67 Get Smart Our Amazing Brain

CHAPTER 1 The Brain: Facts and Myths YOUR BRAIN MAKES YOU WHO YOU ARE, BUT WHAT DO YOU KNOW ABOUT IT? In the past, people knew little about the human brain. The Greek philosopher Aristotle believed we thought with our hearts! Now, thanks to science, we know more. But what do you know about your brain? Read the sentences. Decide whether each one is a fact (true) or myth (not true). 1 People only use about 10 percent of the brain. 2 People use one hemisphere of the brain more than the other. 3 Once brain cells die, new ones cannot grow in their place. 4 The brain, like a computer, has a fixed and limited memory.

5 The white matter in the brain doesn't do anything important. 6 The brain uses almost a quarter of all a person's energy. 7 Teenage brains aren't totally finished developing. 8 Men and women think differently. 9 The brain can repair itself after an accident. 10 The different lobes in the brain do different jobs. The Answers 1. Myth. We use different parts of the brain at different times and for different functions, so we really use a large amount of our brain. In fact, if neurons aren't used, they die. 2. Myth. Until recently, many scientists believed that people used one half of the brain more than the other. Now we know the brain uses both sides together. For example, while the left side processes language, the right side controls the way we speak.

3. Myth. Many people think that as we get older, our brain cells die away, making us less intelligent. Fortunately, adults can grow new neurons by learning new things, doing exercise, and remembering things. 4. Myth. When we remember something, our brain is actually making new memory connections for the first time! 5. Myth. In the past, scientists thought that white matter didn't do anything important. Now they know that it is full of special cells, called glia, which help control the neural signals and also clean and repair neuron cells. 6. Fact. Our brain uses about 20 percent of all our energy and 25 percent of all the oxygen we breathe. 7. Fact. Studies show that teenagers don't use as much of the brain as adults. In particular, the frontal lobe, which controls social feelings and guilt, is less active. In other words, teenagers really are more selfish than adults! However, the brain becomes fully adult by about age 17.

8. Myth. Although it is true that men's and women's brains have different amounts of white and gray matter, new studies show that there seems to be no difference between how well men and women think and solve problems. 9. Fact. The brain is actually very flexible. When a part of the brain is damaged, other parts of the brain often create new connections to do the job of the missing part. 10. Fact. With the frontal lobe we think, plan, and feel emotion. With the parietal lobe we taste things and feel touch, pressure, pain, or temperature. The occipital lobe lets us see the world. The temporal lobe lets us hear things, and it is also important for emotion and memory.

CHAPTER 2 The Brain and Personality HOW MUCH OF OUR PERSONALITY ARE WE BORN WITH? What type of personality do you have? Are you shy or outgoing, cheerful or sad? Many psychologists divide human personality into these five general personality types: Extrovert— how outgoing and social we are Neurotic— how angry, guilty, or worried we are Agreeable— how kind, friendly, and trusting we are Conscientious— how self-controlled, responsible, and organized we are Open— how interested in new things we are Psychologists see our personalities as a mix of different amounts of each type. They use personality tests— special lists of questions— to decide how much of each type a person has.

But how much of a person's personality is learned from other people, and how much are people born with? And are the five types connected to different parts of the brain? In the 1980s, studies were carried out on identical twins (born from the same egg) who had grown up with different families. Although the children often grew up in very different places with different people, scientists found that they usually had extremely similar personalities. These studies led the scientists to realize that our brain controls our behavior and personality much more than they had previously thought. Today, scientists have the technology to take a computer picture, or scan, that shows which areas of the brain are being used when people think, speak, and act. This means they can look for connections between the scans and the results of traditional personality tests. The results are both interesting and complicated. So what is the exact relationship between personality and the areas of the brain?