Is Entire Human Race -- Not Just US Voters -- Getting Stupider?
...rather than getting cleverer, human intelligence peaked several thousand years ago and from then on there has been a slow decline in our intellectual and emotional abilities.Our Fragile Intellect -- PDF article by Gerald Crabtree discussing his theory
Although we are now surrounded by the technological and medical benefits of a scientific revolution, these have masked an underlying decline in brain power which is set to continue into the future leading to the ultimate dumbing-down of the human species...
...Life as a hunter-gatherer was probably more intellectually demanding than widely supposed, he says. “A hunter-gatherer who did not correctly conceive a solution to providing food or shelter probably died, along with his or her progeny, whereas a modern Wall Street executive that made a similar conceptual mistake would receive a substantial bonus and be a more attractive mate,” Professor Crabtree says. _Independent
From a newsrelease on the study:
"The development of our intellectual abilities and the optimization of thousands of intelligence genes probably occurred in relatively non-verbal, dispersed groups of peoples before our ancestors emerged from Africa," says the papers' author, Dr. Gerald Crabtree, of Stanford University. In this environment, intelligence was critical for survival, and there was likely to be immense selective pressure acting on the genes required for intellectual development, leading to a peak in human intelligence. From that point, it's likely that we began to slowly lose ground.On the other hand, there is the 10,000 Year Explosion hypothesis, which outlines how modern Ashkenazi Jews evolved into the most intelligent and productive -- in a scholarly sense -- of all modern populations.
With the development of agriculture, came urbanization, which may have weakened the power of selection to weed out mutations leading to intellectual disabilities.
Based on calculations of the frequency with which deleterious mutations appear in the human genome and the assumption that 2000 to 5000 genes are required for intellectual ability, Dr. Crabtree estimates that within 3000 years (about 120 generations) we have all sustained two or more mutations harmful to our intellectual or emotional stability. Moreover, recent findings from neuroscience suggest that genes involved in brain function are uniquely susceptible to mutations.
Dr. Crabtree argues that the combination of less selective pressure and the large number of easily affected genes is eroding our intellectual and emotional capabilities. _MXP
According to the 10,000 Year Explosion, civilisation actually accelerated human evolution in good ways.
And don't forget the "Lynn - Flynn Effect" (first discovered by Richard Lynn, but grand-standed by James Flynn). According to Flynn's interpretation, in some ways, modern humans are becoming more intelligent than their immediate ancestors, in terms of IQ test scores, at least.
But if we step back from the more focused viewpoints of Crabtree, Cochran & Harpending, and James Flynn, and look at the species as a whole, we see that the global IQ actually is decreasing -- but for different reasons than given above.
Because of differential birthrates between persons of high intelligence and persons of low intelligence, offspring from low IQ matings are much more numerous than offspring from high IQ matings -- and becoming exponentially more so over time.
There is nothing mysterious about this mechanism for the dumbing down of the species, although there is a great deal that is politically incorrect about it -- which is why you will not see it being taught in government schools anytime soon.
If you haven't seen the film Idiocracy, consider looking it up. It would be worth it just for the first 5 or 10 minutes. Here is a preview:
Pay attention to the family tree for the two featured family groups. Notice how the one family tree grows exponentially, while the other withers away.
Regardless, those who are concerned about the intermediate and long term future of the human species will need to pay attention to all levels of demographic change, from the molecular to the national and global.
And then there is the concern over a decline in the number and quality of human sperm -- popularly depicted in the book and film, The Children of Men. While recent Danish research tends to have refuted the idea of a decline in human sperm, males who produce prolific amounts of high quality sperm may be able to supplement their incomes as sperm donors. BTW, at the blog Al Fin, You Sexy Thing!, our writers take a look at the phenomenon of Semen Therapy, a new way for young men to pay their way through college.
The most significant force which is likely to counter-act any natural decline in human intelligence, is the fact that a lot of smart people want to become smarter. And since the genetics of cognition is approaching the stage where humans may be able to intervene to make new generations of humans more intelligent, the possibility of the "engineered evolution of cognition" is becoming a bit more probable as western science progresses.
There are many forces at work shaping the evolution of humans on planet Earth. We should not assume that evolution naturally leads to greater fitness or sophistication. Natural selection would be just as happy to see humans dumbed down as to see them grow smarter. Most corrupt politicians would prefer to see them dumbed down -- they are easier to manipulate that way.