Gene Mutations Lowering Human Intelligence | Natural Health Blog

Intelligence on the Decline

Human Intelligence

“I’m just another guy who thinks he’s smarter than he is, in a long line of them,” said comedian Colin Quinn.1 “Colin Quinn Quotes.” Brainy Quote. 20 February 2013. http://www.brainyquote.com/quotes/authors/c/colin_quinn.html The line that Mr. Quinn refers to might stretch all the way around the globe if Stanford University Professor Gerald Crabtree is to be believed–and we will talk about that a bit later. But first, let’s look at what Dr. Crabtree proposes. According to a paper published in Trends in Genetics, Dr. Crabtree says that people today are less gifted in the intelligence department than their grunting, club-bearing forebears.2 Barrett, Mike. “Leading Geneticist: Human Intelligence is Slowly Declining.” 17 February 2013. Natural Society. 20 February 2013. http://naturalsociety.com/leading-geneticist-human-intelligence-slowly-declining Although we tend not to think of cavemen as particularly brainy, Crabtree insists that humans as a species have been steadily losing intelligence for thousands of years, and he says it looks like the trend will continue. Plus, he posits, we’ve been getting less emotionally stable.

Crabtree blames the ostensible decline in human intelligence on gene mutations. In every generation, he says, about 40 genes out of a total of about 2000 to 5000 mutate.3 “Are We Getting Dumber? Maybe, Scientist Says.” 16 November 2012. NPR. 20 February 2013. http://www.npr.org/2012/11/16/165278524/are-we-getting-dumber-maybe-scientist-says Over hundreds or thousands of years, some of those gene mutations are bound to involve genes that have to do with cognitive ability.  The genes ruling human intelligence are particularly sensitive to mutation. Crabtree says that the natural selection process doesn’t favor preservation of the strongest intellectual genes because of conditions in our modern society.

The problem, says Crabtree, is that we no longer need to strictly depend on intelligence for survival in the immediate way our forebears did. Crabtree says that with the advent of widespread infectious diseases, the natural selection process started leaning in favor of those with the strongest constitutions and the best immune systems, rather than in favor of those with the highest levels of intelligence.4 Kim, Juju. “Human Beings are Getting Dumber, Says Study.” 15 November 2012. Time Newsfeed. 20 February 2013. http://newsfeed.time.com/2012/11/15/research-suggests-humans-are-evolving-to-be-dumber

“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,” says Crabtree.

He places the peak of intellectual development way back in prehistory. “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,” Crabtree says. Also, “If an average citizen from Athens of 1000 BC were to appear suddenly among us, he or she would be among the brightest and most intellectually alive of our colleagues and companions, with a good memory, a broad range of ideas, and a clear-sighted view of important issues. Furthermore, I would guess that he or she would be among the most emotionally stable of our friends and colleagues.”

Crabtree has a slew of detractors who say his theory is mere postulation, but even if they’re right that Plato would lose to the modern intellectual in a debate, the fact is that students today certainly don’t seem up to par when compared to students even 50 years ago. Dr. Crabtree says that genetic changes are not to blame for the recent decline in modern intelligence. At Dr. Crabtree’s projected rate of decline, it should take several thousand years before humans undergo enough mutations to plummet into significant intellectual erosion. In other words, his theory doesn’t explain the fact that students today show evidence of both significant emotional and intellectual slippage in just the last 20 years.5 TEASDALE, T., OWEN, D. “Secular declines in cognitive test scores: A reversal of the Flynn Effect.” Intelligence, 2008 36(2), 121-126. http://www.sciencedirect.com/science/article/pii/S0160289607000189

Although some argue that humans are getting ever smarter–witness the rocket pace of technological development–the fact remains that our attention spans have shrunk to an average of eight seconds.6 “Attention Span Statistics.”16 May 2012. Statistic Brain. 20 February 2013. http://www.statisticbrain.com/attention-span-statistics According to a Gallup survey, the vocabulary of the average high school student today is not even half of what it was for students in 1950.7 “The Grandparent’s Gap.” Wordsmart. 20 February 2013. http://www.wordsmartedu.com/panel1.html And according to the Word Smart organization, 38 percent of American fourth graders don’t have even basic reading proficiency. Of course, cavemen probably didn’t have five-star vocabularies, either, but in the pre-industrial world, survival depended on assets other than literacy.

As far as emotional stability goes, there’s clearly a trend these days toward the toilet. As Jon Barron has noted before, since 1996, adult prescriptions for mental illness have risen by 73 percent and prescriptions for children have gone up by 50 percent. Among seniors over the age of 65, psychiatric drug prescriptions have doubled. In fact, one in every 10 adults has a mental health prescription (including ADHD medications, anti-depressants, Alzheimer’s drugs, and antipsychotics), and one out of every 20 kids has the same prescriptions, sans Alzheimer’s drugs. Score one for Crabtree: you can bet that the ancient Romans didn’t need to pop Prozac before tying the toga in the morning. Or maybe they did and just worked out their lack of focus by taking in some gratuitous bloodletting at the Coliseum.

If we can’t blame genetics for the apparent decline in emotional stability and intellectual health, what can we point to? Some say it’s the fault of the media; others blame the breakdown of the family, and at least some experts point to environmental pollutants and lousy diet. Take the supposedly beneficial fluoride in the water supply, for instance. While fluoride might be saving our kids’ teeth (and there are numerous studies that indicate it doesn’t do that), study after study shows it’s definitely impairing their brains. Recent research published in Environmental Health Perspectives cites 24 studies showing an inverse relationship between fluoride exposure and IQ. Likewise, numerous studies have found that pesticide residues on food lead to impaired cognitive functioning and lower intelligence level. And a recent British study of 14,000 children confirmed that children who ate the most processed foods experienced a significant decline in IQ. Other studies have found intelligence undermined by sugar and high fructose corn syrup.

At current rates of decline, genetically speaking, we have maybe 1000 years to figure out what to do about our mutating genes before we’ll be too stupid to do anything about it, but then again, we may not have that long. The harm to intelligence posed by environmental and social factors can transpire in just a few short years. In the meantime, wecan certainly try to manage the lifestyle variables that allow whatever intelligence we do have to flourish. As always, though, it’s a matter of making choices that promote good health and compensating to the fullest extent possible for environmental (and social) toxins. The bottom line is that we now have one more reason for following the Baseline of Health Program.

References

References
1 “Colin Quinn Quotes.” Brainy Quote. 20 February 2013. http://www.brainyquote.com/quotes/authors/c/colin_quinn.html
2 Barrett, Mike. “Leading Geneticist: Human Intelligence is Slowly Declining.” 17 February 2013. Natural Society. 20 February 2013. http://naturalsociety.com/leading-geneticist-human-intelligence-slowly-declining
3 “Are We Getting Dumber? Maybe, Scientist Says.” 16 November 2012. NPR. 20 February 2013. http://www.npr.org/2012/11/16/165278524/are-we-getting-dumber-maybe-scientist-says
4 Kim, Juju. “Human Beings are Getting Dumber, Says Study.” 15 November 2012. Time Newsfeed. 20 February 2013. http://newsfeed.time.com/2012/11/15/research-suggests-humans-are-evolving-to-be-dumber
5 TEASDALE, T., OWEN, D. “Secular declines in cognitive test scores: A reversal of the Flynn Effect.” Intelligence, 2008 36(2), 121-126. http://www.sciencedirect.com/science/article/pii/S0160289607000189
6 “Attention Span Statistics.”16 May 2012. Statistic Brain. 20 February 2013. http://www.statisticbrain.com/attention-span-statistics
7 “The Grandparent’s Gap.” Wordsmart. 20 February 2013. http://www.wordsmartedu.com/panel1.html