Dome Improvement, by Steven Johnson, explains the Flynn effect and why IQ test scores might be going up:
When Flynn finally published his work in 1984, Jensen objected that Flynn’s numbers were drawing on tests that reflected educational background. He predicted that the Flynn effect would disappear if one were to look at tests — like the Raven Progressive Matrices — that give a closer approximation of g [general intelligence], by measuring abstract reasoning and pattern recognition and eliminating language altogether. And so Flynn dutifully collected IQ data from all over the world. All of it showed dramatic increases. ‘The biggest of all were on Ravens,’ Flynn reports with a hint of glee still in his voice.
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When you take the Ravens test, you’re confronted with a series of visual grids, each containing a mix of shapes that seem vaguely related to one another. Each grid contains a missing shape; to answer the implicit question posed by the test, you need to pick the correct missing shape from a selection of eight possibilities. To “solve” these puzzles, in other words, you have to scrutinize a changing set of icons, looking for unusual patterns and correlations among them.This is not the kind of thinking that happens when you read a book or have a conversation with someone or take a history exam. But it is precisely the kind of mental work you do when you, say, struggle to program a VCR or master the interface on your new cell phone.
Over the last 50 years, we’ve had to cope with an explosion of media, technologies, and interfaces, from the TV clicker to the World Wide Web. And every new form of visual media — interactive visual media in particular — poses an implicit challenge to our brains: We have to work through the logic of the new interface, follow clues, sense relationships. Perhaps unsurprisingly, these are the very skills that the Ravens tests measure — you survey a field of visual icons and look for unusual patterns.