientific spectacles”. His claims that the Flynn effect is a consequence of the changes in how people live and what skills they cultivate brought about by the industrial revolution. We now overwhelmingly keep dogs as pets, not to hunt, and we go to schools where we are not just taught to read but to think abstractly, and to use a common set of abstractions. Flynn refers here to the well-known work done by the great Soviet psychologist A. R. Luria in the 1930s, described in the latter’s Cognitive Development: Its Social and Cultural Foundations
(1974). Luria claimed to show, by means of fieldwork among peasants and nomads in Uzbekistan, that the kind of abstract reasoning skills Flynn points to developed in tandem with literacy, schooling, and participation in the modern economy. While Luria’s work has flaws (an Uzbekistani peasant who had abstract reasoning skills, confronted in the 1930s by a Russian Communist official asking them strange and leading questions, had many excellent reasons to play dumb), his findings are broadly consonant with later work on cross-cultural psychology.
At a larger scale, there is a connection, which Flynn does not draw, to the investigations of historians and sociologists into links between industrialization, nationalism and schooling. Americans may recall that our public schools were consciously used to make this country a melting-pot, to turn the descendants of immigrants from dozens of countries with many languages and cultures into a more-or-less unified people. Similar processes took place in the late 19th and early 20th centuries in all the developed countries — and, somewhat later, took off in the rest of the world. Governments and educated classes sought, in historian Eugen Weber’s phrase, to turn “peasants into Frenchmen” — or into Dutchmen, Germans, Italians, Poles, Serbs, Russians, etc.; at the time Luria worked, the Soviet government was busy turning peasants into Uzbeks.
Out of the blooming, buzzing confusion of local dialects and traditions, intellectuals invented (or, as they saw it, codified) standardized literary languages and “ancient folk customs”, which they then propagated through state-organized universal education and the new mass media. Simultaneously, they took modes of thinking which previously had been the reserve of their own small minority of literate specialists and made them part of everyone’s education. As the sociologist Ernest Gellner emphasized, this was not just an exercise in cultural domination. An industrial economy constantly creates new jobs and destroys old ones, so learning a trade, probably one’s father’s, by immersion from childhood won’t work any longer; more generic and so more abstract training is required. In an industrial society, people constantly face strangers and novelties. Action then cannot be guided by custom and familiar context, but instead by explicit impersonal rules, cultural conventions shared across whole countries rather than single villages, and original thought and decision. An industrial society is one in which the whole economically effective population has to deal with machines and with written communications, again with minimal help from context, and where a large fraction of workers must have some mastery of the abstract, scientific concepts which make industrial technologies comprehensible. Finally, in an industrial society everyone routinely deals with large bureaucracies (when privately owned we call them “corporations”), and actually most people work within them. All of this points towards not just standardized and literate cultures, but also one which reward abstract thinking, and even more a change of atitudes, to be willing or even eager to follow arbitrary-seeming abstract rules with no immediate point or relevance, just because a person in authority tells you to do so.
Again, this did not create new ways of thinking so much as spread ones which had existed for a few millennia but been very rare. If you had asked medieval scholars like Averroes or William of Ockham “how is a rabbit is like a dog?”, they would have replied that rabbits and dogs are both species of the genus “quadruped animals”. (Ockham might have quibbled about the difference between names and things.) They were already “liberated from the concrete”, but they used a somewhat different system of abstractions than we do. William Gibson once said that “the future is already here, it just isn’t widely distributed yet”; the same was once true of this aspect of the present.