Facts about the human brain everyone gets wrong
You use a lot more than 10 percent of your brain
Oh, man. You've heard the old yarn about how humans allegedly use only 10 percent of their brainpower, right? You might've even repeated it a few times. Some people find it wonderful to imagine that there's some mystical 90 percent of untapped cognitive potential that, if accessed, could allow you to think lightning fast, learn 600 new languages, gain awe-inspiring telepathic powers a la Charles Xavier, and maybe even score a B+ on your math test. These possibilities have fueled popular fiction like Lucy, Limitless, and Flight of the Navigator, and people you run into at parties might occasionally suggest that another 30 percent can be unlocked through really potent recreational drugs.
Sorry, it's a load of bunk. As Scientific American explains, humans use 100 percent of their brains, every day. The brain is complex, and there's no space wasted, which is why brain surgery is so ridiculously complicated: Nicking the wrong cluster of neurons could impact your control of individual toes or fingers or internal organs. Even simple activities like making coffee in the morning involve intricate neural processes from disparate brain zones, like the world's fastest WhatsApp chat.
It's hard to say where this myth got started. William James hinted at it as far back as 1907. However, PRI argues that it was popularized by Dale Carnegie's 1936 self-help book How to Win Friends and Influence People, which contained a line about people using only 10 percent of their latent mental ability. Nothing about psionic powers, unfortunately.
Brain size doesn't matter
Human beings are ludicrously smart creatures, even though watching enough dumb YouTube videos might suggest otherwise. Considering the massive craniums perched on our spindly human shoulders, it's easy to believe that human intelligence is due to brain size.
But if the size of your brain really correlated with IQ, perhaps we'd all be speaking whale. The biggest brains in the world belong to sperm whales. According to World Atlas, these mighty creatures have 18-pounders floating between their eyes. Yikes.
But whales also have huge bodies, so what about proportionate weight? By that measure, tree shrews could be masters of the Earth. As Popular Science illustrates, humans are gifted with a rather heavy brain-to-body ratio of 1:40, which is comparably bigger than other intelligent creatures like dolphins and dogs, but tree shrews have us beat with a 1:10 ratio. Even more insultingly, ants put humans to shame at a 1:7 ratio. The key point here is that intelligence is rooted in complexity, not size. Ants might have big ol' noggins for their bodies, but each of their heads possesses only 250,000 brain cells, meaning it takes an entire ant colony to reach a human's level of neurons. So if your big-headed bully ever uses brain size comparisons to say they're smarter than you, you can now put them in their place.
Left-brained or right-brained?
Fold your hands together, with one thumb on top. Is the dominant thumb the left one or the right? Actually, don't bother. While the left-/right-brained paradigm is a useful symbolic way to discuss different thinking styles, it doesn't square with science.
That said, unlike many phony brain theories, Psychology Today reports that the left-/right-brained mythology does contain a kernel of truth: The hemispheres do have different strengths. However, these strengths work together, not apart. For example, while the left hemisphere of the brain is dominant for language processing, the ability to understand the more subtle emotional details of language — such as intonation — comes from the right hemisphere. So while it's fascinating to see how both halves of the brain do their own thing and communicate with each other, it's important to recognize that a properly functioning brain depends on both sides, like Superman and Batman teaming up to fight the bad guys.
Here's the deeper issue with the myth. If a person writes off half of their abilities by saying "I'm a [left- or right-]brained person, so I'm bad at that," it can limit their growth. For instance, the Guardian poses the example of a 12-year-old who struggles with math, decides that she's "right-brained," and doesn't bother studying math (or other "left-brained" activities) anymore, preventing her from improving in that arena. Similarly, those who test as left-brained might convince themselves they have no creative potential. In this, as in everything, balance is key.
The brain stops developing ... when?
While you probably stopped adding inches to your height by the time high school graduation rolled around, your brain never stops evolving, adapting, and changing shape. The brain's ability to continually reorganize itself is called neuroplasticity, according to NICABM, and it's also what allows you to survive strokes and brain injuries. Every new experience in your life, good or bad, changes your brain on a physical level. Every trauma, bit of knowledge, social interaction, or new hobby is continually reshaping your identity. While that cranky middle-aged guy at work might say "I'm just the way I am, and I'm never going to change," the reality is that he's constantly changing.
When brains are damaged, according to the University of Washington, changes help maximize function, as brain cells that surround injured areas take on the old functions as best they can. The Washington Post points out that when adult mice lose their sense of sight (by being kept in the dark, for long enough), their brains re-mold themselves in a way that dramatically improves their sense of hearing.
When you sleep, your brain (doesn't) power down
You might need to get some shut-eye, but your brain doesn't. Whether you lie down for a 15-minute power nap or sluggishly roll out of bed after 10+ hours, your brain spends that whole time buzzing away, fiendishly plotting its escape from the weak, fleshy body that it has been trapped in all these years…
Okay, maybe not that last part. But yes, despite what you've heard, brains don't sleep when you do. First, according to the National Sleep Foundation, the reason most people don't go sleepwalking at night is because the brain stem shoots people full of muscle-relaxing signals, paralyzing the limbs during sleep. Creepy, right? After you drift off, the brilliant demon in your skull keeps on chuggin' away, and the hours you spend sleeping are actually some of the most valuables moments of your day, hence why insomnia is so bad for you. For example, some of your brain's favorite sleepy time activities are flushing out toxins — to protect you from getting sick — as well as giving you dreams, and solidifying newly learned skills like playing guitar, picking up a new language, and so on.
That's right, students. If you want to do well on your test, try getting a good night's rest instead of studying into the wee hours.
Memory lapses aside, old age doesn't ruin your brain
It doesn't take a scientist to tell you that senior citizens sometimes forget things, whether there's dementia involved or not. However, while these moments of confusion — which neuroscientists call by the rather nasty name of "cognitive failures," according to Business Insider — certainly do increase with age, that shouldn't be taken as a sign that old brains are getting mushy.
Certain skills do decline in the aging brain, like the ability to encode new information to memory, but other skills become sharper than any young whippersnapper could hope for. To put it bluntly, older brains think slower but more deeply, according to Harvard. That's because even though the neurons aren't communicating as rapidly, the branching of the dendrites increases, allowing disparate areas of the brain to connect in ways they never could before. In layman's terms, this allows the elderly brain to become more skilled at figuring out how an array of different real-world puzzle pieces all fit together as a whole. Drawing connections becomes easier the more connections you've seen in your life. Basically, this is the physical reason the whole "wisdom" thing happens. So hey, that's worth forgetting a few names, right?
Drinking liquor, beer or wine kills your brain cells
The five rounds of shots you and your friends downed last weekend might do all kinds of messed up things to your Monday morning, but the good news is it won't ruin your brain. At least, not the drinking part. As for what you do when you get drunk, well…
To be clear, as Gizmodo points out, the myth that downing your favorite IPA, stout, or whiskey will slaughter brain cells by itself is loosely based on the fact that, yes, pure alcohol does kill things, which is why it's used as a disinfectant. But drinkable alcohols are a different story, and in order to drink the amount of alcohol needed to destroy your brain (if such a thing were desirable) you'd have to drink enough to kill the rest of your body at the same time. So don't stop drinking for this reason, but do be responsible. While your brain cells are chemically safe, excessive drinking does do damage the dendrites in your brain, thereby making it difficult for the brain cells to communicate effectively with each other. This damage is fully reversible with enough sober time, even for longtime alcoholics, so it's a good reason to schedule a few health days somewhere in your party vacations.
Headaches are brain aches
Headaches suck, and migraines suck even more. However, as painful or disorientating as these sensations might be, the thing that's hurting isn't actually your brain. That lovely organ, as it happens, is unable to feel pain, touch, or any sensation, according to BrainFacts.org, as there are no nociceptors (the fibers that transmit pain) located in brain tissue. In other words, if you were fully conscious as a brain surgeon was cutting through your grey matter with a scalpel, you wouldn't even feel him cutting your brain … you know, once he got past all the hair and scalp and skull. Creepy.
So what body part is tormenting you during a headache? It turns out that between the brain and the skull are layers of tissue known as the dura and pia, which do have nociceptors and are thus able to tell you how they're feeling when they get uncomfortable. Calling it a dura-pia-ache is a bit less catchy than "headache," admittedly.
Alzheimer's/dementia is a normal part of aging
When it comes to Alzheimer's disease, the facts and figures are pretty terrifying. Alzheimer's is the sixth leading cause of death in the United States, as one of every three seniors now dies from Alzheimer's or some other form of dementia. One-tenth of people over the age of 65 have dementia from Alzheimer's, and a staggering 5.7 million people in the U.S. are living with the disease today. So it's easy to see why people assume that dementia is a normal part of aging.
As the Atlantic explains, there's nothing natural about Alzheimer's. It's a fatal disease, which happens to usually — but not always — prey on the elderly, by forming its signature plaques and tangles in the brain, destroying neural connections, and atrophying the hippocampus. As a large number of people come down with this disease every day, it's important to recognize that it is, indeed, a disease — and that's why supplying the funding to create a cure, hopefully in the near future, is a worthwhile endeavor.
Throwing gender stereotypes to the wind
Are there differences between men and women? Certainly. But centuries of discriminatory arguments about the differences between male and female brains are, as you might've guessed, rooted in misunderstandings, falsehoods, and misogyny, rather than science. In fact, as Fast Company says, while male and female brains have minor differences and respond differently to certain disorders, most of the stereotypes you've ever heard about how "women are like this" or "men are like that" tend to be total hogwash.
In reality, 97 percent of humans brains have both male and female components, not one or the other. Even when neuroscientists look at the brain by itself, without knowing the person, they can't identify the person's sex. Another study in 2009, according to Quartz, showed that when brains are exposed to a stress source for 15 minutes, the individual neurons can change between "male" and "female" like flipping a coin. This doesn't change other differences between men and women, but it does clarify that these differences — such as common interests, career paths, communication styles, and so on — are mostly cultural, rather than biological. Diving even further, many of these beliefs are rooted in a binary idea of gender (the notion that one must be "male" or "female" only) that science has demonstrated to be outdated and false.
Comas are just like long naps, right?
From the outside, comas certainly resemble sleep, especially if the only coma you've experienced was when your favorite TV character got put under for three episodes. In real life, though? There's nothing restful about a coma.
As mentioned earlier, the brain works overtime while you sleep, doing tasks like saving memories onto your cognitive hard drive. During a coma? Not so much. As Psychology Today explains, there's a big difference between being "asleep" and being "unconscious," as the latter effect — whether due to being in a coma or being put under anesthesia — is one of amnesia, disconnection, and your brain being powered off to the point where you can't be woken up by someone shaking your leg. Admittedly, people mix these things up partly because of how anesthesiologists often describe themselves as "putting people to sleep," according to the New England Journal of Medicine, but this just a euphemism, since phrasing it the correct way might terrify a few patients.
People with dyslexia see words backward
Whenever a kid writes their letters backward, everyone thinks they have dyslexia. In reality, though, Dyslexia Help explains that plenty of children, both dyslexic and not, reverse letters when they're first learning how to read and write. According to BrainFacts.org, the reason kids sometimes reverse their B's and their D's has nothing to do with being dyslexic, and everything to do with how the human brain has a tough time training itself to read initially. From the beginning, your ever-flexible brain learns to recognize things that are inverted (such as Dad turning to the left, then turning to the right) as the same object, whereas reading and writing doesn't allow for inversion. So while reading is no big deal once you figure it out, it can take a little while to do so.
Now, dyslexic children don't read things backward because dyslexia is not an issue with the eyes. Rather, these individuals can struggle with matching letter shapes to the verbal sounds the letters produce. When dyslexic children do continue to draw backward letters longer than non-dyslexic children, this is simply a sign that they're having difficulty with the concept of letters/sounds altogether and could use some specialized assistance.
Classical music makes babies smarter
Ah, the Mozart effect. While new parents deal with an endless slew of "helpful" suggestions about how to raise their infant, one of the oddest ones is the decades-old theory that having your baby listen to Mozart will make them smarter, faster, etc. In 1998, Georgia Governor Zell Miller asked the state to set money aside to send every newborn a classical music CD, according to the BBC. Yay for a smarter next generation!
Unfortunately, none of this quite lines up with the original 1991 study, which was actually conducted on teenagers, rather than babies. That's Oops #1. Oops #2 is that while listening to Mozart for about 10 minutes did improve the spatial intelligence of these young adults, this great "Mozart effect" only lasted 15 minutes. Not quite a life-long impact. Along comes Oops #3, which is that later studies have shown that this same burst of spatial intelligence improvement can be achieved by listening to other music, a Stephen King audiobook, or anything that makes the listener happy, rather than having anything to do with Mozart's music in particular. Sorry, Wolfgang, no special cognitive effect here. But hey, if you or your baby enjoy classical music, play it as much as you like.