Fact of Fiction: Do We Really Use 10 Percent Of Our Brains?

The new summer movie Lucy is based on the premise that humans use 10% of their brain. But is it really true? INSIDE EDITION finds out.

Lucy is the new summer movie with a fascinating premise.

Morgan Freeman's character in the movie says, "It is estimated human beings only use 10% of the brain's capacity. Imagine if we could access 100%."

Scarlett Johansson stars as Lucy, an innocent woman forced to smuggle a mysterious chemical that has been sewn inside her abdomen. The chemical seeps into her body causing a stunning transformation.  

In the early stages of her transformation, her character says, "I can feel every living thing."

And her powers continue to grow.

The 2011 Bradley Cooper movie Limitless had a similar concept, and The Simpsons did it for laughs.

Pretty inttriguing, but there's one big problem.

Neurologist Josh Cohen at Mount Sinai Hospital in New York says the notion that we only use a small portion of our brain power is ridiculous.

Dr. Cohen told INSIDE EDITION, "It's not true that we only use 10% of our brain. We are constantly using 100% of our brain. Evolutionarily, it wouldn't make sense to have these big brains and only use 10% of it."

The show MythBusters even put the theory to the test with a series of brain scans. The result? "We definitely use more than 10% of our brain," said Mythbusters.

As for Lucy, reviews of the movie have been mostly positive. The New York Post gives Lucy three out of four stars saying, "It contains as well as celebrates ideas."

So, what if some of those ideas aren't really true? It still makes for one entertaining movie.

Hear More From Neurologist Dr. Gary Starkman About the Myth