Evolutionary Novelty and General Intelligence
From Kanazawa (2007, 314-15):
I do not believe that general intelligence is domain-general in its origin. It evolved instead to solve problems in (originally) very narrow domains of life that presented evolutionarily novel problems. Much of life in the ancestral environments was stable, predictable, and recurrent, so general intelligence should not have been particularly important there.
My theory explains why general intelligence does not help us solve evolutionarily familiar problems, such as finding and keeping mates, parenting, socializing with friends and family, and finding our way home. General intelligence has become an important predictor of success in modern life only because our environments have radically changed over the last 10,000 years and most problems that we encounter today are evolutionarily novel. In other words, the fact that general intelligence is so general today is the result of an accident of human evolutionary history.
I have elsewhere argued that the human brain, adapted as it is to the conditions of ancestral environments, has difficulty comprehending and dealing with entities and situations that did not exist in the ancestral environment (Kanazawa, 2004). For example, because realistic images of other humans, such as photographs, films, videos, and television, did not exist in the ancestral environment, our brain implicitly interprets all such images as real. As result, people who watch certain types of television shows frequently are more satisfied with their friendships, as if they had more friends or socialized with them more regularly (Kanazawa, 2002). Our brain may assume that all realistic images of other humans we encounter repeatedly and who don’t kill or hurt us, such as television characters, are friends.
If general intelligence evolved to solve evolutionarily novel problems, and if the human brain has difficulty dealing with evolutionarily novel entities and situations, then it follows that those who have greater general intelligence should possess a greater ability to comprehend such evolutionarily novel entities and situations than those who have less general intelligence. For example, intelligent individuals should have less of a tendency to confuse their “TV friends” with real friends. Indeed, this appears to be the case. The effect of watching television on satisfaction with friendships. . . is largely limited to those who have less than median intelligence. The frequency of watching television has no apparent effect on satisfaction with friendships among men and women above median intelligence (Kanazawa, 2006).
As another example, it turns out that general intelligence does have an effect on the evolutionarily familiar problem of reproduction if it involves evolutionarily novel entities such as modern contraception. Less intelligent individuals have more children than do more intelligent individuals, despite the fact that they do not want or desire to, because they have greater difficulty with the evolutionarily novel means of modern contraception. Reproduction is a more direct function of sexual activities among the less intelligent than among the more intelligent; in fact, the larger the number of sexual partners more intelligent individuals have had, the fewer children they have (Kanazawa, 2005).
The effect of general intelligence on the human ability to comprehend evolutionarily novel entities and situations can also explain why criminals on average have lower intelligence. Much of what counts as crime today, such as theft and interpersonal violence, may have been routine means of solving adaptive problems in the ancestral environments but is now proscribed by evolutionarily novel entities such as written laws, the police, and the judicial system. Perhaps those with lower intelligence unconsciously fail to comprehend these entities and resort to evolutionarily familiar (but now illegal) means to solve their adaptive problems.
(Emphasis in original, some internal citations omitted).