![]() ![]() The concept has a faintly medieval ring: The word left is derived from the Old English lyft, meaning "weak" or "useless." In Latin, left translates as "sinister," and in the Bible it's tantamount to being "cursed into everlasting fire." Most lefties, they suggested, are just righties whose specialized brain centers have been reversed in the womb by abnormally high levels of testosterone. Why, then, are there left-handers? In the 1980s, neurologists at Harvard thought they had the answer. Right-handedness, to this way of thinking, is the most obvious mark of the genetic instructions that separate us from speechless, symmetric beasts. One Oxford neurobiologist went so far as to argue that right-handedness could be traced back 200,000 years to a single mutation-a sort of genetic Big Bang that created hemispheric specialization, language, and higher cognitive functioning in one go. Because handedness and language both seemed uniquely human traits, biologists long assumed that they were closely linked. But in humans, the hemispheres tend to specialize: Nearly all righties process language in the left side of the brain, while many lefties process language on the right. In most primates and other animals, the hemispheres of the brain divide the processing of tasks somewhat equally. Handedness in people is so hard to figure out in part because it seems so deeply rooted in our brains-and in the very peculiarities that seem to make us human. Even identical twins often have opposite hand preferences. And al-though left-handedness runs in families-notably in Queen Elizabeth II, Prince Charles, and Prince William-more than two-thirds of all lefties are born to right-handed couples. presidents (Bill Clinton, George Bush Sr., and Ronald Reagan are all left-handed). But lefties are also more likely to be Mensa members, musicians, and U.S. Among humans, lefties are more likely than righties to suffer from dyslexia, schizophrenia, stuttering, and other disorders. Granted, those theories already have a lot of explaining to do. And if handedness is clearly tied to birth order in chimps, it could throw a monkey wrench into theories of handedness in humans as well. But Winston and his brother point to an even more intriguing pattern: The younger the sibling, the more likely he or she is to be a lefty. Over the past 10 years, Hopkins's research has offered the first definitive proof that apes, like humans, have hand preferences: A third of the Yerkes chimpanzees are lefties and the rest are righties. "That's Winston's younger brother," Hopkins says. This one grabs the pipe with his right hand and digs out the peanut butter with his left. "Winston's a righty," Hopkins says, offering another piece of pipe to a smaller chimp hovering nearby. Using his left hand, he reaches over and grabs a length of PVC pipe from primatologist Bill Hopkins, then he uses his right to scoop out some peanut butter smeared inside. At the Yerkes Regional Primate Research Center in Atlanta, a large chimpanzee named Winston is taking part in an unusually pleasant experiment. ![]()
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