Brain Power - Am I fully utilizing it?

I was talking with one of my friends recently, and he came up with an interesting statistic:

Humans use only 10% of their brain power. And that too this 10% is used by the most brilliant, falling in the Einstein category. The rest, mortals, like me use even less.

I hadn't heard of this statistic before. Understandably I was bemused. Much later I came to find that this was a pretty common knowledge. Even my mom knew about this rather absurd statistic. So this one is not a thing that is cooked up in one of the thousands of senseless mail forwards that we get. And my mom also confirmed that this was known to my grand-mom too! So this is definitely been passed since ages. But I consider this to be a myth. And I'll list out my reasons for the same.

The idea that we only use 10% of our brains is probably such an enduring myth because it's comforting to think we have spare capacity. The 'unused' 90% could take up the slack after brain injury or offer the possibility for miraculous self-improvement. These were some of the thoughts that were passing in my mind to refute this myth.

• If we only use 10% of our brains then damage to some parts of our brains should have no effect on us. As most of you will agree that this is patently not true.
• From an evolutionary perspective it is highly unlikely we developed a resource-guzzling organ, of which we only use 10%. This doesn't make any sense.
  
• Brain imaging such as MRI shows that even while asleep there aren't any areas of our brain that completely 'switch off'. Seen this in one of the episodes of 'House M.D'. I know, it is still a TV show. But it might be true too.
  
• Parts of the body that aren't used soon shrivel and die. Same goes for the brain. Any neurons we weren't using would soon shrivel and die. Its just principles of evolution.

Anyone who still maintains we only use 10% of our brains after all these facts, has to come up with a counter-argument for each one of these. Actually, you might argue that imaging technology is rubbish or the neurons are only working at 10% capacity, but refuting all four, taken together? Now that's tricky.

Whatever its provenance, the 10% myth is certainly a slippery customer. The reason is two-pronged: first, it's impossible to prove something doesn't exist and second, people like to believe it. If I say I've seen God, or visited Mars, or that all our brains have huge untapped potential, you can't definitively prove me wrong.

Perhaps putting it the other way around might deliver the knock-out blow. Instead of talking about the 90% of untapped potential, just ask people why they only use 10% of their brains. Would anyone seriously admit to that? I, for one, am working at maximum capacity. Well, most of the time anyway...