I've also demonsrated that high intelligence people have the undesirable characteristic of being less athletic.
The United States clearly has a dysgenic breeding pattern today. Each generation is about 1/10 of a standard deviation less intelligent than the previous. This doesn't sound like much, but over the course of another century it will probably mean the collapse of democracy in the United States, because another hundred years of dysgenic breeding will bring the average IQ of the United States to the level of countries where democracy doesn't work very well.
The interesting question is, if high intelligence creates a survival disadvantage, how did the human race become so intelligent? For how long has intelligence been decreasing?
My theory is that, before the safety nets and advanced healthcare of modern civilization, the less intelligent and their children had a greater chance of dying. War, famine, disease, and accidents killed a greater share of the less intelligent, more than making up for their greater fertility. But at the same time, higher intelligence people still had less children, preventing the human race from becoming smarter. So mankind reached an evolutionary stable average level of intelligence.
The evolutionary stable average level of intelligence varied by civilization, because the rules set up by society might favor higher or lower intelligence. But each civilization would reach its own evolutionary stable level in which the average intelligence members of society had, on average, the most surviving children.
This theory would explain why highly intelligent people are less attractive to the opposite sex compared to people of average intelligence. If people of average intelligence were predicted to have the most surving children, then favoring sex partners whose intelligence is above or below the average would lead to having fewer surviving children. This theory perfectly explains my chart which shows that unmarried General Social Survey respondents with a Wordsum score of 6 (the median score) were the least likely to have gone the preceding year without sex. People of average intelligence have the easiest time attracting sex partners. Men in the highest IQ category are the most likely to have to pay a prostitute in order to get sex.