Mothers have been repeating the same advice to their kids for decades: “Don’t go swimming after lunch, you’ll get cramps and drown!” Some parents have taken it a step further, declaring that it’s not even safe to bathe after eating a meal. As it turns out, there is zero truth to this “danger” and not a single person has drowned from food-induced stomach cramps.
No one knows for sure how the myth started but the first version actually references baths, not swimming. In the early 1900s, a story popped up that warned parents about the dangers of bathing their children after a meal. The exact details varied with each version but the general idea was that a child should hold off on baths for at least one hour after eating. Over time, this myth got warped into the “no food before swimming” advice. (more…)
The “nature versus nurture” debate is alive and well today, even though science has debunked the entire argument. This might seem surprising since people still claim that certain traits are from genetics while others are from the person’s upbringing. On one side, people theorize that genetics affect everything from a person’s personality to their medical problems. On the other side, there’s the theory that everything is determined by how a person is raised: their environment, family, and childhood experience. As with most debates, the truth lies somewhere in the middle—nature and nurture constantly interplay.
The concept of nature versus nurture was first popularized by John Locke, an English philosopher and doctor. He believed in the “blank slate” theory, which stated that all human behavioral traits were based on their environment and how they had been raised. Later in history, Darwinism was becoming widely accepted and this led scientists to believe that behavioral traits were due to genetics, not the individual’s environment. This theory stated that a person’s personality was caused by genes and already set in stone at birth. Both scientists and philosophers continued the nature versus nurture debate until modern times. Now, scientists generally agree that the argument is a fallacy and reality is much more complicated than genes versus environment. (more…)
Caffeine is the most widely used stimulant in the world and over 80% of Americans consume some form of the chemical daily—whether it’s from tea, coffee, or soda. Caffeinated drinks have been around for most of written history and they’re probably not going away anytime soon. Most societies embrace at least one form of caffeine and after a while, it’s easy to forget that it’s actually a drug.
Caffeine is a psychoactive drug
Caffeine is a central nervous system stimulant—a psychoactive drug that causes increased alertness, faster locomotion, and other mental and physical changes. “Psychoactive” tends to be associated with drugs that cause visual hallucinations but it really just means that the chemical affects a person’s mental state. Both caffeine and cannabis are mild psychoactive stimulants; alcohol is a depressant or “downer.” (more…)
When television shows and movies show events from a dog’s point of view, they usually switch to black-and-white. Dogs, like most mammals, actually do see colors—though not quite the same way humans do.
Human eyes contain photoreceptor cells called rods and cones. While both detect light, cones respond to specific wavelengths and are responsible for our color vision. Humans (and other primates) have three types of cones that can detect the red, yellow, and blue wavelengths. Dogs, on the other hand, only have two kinds of cone cells: yellow and blue. This means they have no trouble seeing shades of blue and yellow but have trouble differentiating them from red and related hues. To a dog, a red ball will simply appear to be a shade of green, similar to what a red-green colorblind human might see.
People who compete with dogs in outdoor sports often recommend certain colors for equipment based on what the dog will see. Although a human may have an easy time spotting yellow agility equipment on green grass, a dog will struggle to differentiate the colors. Instead, agility experts often choose shades of blue, which will usually stand out against greens and other colors in the yellow spectrum.
Dogs mostly rely on their sense of smell and hearing, which are both superior to our human senses. They still use vision, though, and can see colors—just not as many as we can. Understanding how our pets see the world can help us make things easier for them. Utilizing contrasting colors, for example, may help a dog find a toy during fetch or improve reaction times in canine sports. One day we might finally see an accurate depiction of dog vision in media, with shades of blue and green instead of greyscale.
photo: Adrian Smalley (CC)
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The “five second rule” is an unofficial pass to eat food dropped on the floor—provided only a few seconds have elapsed. The general wisdom is that it takes several seconds for bacteria to transfer to the food item, making it safe to eat if picked up quickly. In one survey, 87% of people admitted to eating dropped food at least once. The five second rule was never backed up by science but some researchers have decided to test the idea.
In the first major study, researchers tracked the transfer of common bacteria, including E.coli, to food after it had been dropped. They found that carpet was less likely to transfer bacteria than smooth surfaces. While moist foods could become colonized within seconds, most foods were declared safe. For dry snacks, such as cookies, it could take 30 seconds or longer for bacteria to show up. The researchers decided that the five second rule works—in specific cases. (more…)
A placebo is a sugar pill or similarly ineffective treatment used in medical studies. The placebo acts as a control for comparison when studying the effectiveness of a proposed treatment. Often, patients will notice some improvement in their condition even when taking a placebo. This phenomenon is called the “placebo effect” and recent research is increasing scientists’ understanding of these events.
Deception isn’t necessary
Originally, it was believed that placebos only worked because patients thought they were being treated. In one study, patients with irritable bowel syndrome were treated with placebos. One group was told they were given a placebo with no additional information. The other group was also given placebos but the pills were described as follows:
“Placebo pills made of an inert substance, like sugar pills, that have been shown in clinical studies to produce significant improvement in IBS symptoms through mind-body self-healing processes.”
Both groups showed some improvement but the group given more information had significantly higher global improvement scores. The authors concluded, “Placebos administered without deception may be an effective treatment for IBS.”
The reverse phenomenon is called the “nocebo effect”
If a patient doesn’t think a treatment will be effective, they may experience a worsening of symptoms. This has been called the “nocebo effect” in medical literature. The effect can also be caused by doctors and other clinical staff. If the doctor feels negatively about a treatment or mentions likely side effects, it may affect the patient’s perception. This can cause an ethical dilemma. Doctors are required to properly inform patients of possible side effects or risks. Emphasizing the negative aspects of a treatment may make it less effective, however. More communication training in medical school may help physicians keep patients informed while also framing treatments in a positive way.
How a placebo is administered may change the effects
Some placebos work better than others and the method of administration can increase or decrease effectiveness. In one study, large placebo pills were found to be more effective than small ones and two doses worked better than a single dose. Sham surgeries and injections tend to elicit a stronger placebo effect than a sugar pill. In one study, a sham surgery was just as effective as an actual arthroscopic partial meniscectomy (a surgery used to treat knee osteoarthritis).
Placebos can be considered a viable treatment
Placebos are so effective in certain cases that some researchers have begun to recommend them as treatments. In an analysis of 130 placebo studies, one research team concluded that while placebos don’t work for many diseases, they were effective for pain. Placebos successfully treated pain in 27 different studies of various sample sizes.
Interestingly, placebos can also help treat symptoms of Parkinson’s disease. There have been multiple studies but one in particular stands out. Patients showed significant improvement when they were treated using deep brain stimulation, a technique that involves stimulating the brain with electrical impulses. The treatment was only effective when patients were also given a placebo and told that it was an “antiparkinsonian drug”. Patients who didn’t receive a placebo showed little to no improvement. A similar experiment was later conducted with identical results.
The placebo effect is still poorly understood and the use of a placebo can raise ethical concerns. Placebos may help treat pain, for example, but informed consent prevents a doctor from prescribing sugar pills. At the very least, placebo research provides insights into how expectation and perception can affect the outcome of medical treatments.
Cold season is upon us and even the latest scientific technology can’t prevent us from catching a cold. The lack of a real “cure” has led to all sorts of crazy remedies, including Epsom salts and onions (even I don’t know what’s going on with those!). There are a few major misconceptions surrounding the common cold and I’d like to knock them out one at a time.
Antibiotics will help my cold go away
Colds are usually caused by a group of viruses called rhinoviruses. There are hundreds of viral strains that can cause a cold and these strains change from year to year. This makes it difficult to create a single “cure” for colds. There’s also a reason your doctor can’t simply prescribe antibiotics: they won’t work. Antibiotics only kill bacteria, not viruses. Viruses, including influenza, tend to be trickier to treat. There are some antiviral drugs out there but the most effective defenses against viruses are vaccines. Unfortunately, we don’t yet have a vaccine for the common cold. Since colds are caused by a variety of constantly mutating viruses, it’ll be a while before we see any real preventatives.
Vitamin C will cure my cold
Vitamin C is commonly touted as both a treatment and preventative for the common cold. The idea is that vitamin C supplements will boost your immune system, preventing you from catching a cold (or treating one you already have). Actual research, however, doesn’t support this theory.
There have been multiple studies designed to look for relationships between vitamin C and colds. Currently, there is no evidence that vitamin C will actually prevent a cold. A vitamin C supplement is also unlikely to treat an existing cold. In an analysis of 55 different studies, a research team concluded, “The lack of effect of prophylactic vitamin C supplementation on the incidence of common cold in normal populations throws doubt on the utility of this wide practice.”
There was only one case where vitamin C supplements helped prevent and reduce the duration of cold symptoms. The supplements appeared to help one group of people: those who were already deficient due to lifestyle. Patients who regularly engaged in rigorous exercise benefitted mildly from vitamin C supplements. The same was true for people exposed to extreme temperatures. In both groups, colds were less frequent and symptoms were reduced when participants took vitamin C tablets. In conclusion, a vitamin C supplement won’t help your cold unless you’re a marathon runner or work outside in frigid temperatures.
You should “sweat out” a fever
There’s a strangely common belief that you should purposely sweat during a fever. Proponents of this method will recommend wrapping in blankets, keeping the thermostat turned up, and drinking hot beverages. The idea is that by maintaining a high body temperature, you can kill the virus faster. That’s not how fevers work, however. Fevers are a symptom of your body’s immune system fighting off something—whether a virus, bacteria, or some kind of toxin. The high temperature alone isn’t killing anything and most fevers go away on their own within a day or two. Doctors generally recommend resting, staying hydrated, and taking an antipyretic medication (such as ibuprofen) if the fever is especially bad.
Cough syrup reduces coughing and helps sore throats
I was guilty of believing this one for a while. Most of us know that cough syrup won’t “cure” a cough but we expect it to at least help, right? The general consensus is that cough syrup will reduce coughing and help soothe a sore throat. However, there is very little scientific evidence for these claims. An analysis of commonly available over-the-counter cough syrups found that most of them had the same effectiveness as a placebo.
In a 2007 analysis of codeine, a common ingredient in cough medicine, the authors concluded, “Recent placebo-controlled studies have shown that codeine is no more effective than placebo in suppressing cough caused by either upper respiratory disorders or chronic obstructive pulmonary disease.”
Dextromethorphan is the only cough medicine with any scientific backing. It’s been proven slightly effective but only in adults; studies have shown that the drug is ineffective in children. The benefits are also small enough that some doctors question the value of taking the medication. Interestingly, pure honey provides mild cough relief and was found to be more effective than cough syrups in the same study.
Why do so many of these myths persist? Cold symptoms don’t last long for most people. If someone takes cough medicine and then begins to feel better after a day, they might believe that the medication helped. In reality, the cold symptoms would have improved on their own thanks to the body’s immune system. The best “cure” for the common cold? Time.
Photo: Mike Mozart / MiMo