The Myth of the 10% Brain

By David A. Morton, M.D.

Copyright 2001

We have all heard about "urban myths". There are also psychological myths. One pervasive and tenacious psychological myth about human brain function provokes me to speak out. It is irritating in the same sense as a small intellectual splinter, hardly worth attention, but turning up over and over again with cumulative annoyance until I feel I must say something. This "last straw" comes from a newspaper article quoting a well-known magician as saying, "We only use about ten percent of our brain capacity." Really? Which magician and which newspaper is not important. How many thousands of times has this statement been repeated unchallenged in books, in newspapers, in magazines, on television, on radio talk shows and in conversation?

As a medical doctor and psychologist, I say that the assertion we use only about 10% of our brains is not supported by any scientific evidence. I suspect that some people like to believe this myth, because it gives a sense of mystery, or feels like some potential for power, or gives comfort in the possibility of escaping a dreary daily life. Perhaps the 10% brain myth is also a way for some people to be manipulated into beliefs whereby they pay their money to others to be led into some type of "mind expansion". I am not making fun of people who want to improve themselves, but emotionally comforting assertions or beliefs aren't necessarily true. The fact remains that the 10% brain function belief is just something someone made up. I am unable to determine who started this particular myth; it has been growing unchecked for so many years that the guilty root may remain forever hidden. Once nonsense has spread so far, it is probably impossible to eradicate. Whoever started the 10% brain myth, I suspect that they used only about 10% of their brain in coming to this conclusion.

Of course, I can't prove that we use more than 10% of our brain capacity. On the other hand, the assertion that we don't use more than 10% of our brain isn't true simply because it hasn't been proven false. The burden of proof is on the believers, and I call it a "myth" until proven otherwise. One could say, "To heck with scientific truth and facts; I'll personally decide what's true and false." Fine, then this gives you the convenient option of believing absolutely anything that is emotionally satisfying, which is quite a tempting attitude since it is so quick and easy. That's what humankind did for thousands of years before development of the scientific method, and so our species made very little progress except through trial and error. Putting spins on facts is a problem we all continue to have, but that's the ape-brain way. Like a lurking, greedy, and sticky shadow, ape-brain thinking is ready to take over at the slightest opportunity. However, our brains are bigger than that of apes with some added extra bells and whistles that apes don't have- like more effective frontal lobes that help keep primitive impulses under control. It is in our best interest for the human cerebral organ to reach its full potential, if that means freedom from the dark confusion of our prehistoric ancestors. But do we know what that freedom is?

Ask yourself this: how could someone know that we only use about 10% of our brain capacity? How could you know a glass is 10% full, unless you know the total volume the glass holds? To arrive at a rational answer, we would have to know what capacities constitute 100% of brain function. Unless we want to engage in wild speculation, we would have to find a number of super-people (assuming they exist) and then measure their abilities against the capacities of a number of common folk. Then we could have some meaningful data. Of course, we wouldn't know what to measure�a super-person would have to tell us about their supercapacities and how to rate them. In fact, we might not know a super-person unless they came forward and confessed to being superior. If a super-person uses their brain 10 times better than the rest of us, we could guess that intellectually a super-person would have an IQ of at least 1000. Suppose there was someone who was only really half of a super-person? With their 500 IQ they could probably fool us into thinking they were a fully-developed super-person. We can't measure an IQ of 500 any better than we could measure one of 1000. Such a deceit by a half super-person would ruin the whole experiment. Some people already assure us that they are a super-person who has spiritually reached the highest levels of consciousness, and are ready to bestow that knowledge on the rest of us. There are plenty of people charging for such services, and some of these individuals will become rich and authoritative within their following. But such self-inflation is hardly rational evidence.

For it's small size with a weight of only about 3 lbs, the human brain is a marvelous instrument. However, it is sobering to know that the outer (neocortex) layer of the brain, by which we perform our "higher" thoughts, is only a thin sheet of cells with an average thickness of about 2.5 millimeters, or about 1/10th inch. To see how unimpressive this number is, just look at a ruler. And not all of brain neocortex is "thinking" tissue, since it includes cortical blood vessels and supportive cells for the nerve cell (neuronal) matrix necessary for thought. Without the neocortex, humans and other higher mammals are in a condition known as decorticate rigidity. If you are in this state, you can only lie where you are placed and wish you were as smart as a cabbage.

It might be pointed out that the neocortex doesn't weigh 3 lbs. What about those other pounds of brain tissue not in the neocortex? Aren't they just waiting for higher development? Well, there are large cavities in the brain that don't contain any brain cells; these ventricles are filled with cerebrospinal fluid. Then you have to consider the overall brain weight of other cerebrospinal fluid and blood, blood vessels, supportive ("non-thinking") cells, and large amounts of white matter that simply carries signals between various brain areas and the spinal cord. It is true that, in addition to the neocortex, there are nerve cells (neurons) in the cerebellum and brainstem. These cells are important and perform many activities dealing with autonomic functions in the body, such as regulation of movement, posture, blood pressure, heart rate, and the control of the onset of sleep. But these nervous system functions are much more primitive than the function of the neocortex and of a much more ancient evolutionary origin. (This is not to say there is no interaction between the neocortex and these more primitive brain structures. The newer brain of the neocortex is built on the older brain, and their interaction is intimate. The brainstem is a primitive area of the brain that merges the lower brain into the spinal cord; there is no consciousness with only a brainstem. On the other hand, the neocortex can't even stay awake without constant arousal impulses from the brainstem. Or in regard to the frailty of higher brain functions, one might also note how activation of a emotionprocessing cortex brain area known as the amygdala, under the influence of evolutionally older parts of the brain, can result in anger or fear that overwhelms the more rational parts of the neocortex; in fact, this is a common experience and shows that the neocortex often cannot control impulses from the older, ancestor brain.) Nevertheless, it is the neocortex that is the jewel of the brain's evolution.

The types and numbers of brain cell connections, along with the time-dynamics of their interactions modified by numerous neurotransmitters, results in a complex chemical and electromagnetic environment in the brain. However, that is no argument that we are not using our full brain capacity. While it is in our best interest to try to continue to learn and, if possible, to think more accurately in relation to the physical world and more appropriately in regard to our social world, it may be that we are struggling at or near our limits in regard to the capacities of the brain-mind of the species. This is not pleasing to our self-concept, but it still may be true.

If we are functioning at our mental limits as a species, can we do anything about it? Scientific knowledge or technological change as we continue to experience the world individually or as a species over time is not a change in fundamental mind-brain capacity. What happens if you make the same model of car over and over again, using the same basic plans and parts�the same hereditary material? Clearly, you will get the same type of car rolling off the assembly lines year after year, century after century. Some of those cars may have a few different characteristics, such as differences in paint color or the quality of the radio, but these things do not change the basic nature (model) of the car. Similarly, there is no compelling evidence that fundamental human brain structure or function has changed significantly in the last 100,000 and perhaps 200,000 years. Indeed, the more recent human history that we have recorded shows no basic increase in mental capacity since civilization arose. This fact will not change in the future by simple sexual reproduction involving the coupling of man and woman, which will continue to produce the same basic model of human over and over again.

Genetic treatment of the brain, in order to cause it to regenerate from traumatic injury or reverse the ravages of hereditary or acquired brain diseases, is something to be expected. Such restoration of the brain to a prior, normal human condition will come first and be easily embraced by the public. Similarly, other organs will be taught to self-heal�something that is done very poorly by the human body at the present time. However, a following phase of medical development is likely to involve re-engineering of various human organs, including the brain, to improve their function beyond what was previously considered normal. It is precisely here that great care must be taken to ensure that, if the human race is to endure, the search for the super-human does not change us into the non-human. On the other hand, if our pre-human ancestors stayed the way they were, we would not exist today. We may have to accept the loss of some human characteristics to realize a greater potential. Whatever, the ultimate destiny of the human brain-mind, the myth of the 10% brain can be discarded as nonsense right now. This myth has never had a place in the professional medical or psychological literature, and should not be promoted as fact.