Human Intellect Backsliding From Lack of Evolutionary Pressure: Study
December 08, 2012
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By Dr. Mercola
You might think that human intellect is like riding a bike... once you've got it, it's there for good. But new research from Stanford University suggests that not only is human intellect not a "given"... it may actually be regressing.
Are Humans Losing Their Intelligence?
In the analysis, written by Gerald Crabtree, a genetics professor at Stanford University, it's explained that the optimization of a large number of genes related to intelligence may have peaked in the early stages of human evolution, when your ability to survive depended much more than now on your level of intellect.1
But nowadays, that evolutionary pressure is gone, and you can survive with even minimal levels of intelligence. So the genetic mutations that cause intellectual disabilities have no reason to be removed through selective pressures, from a survival standpoint. It was estimated that while there are anywhere form 2,000 to 5,000 genes that play a role in higher cognitive faculties, all humans now have two or more mutations or deletions that may harm their intellectual or emotional stability.2
"New developments in genetics, anthropology, and neurobiology predict that a very large number of genes underlie our intellectual and emotional abilities, making these abilities genetically surprisingly fragile," the analysis explains.
Analysis of human mutation rates and the number of genes required for human intellectual and emotional fitness indicates that we are almost certainly losing these abilities."
It's likely that such genetic changes will only continue to accumulate, albeit so slowly that, according to Dr. Crabtree, we'll have solutions available in the future to "correct" them.
Are You Being Deceived About Your Own Intelligence?
Do you find it hard to believe that your intelligence may be slipping? Or that you may have adverse genetic changes tied to your intellect or emotional health that didn't exist many generations ago?
This is actually quite common, as "people tend to hold overly favorable views of their abilities in many social and intellectual domains," according to David Dunning, a Cornell professor of social psychology. After conducting four studies, Dunning and a colleague determined that some people overestimate just how smart they are, and the less skilled a person actually is, the less able they are to realize it.
" ... this overestimation occurs, in part, because people who are unskilled in these domains suffer a dual burden: Not only do these people reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the metacognitive ability to realize it," they wrote.3
To put it simply, you have within your realm of experience "known unknowns" and the far more daunting "unknown unknowns. "The latter are those circumstances that are so far removed from our ordinary experience that we cannot even fathom them. A sign of an intelligent person is knowing there are things you don't know, but a sign of an even more intelligent person may be knowing there are things that you don't know you don't know.
When you may run into trouble, on the other hand, is when you believe you know everything and close your mind to learning any new ideas. Unfortunately, a great deal of the underlying premises upon which our society was built fall into this realm. For instance, many "conventional" experts in the field of medicine refuse to believe in these "unknown unknowns" -- a definite sign of ignorance if there ever was one. As Voltaire said, "A state of doubt is unpleasant, but a state of certainty is ridiculous."
Other Evidence of a "Dumbing Down" Effect?
Education is the one social factor that has been consistently linked to longer life, regardless of what country you live in. But the idea that the only way to get properly educated is to go through a formal school system may be a misnomer.
According to Charlotte Iserbyt, who served as Senior Policy Advisor in the Office of Educational Research and Improvement (OERI), U.S. Department of Education, during the first Reagan Administration, the Department of Education's goal is manipulation of public school curriculum to promote a political agenda.
During her tenure as Senior Policy Advisor, Iserbyt was shocked to learn that her employer promoted the purpose of education as a vehicle to change the thoughts, actions and feelings of students. Good teaching is defined as "successfully challenging students' fixed beliefs." In this way, children may come out of the school system as though they are molded cogs in a machine, rather than the independent thinkers they entered in as.
This is in no way a reflection on the many dedicated and talented teachers we have here in the United States. Rather, it's a perspective of some of the issues that are present at higher levels that may make it nearly impossible to provide a solid education no matter how skilled or excellent the teacher is. In a culture where intelligence and education are highly valued, it is, at the very least, interesting to speculate that perhaps the education system itself could be contributing to, rather than combatting, the dumbing down effect that may already be occurring in evolutionary terms.
7 Tricks to Give Your Brainpower a Boost
There's no need to simply sit idly by while your intellect fades away. There is quite a bit you can do to not only protect what brainpower you do have but also to significantly enhance it. Even Dunning found in his study that the participants were able to improve upon their skills, and therefore also their metacognitive competence (which, ironically, helped them realize the limitations of their abilities). If you want to boost your intellect, stave off mental aging, and maybe even pass these intellectual gains on to your children, try:
Exercise encourages your brain to work at optimum capacity by causing nerve cells to multiply, strengthening their interconnections and protecting them from damage. During exercise nerve cells release proteins known as neurotrophic factors. One in particular, called brain-derived neurotrophic factor (BDNF), triggers numerous other chemicals that promote neural health, and directly benefits cognitive functions, including learning. Exercise has even been shown to boost mitochondrial genesis in nerve cells, optimizing their ability to produce energy and function at peak levels.
To get the most out of your workouts, I recommend a comprehensive program that includes Peak Fitness high-intensity exercise, strength training, stretching, and core work.
2. Animal-Based Omega-3 Fats
Docosahexaenoic acid, or DHA, an omega-3 fat, is an essential structural component of both your brain and retina. Approximately 60 percent of your brain is composed of fats—25 percent of which is DHA. DHA is also an essential structural ingredient of breast milk, which is believed to be a major reason why breastfed babies consistently score higher on IQ tests than formula-fed babies.
The influence of omega-3 fat on physical and mental health has been the subject of intense research over the last four decades, and there's compelling evidence that animal-based omega-3 fats can help not only to reduce the symptoms of a variety of psychiatric illnesses and degenerative brain disorders, but also slow, halt and sometimes even reverse the underlying disease process.
Sleep is not only essential for regenerating your physical body, but it is imperative for reaching new mental insights and being able to see new creative solutions to old problems. Sleep removes the blinders and helps "reset" your brain to look at problems from a different perspective, which is crucial to creativity.
Research from Harvard indicates that people are 33 percent more likely to infer connections among distantly related ideas after sleeping, but few realize that their performance has actually improved. Sleep is also known to enhance your memories and help you "practice" and improve your performance of challenging skills. In fact, a single night of sleeping only four to six hours can improve your ability to think clearly the next day.
4. Vitamin D
Activated vitamin D receptors increase nerve growth in your brain, and researchers have also located metabolic pathways for vitamin D in the hippocampus and cerebellum of the brain, areas that are involved in planning, processing of information, and the formation of new memories.
Appropriate sun exposure is all it takes to keep your levels where they need to be for healthy brain function. If this is not an option, a safe tanning bed is the next best alternative, followed by a vitamin D3 supplement.
5. Optimize Your Gut Flora
Your gut is your "second brain," and your gut bacteria transmits information to your brain via the vagus nerve, the tenth cranial nerve that runs from your brain stem into your enteric nervous system (the nervous system of your gastrointestinal tract). There is a close connection between abnormal gut flora and abnormal brain development, and just as you have neurons in your brain, you also have neurons in your gut -- including neurons that produce neurotransmitters like serotonin, which is also found in your brain and is linked to mood.
Limiting sugar and processed foods, while eating traditionally fermented foods (rich in naturally occurring good bacteria), taking a probiotic supplement and breastfeeding your baby are among the best ways to optimize gut flora and subsequently support brain health.
6. Vitamin B12
Vitamin B12, or rather a lack thereof, has been called the "canary in the coal-mine" for your future brain health, and recent research has bolstered the importance of this vitamin in keeping your mind sharp as you age. According to the latest research, people with high levels of markers for vitamin B12 deficiency were more likely to score lower on cognitive tests, as well as have a smaller total brain volume,4 which suggests a lack of the vitamin may contribute to brain shrinkage.
7. Challenge Your Mind
One of the simplest methods to boost your brain function is to keep on learning. The size and structure of neurons and the connections between them actually change as you learn. This can take on many forms above and beyond book learning to include activities like traveling, learning to play a musical instrument or speak a foreign language, or participating in social and community activities.
Another important method? Brain aerobics. As with learning, challenging your brain with mind-training exercises can keep your brain fit as you age. This can be something as simple as thinking of famous people whose first names begin with the letter A, doing crossword puzzles or playing board games that get you thinking.
Research has even shown that surfing the Web activates regions in your brain related to decision-making and complex reasoning.5 So unlike passively watching TV, using the Internet is an engaging task that may actually help to improve your brainpower.