The human body is a fascinating balancing act, constantly fighting against gravity to remain upright and active. Before we had science, humans had to do their best to rationalize the various phenomena that they experienced both inside and around their bodies.
Like most myths, misconceptions surrounding the human body have little to do with scientific facts, and much more to do with our very flawed perception of our bodies.
From the 10 percent myth to palm reading, here are 10 myths and misconceptions about the human body.
10. We Only Use 10 Percent of Our Brain
Hollywood loves pushing this myth. It’s appeared in blockbuster films like the 2011 film Limitless and the 2014 Scarlett Johansson vehicle, Lucy, as well as book series as popular as The Dresden Files.
While educators and neuroscientists since the early 1900s have desperately tried to debunk this myth, like the Terminator franchise, it just won’t die. Even schoolteachers have been known to recite it.
Historians aren’t quite sure how this myth got started, though some believe it originated because of a misunderstanding of William James’ writing in the early 1900s, when he wrote, “We are making use of only a small part of our possible mental and physical resources.”
Now, James was not talking about the brain’s physical properties, in fact the general consensus is that he was speaking on societal problems that drain the energies of the individual, rather than making a claim about the brain’s capacity.
In truth, there is no percentage of the brain that we don’t use. In fact, if we were to use a PET (Positron Emission Tomography) scan on a person who only used 10% of their brain, most of it would appear to be dark on the scan, and this would indicate some pretty heavy brain damage. But that simply isn’t what we see in healthy brains in these types of scans. The entire brain, even in patients with neurological disorders, is extremely active.
9. We Only Have 5 Senses
We’ve all heard about the five senses: taste, touch, sight, hearing, smell, along with that mythical sixth sense that Hollywood is always making movies about. But the idea that humans only have five senses is actually a myth.
While it is true that we humans have five basic senses, we actually have many, many others. For example, proprioception is our sense of space, relating to the position of our limbs. If you’re able to close your eyes and touch your nose, you’re actively using your sense of space. This sense of space is all possible thanks to receptors in our muscles called spindles. These spindles send signals to our brains telling them where all our bits and pieces are.
Beyond proprioception, humans have a bundle of senses like our sense of balance, inner pain sense, our sense of time, and even human echolocation.
In the United States, Daniel Kisch leads a team of blind cyclists who call themselves Team Bat. The cyclists make clicks with their mouths to echolocate through their environment, even at high speeds. And this is a sense that isn’t restricted to blind people either, even humans still possessing their sight can learn to do this.
8. It’s Easier to Catch a Cold When It’s Cold
Developing children around the world have more than likely heard something to the effect of “take a jacket or you’ll catch your death out there,” by their well-meaning mothers on days where the thermometers drop to freezing temperatures.
The idea that colder temperatures lead to getting sick is understandable, seeing as how your chances for getting sick do go up in the winter months, but it has nothing to do with the cold itself. Most viruses are easily killed by ultraviolet radiation during the summer months, something that is in short supply for a variety of reasons in winter.
Studies have also shown that during the colder months of the year humans tend to want to be around other humans, and schools opening during this period of time probably do not help to curb the spread of influenza. Other studies have shown that there is absolutely no correlation between temperature and the rate at which people are infected with viruses like the one responsible for the common cold (rhinovirus).
But for humans growing up before the days of science, it did certainly seem like you could “catch a cold” from venturing into the winter elements without proper preparation, which is where the very idea of a “cold” comes from.
7. Your Death Can Be Foretold by the Lines on Your Hand
The practice of palm reading, or palmistry, is a pseudoscientific practice where fortune tellers attempt to read the lines on a person’s hands, which is thought by practitioners to indicate that person’s possible future.
Despite the fact that palmistry is practiced all over the world in a variety of cultures, it’s a total myth. There are many variations in methods and interpretations of any given line in the palm, and readings can vary wildly between fortune tellers.
There is absolutely no scientific proof to support palm reading. The lines in our hands develop early, around 12 weeks after conception, and are a result of fetuses opening and closing their hands, causing creases to form in the skin. Most people have around 3 lines in their hands, but about 1 in 30 people have a single line. This can be a totally normal development, though in some people it can be a sign of abnormal development, possibly indicating down syndrome, fetal alcohol syndrome, Turner’s Syndrome, Aarskog Syndrome, or Rubella Syndrome.
6. People Can Be Double Jointed
Everyone has had a childhood friend that’s made the boastful claim of being double-jointed before demonstrating their immense flexibility by bending their legs around the back of their head. Even though this may seem totally unnatural and strange, it’s totally normal for most people and has nothing to do with having extra joints.
Being double-jointed is a scientific improbability and these people are probably just really flexible, something which is called hypermobility.
Hypermobility can often be attributed to the soft tissues around a flexible person’s joints, rather than the joints themselves.
Although this kind of extreme flexibility can be beneficial for athletes, it can also indicate benign joint hypermobility syndrome, or BJHS, which can be pretty painful.
Hypermobility can also indicate a lack of stability, causing the individual to have to expend more energy remaining upright or stable, and this is something that scientists are actively studying in regard to dancers.
5. Sweat Can Remove Toxins from Your Body
The idea that someone can remove toxins in the body by simply sweating them out is promoted in hot yoga and the idea, in general, has been wholly embraced by health nuts and Multi Level Marketing scams (or MLMs) peddling essential oils all around the developed world. But there’s not a lick of science to back these lofty claims up.
Toxins are removed from the body through our liver and kidneys, and though the phrase “detox” has been co-opted by pseudoscience peddlers, it originated (and continues to be used) as a medical practice using drugs and other therapies that vary wildly depending on the type of toxins present in the body.
4. Alcohol Kills Brain Cells
Who doesn’t love a pint of beer or a drink after work?
It might be difficult to find a room full of people that haven’t heard the myth that three beers inevitably lead to the death of 10,000 brain cells. In truth, consuming alcohol doesn’t kill brain cells at all, but it is certainly easy to see why people would make the connection between alcohol consumption and cognitive impairment.
What alcohol consumption actually does is damage the ends of neurons, inhibiting the brain’s ability to communicate with other parts of the body. Ethyl alcohol is especially good at killing viruses and cells, but your body doesn’t let it run wild when you drink it, keeping it contained to certain parts of the body and limiting the damage it can do.
Studies have shown that, while alcohol does damage the ends of neurons, even in cases of neuron death in patients with a rare disorder called Wernicke-Korsakoff syndrome were found to have been caused by a B1 or thiamine deficiency attributed to poor nutrition and health.
And in fact, other studies have shown that moderate alcohol consumption can actually reduce the risk of subjects developing cognitive decline and dementia.
3. Big Feet Means a Big… You Know
“Big in the shoes, big in the pants.” It’s a common saying pretty much everyone in western society has heard at one point or another. But studies, including one conducted by the London Urology Clinic, found no correlation between the size of a person’s… member, and the size of their feet.
In 1993, a Canadian study of 63 men measured their height, foot size, and penile length and found little more than a tenuous link between height and foot size and the length of one’s manhood, though the two doctors who conducted the study actually went on to win the 1998 Ig Nobel Prize. The two doctors also went on to say there was no “practical utility” in what they had found in their study.
A 1999 study in Korea measured the flaccid members of 655 men and compared those measurements to their foot size and the rest of their body parts (even going so far as to measure the length of each participant’s car), but found no correlation between any of those things, other than maybe the girth and circumference of a given man’s manhood, but even that wasn’t conclusive.
In fact, every major study since 1999 that has focused on this myth has debunked it.
2. The Appendix is Useless
The appendix is notorious for becoming inflamed or rupturing and has long been rumored to be completely useless, even in the scientific community where it was thought to be a vestigial organ left over from millions of years of natural selection that had failed to excise it from the human body.
This is an evolutionary myth.
But, if so, what is the appendix good for?
Well, according to Heather F. Smith, PhD, associate professor at Midwestern University Arizona College of Osteopathic Medicine, the appendix actually protects beneficial gut bacteria.
In her research, which was published in the journal Comptes Rendus Palevol, she found that the appendix had evolved independently in 30 different species of animals and rarely disappeared after its evolution.
The appendix has also been linked to the regulation of the immune system because it contains immune system tissue.
1. Nails Grow After Death
The myth that nails and hair continue to grow even after death is widespread in the public consciousness, partly because of novels and other media that perpetuate it. Even today, it’s still a commonly held belief about the human body.
But if it’s not true, where does this idea come from?
Believe it or not, it’s actually rooted in the observation of real biological processes. When someone leaves this mortal coil, their organs must be harvested within thirty minutes (if the deceased happens to be an organ donor), though the skin can be harvested for skin grafts up to 12 hours after someone reaches their expiration date. After that period, the skin dries out, retracting and making the fingernails appear to have grown longer.
The same is true of someone’s stubble, the skin on the deceased person’s chin retracts in the same way, making the stubble appear to have grown after death.
In reality, the body stops producing glucose after death, preventing the nails or hair from growing anymore.