Myth Universe: The 10% Myth

The oft-heard thought that we only use 10% of our brain is a farce. Roseanna Shanahan explains how we know this.

 

One of the most commonly heard science tropes is that we only use 10% of our brain. This is a bizarre claim, and there is a great deal of evidence which prove it to be incorrect. This evidence has been around for decades, yet time and time again we see the 10% myth pop up in the media. Since 2011 Hollywood has made over 600 million dollars from films such as Limitless and Lucy which suggest that somewhere out there, there could be a magical drug which will help you tap into that other 90%.

“We, in fact, use all of our brain, not 10% not 25%, but the full 100%.”

This neuromyth has been so pervasive that it’s hard to pinpoint where it began. Some claim that the American Psychologist William James started it about 100 years ago, while others attribute it to Albert Einstein. However, there has been no direct quote to prove that either of them is the culprit. This myth gives us hope that we could have untapped potential and that in fact somewhere in our brain lies a hidden genius, or an extra sense we have yet to discover. However, there is no scientific evidence to support it.

In fact, we use all of our brain, not 10% not 25%, but the full 100%. How do we know this, you might ask? Well, as technology advances, there are many different techniques that can show us what is happening inside our brain, such as functional MRI. When a certain part of the brain is active, oxygen rushes to the site, the fMRI machine detects the location of the oxygen, and displays this activity as colour on a black and white image of the brain. Blobs of red, orange, and yellow show up when an area is highly activated. When you are working out a maths equation, for example, areas of the prefrontal cortex become excited and appear red. If you are not thinking hard about the equation, these areas will exhibit a bluish tone, indicating lower levels of activity. When you are thinking about someone that you love, or looking at a picture of them, your amygdala lights up. When you hear sound, your auditory cortex lights up. Using imaging techniques over the course of a day proves that the entire brain is active, eradicating the notion that we only use 10% of it. Neurons which are not used shrivel and die, something which would not bode well for our brain if we only used 10% of it.

“It would be a waste of metabolic energy to use a high percentage of our daily energy on a brain that only needs 10% of its mass to function..”

Another reason the 10% myth is false is that it would be a waste of metabolic energy to use a high percentage of our daily energy on a brain that only needs 10% of its mass to function. Every protein, cell, tissue, and organ in the body serves a purpose. Therefore you can be guaranteed that whatever is inside your skull is completely essential to your existence. Hauling around a brain that weighs about 1.3 kg and uses one fifth of your oxygen supply is not a good strategy if 90% of it is unnecessary.

Just because we use all of our brain does not mean that we are always at our mental peak, however. As with exercise, in a given day you probably use a vast amount of your muscles, but unless you train your muscles, they will never reach their full potential. Every time we learn something new we train our brain, increasing our mental ability.

“Each of our 86 billion neurons has about 10,000 connections, putting the total number of connections in the trillions.”

The brain is a very dense mesh of wiring. Each of our 86 billion neurons has about 10,000 connections, putting the total number of connections in the trillions. This allows us to encode and process libraries worth of information over the course of a lifetime. So given that we use all of our brain, we have a responsibility to use it wisely. People who read, travel the world, learn a new language or a new style of dance are continuously enhancing their brain, creating more memories by encoding information in their neurons and making neural connections that can last a lifetime. So instead of fantasising about all of the things we would like our brain to do, the truth is the brain can do extraordinary things already – we just have to work at it so that it can reach its full potential.