10% of your brain


If I have to hear this “we only use 10% of our brains, imagine what we could do if we used all of it!” myth one more time, I’m going to have to kill something. It is wrong, and it is stupid, and it has to die, until it is so dead that there will never be a movie based on it again.

After doing a great deal of research for about 5 minutes, I have determined that there are two possible origins for this myth. In both cases, the real fact of the matter is actually easy to understand if you bother to take the time. And in both cases, the assumption that “if only we could use more of our brain, we would be able to think better (or do more stuff, or do things faster, or remember more, or whatnot)!” is completely and utterly and obviously false.

Origin theory #1: One possible explanation is that the 10% statistic referring to brain matter, and the fact that most of the matter in our brains (by weight) is actually not used for conducting the electrical signals that produce thought. Most of the matter in our brains is actually insulation between the wires that carry the electrical signals that produce thought. So, if the brain is 90% insulation and 10% actual “signal carrying matter” then in some sense, we use 10% of our brains.

And if that’s the case, then saying “Imagine what we could do if we used all of our brain!” is like saying, “Imagine how well everything in your house would work if you replaced all of the wire insulation with more wires!!”

The fact is, insulation is just as important as conducting matter when it comes to carrying signals. Removing the insulation doesn’t “free the circuit to do more and better things!” It makes the circuit short out.

Origin theory #2: Another possible explanation is that the 10% statistic is referring to the results of PET scans. PET scans take a snapshot to show areas of electrical activity in the brain at a given point in time. As your thoughts and perceptions and feelings change, the patterns of electrical activity change: some areas are “lit up” more with activity when you are viewing something interesting, other areas are “lit up” with more activity when you are trying to solve a math problem, and so on. And overall, when you look at a lot of PET scan images, you see that at any single point in time, only about 10% of the brain is “lit up” with electrical activity.

And if that’s the case, then saying “Imagine what we could do if we used all of our brain!” is like saying, “Imagine how strong you would be if every single muscle in your body contracted at once!!”

The fact is, different brain areas—like different muscles—work in synchrony with one another and are specialized with different tasks. If every muscle in your body contracted at once, you would literally not move at all: because every muscle pulling on your skeleton would be opposed by another muscle pulling in the opposite direction. You wouldn’t be “super strong”, you would be non-functional. The same is true with the brain: having everything light up at once isn’t being “smarter”, it’s having a seizure.


I so rarely write spontaneous posts like this just to “get something off my chest.” Thank you for letting me vent. Let’s just say, there is one movie coming out this year that I will not be seeing.


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  1. Greg Stevens says:


    You are right, in general, of course. Some sci-fi/fantasy movies offer no "explanations" of their fantastical elements, while others enjoy twisting around real science concepts and jargon to make "plausible-sounding" explanations. In the end, why is using the "10% myth" any worse than (for example) being able to "beam people up" in Star Trek?

    It's tough to articulate why, but for me there IS a difference. It's similar to the fact that I can deal with "warp drive" in Star Trek, but when a person is able to out-run an explosion it BUGS me. Both are "non-science", so why am I able to suspend disbelief for one but not the other?

    I think it has to do with the way it is presented. In any science fiction movie, some things are presents as the "realistic" part, and others are presented as the "speculation" (or "extrapolation") part. When a person is running away from an exploding vehicle, it's a "normal" event and should be "realistic"… unless that person is wearing a special science-fictiony running suite or he's a super-hero with special "genes" or some-such.

    Star Trek explains "beaming people up" with real (albeit vague) ideas about energy, information, and patterns. Those vague ideas are "real" and they are put together in a speculative way that we know is speculative.

    If, on the other hand, Star Trek explained "beaming people up" by saying, "Well, it's well-known that the location of an object is determined by the recipes of the Keebler Elves. When you bean someone up, the machine is simply finding a way to change the recipe of the Keebler Elves!" it would be a much, much worse show. (Hopefully, we can come together on that! 🙂

    To me, any science fiction speculation that BEGINS with the premise, "It's well-known that we only use 10% of our brain" sounds pretty much exactly the same as the "Keebler Elves" explanation of teleportation in Star Trek. I can't take the leap to the speculation, because I'm not solid on the footing that the leap is supposed to be coming from.

  2. duncanji says:

    We can definitely agree that Keebler elf recipes have no place in Star Trek. I think I understand that your issue stems from the presentation of the concept. If the concept is presented in some form of "science fiction" you expect it to be at least tangentially based in fact? In any case, beam me up Scotty.

  3. duncanji says:

    >Why should entertainment be scientific? While it is a misconception, the idea is still fun to play with. The idea is to be something more than you are, to go beyond your human capacity and be someone extraordinary. It is fantasy, not fact.