It is already evident to me, after reading the book [Does your Family Make You Smarter?], that the Flynn effect doesn’t settle as much as some of us thought or hoped it did. And that by 21st-century standards, perhaps Flynn doesn’t quite measure up as a liberal hero.
The answer to the question in the title, Flynn explains, is that your family environment’s effect on your IQ almost disappears by the age of 17. An important exception is in the vocabulary component of IQ tests, where the effect persists into the mid-20s and can make a big difference, at least in the US, to the chances of getting into a top university. The home has most influence in early childhood but is swamped by later environments at school, university and work. And they will more closely match your genes because you will seek out (and be chosen for) environments that match your “genetic potential”, whether it’s basketball, carpentry or mathematics.
I have many more questions but one in particular looms over discussions about IQ and we both know we can’t avoid it. It was, after all, to challenge the late Arthur Jensen, professor of educational psychology at the University of California, Berkeley — who claimed the genes of African Americans were responsible for their inferior IQ scores — that Flynn began to examine the evidence on intelligence. But a sentence from his new book is nagging away at me. American blacks, it says, “come from a cognitively restricted subculture”.
This is hugely sensitive territory because, while it may be good to say genes don’t make people stupid, it isn’t so good to tell anyone their way of life does. Flynn, however, makes no apologies. “It’s whites, not blacks, who complain,” he says. “Blacks know the score. Facts are facts.” On recorded IQ tests, he says, African Americans have persistently lagged behind most other ethnicities in America (including, according to some commentators, black immigrants from, for example, the Caribbean) and this cannot be explained by the Flynn effect since, as he puts it, “blacks don’t live in a time warp”.
He then tells what sounds like a version of those dodgy jokes about the Irishman, the Scotsman and the Englishman. Except this isn’t a joke. “Go to the American suburbs one evening,” says Flynn, “and find three professors. The Chinese professor’s kids immediately do their homework. The Jewish professor’s kids have to be yelled at. The black professor says: ‘Why don’t we go out and shoot a few baskets?’”
As I emit a liberal gasp, he continues: “The parenting is worse in black homes, even when you equate them for socio-economic status. In the late 1970s, an experiment took 46 black adoptees and gave half to black professional families and half to white professionals with all the mothers having 16 years of education. When their IQs were tested at eight-and-a-half, the white-raised kids were 13.5 IQ points ahead. The mothers were asked to do problem-solving with their children. Universally, the blacks were impatient, the whites encouraging. Immediate achievement is rewarded in black subculture but not long-term achievement where you have to forgo immediate gratification.”
He tells me of research showing that “when American troops occupied Germany at the end of the second world war, black soldiers left behind half-black children and white soldiers left behind all-white. By 11, the two groups had identical average IQs. In Germany, there was no black subculture.”
Flynn refuses to speculate about the lingering effects of slavery and subsequent discrimination that have prevented African Americans from entering colleges and professional careers. Universities, he thinks, should do more research on racial differences and a new version of that 1970s study. “I have shown — this wicked person who actually looks at the evidence — that blacks gained 5.5 IQ points on whites between 1972 and 2002. There’s been no changes in family structure [the incidence of single-parent families], no gains in income. I suspect it’s an improvement in parenting. But I can’t prove it.”
I leave that sunlit garden in a troubled frame of mind. Flynn has made a great contribution to human knowledge and understanding. But he hasn’t settled the nature-against-nurture debate — and I wonder if he is now muddying the waters, constructing theories about parenting from flimsy evidence.