This week, Redditor u/GlamourzZ asked, "Whatβs a myth/pseudoscientific belief that has been debunked many times, but people still believe?" There were tons of myths about health, biology, and the human body, so we decided to pull them together. Here are 30 things you might not know aren't true:
Myth #1: Cracking your knuckles will give you arthritis.
The truth:
The cracking, popping sound you hear when you crack your knuckles is from bubbles bursting in the synovial fluid in your finger joints. That synovial fluid helps lubricate your joints, but luckily your body replenishes it on its own. So it's almost definitely not going to cause arthritis, but be careful before you back-talk your mom the next time she tells you to stop the habit: Cracking your knuckles could still cause injury if you do it too hard or bend your fingers in the wrong way. Doctors also suspect it might cause a loss in grip strength in some people. But generally, as long as it doesn't hurt when you're doing it, you should be okay.
Where the myth came from:
You can see how doctors would assume that if you're messing with β or even decreasing β the fluid that lubricates your knuckle joints, your joints would eventually start grinding together and causing arthritic pain. But again, since your body replenishes the fluid, this is very unlikely to happen.
Myth #2: You need to "detox" your body with teas and special diets.
The truth:
Detox teas are, by and large, totally bogus. While the idea of "toxins" in our bodies might be scary β especially with all the microplastics in our environment β our bodies already have ways of dealing with any substances that don't belong in our system. Specifically, your liver and kidneys will do a better job of detoxifying your body than any tea would.
In general, if a product or diet makes a vague claim to eliminate "toxins" from your body, be wary. Most of the time, they aren't even clear about what "toxins" they mean.
Where the myth came from:
Simply put, it's marketing. Companies that produce things like detox teas make vague health claims that are not backed by science, and then push out their products through the influencer pipeline, getting celebrities like the Kardashians or other social media stars to endorse the product. Of course, drinking tea could have some health benefits! If anything, a non-caffeinated herbal tea will most likely be good for hydration. But if you're looking for a tea that will cure cancer, make you lose weight, or eliminate migraines (all claims that some detox tea companies have made), you're going to be disappointed.
Myth #3: Spinach has way more iron than other vegetables.
The truth:
Spinach does have decent iron content, but it's not that much more than other leafy greens, and some vegetables even have significantly more. For example, one cup of raw spinach has about .81 milligrams of iron, while Brussels sprouts have 1.2 milligrams. In fact, the oxalates in spinach might actually prevent you from absorbing the iron in the vegetable, so if you want to increase your iron levels, you should probably avoid spinach as the main contributor.
Where the myth came from:
Believe it or not, the myth came about because of a decimal error. A researcher in the late 1800s accidentally printed that there were close up 35 grams of iron in a certain amount of spinach, as opposed to 3.5 grams, which was the correct amount. Then along came Popeye comics and cartoons, which furthered the idea that spinach had practically supernatural levels of nutrition.
Myth #4: You can determine someone's personality based on their handwriting.
The truth:
The practice of "graphology" β the interpreting of a person's handwriting in order to predict behaviors and personality traits β appears to be inconsistent at best, and completely useless pseudoscience at worst. A meta-analysis of more than 200 studies revealed that analyzing handwriting failed to predict personality with any kind of consistency, indicating that it was mostly guesswork. In fact, one of the studies pitted graphology experts against untrained amateurs, and the experts failed to outperform the amateurs.
Where the myth came from:
A French archaeologist named Jean-Hippolyte Michon coined the term and published a book explaining the practice, leading graphology to become very popular in France. In fact, even today, many French companies use handwriting analysis in hiring decisions. It seems like graphologists might β intentionally or not β use "cold reading" techniques that psychics, palm readers, or mediums often use in order to coax information out of the subject and narrow things down enough to make an educated guess about their personal life. So it's understandable that graphology would be as convincing as those practices.
Myth #5: Dogs only see in black and white.
The truth:
Dogs actually see in color just fine! However, they appear to be missing the receptors that allow them to see reds, so red colors might appear more yellowish to them, and purples will appear more blue. It's suspected that they see colors less vividly than human do as well, so it may be more difficult for them on occasion to differentiate one color from another. However, they make up for their deficiency in color vision with more receptors that allow them to see clearer in low light.
Where the myth came from:
Will Judy, a former publisher of Dog Week magazine, claimedΒ in the 1930s that dogs were only able to see in black and white, and that the whole world appears in grayscale to them. Even in the 1960s, researches suspected that only primates could see color. It wasn't until researchers started doing closer examinations of animal retinae that they started to suspect that dogs could see color as well. Since so many of us own dogs, it's understandable that this old myth would spread via word-of-mouth.
Myth #6: Gum stays in your digestive system for seven years.
The truth:
If you swallow gum, it'll move through your digestive tract and you'll poop it out within a few days. However, children can end up with intestinal blockages if they swallow a large amount of gum, so it's best to avoid swallowing gum when you can.
Where the myth came from:
There's a tiny bit of truth in this myth: You actually can't digest chewing gum. Your stomach won't break it down, and it'll travel through your digestive system and exit out the other side mostly intact. This is why it can cause the aforementioned blockages in those with smaller digestive tracts. So maybe that bit of truth just eventually morphed into the seven-year thing...or maybe an annoyed parent told their kid that lie to get them to stop swallowing it.
Myth #7: We only use ten percent of our brains.
The truth:
We use all of our brain pretty much all the time. Researchers are able to use functional MRI machines to watch brain activity in real time, and have found that large areas of the brain are used for all kinds of tasks. Even if you just think about it logically, if we only used ten percent of our brain mass, then most brain injuries wouldn't cause any problems...of course, we know that isn't the case.
Where the myth came from:
It's tough to say exactly where it started, but it might be just from various sources making vague claims that humans haven't unlocked their full mental potential, and somehow the "10%" bit just got tacked on. The idea was reiterated in the bestseller self-help, book How to Win Friends and Influence People,Β in the 1930s and is popular among self-help authors. And then, of course, there's the pop culture reinforcement of the myth in movies like LimitlessΒ and Lucy, in which the main characters "unlock" 100% of their brain's capacity and are suddenly imbued with superhuman abilities.
Myth #8: According to all known laws of aviation, there's no way a bee should be able to fly.
The truth:
Bees are (obviously) perfectly able to fly. We know this because bees fly.
Where the myth came from:
An entomologist in the 1930s considered a bee's body weight, aerodynamics, wing span, and so on, and determined that they shouldn't be able to fly, all things considered. However, bees don't fly the same way as airplanes, or even birds: Their wings don't stay out straight or flap up and down. Instead, they flap in a back-and-forth motion.
So when you add to that the meme-worthy Bee MovieΒ intro, it's clear how this myth perpetuated.
Myth #9: You swallow eight spiders a year in your sleep.
Suggested by u/sir_ornitholestes
The truth:
You probably swallow zero spiders in your sleep during your entire life. The fact is, spiders are probably terrified of us, even when we're sleeping. We're big and we make noises and sometime snore, so they will want to avoid us if possible. Even our heartbeats can scare a spider away from crawling on us. If you're in a heavily infested area and you're a very still sleeper, you could end up with a spider crawling on your face, but the sensation would probably wake you up. And even if it didn't, you'd have to be sleeping with your mouth open, and the spider would have to be dumb enough to crawl right into a predator's pie-hole.
Of course, it's ~technically possible~ that you could swallow a spider in your sleep, but it would be so random and statistically unlikely that you don't have to worry about it.
Where the myth came from:
There was a 1993 magazine article about misinformation, which discussed how people readily accept outlandish lies and spread them as fact. The author completely made up the spider myth in that same article as an example, and then β lo and behold β it spread on the internet. Thanks, internet.
Myth #10: You have specific "taste zones" on your tongue that taste sour, sweet, etc.
The truth:
Your entire tongue contributes to tasting what you eat, and while there are clusters of taste buds, they are not specifically designated to taste sour, sweet, umami, or salty tastes. All of your taste buds will process all kinds of flavors.
Where the myth came from:
A German scientist in the 1930s found that there were more taste receptors at the edges of the tongue, and fewer in the center. That's scientifically accurate, but somehow over time people added in the bit about the "taste map."
Myth #11: Caffeine stunts your growth.
The truth:
There's no proven scientific evidence that caffeine prevents growth. Of course, most of your growth is done by the time you're in your mid to late teens, and it's unlikely you're going to be drinking much caffeine before that point anyway.
Where the myth came from:
Caffeine, when consumed in large enough amounts, can slightly increase the rate at which the body excretes calcium. A lack of calcium can cause osteoporosis. However, the effect is minimal, and it might be that coffee drinkers in the study were simply drinking less milk as a result of their coffee consumption, leading them to have lower levels of calcium to begin with. And while osteoporosis can cause bone issues, there's no evidence that it will actually cause people to shrink...once bone growth is completed, it can't be reversed.
Myth #12: Your blood is blue inside your body, and it only turns red when it's exposed to oxygen.
The truth:
Blood is always red. It does change color a bit when it's oxygenated, but the color change is from a brighter red to a darker red. It also gets darker as it dries, so if you've ever gotten a blood stain on an article of clothing, it will appear darker the longer it stays on there.
Where the myth came from:
It might be because veins appear blue when you look at them on your arms, legs, or elsewhere where they're visible under your skin. But that's just an optical illusion because of how light is absorbed and refracted through our skin. It's also probably reinforced by science textbooks, which often show arteries as red and veins as blue in order to differentiate them in illustrations. Heck, even the movie Fantastic VoyageΒ depicted blood in the veins as blue.
Myth #13: Tomatoes aren't vegetables, they're fruit.
The truth:
Tomatoes are fruit. They are ALSO vegetables. The trick here is that botanically, tomatoes are classified as a fruit, because botanically, there is no classification of "vegetable." That's reserved for the culinary/nutrition world, which can call a tomato a vegetable if it wants to.
Where the myth came from:
It's likely that this big debate β fruit or vegetable β was popularized by a Supreme Court case in 1893, Nix v Hedden. Basically, the court had to decide how to classify tomatoes with reference to tariffs, as it would make a difference in how they were taxed. The court decided that tomatoes were vegetables in that case, which may have annoyed some botanists.
Myth #14: You'll catch a cold if you go outside in the cold with wet hair.
The truth:
Viruses and bacteria cause illnesses. If you go out in the cold, it's possible that you might become sicker if you're already exposed to or infected by a virus or bacteria, but you won't get sick purely from the exposure to the cold. The same goes for wearing wet socks, not wearing a hat outside, and other variations on this myth.
Where the myth came from:
As mentioned before, there's a sliver of truth here. Any stressor on your body can potentially weaken your immune system, meaning that a harmful pathogen could cause an infection where otherwise your immune system would have stopped it (or at least kept it asymptomatic). Being exceptionally cold will put some stress on your body, so it could help a pathogen take hold where it wouldn't have in warmer weather. The same can be said for lack of sleep, poor diet, and other factors that can affect your body.
Myth #15: Wolf packs β and human packs β have alpha males.
The truth:
Wolf pack leaders β what some might call "alphas" β are simply wolves that have bred and now lead their offspring. They may be male or female, but generally the dynamic is that they're simply parents that have created their own pack that they now lead.
Where the myth came from:
In 1947, a man named Rudolph Schenkel wrote a paper that theorized that male wolves fought within their pack, and the winner of those fights would become the "alpha." Later, Dr. David L. Mech β the founder of the International Wolf Center β wrote a book that referenced Schenkel's paper, reinforcing the alpha myth. Since then, Mech has been outspoken in attempting to refute the myth, even asking his publisher to stop publishing his book due to the outdated information.
Nowadays, particularly in the age of the internet, the idea of an "alpha male" in the context of human socialization and behavior has also become popular. Generally, in this context an "alpha male" is aggressive or overbearing. Ironically, in the context of wolves, a true alpha male would actually just be a dad, nurturing and caring for his family.
Myth #16: Vaccines cause autism.
The truth:
Vaccines do not cause autism. Nor do they contain microchips.
Where the myth came from:
A study by a man named Andrew Wakefield was published in the scientific journal, The Lancet, in 1997. Wakefield claimed that the MMR (measles, mumps, and rubella) vaccine was causing autism in children in the UK. However, the paper was found to have serious procedural errors, fudged data, financial conflicts of interest that were not disclosed, and ethical violations. For example, Wakefield was found to have been involved in several businesses related to autism treatment, so proving that the MMR vaccine caused autism would be financially beneficial to him as he would provide alternatives and treatments based on his findings.Β
Myth #17: The left and right halves of your brain determine if you're more creative or logical, because one side is dominant.
The truth:
While some people are more logical and others are more creative, there's no evidence to show that these traits are tied to a specific half of the brain, nor does one half of the brain have dominance over the other in these cases. With brain imaging advances, we can see that various areas light up during activities, and they are generally not limited to one hemisphere of the brain.
Where the myth came from:
There is some science that suggests that specific areas of the brain handle specific tasks, and those areas may be limited to one hemisphere of the brain. Generally, the right side is more proficient at spatial reasoning, while the left side handles language and problem-solving. These findings may have spun off into the idea that people were dominant on one side, similar to the way they might be right- or left-handed.
Myth #18: You'll drown if you swim less than 30 minutes after eating.
The truth:
It's possible that you may experience some minorΒ stomach or muscle cramping if you swim too soon after eating, but it's unlikely to cause you to be unable to swim. Most likely it'll just be uncomfortable.Β
Where the myth came from:
The idea behind this was that your body diverts blood to your digestive system so that you can effectively digest your food, which would mean your arms and legs wouldn't be getting enough blood to function properly. The part about your digestive system is true β your body does supply extra blood while you're digesting β but it's not enough blood to cause the rest of your body to dysfunction.Β
Of course, it's also possible that parents perpetuated this myth as a way to get a little rest after a meal before having to supervise their kids while swimming, or to prevent kids from throwing up in the pool from exerting themselves right after a big meal.
Myth #19: Eating lots of carrots will give you excellent vision, or even help you see in the dark.
The truth:
Carrots are indeed good for your eye health, as they're rich in vitamin A. But you'd have to eat a TON of carrots in order to actually improve your vision β you'd more likely have to take vitamin A supplements in order to get the levels you'd need, and it would only make a difference if your poor vision was a result of a vitamin A deficiency. And there's no way carrots can give you night vision.
Where the myth came from:
This myth was almost definitely popularized during World War II, as part of a British propaganda campaign. Since the Luftwaffe mostly struck at night, the UK would turn off as many lights as possible across the country to make it harder for the Nazis to strike their targets. At the same time, the RAF began using a new form of radar in order to combat the enemy aircraft in such low-visibility conditions. The British military wanted to keep the new radar technology a secret, so a propaganda campaign was pushed out through the newspapers attributing RAF pilots' extraordinary performance at night to excellent vision from eating a bunch of carrots.
Myth #20: MSG is worse for your health than salt.
The truth:
MSG β monosodium glutamate β is a naturally-occurring flavor enhancer that is also added to many foods, like french fries, potato chips, salad dressings, soups, and most infamously, Chinese takeout. While there are some people who are sensitive to MSG, it's generally not harmful and is usually present in small enough amounts that even those sensitive to it won't feel any effects. The only real danger MSG presents is in elevating sodium levels, which happens when you consume salt as well. So you don't want to eat too much food with MSG (or salt) as part of a healthy diet.
Where the myth came from:
Somehow, MSG started being blamed for all kinds of health issues and was even labeled "toxic" back in the 1960s. It seems that people started reporting symptoms around 1968 of MSG sensitivity, which included headaches, nausea, or palpitations. However, even those sensitive to MSG have to consume a significant amount of it ~without~ food, which is unlikely to happen, and only a small percentage of people sensitive to MSG experience any symptoms at all. Since a little bit of MSG goes a long way in enhancing flavor, you're unlikely to eat much of it in your food. Fears over MSG were mostly aimed at Chinese restaurants β almost definitelyΒ due to racism β which may have perpetuated the myth, despite the fact that MSG appears in all kinds of foods.
Myth #21: Lie detector tests are accurate.
The truth:
The efficacy of lie detector tests varies widely, as it may be accurate for some people and completely inaccurate for others. Polygraph tests work by measuring the subject's physical responses, including heart rate, respiration, and skin conductivity. So in theory, if a person suddenly gets nervous when they're about to lie, the machine would pick up the physiological changes that come with lying. However, some people might just not have the same physical response while lying, or might not have a physical response at all. Others might be so afraid of taking the test (or afraid of law enforcement, etc.) that they have fear responses that trigger the test unnecessarily. Additionally, there are several ways to "beat" the test, including taking certain medications or using physical movements to alter the subject's responses.
Where the myth came from:
Polygraph tests are definitely still in use, but are generally not admissible in court. Of course, if you watch movies or TV shows, you'd think they're infallible machines capable of catching criminals in a lie every time. So you can probably blame Hollywood for this one.
Myth #22: Drinking red wine is healthy.
The truth:
There may be some health benefits to drinking red wine, as the resveratrol present is suspected to help keep the lining of your arteries healthy. However, evidence of this is limited and some studies have shown no benefit at all, and you're likely to get the same benefits from drinking grape juice, or just eating grapes. The alcohol in wine is suspected to help increase your levels of "good" cholesterol, also known as HDL, but you could get these benefits from drinking any kind of alcohol, not just red wine specifically. Additionally, it's not recommended that you start drinking alcohol for health reasons, as the downsides can easily outweigh the benefits, especially since alcohol can be addictive and the "correct" amount for health benefits can vary widely from person to person.
Where the myth came from:
It's not clear whether there are other factors in the lives of people who drink wine that might cause them to have better heart health. Wine is more expensive, and is often paired with high-quality food, so wealthier people or people who eat healthier food might also happen to be wine drinkers more often. Combine this with the internet, and of course people are going to run with the "wine is healthy" idea.
Myth #23: Sugar makes you hyper.
The truth:
Β Some kids with ADHD might also be sensitive to sugar, which could cause their behavior to change if they consume a lot of it at once.Β And while some people β and children β might react more sensitively to blood sugar spikes in general, most people won't be bouncing off the walls after eating some candy. In fact, studies show that when you ingest sugar, you're more likely to be fatigued or less alert than energetic.
Where the myth came from:
If you think about it, kids are usually exposed to high amounts of sugar when they're in a fun, high-energy, stimulating environment. For example, at birthday parties kids will probably have soda and cake, or at an amusement park they might have ice cream or other sugary treats. So it might be that parents are observing their kids running around and acting wild because they're excited, and ascribing the behavior to the sugar instead of the environment around them.
Myth #24: Daddy long legs spiders (cellar spiders) have a strong enough venom to kill adult humans.
The truth:
There are two types of arachnids that people generally call "daddy long legs" spiders. One is Opiliones, aka harvestmen (which are not actually spiders), that are unable to bite at all since they don't have fangs. These arachnids do have a defensive secretion that can be harmful to small animals if they ingest it, but they pose no threat to humans. The other type is the cellar spider, which DOES have fangs and venom, but they rarely bite, and when they do, all the venom does is cause minor irritation. This myth was actually tested on the TV show,Β Mythbusters, wherein they coaxed a cellar spider into biting co-host, Adam Savage, who only had a minor burning sensation that lasted a few seconds.
Where the myth came from:
This one appears to just be one of those urban legends that popped up and had staying power. Who knows?
Myth #25: The hymen is an indication of virginity.
The truth:
First of all, virginity is a social construct that mostly exists to chastity-shame teenagers and young adults (mostly women) and falsely suggests that penetrative sex is "real" sex. Second, the hymen is fairly elastic and flexible, and is often torn by other means (rigorous exercise, tampons, gynecological exams, etc.). So a person who has never had penetrative sex could easily have a torn hymen.
Where the myth came from:
Media, the patriarchy, centuries-long puritanical traditions...you name it.
Myth #26: Butter is effective at healing burns.
The truth:
Any cool substance applied to a fresh burn will help ease pain, but creating a barrier between the skin and the air can actually trap in heat and cause the skin to continue burning. As such, you should avoid using oil, butter, lard, or anything else that could coat the burn and trap in heat. Ice is also not recommended as the extreme cold can cause further damage to the skin.
Instead, it's best to put the burn under cold running water as soon as possible for at least 20 minutes. Be sure to remove any clothing and jewelry from the area to prevent the trapping of heat. The cold water will not only soothe the pain by numbing the area, but it will also prevent any further burning by releasing heat, and can also help the burn heal faster.
Where the myth came from:
There are tons of folk remedies for burns, most likely because burns are so immediately painful that people reach for whatever object or substance near them that might help ease the pain. Since many burn injuries happen in the kitchen, it makes sense that people would open the fridge and grab a cool stick of butter that's nearby.
Myth #27: The "five-second rule."
The truth:
If you drop a piece of food on the floor, bacteria can adhere to it almost immediately. How long a piece of food can stay on the floor before becoming dangerously contaminated β enough to make you sick, say β depends on a bunch of factors. How contaminated is the floor? Is there a dangerous bacteria like salmonella present in great enough numbers? Is the food wet or dry, which might affect how much dirt and therefore bacteria adhere to it? How strong is your immune system? When you consider all of this, the "five-second rule" might be the "zero-second rule" in some cases and the "30-second rule" in others.
Where the myth came from:
Some trace this myth to TV chef, Julia Child, after she dropped a potato pancake on the stove. She picked it up and put it back in the pan, saying, "But you can always pick it up, and if you are alone in the kitchen, who is going to see?"
Studies on this subject have shown that people are more likely to invoke the five-second rule if they drop a cookie or candy, than if they drop a piece of broccoli. Makes sense, right? Chances are this myth perpetuates not because people believe it, but because it's something they say to convince themselves it's fine to not let that delicious cookie go to waste.
Myth #28: Twinkies never go bad.
The truth:
Twinkies currently have a shelf life of about 45 days, according to the packaging. Some Twinkies might last longer than others depending on the conditions under which they're stored, but one look at a Twitter thread from a Twinkie enthusiast, who opened up an old pack of Twinkies, shows that they definitely do NOT last even eight years, much less forever. The Twinkies β which had been purchased in 2012, back when Hostess filed for bankruptcy, causing a run on their products for fear they'd disappear from shelves β were in various states of decay and smelled and tasted rotten. Researchers examined these Twinkies and found mold and fungi growing on them, despite the fact that they were vacuum-sealed when they left the factory.
Where the myth came from:
When Twinkies first went on sale in the 1930s, they only lasted a couple of days. It's possible that the longevity of the product, along with the drastic difference in their shelf life from then to now, has given people the impression that they last forever. Of course, the movie ZombielandΒ β in which Woody Harrelson's character hunts for Twinkies in a zombie apocalypse and insists they last forever β probably contributed to the myth, as did the craze in 2012 surrounding Hostess's bankruptcy filing.
Myth #29: Fingerprints are unique.
The truth:
Fingerprints ~might~ be unique, but we just don't know. Nobody has taken the time to fingerprint every person in the world and compare them all. However, there are certain patterns that repeat in fingerprints, which is how people who analyze fingerprints categorize them. Like most facets of forensic science, fingerprint evidence isn't foolproof; at least 23 people have been wrongly connected to crime-scene fingerprints. This is because many prints at crime scenes are incomplete, so analysts may have limited data to work with. There's also no national standard in the United States for how many individual patterns on a fingerprint one has to use in order for it to be admissible as evidence.
Where the myth came from:
A scientist by the name of J.C.A. Mayers claimed in 1788 that "the arrangement of skin ridges is never duplicated in two persons." As mentioned, that still hasn't been proven, but cop shows and movies have most likely made it seem like fingerprints are infallible.
Myth #30: Video games cause gun violence.
The truth:
While there are some studies that show video games are associated with aggressive behavior, there's no evidence that video games cause gun violence. If it were true, there would be a correlation between gaming and gun violence worldwide, but gun violence rates are far higher in the US than they are in other countries, like the UK or Japan, where video games are also popular.
Where the myth came from:
Video games can sometimes be tastelessly violent, and I say that as an avid gamer. Platforms where indie game designers can upload their own projects have muddied the waters a bit as well, as sometimes these platforms will allow particularly offensiveΒ games to be sold, like the school shooting video game that was available on Steam several years ago.