Years later, when the adolescents were in their 20s, they were interviewed again, and at that time they were indeed asked about their values. By linking their answers to their performance in the IQ tests, Kanazawa came up with the support for his argument.
The higher the intelligence in junior high and high school, "the more liberal they grow up to be in their early adulthood," he concluded. Likewise, for their belief in God. The brighter kids accepted the "evolutionarily novel" concept of no god, or at least they described themselves as caring very little or not at all about religion.
But what about that claim that bright guys, though not necessarily bright gals, value fidelity -- or "exclusivity," as Kanazawa put it -- in their relationships? Again, he found that the data supported his theory.
Throughout our ancient past, he says, humans have had a "mildly polygamous" evolutionary history. It was OK for a guy to have several females in the clan, so it wasn't important for him to be faithful to any one of them.
But the females were expected to remain faithful. Thus, for a man to value marital fidelity is "evolutionarily novel," but it wouldn't be novel for a woman to hold the same value because she historically has been expected to.
Again, Kanazawa found that smarter males valued "exclusivity" more than their less intelligent colleagues, but higher intelligence had no effect on the women's values, just as he had hypothesized.
The IQ difference was not all that great -- around 103 for the smarter kids and 97 for the lesser lights, but Kanazawa insists the difference is "statistically significant."
He concedes there is something of a problem with that data. The participants were all in their twenties, and "the findings from them may or may not generalize to all Americans across generations," he adds.
That's a reasonable point, considering that many of us probably hold very different values from those that we held in our twenties, before we fully entered the labor force, started our families, went off to war, and took a serious interest in politics.
So Kanazawa turned to a second study, conducted since 1972 by the National Opinion Research Center at the University of Chicago, called the General Social Surveys. Intelligence is measured by how each respondent answers 10 questions in which they are asked to select a synonym for a word out of five candidates.
They were also asked to select which position most closely matched their own. For example, for religiosity, the statements ranged from "I don't believe in God" to "I know God really exists and I have no doubts about it."
Again, Kanazawa found the answers that fit his theory. Participants "who are more intelligent are significantly more liberal than those who are less intelligent."
"More intelligent individuals have a significantly weaker belief in God." So not just bright kids, but brighter adults, as well, tend to be more politically liberal and less religious, he concludes.
It's safe to say that anyone who reads this is going to have many doubts about Kanazawa's findings. We all know too many exceptions.