Do we only use 10% of our brain?

An extraordinary belief that still lives on…here’s why it shouldn’t.

If you give this any serious thought it does seem ludicrous but yet it really does persist. In a 2012 study 26% of teachers thought this was correct and a further 26% didn’t know if this was correct (Dekker et al. 2012).

Where did it come from?

The most likely explanation is that it was a misinterpretation of William James (considered to be the father of modern Psychology) when he said ‘Most of us do not meet our mental potential’ which was later actually misquoted in the foreword of ‘How to win friends and influence people’. Einstein is also noted as saying that he only used 10% of his brain (though with all quotes attributed to Einstein there is no record!).

In the 1920s the self-help movement then perpetuated this myth, using it in advertising for various treatments and brochures.

Further to this in the late 19th and early 20th Century there were various areas of the brain that areas as psychologists could not figure out what they did, damage to these areas had no clear observable effects (the effects were subtle). Then experiments in the 1930s by Lashley where electrical stimulation to various parts of the brain failed to show any response, he ended up labelling these as silent areas which continued the idea of 10%.

I also wonder – though I have no basis for this – whether the use of the iceberg analogy for consciousness when considering Freudian Theory has also perpetuated it – nicely 10% of the iceberg is above water so if you had heard the myth this might reinforce the idea.

In more recent years there has been the case of Noah Wall – born with hydrocephaly (fluid in his brain) could have added to the myth as you can see on his scan his probably only had about 10% of brain volume compared to most infants. And this is not the only such case.

So how can this myth be challenged

1. Energy use

Evolution hates waste! The brain makes up approximately 2% of the body’s weight and yet uses 20% of the body’s daily energy. It is a high cost organ – evolution would not create an organ that is so energy intensive if it was so inefficient as to only use 10% of capacity.

2. Damage

Despite early research tiny amounts of damage to the brain can cause severe impairments to subtle cognitive functioning. If we only use 10% of our brain it would suggest that damage to 90% would mean we could still function and this simply isn’t the case!

3. Brain Mapping

With the advent of scanning such as PET and MRI all areas have been mapped and there are no functionless areas.

4. Scanning

Scanning techniques also show that in a healthy brain there is activity throughout the brain at all times.

5. Pruning

We know also that neuronal projections that aren’t used tend to degenerate, so if we didn’t use 90% of our brain we would see much more degeneration.

So let’s hope that puts your mind at rest. Despite the claims of people like Uri geller the extra ‘unused’ 90% is not usable for psychic power or psychokinesis or any other superpower!