Why do scientists say that we only use 30 percent of our brain power?

Question

I mean, what else could we possibly do?

Answer 1

Given some of the people I've talked to, some use a lot less than that!  :-)

Also provides an interesting debating point with evolutionists. If everything evolves to meet a survival need, why would we evolve 70% more capacity than seems to be needed?

Are we using LESS brain power now than we used to?

Answer 2

I know of no scientists who make that claim.  I do hear the statement from people who know little about the brain.

Answer 3

I'm not aware of any scientist who has claimed that we only use 30% of our brain power.  It's a common urban myth, mostly put about my psychics and other charlatans (who claim that magical powers live in the other "unused" parts) that we only use a small percentage of our brain (the figure I hear quoted most often is 10%).

The fact is that the level of brain activity is highly dependant on what were doing.  Every part of your brain has a function, there is no useless 70% knocking around in your skull!

Answer 4

In Australia the national average is running at  > 01% of potential, as is evident by the politcians we elect.

Answer 5

you only use some parts of your brain at any single time, but overall if you are mentally healthy you use your whole brain. For example, you cant be hearing, understanding what youre hearing, and speaking rational thoughts all at the same time, can you?

Answer 6

Our brain continues to regulate circulation, breathing, kidney function, balance, immune systems, cellular communication, organ repair, and control our internal temperature at all times despite whatever else is happening. Whether we remember or not the brain is constantly processing the sensory input from touch, temperature, sight, smell, and sound, cross referencing it with what is normal and forgetting it by not sending it to long term memory. These basic systems operate to alert us to the unusual stimuli but not take up conscious processing for background stimuli.

http://www.sciam.com/article.cfm?id=forg...

This is why damage to the brain is not a light matter. If only a fraction where needed for us to maintain full function then there would be little to worry about head traumas. However that is not the case and even small head injuries can have enormous repercussions.

http://www.sciam.com/article.cfm?id=peop...

Evidence for the brains level of activity comes in the relative metabolic needs of different organs. The brain is a very small fraction of the body’s mass. At about 3 lb it is only ~2% of a typical body but uses 25% of its energy, 15% of the cardiac effort, and 20% of the oxygen. The rate of the brain's metabolism remains constant at about this level despite widely varying mental and motor activities. If the energy level is lowered, as it is in anesthesia, then the brain is reduced to basic functions and no upper cognition or memory is possible. Estimates vary but ~80% of the brain's metabolic energy needs may be taken by basal life operations keeping the body functioning. This means the brain gets 1/4 of the bodies total energy use but more than 3/4 is for basic house keeping.

http://www.pnas.org/content/99/16/10237....

http://www.acnp.org/g4/gn401000064/CH064...

Answer 7

It's a myth.