Test sophistication

What I put up yesterday about IQ was preparatory to what I want to say today. I have been thinking about the Lynn effect -- which is usually called the Flynn effect -- after its main publicist -- James Flynn. It was however discovered by Richard Lynn. What it refers to is the fact that average IQ test scores rose steadily thoroughout the 20th century. The process may however have reached an asymptote (peaked) now.

For a long time, I accepted that the rising scores represented a real increase in 'g' (underlying general intelligence). Two of my three very minor contributions to the academic literature on IQ were based on that view (See here and here). There were good reasons for that view. Nutrition does have a (usually small) effect on IQ and nutrition did improve over the 20th century. IQ can be influenced in some ways by general health -- and medical care did improve over the 20th century -- with improved perinatal care being an obvious candidate for positive effects. And signs that people were in fact better off physically were there -- an increase in average brain size particularly. And brain size does correlate to a degree (correlation of around .40) with IQ.

BUT: It seems that I was wrong. Although scores on all sorts of IQ subtests (puzzle categories) rose, they did not rise evenly. And the scores that rose least were for those problems that loaded most highly on 'g' (See e.g. here). The implication is that scores on a perfect measure of 'g' would not have risen at all.

So how do we explain the Lynn effect? There is no general agreement but I find the commonest explanation to be pretty persuasive -- that it reflects increasing test sophistication. Kids now spend MANY more years in the educational system than they once did and although there is probably little to show for that overall, kids DO get a lot of practice in passing tests of various sorts. And practice may not make perfect but it would be surprising if test-taking skills and strategies (such as guessing when you are not certain) were not improved by many years of extra practice at taking such tests.

(For more postings from me, see EDUCATION WATCH, GREENIE WATCH, POLITICAL CORRECTNESS WATCH, GUN WATCH, SOCIALIZED MEDICINE, AUSTRALIAN POLITICS and DISSECTING LEFTISM. My Home Page. Email me (John Ray) here.)

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