Flynn came to Manhattan to debate Charles Murray at a forum sponsored by the Manhattan Institute. Their subject was the black-white I.Q. gap in America. During the twenty-five years after the Second World War, that gap closed considerably. The I.Q.s of white Americans rose, as part of the general worldwide Flynn effect, but the I.Q.s of black Americans rose faster. Then, for about a period of twenty-five years, that trend stalled—and the question was why.
Murray showed a series of PowerPoint slides, each representing different statistical formulations of the I.Q. gap. He appeared to be pessimistic that the racial difference would narrow in the future. “By the nineteen-seventies, you had gotten most of the juice out of the environment that you were going to get,” he said. That gap, he seemed to think, reflected some inherent difference between the races. “Starting in the nineteen-seventies, to put it very crudely, you had a higher proportion of black kids being born to really dumb mothers,” he said. When the debate’s moderator, Jane Waldfogel, informed him that the most recent data showed that the race gap had begun to close again, Murray seemed unimpressed, as if the possibility that blacks could ever make further progress was inconceivable.
Flynn took a different approach. The black-white gap, he pointed out, differs dramatically by age. He noted that the tests we have for measuring the cognitive functioning of infants, though admittedly crude, show the races to be almost the same. By age four, the average black I.Q. is 95.4—only four and a half points behind the average white I.Q. Then the real gap emerges: from age four through twenty-four, blacks lose six-tenths of a point a year, until their scores settle at 83.4.
That steady decline, Flynn said, did not resemble the usual pattern of genetic influence. Instead, it was exactly what you would expect, given the disparate cognitive environments that whites and blacks encounter as they grow older. Black children are more likely to be raised in single-parent homes than are white children—and single-parent homes are less cognitively complex than two-parent homes. The average I.Q. of first-grade students in schools that blacks attend is 95, which means that “kids who want to be above average don’t have to aim as high.” There were possibly adverse differences between black teen-age culture and white teen-age culture, and an enormous number of young black men are in jail—which is hardly the kind of environment in which someone would learn to put on scientific spectacles.
Flynn then talked about what we’ve learned from studies of adoption and mixed-race children—and that evidence didn’t fit a genetic model, either. If I.Q. is innate, it shouldn’t make a difference whether it’s a mixed-race child’s mother or father who is black. But it does: children with a white mother and a black father have an eight-point I.Q. advantage over those with a black mother and a white father. And it shouldn’t make much of a difference where a mixed-race child is born. But, again, it does: the children fathered by black American G.I.s in postwar Germany and brought up by their German mothers have the same I.Q.s as the children of white American G.I.s and German mothers. The difference, in that case, was not the fact of the children’s blackness, as a fundamentalist would say. It was the fact of their Germanness—of their being brought up in a different culture, under different circumstances. “The mind is much more like a muscle than we’ve ever realized,” Flynn said. “It needs to get cognitive exercise. It’s not some piece of clay on which you put an indelible mark.” The lesson to be drawn from black and white differences was the same as the lesson from the Netherlands years ago: I.Q. measures not the quality of a person’s mind but the quality of the world that person lives in.
(and privileges certain worlds over others)