Sunday, April 19, 2009

Brain Myths—Busted

Brain & Body

The human brain has received unprecedented press coverage in the past few years, thanks in large part to big leaps in science's understanding of what goes on in the space between our ears. Yet, some stubborn myths remain.

For this special installment of Brain & Body, we're offering insights into which commonly held beliefs stem from reliable studies in neuroscience—and which are just plain mindless. For further information on these fallacies, we've consulted our favorite research neuroscientist and go-to brain guy, Istvan Molnar-Szakacs, Ph.D., of the Semel Institute's Tennenbaum Center for the Biology of Creativity at UCLA.

Myth: Listening to Mozart makes you smarter.

Reality: It may make you feel superior, but listening to Mozart won't make you any smarter than bumping along to the latest cut by Lil' Wayne. The Mozart idea first took hold following a 1993 study published in Nature that showed that 12 students scored higher on a spatial IQ test after listening to a Mozart sonata. Author Don Campbell ran with the notion in his pop-psychology book The Mozart Effect, and a multi-million–dollar industry arose selling CDs and videos to parents holding out hope their little ones would harness the intellectual power of Amadeus.

However, subsequent research failed to replicate the (small) study's results. And the original researchers later re-emphasized the qualifications in their findings; notably, that the effect was temporary, not extending beyond 10 or 15 minutes. "The myth does bring attention to the value of music as a tool for stimulating the brain," says Molnar-Szakacs. "We know thatplaying a musical instrument in childhood improves performance in academic areas other than music. But just listening to Mozart while cramming for a test is no reliable way to improve your score, let alone your IQ."

Myth: People with autism have genius talents.

Reality: There's not a great deal known about savant syndrome, the very curious condition in which people with developmental disorders such as autism show astonishing skills in music, art, or math. But we do know that the widespread misconception about its prominence is traceable to the 1988 film "Rain Man," and that the movie's hero would be exceptionally skilled, and exceptionally rare, even among savants.

According to Darold A. Treffert, M.D., of the Wisconsin Medical Society—a recognized expert on savant syndrome— approximately one in 10 people with autism spectrum disorder has some savant skills. (Among those with other developmental disabilities, fewer than 1 in 100 are savants.) Treffert estimates that no more than 50 people in the world are "prodigious savants" like the toothpick-counting character portrayed by Dustin Hoffman.

Beware the characterization of genius, too. The famous "calculating twins" written about by Oliver Sacks, M.D., in The Man Who Mistook His Wife for a Hatcould see prime numbers in a fallen stack of matches or tell you which day of the week July 4 would fall on in the year 3024, but they couldn't do simple multiplication.

Myth: Smarter animals have bigger brains.

Reality: A sperm whale's brain is more than five times the weight of a human's—yet the animal with the world's largest brain still can't play a decent game of chess. What gives?

"The relationship isn't directly between brain size and smarts, but rather in the ratio of brain weight to body weight and smarts," explains Molnar-Szakacs. "In a human, whose brain weighs around 3 pounds, the ratio is about 1:50. But in other mammals it's closer to 1:80 or 1:200. So, the smaller the ratio, the more intelligent the animal."

Molnar-Szakacs adds that, even beyond the brain-to-body weight ratio, it is what's inside the cranium that counts. "The parts of the human brain that control higher cognitive functions are the cerebral cortices," he says. "These are the areas responsible for the uniquely [high-functioning] human abilities of language, memory, and planning for the future. The cerebral cortices enable us to learn and adapt our responses to our environment in much more sophisticated ways than other animals. For example, we have the capability to override predominant, stimulus-driven responses, so that we can say 'no' to chocolate cake if it'll break our diet even if we are still hungry and know it would taste really good."

Myth: Drink enough alcohol and you'll start killing brain cells.

Reality: Drunken frat boys head-butting one another in a bar may give you pause to consider this one, but alcohol does not kill neurons or create holes in the brain. However, there's no denying that alcohol and other drugs of abuse impact brain systems. It's their effect on the neurotransmitters dopamine and serotonin that goose the brain's reward system, leading to feelings of euphoria—and, when more of the drug is needed to create the same effect, to tolerance and addiction.

"Over the short-term, alcohol and drugs alter brain function rather than affecting brain structure," Molnar-Szakacs clarifies. "Slurred speech, impaired motor response, and impaired judgment are all symptomatic of compromised frontal lobes, the centers of the brain that direct higher-level decision making."

Rarely, a chronic drinker may develop Wernicke-Korsakoff's Syndrome, a condition characterized by atrophy or shrinking of the thalamus and hypothalamus and the inability to recall or form memories. This syndrome's not a direct effect of drinking, but rather a secondary result of alcohol abuse so severe that absorption of vitamin B-1 is prevented, leaving the brain malnourished.

Myth: Most people use only 10 percent of their brain.

Reality: A quote from William James that's been mangled, misinterpreted, and misused may explain the myth's origins. In making a general point about human potential, the philosophical psychologist said that people "make use of a very small portion of their possible consciousness, and of their soul's resources in general." Anecdotal evidence of individuals suffering physical damage to the brain and continuing to function, such as the famous story of Phineas Gage, may also have contributed over the years.

Thanks to the development of neuroimaging technologies—machines that allow us to view not only structures but functions of the brain at work—this myth is handily debunked. While we may not use all of our brain all of time, multiple areas are simultaneously recruited for every task we undertake. For example, all the different parts of the brain responsible for vision, sensation, planning, motor coordination, muscle activity, and homeostasis are required to play a game of tennis or write words on a page. In fact, new studies examining the brain at rest reveal that an entire network of regions is active even when a person is "doing nothing," notes Molnar-Szakacs.

By Rich Maloof

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