not sure why nobody actually answered this question
but unless it was entirely meant as a joke, the question doesn't exactly make sense, because they were harvesting brains from all over the planet.. at the end they showed other cities around the world.
the story we see is just following these certain people for whatever reason.
as for what % of the brain people use work 3rd shift retail, there are plenty of people that use a very low percentage of their brains power.
also, not to argue the point of whether humans in general use all their brain power or not doesn't mean that 90% or 96% of the brain is completely not used, but it's like a car's engine if you step on the gas just a little you are only using a small percentage of the engine's power, that certainly doesn't mean you could remove 90% of the engine and it would still run.

According to this article people can function with only half of their brain.
http://en.wikipedia.org/wiki/Hemispherectomy
Check out the "further reading" links at the bottom of the article

Why harvest brains from LA?
Same reason you buy a car with low mileage.
They're unused.

The aliens were harvesting the brains in the hope that they could find a brain that could write a better movie script than the one they were stuck in.

This is true, but how old are the people who think we only use x% of our brains? This concept has been explained to be untrue years ago. I assume the people who still believe are either stupid, kids or american. Or all of the above.

Hehe all American's are dumb asses, you picked the wrong country.

LMAO - maybe the Aliens knew that the average LA brain is already programmed with trivial nonsense (celebrity culture etc) so job done .
That which does not Kill me makes me Stranger

Cause LA brains have the least wear and tear from usage on this continent
MrsPrimitiveBoomstick's bit of stuff

Lol! Well, you could say that these aliens are huge movie fans!

Brains from Los Angeles would be oxymoronic, wouldn't it?
Obamunism: The end of the Republic.
At times like these, I really hate being right!

Because the whole thing is a metaphor for the soul-sucking properties of LA.
maybe they were after those Hollywood script writers brains

Because the whole thing is a metaphor for the soul-sucking properties of LA.

king, youre a dum-dum.
Oh this should be good
to say that 'if we only use 4% of our brains, then we can destroy 96%' was a dum-dum argument.
No, the suggestion that we only use 4% of our brain is an idiotic argument, since it's factually incorrect.
it is said that we only use 4% of what our brains should theoretically be capable of using.
That saying is flat out wrong. Even if we were only using 4% of our brains potential, we're still not only using 4% of our brain. The two mean completely different things.
Also, how exactly do you measure what the brain is potentially capable of if nobody has ever used 100% of their brains potential?
Prof. Farnsworth: Oh. A lesson in not changing history from Mr. I'm-My-Own-Grandpa!

king, youre a dum-dum. to say that 'if we only use 4% of our brains, then we can destroy 96%' was a dum-dum argument. it is said that we only use 4% of what our brains should theoretically be capable of using. not that theres a 4% chunk of our brain that we use and the other 96% is just squishy filler.

The idea that we only use a certain portion of our brain is absolutely ridiculous, and only shows that people who make such a suggestion don't really understand how the brain works at all.
Prof. Farnsworth: Oh. A lesson in not changing history from Mr. I'm-My-Own-Grandpa!

Thank you for addressing the "we only use X% of our brains" silliness. While this is nonesense, at times I wonder if the people who believe this are the few that IN FACT do only use 4%. Analogous to only those that believe in a given religion get to go to that religion's version of heaven.

They're most likely using brains in place of processors. The people whose brains are taken are not in control of the machines.
Prof. Farnsworth: Oh. A lesson in not changing history from Mr. I'm-My-Own-Grandpa!

I'll bite. It was LA for 99% of the film, and at the end they showed a few other world cities that had been conquered, including NYC and London, and maybe a couple of others (Hong Kong?) that I didn't get a good look at

they should have harvested ASIAN brains.

All good. Certainly not the first time I was wrong about something
Two cheers for reductionism!!

You are wrong. When you see the Statue of Liberty the film maker is showing you various parts of the world where the aliens have landed. The majority of the film absolutely takes place in L.A..
Prof. Farnsworth: Oh. A lesson in not changing history from Mr. I'm-My-Own-Grandpa!

lol funny thread
Cool
Ice cold
Barrack Obama Ftw!!!, lukejedi203.inc

In the beginning of the movie Terry is trying to get Jarrod to move to the city and they say that it's Los Angeles. The end of the movie shows the Statue of Liberty in New York, The London Eye in England, and several other large cities to let the viewer know that the attack is taking place world wide.

I was wondering what city this was supposed to be for most of the film. But, the Statue of Liberty at the end tipped me off that it was not L.A
Two cheers for reductionism!!