Top Ten Myths About the Brain- page 2 | Science | Smithsonian
Current Issue
July / August 2014  magazine cover
Subscribe

Save 81% off the newsstand price!

Repeated in pop culture for a century, the notion that humans only use 10 percent of our brains is false. Scans have shown that much of the brain is engaged even during simple tasks. (Allen Bell / Corbis)

Top Ten Myths About the Brain

When it comes to this complex, mysterious, fascinating organ, what do—and don’t—we know?

smithsonian.com

(Continued from page 1)

6. The brain is hard-wired.
This is one of the most enduring legacies of the old “brains are electrical circuits” metaphor. There’s some truth to it, as with many metaphors: the brain is organized in a standard way, with certain bits specialized to take on certain tasks, and those bits are connected along predictable neural pathways (sort of like wires) and communicate in part by releasing ions (pulses of electricity).

But one of the biggest discoveries in neuroscience in the past few decades is that the brain is remarkably plastic. In blind people, parts of the brain that normally process sight are instead devoted to hearing. Someone practicing a new skill, like learning to play the violin, “rewires” parts of the brain that are responsible for fine motor control. People with brain injuries can recruit other parts of the brain to compensate for the lost tissue.

7. A conk on the head can cause amnesia.
Next to babies switched at birth, this is a favorite trope of soap operas: Someone is in a tragic accident and wakes up in the hospital unable to recognize loved ones or remember his or her own name or history. (The only cure for this form of amnesia, of course, is another conk on the head.)

In the real world, there are two main forms of amnesia: anterograde (the inability to form new memories) and retrograde (the inability to recall past events). Science’s most famous amnesia patient, H.M., was unable to remember anything that happened after a 1953 surgery that removed most of his hippocampus. He remembered earlier events, however, and was able to learn new skills and vocabulary, showing that encoding “episodic” memories of new experiences relies on different brain regions than other types of learning and memory do. Retrograde amnesia can be caused by Alzheimer’s disease, traumatic brain injury (ask an NFL player), thiamine deficiency or other insults. But a brain injury doesn’t selectively impair autobiographical memory—much less bring it back.

8. We know what will make us happy.
In some cases we haven’t a clue. We routinely overestimate how happy something will make us, whether it’s a birthday, free pizza, a new car, a victory for our favorite sports team or political candidate, winning the lottery or raising children. Money does make people happier, but only to a point—poor people are less happy than the middle class, but the middle class are just as happy as the rich. We overestimate the pleasures of solitude and leisure and underestimate how much happiness we get from social relationships.

On the flip side, the things we dread don’t make us as unhappy as expected. Monday mornings aren’t as unpleasant as people predict. Seemingly unendurable tragedies—paralysis, the death of a loved one—cause grief and despair, but the unhappiness doesn’t last as long as people think it will. People are remarkably resilient.

9. We see the world as it is.
We are not passive recipients of external information that enters our brain through our sensory organs. Instead, we actively search for patterns (like a Dalmatian dog that suddenly appears in a field of black and white dots), turn ambiguous scenes into ones that fit our expectations (it’s a vase; it’s a face) and completely miss details we aren’t expecting. In one famous psychology experiment, about half of all viewers told to count the number of times a group of people pass a basketball do not notice that a guy in a gorilla suit is hulking around among the ball-throwers.

We have a limited ability to pay attention (which is why talking on a cellphone while driving can be as dangerous as drunk driving), and plenty of biases about what we expect or want to see. Our perception of the world isn’t just “bottom-up”—built of objective observations layered together in a logical way. It’s “top-down,” driven by expectations and interpretations.

10. Men are from Mars, women are from Venus.
Some of the sloppiest, shoddiest, most biased, least reproducible, worst designed and most overinterpreted research in the history of science purports to provide biological explanations for differences between men and women. Eminent neuroscientists once claimed that head size, spinal ganglia or brain stem structures were responsible for women’s inability to think creatively, vote logically or practice medicine. Today the theories are a bit more sophisticated: men supposedly have more specialized brain hemispheres, women more elaborate emotion circuits. Though there are some differences (minor and uncorrelated with any particular ability) between male and female brains, the main problem with looking for correlations with behavior is that sex differences in cognition are massively exaggerated.

Women are thought to outperform men on tests of empathy. They do—unless test subjects are told that men are particularly good at the test, in which case men perform as well as or better than women. The same pattern holds in reverse for tests of spatial reasoning. Whenever stereotypes are brought to mind, even by something as simple as asking test subjects to check a box next to their gender, sex differences are exaggerated. Women college students told that a test is something women usually do poorly on, do poorly. Women college students told that a test is something college students usually do well on, do well. Across countries—and across time—the more prevalent the belief is that men are better than women in math, the greater the difference in girls’ and boys’ math scores. And that’s not because girls in Iceland have more specialized brain hemispheres than do girls in Italy.

Tags

Comment on this Story

comments powered by Disqus