Genius and the Brain

Your brain regulates your body's organ systems. When you move around, it sends impulses along your nerves and tells your muscles what to do. Your brain controls your senses of smell, taste, touch, sight and hearing, and you experience and process emotions using your brain. On top of all that, your brain allows you to think, analyze information and solve problems. But how does it make you smart?

Scientists haven't figured out exactly how all the gray matter in your brain works, but they do have an idea of which part lets you think. The cerebral cortex, which is the outermost part of your brain, is where thought and reasoning happen. These are your brain's higher functions -- the lower functions, which relate to basic survival, take place deeper in the brain.

Hover your mouse pointer over the labels to see where each lobe of the brain is located.

Your cerebral cortex is the largest part of your brain, and it's full of wrinkles and folds that allow it to fit in your skull. If you removed and stretched out an adult human's cerebral cortex, it would be about as large as a few pages of a newspaper. It's divided into several lobes, and different regions within these lobes handle specific tasks related to how you think. You can learn about them in more detail in How Your Brain Works, but here's a quick overview of what each lobe handles:

• Frontal: speech, thought and memory
• Parietal: sensory input from your body
• Temporal: auditory information from your ears
• Occipital: visual information from your eyes

Smoking: Not Smart According to research findings released in 2004, smokers and former smokers did not perform as well on tests as nonsmokers. Four hundred sixty-five subjects had taken a test that measured cognitive ability in 1947 at age 11. They took the test again between 2000 and 2004. Based on the results, smoking appeared to cause a one percent drop in cognitive function. A possible explanation for this correlation is that smoking-related lung damage caused less oxygen to reach people's brains.

It's obvious that your cerebral cortex has a big impact on how you think. But studying exactly how it makes you smart is a little tricky, because:

• Your brain is hard to get to -- it's encased in your skull.
• Tools for looking at the brain, such as magnetic resonance imaging (MRI) machines, can require a person to be partially or completely still. This can make it hard for doctors to observe people's brain activity during real-life activities.
• Brains, like all organs, undergo changes after a person dies. These changes may make it difficult to tell how someone's brain compared to other brains while that person was alive. In addition, postmortem examinations cannot evaluate brain activity.

Image courtesy U.S. Department of Health and Human Services

In spite of all those challenges, researchers have figured out a few things about how the brain affects intelligence. A 2004 study at the University of California, Irvine found that the volume of gray matter in parts of the cerebral cortex had a greater impact on intelligence than the brain's total volume. The findings suggest that the physical attributes of many parts of the brain -- rather than a centralized "intelligence center" -- determine how smart a person is.

A 1999 analysis of Albert Einstein's brain also seems to support this theory. Einstein's brain was slightly smaller than the average brain. However, parts of his parietal lobe were wider than most people's brains. The larger areas in Einstein's brain are related to mathematics and spatial reasoning. Einstein's parietal lobe was also nearly missing a fissure found in most people's brains. Analysts theorized that the absence of the fissure meant that different regions of his brain could communicate better.

A 2006 paper in the journal "Nature" theorized that the way the brain develops is more important than the size of the brain itself. A person's cerebral cortex gets thicker during childhood and thinner during adolescence. According to the study, the brains of children with higher IQs thickened faster than those of other children. Studies also suggest that, to some extent, children inherit intelligence from their parents. Some researchers theorize that this is because the physical structure of the brain can be an inherited trait. In addition, the process of becoming really good at something both requires and encourages your brain to wire itself to handle that particular task better.

Even though scientists are not sure exactly how or why it happens, it's clear that the human brain plays a part in determining a person's intelligence. But what's the difference between genius and intelligence? And what makes one person more intelligent than another? We'll look at how intelligence relates to genius next.

Brainy Babies? Image courtesy Amazon "Baby Needs Mozart" CD cover After studies showed that listening to Mozart could raise IQ scores, parents started playing Mozart for babies, hoping to take advantage of the "Mozart effect." One explanation for the effect is that music makes people more awake and alert. Another is that listening to Mozart and mathematical or spatial reasoning tasks rely on the same neurons within the brain. However, none of the studies involving Mozart's music have used babies as test subjects, and the Mozart effect in adults is usually temporary.