Are Humans Getting Dumber as Our Brains are Shrinking?

Did you know that our brains are actually shrinking? reported, “Cro-Magnon man, who lived in Europe 20,000 to 30,000 years ago, had the biggest brains of any human species.  In comparison, today’s human brain is about 10 percent smaller.”

The human brain is still an enigma is many respects.  Are there differences in the human brain that cause people like Einstein to achieve so much?  Studies were completed on Einstein’s brain and they actually found he had some differences.  There is speculation that due to the way that Einstein’s brain was missing a part of a bordering region, that this enabled neurons to communicate more efficiently.  

With all of the technological inventions, one might think that people should be getting smarter. However, in the NPR article, this decreasing in brain size may have a negative impact, “The experts aren’t sure about the implications of this evolutionary trend.  Some think it might be a dumbing-down process. One cognitive scientist, David Geary, argues that as human society grows increasingly complex, individuals don’t need to be as intelligent in order to survive and reproduce.” 

If this is true, the movie Idiocracy may be foreshadowing some frightening possibilities.  The movie displays what life would be like if people continue on their current path of finding entertainment in reality shows, tattooing, partying and enjoying other less than useful activities.  This movie seemed to play off of studies done by Lentz in 1927 that claimed the intelligent people were having fewer children than the less intelligent people.  This would lead to a society of less intelligent people.  The Examiner claims Lentz’s work has merit, stating “This conjecture has been confirmed by studies like that of Hernstein and Murray (1994), who demonstrated that in the U.S. females with an average IQ of 111 had 1.6 children, whereas females with an average IQ of 81 had 2.6 children.”

The Examiner claims that there is hope for improvements, though, due to something called the Flynn effect. “Even if genotypic IQ is heading towards a decline across the world, there is still phenotypic intelligence that has increased over the last few generations. This phenomenon, also known as Flynn effect, is attributable to advancements in nutrition, education, and a more intellectually stimulating environment. The Flynn effect has led to gains of 7.5 IQ points a generation, much greater than .43 IQ points decline in genotypic IQ.”
There is something called Spearman’s g that refers to one’s general intelligence that was postulated in 1904 by Charles Spearman.  g, written in lower case like, now refers to general intelligence. A neuroscientist named John Duncan explained Spearman’s work in his book How Intelligence Happens.  The Wall Street Journal explained, “Mr. Duncan makes a convincing case that these brain areas constitute a special circuit that is crucial for both Spearman’s “g” and for intelligent behavior more generally. But his book elides the question of whether this circuit is also the source of IQ differences. That is, do people who score high on IQ tests use the frontal and parietal areas of their brains differently from people who score lower? The answer, discovered by other researchers, turns out to be yes.”

It appears that our brains are decreasing in size, more people with lower IQ scores are having children, but we can increase our education and nutrition.  We can also learn more about how our frontal and parietal areas can be improved.  There is hope that we are not necessarily headed for an Idiocracy-like future.

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