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The "10% of Your Brain" Myth

I am all about debunking human illusions so we can see clearer, perform better, and make better decisions. One particular illusion both concerns and fascinates me because it is so pervasive. In fact, there is a good chance you believe it.

Here it is: We only use 10% of our brain.

You may have heard a different small percentage - 15 or 20 perhaps - but the idea is that most of your brain power is untapped and if you could just figure out how to access it, you could be a genius!

Is it true? With the development of PET (Positron Emission Tomography) scans and fMRI (functional Magnetic Resonance Imaging) over the last 25 years, neuroscientists can easily measure brain activity. Those scans show that we clearly use our whole brain, even during sleep. Those with diminished mental functioning, such as people with Alzheimer’s or Parkinson’s disease, still use well over 10%.

Even though it was debunked years ago and there is zero evidence to support it, the myth lives on. Over 65% of Americans believe it. Even more concerning - about 50% of primary and secondary teachers endorse the 10% Myth.

(Actually, it is one of many widely accepted but false myths about the brain and its functions. They even have a name - neuromyths. Other common neuromyths include the belief that people are either “left-brained” or “right-brained,” and that the brain completes its development at puberty. Both are false.)


The origin of the myth is not certain, but likely comes from the misinterpretation of a statement by psychologist William James’ in the 1890s. In a speech James gave in 1908, he said, “We are making use of only a small part of our possible mental and physical resources.” He said nothing about how much of the physical brain itself is used, nor did he give a percentage.

How it morphed into the popular 10% myth is unknown, but many self-help book writers and motivational speakers ran with it and it entered the popular consciousness where it remains today. We tend to believe things we want to be true, and this certainly fills the bill.

So what?

This seems like a harmless enough illusion to believe but it is actually counterproductive for those that take it to heart. If you believe that you have this untapped brain that can be utilized if you just knew how, you may either, 1) constantly be susceptible to purchasing spurious secrets or supplements to unlock that power, or 2) throw up your hands in despair because you’ll die someday never having succeeded at using your brain’s full potential.

Or you may just look at it as a curious fact of biology that doesn’t really bother you. In truth, it is an illusion that misdirects you from what you actually can do to improve your brain.

Real actionable brain boosters

We do use our entire brain, but there are ways to make it work better and more efficiently.

- Physical exercise

Physical exercise can cause the hippocampus to actually grow and improve your ability to retain information.

Other benefits of exercise on the brain include reducing stress, increasing mental energy, and staving off the degenerative effects of aging, including the risk of developing Alzheimer’s Disease. It can also reduce your risk of stroke.

- Diet

The idea that some foods are “brain foods” is not a myth. Some of the foods that are “brain smart” include fish, nuts like pecans and pistachios, apples, red grapes, and leafy green vegetables like spinach. In addition, obesity, high blood pressure, and diabetes are known to actually reduce brain size, so maintaining a healthy weight with a diet low in trans fats, salt, and sugar is also important for brain health.

- Sleep

Getting enough sleep helps neurons communicate with each other, and recent findings suggest that sleep plays a housekeeping role that removes toxins in your brain that build up while you are awake

- Hydration

Studies show that dehydration is associated with significant impairments on attention, executive function, and motor coordination. Also, increasing daily water intake by just a few glasses per day can lead to positive emotional changes and increased energy.

- Mental exercise

We need cognitive stimulation to keep the brain cells healthy and the oxygen flowing up there. Always be striving to learn new things. Learn to play an instrument or pick up a new language, or take a writing or acting class. Puzzles and strategy games that make you think in different ways are not just fun diversions but great for your brain health.

A good rule of thumb - the widely known strategies for improving your overall health are good for your brain too. All 100% of it.

Think well and be well.

- Steve Haffner

Want to learn more about improving your decision performance?

Click here for my free book, 7 Strategies for Making Better Decisions


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