You know, you're only using 10 percent of your brain. Just imagine what you could accomplish if you used the other 90 percent!"
Chances are high that you have heard someone make a similar comment at some time or another. The popularly and widely spread belief that we only use or have access to 10 percent of our brain's power is often used to speculate about the extent of human abilities if only we could utilize our brain's full capacity.
In reality, this claim is 100 percent myth. We use all of our brain. The only instances where there are unused regions of the brain are those in which brain damage or disease has destroyed certain regions.

The Origins of the Myth

Researchers suggest that this popular urban legend has existed since at least the early 1900s. It may have been influenced by people misunderstanding or misinterpreting neurological research. The 10 percent myth may have emerged from the writings of psychologist and philosopher William James. In his 1908 book, The Energies of Men, he wrote, "We are making use of only a small part of our possible mental and physical resources."
The myth has perpetuated much like other urban legends. Well-intentioned people such as motivational speakers or teachers often cite the 10 percent myth as a way to demonstrate that all people should strive to live up to their full potential. Unfortunately, less well-meaning people have also used the myth to promote and sell products and services that they claim will unlock your brain's hidden potential.

Debunking the 10 Percent Myth

Neuroscientists point out a number of reasons why the 10 percent myth is false:

• Brain imaging scans clearly show that almost all regions of the brain are active during even fairly routine tasks such as talking, walking, and listening to music.


• If the 10 percent myth were true, people who suffer brain damage as the result of an accident or stroke would probably not notice any real effect. In reality, there isn't a single area of the brain that can be damaged without resulting in some sort of consequence.


• We would not have evolved such large brains if we were only using such a tiny portion of them.


• The brain uses approximately 20 percent of the body's energy. It would make little evolutionary sense to have such a large portion of our energy resources utilized by such a tiny amount of the brain.


• Brain mapping research has yet to find any region of the brain that does not serve a function. "Numerous types of brain imaging studies show that no area of the brain is completely silent or inactive," wrote Dr. Rachel C. Vreeman and Dr. Aaron E. Carroll in a study of medical myths. "Detailed probing of the brain has failed to identify the 'non-functioning' 90 percent."

Unfortunately, the 10 percent myth remains both popular and persistent. It has been repeated in popular culture in everything from advertisements to television programs. The next time you hear someone claim that we only use 10 percent of our brains, you'll be able to explain why this statement is not true. Not to say that human beings don't have amazing potential – we just use 100 percent of our brains to accomplish these remarkable feats.
_{References
Beyerstein, B. L. (1999). Whence cometh the myth that we only use 10% of our brains? In Sergio Della Sala. Mind Myths: Exploring Popular Assumptions About the Mind and Brain.. New York: John Wiley & Sons.
Vreeman, R. C. & Carroll, A. E. (2007). Medical myths. BMJ, 33, 1288.}

What Is Extrinsic Motivation?
Extrinsic motivation refers to behavior that is driven by external rewards such as money, fame, grades, and praise. This type of motivation arises from outside the individual, as opposed to intrinsic motivation, which originates inside of the individual.
Think about your own motivation for reading this article. Are you trying to learn the material so that you can get a good grade in your psychology class? This means that you are studying the material to gain external reinforcement (getting a good grade), which means that your behavior is extrinsically motivated.
Definitions of Extrinsic Motivation
"Extrinsic motivation refers to our tendency to perform activities for known external rewards, whether they be tangible (e.g., money) or psychological (e.g., praise) in nature."
(Brown, Psychology of Motivation, 2007)
"Motivation can come from the outside, such as the motivation to win medals, receive financial rewards, and attract attention from the media. This is known as external, or extrinsic, motivation because it involves participation in sport for some kind of reward that is external to the process of participation."
(Karageorghis & Terry, Inside Sport Psychology, 1969)
Extrinsic Rewards and Motivation
Do extrinsic rewards increase motivation?
While offering rewards can increase motivation in some cases, researchers have also found that this is not always the case. In fact, offering excessive rewards can actually lead to a decrease in intrinsic motivation.
The tendency of extrinsic motivation to interfere with intrinsic motivation is known as the overjustification effect. This involves a decrease in intrinsically motivated behaviors after the behavior is extrinsically rewarded and the reinforcement is subsequently discontinued.
In a classic experiment by Lepper, Greene, & Nisbett (1973), children were rewarded lavishly for drawing with felt-tip pens, an activity that they had previously enjoyed doing on their own during play time. When the children were later offered the chance to play with the pens during play time, the children who had been rewarded for using them previously showed little interest in playing with the pens again. The kids who had not been rewarded, however, continued to play with the pens.
Why would rewarding an already intrinsically rewarding behavior lead to this sudden disinterest? One reason is that people tend to analyze their own motivations for engaging in an activity. Once they have been externally rewarded for performing an action, they assign too much importance to the role of the reinforcement in their behavior. Another possible reason is that activities that initially feel like play or fun can be transformed into work or obligations when tied to an external reward.
Extrinsic rewards can be an important tool in motivating behavior, but experts caution that they should be used with caution, especially with children. Extrinsic motivators are best applied in situations where people have little initial interest in performing the activity or in cases where basic skills are lacking, but these rewards should be kept small and should be tied directly to the performance of a specific behavior. Once some intrinsic interest has been generated and some essential skills have been established, the external motivators should be slowly phased out.
Observations
"The overjustification effect imposes a limitation on operant conditioning and its effectiveness in applied settings. It tells us that we need to be careful in our use of operant conditioning so that we do not undermine intrinsic motivation. It also tells us that we must consider the possible cognitive consequences of using extrinsic reinforcement."
(Griggs, Psychology: A Concise Introduction, 2010)
"To sense the difference between extrinsic and intrinsic motivation, you might reflect on your own current experience. Are you feeling pressured to get this reading done before a deadline? Worried about your course grade? Eager for rewards that depend on your doing well? If yes, then you are extrinsically motivated (as, to some extent, all students are). Are you also finding the course material interesting? Does learning it lead to you feel more competent? If there were no grade at stake, might you be curious enough to want to learn the material for its own sake? If yes, then intrinsic motivation also fuels your efforts."
(Myers, Exploring Psychology, 2005)