“A human typically uses a small percentage of their brain.”

In the average adult human, the brain represents about 2% of the body weight. Remarkably, despite its relatively small size, the brain accounts for about 20% of the oxygen and, hence, calories consumed by the body. This high rate of metabolism is remarkably constant despite widely varying mental and motoric activity.

The paper reviews evidence that “experiments have shown variations between 62 and 94 bn neurons in the human brain (n = 9)” and similar ranges in other studies. While the focus is on estimating neuron counts, it notes that the human brain is highly metabolically expensive, with tens of billions of neurons maintained and functioning. This large, energy-demanding neuron population underlies the understanding that the brain is broadly active rather than mostly dormant.

“Unfortunately, the idea that people only use 10% of our brains and could use more is not true.” The article explains that this is a persistent myth and notes that it may have originated from a misinterpretation of William James’s statement that "We are making use of only a small part of our possible mental and physical resources."

For the average adult in a resting state, the brain consumes about 20 percent of the body’s energy. ... There’s a myth that you only use 10 percent of your brain, and a magic pill could unlock the remaining 90 percent. The bulk of your neurons are relatively silent for long stretches of time, waiting to spring into action when activated. But they’re doing so to remain energy efficient.

“It’s thought that most of us use just 10% of our brain.” After discussing why this notion arose and evidence from brain injury and imaging, the article concludes: “That 10% claim? Consider it 100% fiction.”

In answering the question directly, neurologist Barry Gordon writes: “It is certainly not true that we use only 10 percent of our brains.” He explains that brain imaging studies show that much of the brain is active even during simple tasks and at rest, and that “the brain represents three percent of the body’s weight and consumes 20 percent of the body’s energy—hardly something nature would support if 90 percent of it were unnecessary.”

Scientific American describes the popular claim and quotes neurologist Barry Gordon of Johns Hopkins School of Medicine: “We use virtually every part of the brain, and most of the brain is active almost all the time.” The article notes that brain imaging and clinical observations in neurology “refute the idea that 90 percent of the brain is dormant or unused.”

The findings also offer a valuable explanation for the brain’s surprising efficiency. The waking adult brain generates only about 20 watts of continuous power—as much as a very dim light bulb. ... The new work also answers a longstanding question as to how the brain is so energy efficient and could help engineers build computers that are incredibly powerful but also conserve energy.

MYTH: You only use 10 percent of your brain. FACT: You use all of your brain. Brain scans show activity coursing through the entire organ, including a resting state network that remains active even when you are at rest. Even simple tasks engage multiple brain regions, not just a small percentage.

“Many believe that a person only ever uses 10 percent of their brain. However, research suggests people use most of their brain.” The article cites neurologist Barry Gordon: “He explained that the majority of the brain is almost always active.” It also notes that “The 10 percent myth was also debunked in a study published in Frontiers in Human Neuroscience.”

“Two-thirds of the population believes a myth that has been propagated for over a century: that we use only 10 percent of our brains. Hardly! Our neuron-dense brains have evolved to use the least amount of energy while carrying the most information possible – a feat that requires the entire brain.” The piece explains that brain imaging shows “even simple tasks activate many areas of the brain, not a small isolated region.”

“The belief that you use only 10% of your brain has been mistakenly propagated as a myth. In reality, the human brain is a highly complex organ… In conclusion, the idea that we use only 10% of our brain is not true. Modern brain imaging studies show that different parts of our brain are active when we think, solve problems, or even sleep. So, remember, you're using your entire brain, not just a small fraction of it!”

A common myth claims that people use only 10% of their brains. Neuroscientists, however, have shown that this is false: brain imaging technologies such as PET and fMRI reveal activity throughout the brain, even while we are asleep. Furthermore, if 90% of the brain were normally unused, damage to those regions would not impair function, which is contrary to what is observed in clinical practice.

The belief that we use only 10 percent of our brains is so widespread that about two-thirds of the public and even many psychology undergraduates accept it. However, psychologists and neuroscientists uniformly reject this idea. Evidence from brain injury, brain imaging, and other lines of research indicates that virtually all areas of the brain have a function and are used.

“It is a myth that humans only use 10% of our brain. We actually use all of it. We’re even using more than 10 percent when we sleep. Although it’s true that at any given moment all of the brain’s regions are not concurrently firing, brain researchers using imaging technology have shown that, like the body’s muscles, most are continually active over a 24-hour period.”

Two thirds of the population believes a myth that has been propagated for over a century: that we use only 10% of our brains. Hardly! ... Our neuron-dense brains have evolved to use the least amount of energy while carrying the most information possible — a feat that requires the entire brain. ... The idea that 9/10 of your brain sits idly by in your skull looks silly when we calculate how the brain uses energy.

Contemporary neuroscience holds that humans use virtually all regions of the brain over the course of normal daily life, rather than a small fixed percentage. Brain imaging techniques such as fMRI and PET show activity distributed across the entire brain, including during rest, and damage to even small areas typically produces detectable deficits. The popular claim that we "use only 10 percent of our brain" is therefore treated by neuroscientists as a myth with no empirical basis.

In this clip, they discuss: "The 10% Brain Myth – Clarifies that we don’t ‘only use 10%’ of our brain". Around 1:19, Edward Chang says that there is maybe about 10 or 15 percent of the brain that is very critical for our basic functions, such as movement, speech, and vision, but this is not the same as saying the rest is unused. The conversation explicitly labels the idea that we only use 10 percent of our brain as a myth.

Despite neuroscientific consensus that nearly all brain regions have functions and show activity over time, a significant fraction of the public still believes that humans use only a small percentage of their brains. Surveys in multiple countries have found that around 50–65% of respondents endorse some version of the “10 percent of the brain” idea. This persistence reflects popularization in self-help literature and films rather than scientific evidence.