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78 CHAPTER 2 Neuroscience and BehaviorSCIENCE VERSUS PSEUDOSCIENCEBrain MythsIs it true that we only use 10 percent of our brain?Sorry, but this popular notion simply isn’t true. Think about the informationpresented in this chapter. As brain-imaging techniquesclearly show, multiple brain areas are activated in response to evensimple tasks, such as speaking or listening to music. Further, if weused only 10 percent of our brain, then people who have a strokeor brain injury would probably not experience any obvious consequences.Of course, that’s not what happens. There is no area ofthe brain that can be damaged without some kind of consequences.Finally, how well do you think you would function if abrain injury destroyed a “mere” 25 percent of your brain?So where did the 10 percent myth come from?The famous psychologist William James may have inadvertenlycontributed to the 10 percent myth when he wrote in 1908,“We are making use of only a small part of our possible mentaland physical resources.” Whether James contributed to the mythor not, the myth has been around since at least the early 1900s(Beyerstein, 1999). Some of those who perpetuate the 10 percentmyth probably mean well, like teachers, coaches, and motivationalspeakers. Their basic message is that each of us shouldstrive to reach our full potential. Others, however, are hawking aproduct that they promise will enhance your creativity, psychicpowers, intelligence, or other hidden potential. But you willnever hear a neuroscientist make the 10 percent claim. In fact,you’ll hear just the opposite. As neuroscientist Barry Gordon(2008) comments, “It turns out that we use virtually every partof the brain, and that the brain is active almost all the time. Let’sput it this way: the brain represents three percent of the body’sweight and uses 20 percent of the body’s energy.”Most right-handed people are strongly right-handed. Isthe same true of lefties?The vast majority of people are strongly right-handed, using theirright hands for virtually all tasks requiring dexterity. About 10 to13 percent of the population identify themselves as left-handed(Basso, 2007). But most left-handers actually show a pattern ofmixed-handedness. For example, your author Don uses his lefthand to write and hold a fork but his right hand to swing a tennisracquet and hammer nails. Strong left-handedness isextremely rare: only 2 or 3 percent of the population is stronglyleft-handed (Wolman, 2005).Is it true that left-handed people process speech andlanguage in their right cerebral hemisphere? Are theyright-hemisphere dominant?No. About 70 percent of left-handers are left-hemisphere dominantfor language, just like the vast majority of right-handedpeople (Toga & Thompson, 2003). Only about 15 percent of lefthandersare right-hemisphere dominant for language. Another15 percent are bilateral, using both hemispheres for speech andlanguage functions (Jörgens & others, 2007). Just for the record,about 3 percent of right-handed people are either righthemisphereor bilaterally specialized for language.Is it true that some people are “right-brained” and otherpeople “left-brained”?It certainly seems as if some people are more logical, analytical,or detail-oriented than others, especially in the way that theyLeft Brain, Right Brain? As this image rather playfully suggests,many people see the two hemispheres as representing diametricallyopposed ways of thinking and behaving: the left brain iscold, rational, and analytical; the right brain is emotional, artistic,and free-spirited. But how much truth is there to this myth?make decisions or tackle problems. However, in the normal,intact human brain, left and right hemispheres are highly interconnected.So, unless their corpus callosum has been surgicallysliced, all humans rely on the smooth integrated functioning ofboth their left and right hemispheres to speak, learn, and generallynavigate everyday life. In fact, the more complex the task,the greater the likelihood that both hemispheres will be involvedin performing it (Allen & others, 2007; Weissman & Banich,2000; Yoshizaki & others, 2007). So, in that sense, the simpleanswer to this question is “No.”Is the right brain responsible for creativity and intuition?Can you train your right brain?Although the right hemisphere is specialized for holistic processing,there is no evidence that the right hemisphere is any more“intuitive” or “creative” than the left hemisphere (Gazzaniga,2005). Nor is there evidence that any teacher, however skilled,could somehow selectively “educate” one side of your brain inisolation from the other (Goswami, 2006). While it is true thateach hemisphere is specialized for different abilities, you rely onthe smooth, integrated functioning of both hemispheres to accomplishmost tasks. This is especially true for such cognitivelydemanding tasks as artistic creativity, musical performance, orfinding innovative solutions to complex problems.