How much brain is used in higher thought?

Answer 1

The question is essentially meaningless.

I'm guessing you've heard some variant on "most people only use 10% of their brain", which is, if it's not completely made up, at least seriously mistaken/dumbed-down from some original statement that might have been approximately true.

Less than 10% of your brain's neurons are firing at any given time, most of the time... that's true. There's a word (well, a phrase) for when the firing percentage is higher than that, and that phrase is "epileptic seizure."

It's also probably true that at the time it was said scientists knew what around 10% of the brain actually did. The rest of it didn't seem to be obviously connected to anything important, like sensory neurons or motor neurons. Science marches on, and we now know what a lot of parts of the brain do, at least in vague terms ... some parts seem to have to do with memory, other parts are related to imagination or abstract thinking, some parts have to do with emotions, and so on.

In other words, most people use 100% of their brain. The parts that are storing grandma's cookie recipe probably aren't terribly involved when you're thinking about whether or not marijuana should be legalized, but it would be foolish to attempt to assign a percentage ... after all, you might start thinking something along the lines of "I wonder how much hash I could add without spoiling the flavor? Let's see, there's 3 eggs..."