Mythbusting Monday V: People Only Use 10% of Their Brains

First, a few housekeeping issues: You can now email any post on this site by clicking on the envelope icon at the bottom of each post.

Secondly, I've added a function on the right, just below my profile info, which provides you with a randomly selected Deep Thought from Jack Handey each time you load the page (refresh to get a different one.) Currently there are about 23 38 53 different ones, but I'll add more as I come across them.

This week's myth is the old 'you only use 10% (or x%) of your brain.' This myth is more than 100 years old, and has worked its way deep into the imagination largely because most of us have a desire to magically unlock some sort of hidden potential within ourselves, enabling us to effortlessly gain deep wisdom and intelligence. Who wouldn't want that? Unfortunately it has been the selling point used in many pseudoscience/new age systems, promising to enable you to unlock that further 90% for just 4 easy payments of $49.99! (Wow!)

This week's myth is rather fuzzily defined, so we'll approach it from a few different angles. The questions, 'what counts as the brain?' and 'what counts as use?' have more than one interpretation.

First, a short, simple answer: all of your brain is useful and has a known function (100% of it) - though there are also many functions we still don't fully understand. Additionally, most thought processes are very dispersed (processed in many parts of the brain simultaneously). We use all of the brain all of the time, even if the activity level varies - just like we are still 'using' our body when we sit down or sleep.

Now a more detailed answer... So, what counts as the the brain? Well, most people think neurons, and yes, the brain has neurons, but it is actually mostly glial cells (glia being Greek for glue.) In fact, only about 10% of brain cells are actually neurons - the rest are glial cells. But those glial cells are still vitally important - they support the neurons, provide them with nutrients, take away waste, insulate neurons from each others, and are implicated in some thought processes. Neurons would not function without glial cells. This could be one origin of the myth, since only 10% of your brain is neurons, but you still depend on and use that remaining 90%.

What counts as use? One interpretation of use is whether the cell is synaptically active (ie, the neuron is firing.) And indeed, only a small percentage of neurons are firing at any one time. So what would happen if all (or most) of your neurons fired at once? You would have a seizure. In fact, that is exactly what an electrical seizure is. If it happens long enough (and it usually doesn't), you would die. It is the brain equivalent of tensing all your muscles at once - it doesn't make you a super-athlete, it paralyzes you. You don't want to 'unlock' all those remaining neurons at once.

Another interpretation of use is 'potential,' ie, we only use 10% of the brain's potential. This is inherently an unanswerable question, because potential is virtually unknowable. However, our best evidence suggests that this too is poppycock. Most measures of cognitive function show people are actually very similar to each other - we all read at roughly the same speed (200 w/m), and we all have short term memories of about the same size (6 to 8 items). The rare individuals who excel dramatically in one area (for example, mathematics or memory), often have deficits in other areas (social functioning or language), suggesting that these people are not unlocking hidden reserves, but have brains that are specialized in a few areas at the cost of others.

We know the 10% myth is BS, but there are many things you can do to increase your mental performance. However, these involve behaviours and techniques, and do not change how your brains works, but rather take advantage of how it already works.

1. Use your brain - really challenge yourself until your head hurts. Your brain is like a muscle, and using it keeps it healthy - also like in muscle-building, very hard work gives better results than simple work. In fact, trying hard to solve a puzzle and failing is great for your brain - better than actually solving it. You won't become a genius this way, just like going to the gym won't make you a body-builder, but the effects will be beneficial.
   
2. Take advantage of the automaticity of habits. Once we are habituated to a behaviour, we do it automatically without thinking. Form habits like reading, puzzle solving, and game-playing and you are building in regular brain work-outs with minimal planning effort.
3. Use techniques like chunking and mnemonics to boost how much you remember. Also, you remember/understand things better once you have slept - staying up all night to study is a bad idea. There are hundreds of little techniques you can use to get better cognitive results without actually being any smarter.
4. Stay physically and emotionally healthy. There is a positive correlation between physical health and mental ability (counter to the unhealthy nerd/dumb athlete stereotype). Aerobic exercise, good nutrition, and adequate sleep are all critical to optimal mental functioning. Exercise is also especially important for emotional balance.

Enjoy your brain!

UPDATE: This is a very well done documentary on autistic savants, particularly Daniel Tammet. Watch it, and be amazed.