[mamcx]

Not that crazy to say "You only use % of your brain!".

So, naive question: Could be correct to think that if half the brain is "enough" to have a full life, then the other half is utilized (in normal brains) but is wasting in doing unnecesary work? ie: Could be the brain is truly under-utilized, under-performing all the time? Like, is lazy?

[tim333]

Brains are probably lazy for the same reason animals in general are lazy - to save energy. The brain accounts for something like 25% of the body's energy use. I'm guessing it's similar to CPUs where most of the time they are under-utilised but can fire up when needed.

[Symmetry]

You're only using a certain percent at a time, but all the different sections of your brain do different things. And they are lazy when they can get away with it, read Thinking, Fast and Slow for some more details but even when you're thinking hard you're not using your whole brain. It's not at all obvious to me that the glucose supply, oxygen supply, or cooling of the brain are sufficient for you to run it at 100% without dying.