28 myths of modern life exposed

Do mice really love cheese? Does sugar make kids hyperactive? Do you actually need your five-a-day? We put common beliefs under the microscope to sort the fact from the fantasy

19th January 2017
28 myths of modern life exposed © James Olstein/BBC Focus magazine

Image © James Olstein/BBC Focus magazine

Fake news might be making headlines, but the myths of modern life have been fooling us for years. We put some of these factual inaccuracies to the test and see what science has to say about them:

A penny dropped from the top of the Eiffel Tower could kill someone

 

The building used as the basis of this myth varies. Much more constant is the terminal velocity of a penny, which is around 44km/h (27mph). The penny reaches that speed after it has been falling for about 15 metres. Once the penny has reached its terminal velocity, it will not accelerate any further.

Physicist Louis Bloomfield at the University of Virginia used this calculation to replicate the fall of pennies from tall buildings. He found that pennies at that speed would not break the skin – at most, they would just sting a little.

Bumblebees defy physics

They are big and fat with seemingly tiny wings, making their flight seem improbable. But since science is updated when there is new evidence, if a bumblebee’s flight really couldn’t be explained by current models then the physics would change. In reality, bees do not defy any laws of nature. Those wings do indeed provide enough lift to hold up the entirety of a bumblebee’s 0.2g.

Local honey cures hay fever

Tablets containing pollen are somewhat effective at combating hay fever. Since some honey contains pollen, honey as a hay fever remedy seems plausible. But most honey contains little or no pollen. Even unfiltered local honey has no apparent impact on hay fever.

Goldfish only have a three-second memory

The life of a goldfish isn’t always filled with joys that are worth remembering: countless numbers of these small fish have little to look back on other than a short trip in a tiny bag before being flushed down a toilet. But goldfish do have a better memory than just three seconds – much better in fact. Goldfish can remember the route to take in a simple maze, for example.

A study by researchers at the University of Seville also suggested that the fish are able to develop and remember a mental picture of their environment. In the maze experiment, the fish could find their way to a goal from a start point other than the one from which they were trained.

Turning the thermostat up high will increase the rate of heating

Unlike humans, who might meet an ambitious challenge by working harder, heating systems don’t put more effort in when they have further to go. Setting your thermostat to 30°C will only change the target temperature, not the heating speed. A higher setting will just risk wasting energy while getting you too hot.

You need to drink eight glasses of water a day

Being dehydrated isn’t great for your health, but the idea that we need to drink eight glasses (around two litres) of water in order to stay hydrated has no real scientific backing. Research suggests that health can be maintained with a much lower water intake.

As concluded by Dr Heinz Valtin from Dartmouth Medical School, there’s also no evidence to specifically drink plain water. You can stay hydrated with any other fluids and the water that’s found in most food.

Mice love cheese

You’re not alone if you feel a sense of disillusionment after learning that your childhood cartoons were misleading you. Scientists from the University of Birmingham have confirmed earlier research by showing that wild-caught mice do not appear to have any apparent preference for cheese, and probably prefer seeds and grains. Crunchy peanut butter, another common mouse bait, was also not preferred (perhaps they prefer smooth).

Given that adult mammals tend to have little of the enzyme lactase, required for lactose digestion, cheese probably isn’t great for a mouse’s health, either. Plus, feeding cheese to a mouse is a criminal waste of cheese!

Houseflies only live for 24 hours

It may seem unfortunate that the annoying housefly lives for more than a day. They can actually live for several weeks. The 24-hour myth probably comes from confusion with the mayfly, of which many species do have incredibly short lifespans in their adult stage. Part of the reason mayflies can get away with such a short lifespan, while still being able to find a mate, is that they swarm. Since a swarm of houseflies might be more of a nuisance than the odd one buzzing round your kitchen, we should probably be thankful that they do not share the mayfly’s lifecycle.

Humans have five senses

A significant problem with the idea that we have five senses is that there is no uncontroversial definition for what constitutes a discrete sense. Regardless of how you define a sense, it’s clear that we have many more than five of them. The ‘non-traditional’ senses include nociception (the sense of pain), thermoception (the sense of temperature) and equilibrioception (the sense of balance). Admittedly, The Sixth Sense might not have been nominated for as many Oscars had it been about a boy who was able to sense how cold he was…

Sharks don’t get cancer

There are plenty of documented examples of sharks with cancer. This myth has been used as the pseudoscientific basis for the use of shark cartilage as an alternative cancer treatment and is implicated in diminishing shark populations. The world of alternative medicine is filled with myths that could be included on this list, but not all such myths put entire species at risk. This one does.

You need to eat five portions of fruit and veg a day

Campaigns that aim to increase the amount of fruit and vegetables the average person consumes have taken place across the world. For example, in Australia they have the ‘2 & 5’ campaign. These campaigns are based on the World Health Organization’s recommendation of 400g of fruit and veg per day. The five-a-day target is pretty arbitrary – you probably won’t be a lot worse off if you only manage four, and six would probably be slightly better. Five a day might be a reasonable target if you currently eat little or no fruit or vegetables, but there’s nothing special about that figure in particular.

Superfoods are really good for you

Put simply, there is no academically recognised definition for ‘superfood’ – it is essentially a marketing term. While adding some berries and kale to your diet may be beneficial to your health, many of the specific claims made about various superfoods aren’t based on any real evidence. No single food has shown to be a health panacea worthy of the term ‘super’, and no one should think they can counteract the effects of a huge bowl of ice cream by liberally sprinkling it with goji berries.

MSG is bad for you

Monosodium glutamate (MSG) is a common source of the savoury ‘umami’ flavour found in many foods, such as tomatoes, soy sauce and parmesan cheese. It is used as a flavour enhancer by the food industry, but claims about MSG’s negative health effects have been around for a while, with supposed ill effects ranging from headaches to cancer. As a result, MSG has been studied extensively, and in 2007, a team at the University of Hohenheim examined all the research on MSG and concluded that even unusually high doses are not harmful. It has also been conclusively established that MSG makes things taste even more delicious.

Sugar makes kids hyperactive

It’s easy to understand why so many believe that sugar (a source of quick energy) causes hyperactivity, but numerous controlled experiments have failed to establish any causal relationship. The belief might be perpetuated by ‘confirmation bias’: a study at the University of Kentucky showed that when a parent was told that their child had just eaten a lot of sugar (even when they hadn’t), the parent was far more likely to describe their kid as hyperactive. Of course, this doesn’t mean feeding your children vast quantities of sugar is to be recommended.

Alcohol keeps you warm

Many a drinker has found alcohol makes them feel more resistant to cold weather on the walk home from the pub. This ‘beer jacket’ is the result of the blood vessels dilating, resulting in more blood travelling to the surface of the skin. Far from keeping you warm, alcohol is more likely to put you at risk of hypothermia as it can impair the body’s ability to regulate its temperature.

Adults can’t generate new brain cells

Several areas of the adult brain contain the neural stem cells required for the growth of neurons. These areas include the dentate gyrus, thought to be involved in memory formation, and the olfactory bulb, which is involved in our sense of smell.

The tongue is divided up into different sections

The absence of an umami section is not the biggest problem with the tongue map. The idea that our tongues are split into sections has been perpetuated by textbooks and teachers for decades, yet it has no basis in physiology. The receptor cells that identify the molecules underlying the basic tastes (sweet, sour, salt, bitter and umami) are distributed on taste buds all over the tongue.

Caffeine dehydrates you

You may find yourself visiting the bathroom more frequently after consuming tea or coffee. This is probably due to the diuretic effect of caffeine, which is suspected to irritate muscles in the bladder. But even if you do pee more often, it doesn’t mean you’re passing a greater volume overall. The effect of caffeine on urine output has been investigated in numerous studies, which have been reviewed by dietician Dr Carrie Ruxton. She found that a moderate intake of caffeinated drinks is unlikely to have any significant effect on your overall level of hydration.

We use only 10 per cent of our brains

The origin of this myth is uncertain, but it didn’t originate from the scientific study of the brain. The myth is often found in self-help books that claim to tell you how to harness the power of the brain’s other 90 per cent. In reality, all the parts of the brain are highly specialised and there don’t appear to be any unused sections that you could learn to activate in an attempt at self-improvement.

Ginger-haired people are going extinct

Red hair is caused by a recessive variant of a gene, which means you need two copies of it to be a redhead. Currently, redhead alleles are found at a much higher concentration in some populations in northern and western Europe. It’s possible that as those genes spread out the probability of two people with a redhead allele having a child will diminish, which might make redheads less common, but as long as the genes are there, we will still have redheads.

Left-brained people are logical, right-brained people are creative

 

As described by the University of Utah’s Jared Nielsen in a study of brain scans from over 1,000 individuals, there is no evidence of left- or right-brain dominance. The idea that there are left-brained people who are logical and right-brained people who are creative may be a useful metaphor, but it has no more basis in actual science than astrology does. Though a left-brained Gemini like myself would say that.

Shaving causes hair to grow back faster and thicker

Shaved hair that hasn’t yet been exposed to the bleaching effects of sunlight may appear darker. And compared to the tapered end of an unshaved strand of hair, the sheared ends usually feel coarser. While these two effects might make recently shaved hair seem thicker, there is no evidence that shaving influences the growth rate or thickness of hair.

There’s a chemical that turns purple when someone wees in a swimming pool

Although this myth might serve a noble purpose, there is no ‘urine indicator’ that could be put into pools. In principle it may be possible to create a chemical that is colourless in the absence of urine, but colourful in its presence. But the difficulty in ensuring that it doesn’t result in false positives probably wouldn’t be worth the investment. Along with the difficulties in developing such a dye, you could probably also guarantee that any pool that used it would have a constant purple tinge.

You lose a lot of body heat through your head

If you leave any one body part exposed to the elements, that body part will play a major part in your heat loss. The 7 per cent of your body’s surface area that covers your head isn’t in any way special, however. The myth often claims a figure of around 50 per cent heat loss through the head. The implication of this percentage is that you’d be as warm if you went out wearing nothing but a balaclava as you would be if you went out fully clothed but without a hat. Feel free to try this at home.

Barefoot running is better for you

Barefoot running has grown in popularity over the past few years. The proponents usually claim that running without traditional running shoes improves form, prevents high impact ‘heel strikes’ and reduces injury rates. However, media articles supporting barefoot running generally rely on questionable evolutionary hypotheses or anecdotes.

A group of researchers at the University of Cape Town examined papers looking at the biomechanics of barefoot versus traditional running. Dr Nicholas Tam and his team concluded that while barefoot running might reduce the risk of certain injuries, such as knee pain, it may also increase the risk of others, such as stress fractures to the feet. Individual experience may vary, but there is so far no scientific basis on which to prescribe barefoot running to reduce injury rates.

Playing classical music to babies makes them grow up smarter

There may or may not be a correlation between intelligence and an appreciation for classical music. ‘The Mozart Effect’ that suggests classical music improves children’s intelligence was first described in an early 1990s study, but since then, it has not been established as a robust phenomenon that survives study replication. Parents’ time is probably better spent teaching their children that correlation does not imply causation.

Stretching before exercise prevents injury

 

Finnish researchers analysed studies covering almost 5,000 participants and concluded that stretching before exercise had no effect on injury rates. However, a gentle aerobic warm-up will prepare the muscles for a workout.

A malfunction at a particle accelerator could suck the entire planet into a black hole

The idea that particle accelerators, particularly the Large Hadron Collider (LHC), might cause Earth-threatening black holes has been in the news since the LHC opened. Micro black holes are hypothesised to be generated by high-energy particle accelerators like the LHC, but they wouldn’t be a threat to the planet. Unlike their massive astronomical cousins, the hypothetical micro black holes would evaporate almost instantly. And although it would be an important discovery, no micro black holes have been detected at the LHC so far.

 


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