Ten percent of the brain myth

The 10% of brain myth is the widely-perpetuated myth that most or all humans only use 10% of their brains. By association, it is often suggested that by some process a human being may harness this unused potential and in so doing inherit several magnitudes more intelligence.

Though many factors of intelligence may be increased with training, the idea that large parts of the brain remain unused is without substantial foundation. Although many mysteries regarding brain function remain, every part of the brain has a known function.

Origins

• The 10% myth most likely arose from a misunderstanding (or public misrepresentation) of neurological research undertaken in the late 1800s or early 1900s when researchers either:
  • discovered that only about 10% of the neurons in the brain are firing at any given time; or
  • announced that they had only mapped the functions of 10% of the brain at that time (accounts differ on this point).
• Another possible origin of the 10% myth is that neurons only compose approximately 10% of the cells in the brain; the rest are glial cells that, despite being involved in learning, function differently to neurons.
• In the early 20th Century, the myth was attributed to William James who wrote in 1908: "We are making use of only a small part of our possible mental and physical resources"
• Albert Einstein is reported as quipping that people typically only use 10% of their brains. Although a facetious remark, the media took this as fact.
• There is not a direct relationship between the performance of the brain and its level of activation; this variable has confounded scientists, because some 'gifted' individuals showed less brain activity than those with brain performance considered average. Haier proposed that indeed more gifted individuals might possess more efficient brain circuits.
• Dr. James W. Kalat, author of the textbook Biological Psychology, points out that neuroscientists in the 1930s knew about the existence of the large number of "local" neurons in the brain, but only knew that these cells were small. The misunderstanding of the function of local neurons may have led to the 10% myth.

Refutation

Neuroscientist Barry Beyerstein sets out seven kinds of evidence against the ten percent myth:

• Studies of brain damage: If 90% of the brain is normally unused, then damage to these areas should not impair performance. Instead, there is almost no area of the brain that can be damaged without loss of abilities. Even small areas of damage can have profound effects.
• Evolution: The brain is enormously costly to the rest of the body, in terms of oxygen and nutrient consumption. If 90% of it were unnecessary, there would be a large survival advantage to humans with smaller, more efficient brains. So the process of natural selection would have eliminated the inefficient brains.
• Brain imaging: Technologies such as Positron Emission Tomography (PET) and Functional Magnetic Resonance Imaging (fMRI) allow the activity of the living brain to be monitored. They reveal that even during sleep, all parts of the brain show some level of activity. Only in the case of serious damage does a brain have "silent" areas.
• Localization of function: Rather than acting as a single mass, the brain has distinct regions for different kinds of information processing. Decades of research has gone into mapping functions onto areas of the brain, and no function-less areas have been found.
• Microstructural analysis: In the single-unit recording technique, researchers insert a tiny electrode into the brain to monitor the activity of a single cell. If 90% of cells were unused, then this technique would have revealed that.
• Metabolic studies: Another scientific technique involves studying the take-up of radioactively labelled 2-deoxyglucose molecules by the brain. If 90 percent of the brain were inactive, then those inactive cells would be show up as blank areas in a radiograph of the brain. Again, there is no such result.
• Neural disease: Brain cells that are not used have a tendency to degenerate. Hence if 90% of the brain were inactive, autopsy of adult brains would reveal large-scale degeneration.

Perpetuation

The 10% myth has been spread both unwittingly, by individuals believing it to be fact, and deliberately as an advantageous deception. It is frequently used to give strength to arguments in cognitive training or counseling.

The 10% brain myth occurs frequently in advertisements.

Some New Age proponents propagate this belief by asserting that the "unused" ninety percent of the human brain is capable of exhibiting psychic powers and can be trained to perform psychokinesis and extra-sensory perception. In addition to the fact that humans use their entire brain, there is no scientific evidence supporting the existence of psychic powers at all.

In popular culture

• The DC Comics character Deathstroke gained superhuman powers by increasing the use of his brain from 10% to 90%.
• In the film Wedding Crashers, Owen Wilson says the myth as a pick up line for the bridesmaid "You know how they say we only use 10 percent of our brains, I think we only use 10 percent of our hearts."
• In Stargate, mainly in the Stargate SG-1 and Stargate Atlantis series, the Ancients ascended to an all powerful form of being after expanding their brain function above 90%.
• In Kyle XY the main character uses 70% of his brain, having supernatural powers and being able to learn as quickly as snapping fingers.
• In The Simpsons episode Brother's Little Helper, Bart takes a prescription pill called Focusyn. When bragging about his newfound smarts, Bart tells his sister Lisa, "Did you know that most people use 10% of their brains? I am now one of them!"
• In the 2009 film Race to Witch Mountain, the extraterrestrial humans Sarah and Seth have access to telekinesis, telepathy, and phasing, which Sarah states the humans on Earth can not use yet, because they "haven't learned to use that part of [their] brain yet." Ironically, in an interview with AnnaSophia Robb, who plays Sarah, she confirmed that the director wrote that line in because he wanted to be "as scientifically accurate as possible."
• The 'fact' of small percentage of brain use is central to the plot of the film Defending Your Life. People from Earth are said to use only 3-5% of their brains, and hence derisively called "little brain" by people in Judgment City who use higher percentages.
• The concept of increased brain usage resulting in superhuman powers such as telekinesis etc. is also central to the plot of the film Phenomenon, where John Travolta's character George gains the aforementioned powers due to an eventually fatal brain tumour that 'activates' more of his brain than in the case of any human ever tested.

See also

• Common misconceptions about the brain
• Educational psychology
• List of misconceptions