Medical How much of our brain do we actually use?

  1. Yeah I was told by a friend we only used 90% of our brains? Is this true?
  2. jcsd
  3. No, we use the whole thing. Maybe not to the fullest capacity, but we use the whole volume and mass of it.
  4. selfAdjoint

    selfAdjoint 7,521
    Staff Emeritus
    Gold Member

    Way back in the 1920s, some newspaper published somebody's idea that we only use 10% of our brain. Needless to say, almost nothing was known about the living brain in those days, and the opinion was worthless. However it got picked up and turned into an urban legend as friend heard it and retold it to friend. Your friend was a link in such a chain, but he got the percentages backwards.
  5. Our brains function like multicore CPU, with each core being specialised at a particular task. When that task isn't required, that area of the brain shows decreased levels of activity. Because the areas seem to be somewhat specialised, the areas with decreased levels of activity don't, or more likely can't, pick up work from the one's that are busy.

    So, when you image someone's brain, you can find that quite a lot of the brain tissue isn't actually doing much. It's not helped by the fact that a lot of activity scans are extremely specific, for instance, noting colours or smells and nothing else. In such a test, you'd expect to see only small areas of activity, and that's what they're after so's that they can try to pinpoint specific areas related to specific tasks. If you were walking down an unfamiliar street, much more of your brain would probably start coming on as each of the 'cores' began evaluating the new environment.
  6. somasimple

    somasimple 716
    Gold Member


    Normally we are using around 70% of our brain ressources but fortunately not at the same time. (temperature problem).

    The myth of the 10% is just an old meme to forget.
  7. Is it a well-defined question? What quantitive measure can it be answered with? I don't think looking at an MRI and measuring the volume in which there is activity addresses this.
  8. The title of this thread is quite ironic, by the way.
  9. there is only a small portion of our brain we use at any given time
    as to say yes or no and know the meaning at that time given. In other
    words on a yes reply your brain is giving you the go ahead in acceptance
    to where if you used the total brain you would crash
  10. Where does the 70% come from?
  11. If you have to use 70% of your brain just to answer a question
    yes or no somethings wrong. most people would use up about
    5% of their brain to hear a question and about 5% to answer yes or no
    to say it took 70% is astronormical.
  12. Moonbear

    Moonbear 11,955
    Staff Emeritus
    Science Advisor
    Gold Member

    Those scans don't actually tell us much about what parts of the brain are active; instead, they tell us which parts of the brain are MORE active compared to a baseline value. This misunderstanding of how to interpret those scans only contributes to the myth that we use only a small portion of our brains at any given time.
  13. That's why I'm interested to know whether there even exists a meaningful, quantitative way to ask this question. Given that the whole business is emergent phenomena, I'm leaning towards "no".
  14. selfAdjoint

    selfAdjoint 7,521
    Staff Emeritus
    Gold Member

    What percentage of the internet is active at any given moment? I agree with you; it's very close to a meaningless question as stated.
  15. That's a good point, but even still I don't think our brain is running anywhere near it's full capacity all of the time. If it was, we could expect to see very little / next to no change when you asked the person to concentrate on something specific, like a picture of a flower on a screen. Neither would there be much of a difference between normal, sitting around the house doing nothing levels of concentration and revision / idea generation levels. Where as we all know from personal experience that there's a big difference.

    The brain lives in a dynamic environment and doesn't process things like a computer (one block after another), it has to work on demand a lot of the time and can't afford to go out of real time to formulate answers for things - least it be flattend by the approaching bus. So it's a good thing it has at least some degree of dynamic range spare for complex problems that require an immediate solution.
  16. somasimple

    somasimple 716
    Gold Member

    I saw a scientific emission which stated it.:redface:
    As I said, it was only a computation with oxygen consumption and heat produced?! If the percentage was reached, temperature rises to dangerous level. But it may be only a meme.
  17. Isn't this kind of like asking "how much our arms do we actually use"
    If you are resting, I suppose one's arms are not used much. But if one is lifting something, I suppose the usage is greater.

    So isn't the "usage" conditional on situational application?

    But perhaps you are rather asking if one can increase the potential capacity. If that's the case, using the example of arms, one could increase their lifting capacity by nutrition and exercise training.

    I would suppose that the human brain can similary benefit through nutrition and "training"
  18. Okay, let refine the question to how much of our brain do we use through are entire life time for any action like walking, talking, watching girls, playing games, thinking. Everything, what percent don't we ever use, or don't now how we use it.
  19. The brain isn't really my specialty so please forgive me if this question is "dumb"...
    If we could potentially use 100% of our brains at any given time then why do we forget things? It would seem where I parked would be well within the brain capacity and yet I have forgotten where I parked before...
  20. DaveC426913

    DaveC426913 16,532
    Gold Member

    This is really about memeory retrieval. We are so busy with a million thoughts at once, we often have lose track of, not the memory, but the "tag" that allows us to retrieve the memory easily.

    I'll bet dollars to donuts that,once you found your car again, you "re-remembered" its location. If you had actually lost the memory, you would look at your car and say "huh, I honestly still do not remember parking it here."

    It's even more pronounced when someone tries to make you remember a movie you saw a long time ago.
    "Remember? We saw it downtown at the Imperial theatre."
    "Don't remember."
    "In July?"
    "Don't remember."
    "It had Peter Mayhew in it."
    "There was a circular chess board?"
    "Nope, nuthin'"
    "You got sick on the popcorn."
    "Oh yeah. Coming back to me now.."
    "Big guy in black. Wears an coffee maker on his chest. Makes sounds like a vaporizer?"
    Oh yeah! Star Wars!
  21. with the thread title....perhaps people should define the concept of "use" in relation to the brain as pertaining to the question

    "how mcuh of our brain do we use".
    On a related question one could ask what is the longest time interval to which a neuron could remain idle or not fire an AP?
Know someone interested in this topic? Share this thead via email, Google+, Twitter, or Facebook

Have something to add?