Fact or Fiction: We only use 10% of our brains?

By Casey Frye, CNN Writer

brain scan image
We definitely use way more than 10% of our brains.

The brain is a powerful organ that governs our behaviors and influences our moods. Though it only makes up about 3% of our weight, the brain uses about 20% of the body’s energy! Could it be that such an energetically expensive part of ourselves is only functioning at 10% capacity, like the popular myth would have us believe? As fun as it might be to believe there’s 90% of our untapped intelligence just waiting to be unleashed and turn us into super geniuses, that “fact” is absolutely false.

The truth is that all of our old noggin’ is active… all of the time! See, the brain is a living organ made up of billions of cells called neurons, and just about everything we do is made possible by these active cells. For example, right now your brain is monitoring your heartbeat, regulating your breathing, reading the words on the screen, holding your body upright, actively listening to the environment around you, and probably digesting food… all at once!

And, you don’t even have to think about doing these behaviors, because the brain basically does it all on its own. In other words, we definitely use more than 10% at any given time. Even though there are certain parts of our brains that are not as active during a particular activity, there is evidence to suggest that the different regions are still standing alert, ready to be put to use at a moment’s notice.

If that’s the case, why aren’t brain scan pictures filled with a bright rainbow of colors? Well, most of those images come from a process known as functional magnetic resonance imaging (fMRI), and the way they work is that only the most active parts of the brain at that moment show up with colors. That means the parts of the brain that aren’t as active will be grayed out to emphasize the parts that are chugging away in overtime. As New York University neuroscientist and psychologist Joe LeDoux explains, “the brain could be one hundred percent active during a task with only a small percentage of brain activity unique to the task.” It’s that small percentage that gets all the fancy blobs of color. So, whether we are busting our heads trying to solve a math problem, taking a jog down the street, or simply laying down for a nap, our brains never take a break!

Featured image courtesy of Clayton Cottingham on Flickr. Image of brain model courtesy of Ars Electronica on Flickr.