är på nedgång
The dark blue line is the average IQ of the world. I've also plotted the population growth of the five most populous countries, India, China, the U.S., Indonesia, and Nigeria; the average IQ of each of these countries is in parenthesis. (Nigeria is currently ninth, with Brazil (87), Pakistan (81), Russia (96), and Bangladesh (81) intervening, but by 2050 it will be fifth.) As you can see, in a 100 year period the world's average IQ will have dropped from 92 to 86, a change of 6%. That is pretty darn significant. And all because of differential population growth.
I extrapolated the population growth of each country another 50 years to the year 2100 (lightly shaded region of graph). At that time the world's average IQ will have dropped below 84. Within this time period of 150 years, extremely short by any evolutionary standard, an incredibly significant change in this key metric will have occurred. And there is no sign of the trend bottoming out, because the growth rate of countries with lower IQs exceeds the growth rate of countries with higher IQs. The most populous country today is China, which has a high IQ (100), but its growth is actually projected to be negative because of their "one child" policy. After about 2030 India will be the most populous country, and it has relatively low IQ (81). At current growth rates by 2100 Nigeria will be the third most populous country, and it has a low IQ (67). 1
Detta är inte speciellt förvånande: medan människor av medel till låg IQ reproducerar sig i höga antal, spenderar människor med hög IQ sin tid på arbete och karriär, och på så vis minskar mängden intelligenta människor i samhället som helhet.
The German public was recently shocked to learn that 30% of "their" women are childless — the highest proportion of any country in the world. And this is not a result of infertility; it's intentional childlessness.
It is notable that child-wariness is not only characteristic of highly developed Germany (and northern Europe as a whole), but that it rises from 30% to more than 40% among German women who are college graduates. 2
Med sådana här studier, som gång på gång visar hur människan kan avla sig ner till samma intelligensnivå som schimpanser, blir argumenten mot rashygien och familjeplanering färre och mindre trovärdiga.
1 Gene Expression, "IQ and Populations"
2 Los Angeles Times, "Sex is essential, kids aren't"