"Well, in a way, left-handed people are smarter, and I'll tell you why," Dr. Oz says. "Left-handed people can deal with more incoming information that doesn't come in an organized way." Dr. Oz says this is because of the way the brain develops when a baby is in its mother's womb. "The left brain normally controls your right side, which is really powerful," he says. "[In left-handed people], it allows the other side, the right brain, to become an equal partner."
Because left-handed people can use both sides of their brain more readily, Dr. Oz says, they can process information coming into their brain in different ways more easily. "That's why athletes do so well when they're left-handed. And there are a lot of presidents who have been left-handed, and there are a lot of folks who, because they can deal with a lot of complicated issues at once, work pretty effectively," he says.
But Dr. Oz says although you may write with one hand, parts of the body on the other side—such as an eye—can still be dominant. To determine which eye is dominant, Dr. Oz says to cut a pencil-sized hole in a piece of paper and hold it away from your face. Look through the hole at an object using only your right eye, then only your left. Dr. Oz says whichever eye you can still see the object through the hole with is your dominant eye.
Dr. Oz says many people are dominant with one eye and dominant with the opposite hand. "There are lots of different reasons you want to know [which eye is dominant]. If you were playing sports, it's sort of helpful," he says. "But folks actually use their different parts of their brain very differently, and it's sort of cool to understand how it all comes up."