Ask most people the percentage of our brain we actually use, and you are likely to get the common answer of “10%.” It is often asked to motivate people to access those untapped resources that lie within our cortices. But is it true? Do we only use 10% of our brain? If so, what is the rest of it doing? And if not, where did we get that number?
I can attest to the ubiquitous idea of the 10%, as I have posed that question at the start of almost all of my functional neuroanatomy courses. Every year for the last 20 years, a large contingent of my students begin the course believing in the 10% concept. Of those that don’t, they are often unable to provide an estimate of how much of our brain is used.
So, is it true?
Decades of brain research dedicated to functional neuroanatomy have used cutting edge technologies to reveal activity throughout our entire brain. Functional imaging technologies such as fMRI, PET/SPECT and techniques measuring the brain’s electrical activity such as EEG/QEEG have all been used in testing this theory.
Through years of brain research utilizing the many available tools, we have learned that different activities will call on different brain regions at different times throughout our day. In the end, we certainly do wind up using virtually all of our brain’s resources at various times during the day. Of course, there will be times when much less of our brain’s processing abilities are used, like when we are at rest and not particularly focused on any specific activity or thought.
The concept of the brain as the source of our behavior and cognition can be traced as far back as the work of Hippocrates and Galen, both Greek physicians who studied the human anatomy. They also had the opportunity to observe the effects of different brain injuries such as those in soldiers returning from battle. By the 1960’s and the advent of neuropsychological assessment techniques, science developed the capacity to assess different brain functions. And with the introduction of imaging such as CT and MRI, they gained the ability to corelate brain functions with areas of damage.
Through our continually growing knowledge of brain functioning, the complexity of even seemingly simple acts come to light. A student simply sitting in class during a lecture shows multiple brain regions working in concert—the occipital processing the visual information being presented on the board, the temporal lobes processing the teachers voice and words, and the parietal lobes assembling he auditory and visual information to unify those sensory experiences. Deeper pathways move the information to the frontal lobes to give the student the ability to take notes on the new information. This is followed by the execution of motor programs to control the muscles in the hands to strike the correct keys on the keyboard in the correct sequence to transfer the new information to the screen. This is an oversimplified version of the process but underscores that even the seemingly mundane act of sitting in class activates numerous brain activities and functions simultaneously.
With all of the accumulated evidence, we can answer quite definitively that the idea that we use only 10% of our brains, while inspiring, is 100% false. If it is false, then where did the idea originate? This seems to be the subject of some debate. The 10% concept has been attributed to Dale Carnegie and the popular How to Win Friends and Influence People. The American psychologist, in the early 1900’s spoke of people using only a fraction of their full capacity. It has been speculated by some that Dale Carnegie tagged a number to James’ assertion as a motivational hook for his audiences. In the end, it is merely a myth that we use only 10% of our brains. In fact, it seems that even that concept was stretched from the likely original idea that we use only 10% of our brain’s potential. Regardless, both ideas fly in the face of centuries of accumulated observations and scientific data. Our understanding of the human brain’s capacity to process our world is inspiration enough to expand our horizons without having an arbitrary and misleading number applied to it.