There is a common misconception that humans use only 10% of their brain, while the remaining 90% lies “dormant,” waiting to be unlocked. Many exploit this myth, promising to “activate” hidden brain potential with methods “based on neuroscience.” In reality, however, they only “activate” your wallet.
According to surveys, two-thirds of the public and nearly half of science teachers still believe this myth. Its origin may date back to the 1890s, when William James, the father of American psychology, remarked that “most of us do not meet our mental potential.” James never meant to imply that only a small part of the brain is used, but the misunderstanding has persisted for decades.
How Does the Brain Use Energy?
The idea that 90% of the brain “sits idle” is absurd when you consider how it consumes energy.
An adult brain, while accounting for only 2% of body weight, uses up to 20% of the body’s daily glucose. In children, this figure rises to 50%, and in infants, it reaches 60%.
Although the brains of animals like mice, dogs, or monkeys consume less energy, the human brain stands out due to its exceptionally dense neuron packing. Our 1.5-kilogram brain contains 86 billion neurons, 40% more than other primates.
The invention of cooking, about 1.5 million years ago, revolutionized our ability to digest food more efficiently. Cooked food provided more energy, enabling humans to sustain a brain with such a dense network of neurons.
Why Don’t All Neurons Fire at Once?
Maintaining the activity of 86 billion neurons requires a massive energy investment. Half of this energy is used to keep neurons in a resting state, pumping ions across cell membranes to maintain electrical charges. If all neurons fired simultaneously, the energy demand would overwhelm the body.
This is why the brain uses “sparse coding” – activating only a small percentage of neurons at a time. By keeping 1% to 16% of neurons active at any given moment, the brain achieves optimal energy efficiency while still processing complex information.
The Limits of Consciousness and Energy Efficiency
Most of the brain’s operations occur outside of consciousness to conserve energy. This is why multitasking is often ineffective. Trying to do multiple tasks at once divides the brain’s energy, reducing the quality of each task.
Your brain is designed to be smart and powerful while conserving energy. Forget the 10% brain myth and recognize that your true strength lies in your brain’s ability to manage energy efficiently. Don’t waste it – your billions of neurons need to be sustained. Instead, use your brain effectively to unlock its full potential.
This content was shared in a TED-Ed YouTube video, which has garnered nearly 5 million views and over 3,000 comments. Watch the full video HERE.
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