Lately there’s been a lot of rabble going on regarding the old myth of “we only use 10% of our brains” and it got me thinking:

• Is this true?
• ARE we actually only utilizing such a small percentage?
• Or is there more to this myth than meets the statistic?

If the answers to these questions are a resounding “yes”, then knowing how to access the “unused” part of our brain should unleash amazing untapped mental powers and allow us perform at “superhuman” capacity, shouldn’t it?

So I decided to do a little research and see if I could get to the bottom of this age old myth.

In the Media

Several public figures have made reference to the 10% brain use statement.

In 1908, American psychologist William James wrote:

We are making use of only a small part of our possible mental and physical resources.

Some other famous people (without training in neuroscience), such as physicist Albert Einstein and anthropologist Margaret Mead, are also attributed with statements regarding the use of only a small portion of the brain.

Regardless of its origin, the statement that we use only 10% of our brains has been promoted by the popular media for many years.  Many advertisers have also jumped onto this popular statement bandwagon to sell their products.  According to these advertisements, if we buy their products, devices, or programs, or utilize their services, we will be able to tap into the brain’s “unused powers” and enrich our lives.

But what exactly does it mean to “only use 10% of your brain” ?

Does this statement imply that only 10% of the brain’s neurons are active at any one time?

And if so, how could this possibly be measured?

Or perhaps this statement assumes that only 10% of the brain is firing action potentials at one specific time? But then again… even if this was true, the discharge of action potentials is not the only function of neurons.

Neurons receive a constant bombardment of signals from other neurons that result in post-synaptic potentials. Post-synaptic potentials do not always result in the generation of action potentials. Nevertheless, these neurons, even in the absence of generating action potentials, are active.

 

Make it STOP…

Some might argue that if all neurons of the brain were generating action potentials at the same time, it is highly likely to result in mental and behavioural dysfunction. In fact, some neurotransmitters have the specific function to inhibit the activity of neurons and reduce action potential (such as GABA).  As a matter of fact, massive excitation of neurons in the cerebral cortex may result in seizures such as those that occur during epilepsy.
Hence, inhibition of neural activity is a normal and important function of the brain.

In other words, some areas of the brain are designed keep other areas quiet.

Something else to keep in mind (pardon the pun), is that neurons are not the only type of brain cell.  Although there are an estimated 100 billion neurons in the human brain, there are another ten to fifty times that number of glial cells (also called Neuroglia) in the brain as well.

Although Neuroglia do not generate action potential, their function is to:

• support the brain structurally
• insulate axons
• clean up cellular debris around neurons
• regulate the chemical composition of the extracellular space

Now the questions arise:

• Would we behave normally without 90 billion neurons and billions of glial cells?
• Would we be just fine if 90% of our brains was removed?

Let’s put it into a different perspective…
If the average human brain weighs 1,4 kilograms and 90% of it was removed, that would leave 140 grams of brain tissue, which is roughly the size of a sheep’s brain…. (Baaaaaad idea)

Yet, clinical evidence indicates that damage to even a small area of the brain, such as that caused by a stroke, may have devastating effects.  Some neurological disorders (e.g. Parkinson’s disease) also affect only specific areas of the brain.

There are also cases where serious disabilities arose after damage occurred to far less than 90% of any particular area of the brain.

Because removal of small essential brain areas may have severe functional consequences, neurosurgeons must map the brain carefully before removing brain tissue during operations in cases of epilepsy or brain tumours.

 

Because Science Says So…

In addition to clinical evidence, brain imaging methods also appear to contradict the 10% brain use statement.

For example, positron emission tomography (PET) scans show that much of the brain is active during many different tasks.  Often when brain scans are reviewed, they have been manipulated to show relative amounts of brain activity rather than absolute activity.  This graphical presentation of the data shows large differences in brain activity.

What this means is that, although it may appear that some areas of the brain are inactive, they are in fact active, albeit at a lower level compared to other areas.

Brain scans only show activity for the carefully designed isolated tasks being tested, such as memory or visual processing.  They do not show activity related to other untested abilities.

To put that into easier to understand terms, let’s imagine the brain as a restaurant kitchen…

If you looked in on the kitchen at one time, you may see the chef preparing a delicious, healthy salad.  You may not, however, notice that the main course is also busy cooking in the oven.  Similarly, if you image the brain during a visual task, you will not notice the other patterns of activity associated with performing different tasks simultaneously.

Evolutionary Perspective

From an evolutionary perspective, it is highly unlikely that a brain that is 90% useless would develop. The brain is a large and “expensive” (in terms of the body’s energy resources) organ to maintain.  Certainly there are redundant pathways that serve similar functions…?

If I may speculate; This redundancy may be a type of “safety mechanism” in the event that one pathway for a specific function were to fail.  However, functional brain imaging studies show that all parts of the brain are functional.  Even during sleep, the brain is active and is still being “used”; it is just in a different state.

Developmental Perspective

From a developmental perspective, the 10% of the brain statement also fails to come to par.

Ever heard the phrase “use it or lose it”?  This seems to apply to the developing nervous system as well.

Nobel prize winners David H. Hubel and Torsten N. Wiesel demonstrated that; During development, many new synapses in the brain are formed and after birth, many synapses are eliminated later on in development.  This period of synaptic development and elimination goes on to “fine tune” the wiring of the nervous system.  It appears that correct input is required to maintain a synapse.  If input to a particular neural system is eliminated, then neurons in this system may not function properly.

In the visual system, for example, they showed that complete loss of vision would occur when visual information was eliminated during early development. It seems reasonable to suggest that if 90% of the brain was not used, then many neural pathways would likely degenerate.

Apparently, brains are quite adaptable and do have the ability to recover after damage.  When a brain is damaged, remaining neural tissue can sometimes take over and compensate for the loss.  The ability of the brain to recover lost functions does not indicate that the damaged tissue had no function, but rather, this ability illustrates the brain’s capacity to reorganize and rewire itself.

And thus it appears, unfortunately, that there is no “hidden vault” of untapped brain power, located “somewhere” in the unconscious.

 

Agree or Disagree…?

Let us know in the comment section below…