This reminds me of the movie Limitless, in which a drug is invented that gives people who take it access to the 80% of their brain that they don't normally use.
The brain has evolved over time. It has an amazing amount of elasticity with and a bunch of hardwired features. But other than that it's not filled with secret potential.
There is grain of truth on the "we only use 10 % of our brains" saying, that we don't usually use our whole brain at once. It is possible, but not very comfortable, the closest you can get would be something like solving differential equations in you head and driving a car at the same time, while singing and thinking about you wife.
The same is true of circuits. If you're a pipeline stage in a multiplier inside an ALU, you're only "used" when a multiply instruction passes by. If only 10% of instructions in a given program are multiplies, you're 90% idle. That doesn't mean that the multiplier is a useless circuit.
I've never seen a scientist make that actual claim. New-agers yes, eastern philosophers yes, comic books yes, scientists? Can't say I can remember any such instance.
> but I think that we only use 10% of our hearts.
The only way to only use 10% of your heart is to suffer from massive ischaemia, and that leads to death on pretty damn short order.
Very cute; I agree. Thank you :)