8 Brain 'Facts' We All Get Wrong

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Are you left-brained or right-brained? The correct answer is “neither.” Read on to find out the science behind this and seven other brain “facts” we all get wrong.

1. A BIGGER BRAIN IS A BETTER BRAIN.

Nope. After all, humans believe we’re the smartest animals on the planet, but elephant brains are three times larger than ours. And whale brains? Forget it. 

Intelligence isn’t about relative size, either. Human brains make up about 2 percent of our body mass, which is pretty impressive. But tree shrew brains are a full 10 percent of their body mass, and they drink beer for a living.

So when it comes to brains, size isn't the most important thing. Hominid brain size did increase as we evolved, but scientists say that the secret to our smarts is complexity. And nobody can beat us there; neuroscientist Gerard Edelman has even described the human brain as “the most complicated object in the universe.” Your cerebral cortex alone has between 19 and 23 billion neurons, and each neuron can connect to other neurons tens of thousands of times. 

2. PEOPLE ARE EITHER LEFT-BRAINED OR RIGHT-BRAINED.

There are certain tasks that draw more on one side of your brain than the other, but everything you do uses both hemispheres. There’s no evidence that the right half of your brain is more creative, or that the left is more analytical. The myth originated in the 1970s, from a paper by CalTech neuroscientist Roger W. Sperry. Sperry reported finding cognitive differences between the hemispheres. The media took the idea and ran with it. Sperry warned against oversimplifying or misinterpreting his findings, but by then the proverbial horse was out of the barn. 

The only people who are truly left- or right-brained are those who have undergone hemispherectomies—a surgery in which half of the brain is removed. The procedure is more common than you might think, and patients often go on to live full lives with no cognitive troubles. We'll have a story about this procedure and the impact it had on the life of one remarkable young woman later this week. 

3. WE ONLY USE 10 PERCENT OF OUR BRAINS.

Oh yeah? Which part are you using right now? The entire brain may not be active every second of every day, but if you want to breathe, sleep, and digest your food, you need the whole thing. 

Modern brain imaging techniques have given us actual pictures of the whole brain in action, which should have put this myth to bed. Instead, the 10 percent legend has persisted for years and years, in part thanks to movies and psychics who argue that the “other 90 percent" of your brain must be reserved for some supernatural purpose. This is absolute bunk. We'll look at this myth in more detail later in the week too.

4. GETTING OLDER MEANS LOSING YOUR MENTAL EDGE.

It’s not that black and white. Yes, certain cognitive functions like short-term memory, attention, and language learning begin to decline with age, but other mental skills actually improve. Many of these are social and emotional in nature, rather than analytical. This may be why these gains haven’t gotten as much attention as the losses: Laboratory tests focus more on cerebral tasks than on practical mental skills. 

Studies have shown that older people have larger vocabularies than younger people, and that they make better use of them. Older adults are happier with their lives, and their relationships are more harmonious. Being older means that you have access to a mental database of past problems and solutions, which helps you make choices in the present. Scientists call this a “cognitive template,” but most of us know it better as wisdom.

5. CLASSICAL MUSIC MAKES YOU SMARTER.

Making yourself (or your baby) sit through symphonies won’t do anything for your IQ. A 1993 study [PDF] did show that listening to Mozart improved spatial reasoning—but only spatial reasoning, and only for 15 minutes. Even that modest effect might have been overstated. A 2010 review of 40 studies on the subject found that none of them could reproduce the results of the original experiment.

And those classical music videos for babies aren’t doing anybody any favors. Infants and toddlers who watch TV—even Baby Mozart—learn fewer words than their peers.

Classical music is not like broccoli. You can’t put cheese on it, and the only reason to consume it is if you (or your baby) actually like it.

6. CROSSWORD PUZZLES WILL KEEP YOU SHARP.

Like classical music, crossword and Sudoku puzzles are terrific—but only if you actually enjoy them. 

In an interview on the subject with The New York Times, neuroscientist Molly Wagster of the National Institute on Aging was unequivocal: “People who have done puzzles all their lives have no particular cognitive advantage over anyone else.” 

There is one thing that doing crossword puzzles will make you good at: doing crossword puzzles. The more puzzles you complete, the better equipped you’ll be to notice patterns and recognize frequently used clues.

7. MEN ARE NATURALLY BETTER THAN WOMEN AT MATH.

Just like women are naturally better at washing the dishes, right? No. Come on.

Study after study [PDF] has shown that the gap in math and science test scores between girls and boys can be attributed not to natural ability, but to cultural messages. It’s called the stereotype threat: When a member of a group is exposed to negative stereotypes about that group, they perform poorly. Just requiring girls to check “female” before beginning a standardized test has been shown to significantly reduce their scores. The more a person is bombarded with expectations of failure, the more likely it is that he or she will fail.

Researchers from the University of Wisconsin analyzed test scores [PDF] from 86 countries and found that average math scores for girls and boys were equal. Even in the United States, the gap has begun to narrow. 

"We have to stop selling T-shirts to girls that say, ‘I'm too pretty to do math,'” study co-author Jonathan Kane told CNN. "Our stereotypes are hurting our math education.”

8. YOUR BRAIN CAN'T CHANGE OR HEAL.

The brain you have now is the brain you’ve always had and always will … right? Wrong.

The human brain is astonishingly plastic and can adapt to all kinds of extreme situations. People who lose their sight find that their sense of hearing improves dramatically, because the brain dedicates more energy to auditory processing. And, as we’ve seen, people who’ve had half their brain removed can still function, because the remaining half takes up all the responsibilities. Our brains are not hard-wired in any sense of the word.

Our brains are also not a finite resource. Cells in the rest of our bodies are constantly dying and being replaced. For a long time, scientists believed that the brain was the exception to this rule, and that damaged brain cells would never grow back. We now know this isn’t the case.

5 Signs Humans Are Still Evolving

Lealisa Westerhoff, AFP/Getty Images
Lealisa Westerhoff, AFP/Getty Images

When we think of human evolution, our minds wander back to the millions of years it took natural selection to produce modern-day man. Recent research suggests that, despite modern technology and industrialization, humans continue to evolve. "It is a common misunderstanding that evolution took place a long time ago, and that to understand ourselves we must look back to the hunter-gatherer days of humans," Dr. Virpi Lummaa, a professor at the University of Turku, told Gizmodo.

But not only are we still evolving, we're doing so even faster than before. In the last 10,000 years, the pace of our evolution has sped up, creating more mutations in our genes, and more natural selections from those mutations. Here are some clues that show humans are continuing to evolve.

1. Humans drink milk.

Historically, the gene that regulated humans' ability to digest lactose shut down as we were weaned off our mothers' breast milk. But when we began domesticating cows, sheep, and goats, being able to drink milk became a nutritionally advantageous quality, and people with the genetic mutation that allowed them to digest lactose were better able to propagate their genes.

The gene was first identified in 2002 in a population of northern Europeans that lived between 6000 and 5000 years ago. The genetic mutation for digesting milk is now carried by more than 95 percent of northern European descendants. In addition, a 2006 study suggests this tolerance for lactose developed again, independently of the European population, 3000 years ago in East Africa.

2. We're losing our wisdom teeth.

Our ancestors had much bigger jaws than we do, which helped them chew a tough diet of roots, nuts, and leaves. And what meat they ate they tore apart with their teeth, all of which led to worn-down chompers that needed replacing. Enter the wisdom teeth: A third set of molars is believed to be the evolutionary answer to accommodate our ancestors' eating habits.

Today, we have utensils to cut our food. Our meals are softer and easier to chew, and our jaws are much smaller, which is why wisdom teeth are often impacted when they come in — there just isn't room for them. Unlike the appendix, wisdom teeth have become vestigial organs. One estimate says 35 percent of the population is born without wisdom teeth, and some say they may disappear altogether.

3. We're resisting infectious diseases.

In 2007, a group of researchers looking for signs of recent evolution identified 1800 genes that have only become prevalent in humans in the last 40,000 years, many of which are devoted to fighting infectious diseases like malaria. More than a dozen new genetic variants for fighting malaria are spreading rapidly among Africans. Another study found that natural selection has favored city-dwellers. Living in cities has produced a genetic variant that allows us to be more resistant to diseases like tuberculosis and leprosy. "This seems to be an elegant example of evolution in action," says Dr. Ian Barnes, an evolutionary biologist at London's Natural History Museum, said in 2010 statement. "It flags up the importance of a very recent aspect of our evolution as a species, the development of cities as a selective force."

4. Our brains are shrinking.

While we may like to believe our big brains make us smarter than the rest of the animal world, our brains have actually been shrinking over the last 30,000 years. The average volume of the human brain has decreased from 1500 cubic centimeters to 1350 cubic centimeters, which is an amount equivalent to the size of a tennis ball.

There are several different conclusions as to why this is: One group of researchers suspects our shrinking brains mean we are in fact getting dumber. Historically, brain size decreased as societies became larger and more complex, suggesting that the safety net of modern society negated the correlation between intelligence and survival. But another, more encouraging theory says our brains are shrinking not because we're getting dumber, but because smaller brains are more efficient. This theory suggests that, as they shrink, our brains are being rewired to work faster but take up less room. There's also a theory that smaller brains are an evolutionary advantage because they make us less aggressive beings, allowing us to work together to solve problems, rather than tear each other to shreds.

5. Some of us have blue eyes.

Originally, we all had brown eyes. But about 10,000 years ago, someone who lived near the Black Sea developed a genetic mutation that turned brown eyes blue. While the reason blue eyes have persisted remains a bit of a mystery, one theory is that they act as a sort of paternity test. “There is strong evolutionary pressure for a man not to invest his paternal resources in another man’s child,” Bruno Laeng, lead author of a 2006 study on the development of blue eyes, told The New York Times. Because it is virtually impossible for two blue-eyed mates to create a brown-eyed baby, our blue-eyed male ancestors may have sought out blue-eyed mates as a way of ensuring fidelity. This would partially explain why, in a recent study, blue-eyed men rated blue-eyed women as more attractive compared to brown-eyed women, whereas females and brown-eyed men expressed no preference.

Now Ear This: A New App Can Detect a Child's Ear Infection

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iStock.com/Techin24

Generally speaking, using an internet connection to diagnose a medical condition is rarely recommended. But technology is getting better at outpacing skepticism over handheld devices guiding decisions and suggesting treatment relating to health care. The most recent example is an app that promises to identify one of the key symptoms of ear infections in kids.

The Associated Press reports that researchers at the University of Washington are close to finalizing an app that would allow a parent to assess whether or not their child has an ear infection using their phone, some paper, and some soft noises. A small piece of paper is folded into a funnel shape and inserted into the ear canal to focus the app's sounds (which resemble bird chirps) toward the child’s ear. The app measures sound waves bouncing off the eardrum. If pus or fluid is present, the sound waves will be altered, indicating a possible infection. The parent would then receive a text from the app notifying them of the presence of buildup in the middle ear.

The University of Washington tested the efficacy of the app by evaluating roughly 50 patients scheduled to undergo ear surgery at Seattle Children’s Hospital. The app was able to identify fluid in patients' ears about 85 percent of the time. That’s roughly as well as traditional exams, which involve visual identification as well as specialized acoustic devices.

While the system looks promising, not all cases of fluid in the ear are the result of infections or require medical attention. Parents would need to evaluate other symptoms, such as fever, if they intend to use the app to decide whether or not to seek medical attention. It may prove most beneficial in children with persistent fluid accumulation, a condition that needs to be monitored over the course of months when deciding whether a drain tube needs to be placed. Checking for fluid at home would save both time and money compared to repeated visits to a physician.

The app does not yet have Food and Drug Administration (FDA) approval and there is no timetable for when it might be commercially available. If it passes muster, it would join a number of FDA-approved “smart” medical diagnostic tools, including the AliveKor CardiaBand for the Apple Watch, which conducts EKG monitoring for heart irregularities.

[h/t WGRZ]

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