Blame it on cartoons, outdated textbooks, or your grandma’s confident (but very wrong) kitchen advice—some of the things we were raised to believe are straight-up fiction. From what animals actually eat to what your body does when you swallow gum, we’ve inherited a grab bag of myths that feel true but flunk the facts. The weirdest part? Many of these old-school beliefs were based on someone’s logic at the time, even if science has since torn it to shreds.
So if you’re still side-eyeing a toad thinking it’ll give you warts, or stashing cheese in a mousetrap like it’s the 1950s, it’s time to clear the air. These are the myths we all took as gospel growing up—until the research, the reality, and a few irritated scientists said, “Actually… not quite.”
1. Mice Actually Don’t Like Cheese
You’ve seen it in every cartoon since birth: the classic trap, the hunched-over mouse, the big ol’ triangle of Swiss. But here’s the twist—mice aren’t big fans of cheese. In fact, they often avoid it altogether. A study featured by National Geographic found that mice actually prefer grains, fruit, and sugary snacks over dairy. Their sensitive noses often reject the pungent smell of cheese, especially aged varieties. So if you’re stocking a trap, skip the cheddar and go for peanut butter.
So where did the myth come from? Most likely from medieval food storage habits—grains and bread were kept sealed, while cheese was left exposed. Mice went for what was available, and the cheese got the blame. But modern mice with choices? They’ll take a cookie crumb over Camembert every time. If you’re dealing with a pest, think pantry, not charcuterie board.
2. You Only Use 10% of Your Brain
It sounds like the plot of every bad sci-fi movie: what if we could just unlock the other 90% of our brain and become geniuses, psychics, or telekinetic masterminds? But here’s the truth—this idea is pure bunk. According to neuroscientists at Cleveland Clinic, we use virtually all parts of our brain, even while resting. Functional MRIs light up multiple regions as we go about everyday tasks—proving that your gray matter is not lounging on the job.
The myth likely came from misinterpreted statements about untapped potential, later warped by motivational speakers and pop culture. At some point, Einstein’s name got tossed in for extra flair (though he never said anything about it). But modern neuroscience has put this one to bed. Whether you’re crafting a PowerPoint or crying in the car to a podcast, your brain is firing on all cylinders.
3. Goldfish Have a Three-Second Memory
Goldfish have been unfairly slandered as forgetful little swimmers, doomed to eternal confusion in their bowls. But in truth, they’ve got memory skills that put that myth to shame. According to Scientific American, goldfish can retain information for months—not seconds. In lab tests, they’ve been trained to navigate mazes, associate sounds with feeding, and even recognize colors and shapes. That’s a far cry from the mindless looping we’ve been led to believe.
So where did the three-second myth even come from? Most likely, it’s a combo of their blank expressions and our own human projection. Because goldfish don’t bark, blink, or beg, we assume there’s nothing going on upstairs—but they’re quietly observing, learning, and adapting. In fact, their ability to recall feeding times and even who feeds them makes them a common test subject in behavioral science. Bottom line: just because your goldfish isn’t solving crosswords doesn’t mean it forgot you exist. It probably just knows you never give it the good flakes.
4. Swallowed Gum Stays in Your Body for Seven Years
We all heard the warning: swallow your gum and it’ll sit in your stomach for seven years, just lurking there, waiting to haunt your digestive tract. But that’s nothing more than playground legend. While it’s true your body can’t digest gum, it doesn’t mean it hangs around for years. According to Cleveland Clinic, swallowed gum typically passes through your system in a few days, right along with the rest of your lunch. Your digestive tract is surprisingly efficient, even when it comes to something as stubborn as synthetic chew.
So why did this myth stick? It likely began as a well-meaning parental scare tactic—one with just enough stickiness to last generations. And while doctors warn against swallowing gum frequently or in large amounts (especially for kids), a single swallowed piece won’t hurt you. Your stomach doesn’t trap it in a dungeon; it simply escorts it out the back door like anything else that refuses to break down. Crisis averted. But maybe still stick to chewing—not chugging.
5. Shaving Makes Hair Grow Back Thicker and Darker
It’s one of those “facts” we’ve all heard—usually from an older cousin wielding a razor like a cautionary tale: once you shave, the hair grows back thicker, darker, and coarser. But here’s the real deal: shaving doesn’t change your hair’s thickness, color, or rate of growth. What it does do is blunt the hair at the surface, making the regrowth feel stubbly or rough. According to the Mayo Clinic, shaving has zero impact on the root, follicle, or pigment—just the texture of what’s peeking above the skin.
The reason it looks darker or thicker? It’s all about illusion. Hair naturally tapers at the end, so when you shave it straight across, the edge appears thicker and feels more noticeable as it grows. Plus, the new hair hasn’t been lightened by sun or soap, so it may seem darker—especially against pale winter skin. But biologically? Nothing’s changed. Whether it’s your legs, your face, or that rogue chin hair, shaving is just a surface-level act. The hair’s not coming back with a vengeance… though it might still arrive fashionably late and uninvited.
6. You Can Catch a Cold from Being Cold
It’s the classic mom line: “Put on a jacket or you’ll catch a cold!” But while shivering may be uncomfortable, it won’t give you a virus. The common cold is caused by viruses—most notably rhinoviruses—not chilly air. You can stand outside in a tank top during a snowstorm and still stay healthy… as long as no virus is around to infect you. According to experts at Harvard Medical School, exposure to cold temperatures doesn’t cause colds—it may slightly suppress your immune response, but you still need actual contact with the virus to get sick.
So where did the myth come from? Probably because cold and flu season does happen in colder months—but that’s due to increased time spent indoors, poor ventilation, and closer contact with others. Viruses love that cozy, recycled air just as much as you do. Plus, lower humidity in winter can dry out your nasal passages, making it easier for viruses to slip past your defenses. But the weather itself isn’t the villain. So wear your coat to stay warm—but don’t give it credit for keeping you flu-free. That’s your immune system’s job.
7. Cracking Your Knuckles Causes Arthritis
It’s the sound that made every adult wince: pop-pop-pop—and then came the lecture. “Keep that up and you’ll get arthritis!” But despite what your aunt swore while swatting your hand away, cracking your knuckles doesn’t cause joint damage or arthritis. What you’re hearing is the release of gas bubbles in the synovial fluid that lubricates your joints. According to a study published in PLOS ONE, the popping sound is caused by a phenomenon called “tribonucleation”—a rapid separation of joint surfaces creating a bubble, not damage.
Long-term studies back it up, too. One famously eccentric doctor, Donald Unger, cracked the knuckles of just one hand every day for 60 years and left the other untouched. The result? No difference in arthritis or joint issues. He even won an Ig Nobel Prize for his trouble. While excessive knuckle cracking might lead to temporary swelling or weakened grip (if you’re really overdoing it), arthritis is linked to genetics, age, and inflammation—not your fidgety fingers. So crack away… just maybe not during a job interview.
8. Touching a Toad Will Give You Warts
It’s the campfire warning that launched a thousand squeals: Don’t touch that toad—it’ll give you warts! But here’s the truth: warts come from viruses, not amphibians. Specifically, they’re caused by certain strains of the human papillomavirus (HPV), which has nothing to do with frogs, toads, or your swampy summer adventures. According to KidsHealth from Nemours, you get warts from skin-to-skin contact with an infected person or surface—not from wildlife.
So why the bad PR for toads? Probably because of their bumpy, wart-like skin. Toads have glands called parotoid glands behind their eyes that secrete a protective substance—gross, yes, but not contagious. Over time, those bumps got lumped in with actual warts, and boom: guilt by association. While handling toads isn’t encouraged (some secrete mild toxins that can irritate your skin or eyes), they’re not walking disease factories. If you do touch one, just wash your hands—not because of warts, but because nobody wants mystery goo lingering at snack time.
9. Lightning Never Strikes the Same Place Twice
It sounds poetic, reassuring even—but it’s dead wrong. Lightning absolutely can and often does strike the same place multiple times. In fact, tall, isolated, or conductive objects are more likely to be repeat targets. Take the Empire State Building: it’s hit by lightning around 20 to 25 times per year, according to the National Weather Service. That myth about once-and-done? It’s as unreliable as standing under a tree during a storm.
The truth is, lightning looks for the quickest path to the ground, and anything that offers height or metal—like skyscrapers, radio towers, or even certain trees—becomes a lightning magnet. It doesn’t care if it’s been there before. Even people have been struck more than once (look up Roy Sullivan, who survived seven strikes). So yes, lightning can double-dip—and it’s not shy about it. The lesson? Don’t assume safety based on past strikes. If thunder roars, go indoors—every time.
So… What Else Have We Been Wrong About?
Turns out, a lot. From lightning’s alleged loyalty to goldfish memory slander, the world is full of myths that stuck around because they felt true, sounded dramatic, or made for a great one-liner. But science has a way of ruining the party—in the best possible way. The good news? Knowing the truth doesn’t just make you smarter at dinner parties; it gives you permission to stop fearing toads, ditch the gum guilt, and stop blaming your razor for your five o’clock shadow.
So next time someone repeats one of these childhood classics, you’ll know better—and maybe (just maybe) be the buzzkill with the facts. Or, better yet, let them finish… then hit them with the truth and a wink. Because busting myths? That never gets old.
