Intelligence may be hard to define, but there's one thing you can be sure of after reading Ken Richardson's "The Making of Intelligence": Whatever it is, psychologists don't have much of it. Psychology is a "backwards discipline," according to Richardson, who paints a picture of Laurel-and-Hardyesque psychologists who "seem to heave a sigh of relief when they feel they can attribute something to a genetic code ('Whew, I'm glad that that's off my mind')." Richardson outlines the confused, as he sees it, history of intelligence studies, from the early 20th century crackpots who explained poverty as a function of natural intelligence (some have it, some don't, tough luck) to developments in modern cognitive science such as the battery of new surgical and imaging techniques for exploring the brain. He advances an alternative theory that sidesteps the differences between individuals and focuses on the intelligence of the human species as a whole. Everyone is intelligent, he says; what a person scores on an IQ test is far less important than why the species has evolved the particular mental abilities it has. Not surprisingly, he makes an impassioned case for abolishing IQ altogether.
Ever since Charles Spearman, a British psychometrist, came up with the idea of "g," an innate, measurable general intelligence, the idea of "mental aptitude" has been a thorny topic. Researchers disagree about whether it's genetically determined and about how many separate components it's made up of (theories range from two through 70). For his part, Richardson dismisses Spearman's "g" and its conceptual cousins as acts of imagination, and for good measure he points out the famed statistician's bad math.
According to Richardson, IQ tests do not measure fixed cognitive ability but rather cultural background, education and, to some degree, confidence. General knowledge questions on IQ tests are clearly culturally biased, but even supposedly culture-neutral logical items, such as "All A's are B's/Are all B's A's?" elicit more correct responses if couched in more familiar language. Richardson shows how even nonverbal questions that require the completion of line drawings carry cultural baggage that can prefigure the testee's response. What's more, he points out that various studies have found little or even negative correlation between performance on an IQ test and the ability to solve complex, on-the-job problems.
Most interesting is Richardson's take on the factors that shape individuals and their intelligence. Human potential, he explains, is always a complex matrix: Contrary to the popular notion that a person is a genetic framework that is simply overlaid with environmental effects (nutrition, education, the love of a good mother), there are many ways nature and nurture interact to produce an individual or a characteristic like intelligence.
Some of Richardson's criticisms are familiar (many were outlined 20 years ago in Stephen Jay Gould's "The Mismeasure of Man"), but they are still relevant. As he points out, we've seen several modern attempts to use IQ as a "weapon of social policy," such as Richard J. Herrnstein and Charles Murray's controversial 1996 book, "The Bell Curve."
"The Making of Intelligence" draws from many sources, and this broad sweep is both the book's strength and its weakness. It gives the reader access to slices of thought from linguistics, philosophy, biology and neuroscience. But Richardson's jostling sound bites are often wide of the mark: for instance, his take on the field of linguistics, which he presents, wrongly, as completely dominated by an oversimplification of Noam Chomsky's theories.
And, unfortunately, he doesn't address in any satisfying way the question of why, if IQ is culturally determined, obvious IQ differences are found within the same socioeconomic group. This is disappointing, since these differences help explain why people are so willing to believe that an IQ score is an indelible intelligence brand. As things stand now, once that number has been burned into your rump, it can feel like you're marked for life. "The Making of Intelligence" is unlikely to change that, but it's an admirable attempt.