Atricle Summary About Handedness

Because people with left handedness have had plenty of stigma and curiosity surrounding them, a reporter from the Wall Street Journal, Christina Tsuei looked into the reasons behind a person being left handed and different statistics having to do with handedness. The article says that about ten percent of people are left handed and one percent is “mixed-handed “which means they are not dominant with either hand. Handedness is only partially linked to genetics. Because handedness has to do with how our brain is wired researching handedness may give insight on different disorders. Research that was published in 2009 estimated that only twenty five percent of someone’s preference of hand has to do with genetics. Identical twins who have all the same genes might not share the same handedness. Environmental factors can also contribute to handedness. Things like the mother being highly stressed during pregnancy and low birth weight are thought to contribute to a child being left handed. For unknown reasons, handedness has a lot to do with how a baby’s brain develops while in the womb. There are no significant differences in IQ between people who are left handed and people who are right handed. It was found in research performed at Harvard that lefties might be better at divergent thinking but the salaries of people who favor their left hand are, on average, ten percent lower than righties. Usually with people who are right handed the left side of their brain is dominant whereas in the brains of lefties about seventy percent of them rely on the left half. Left handedness is sometimes associated with a greater risk for several psychiatric and developmental disorders. Symmetry is when neither side of the brain is dominant and is believed to be linked to disorders. Having a dominant hemisphere is more efficient and typical. People with schizophrenia tend to have more symmetry in their brains. In 2008 it was found in a study that people who are mixed of left handed may have more difficulty with language and ADHD. Another study found that ADHD symptoms may actually be more linked to mixed handed children. Some research studies have reported that reported that there is a link between left handedness and various mood disorders along with dyslexia and ADHD. Handedness also might have an effect on someone’s athletic abilities. Lefties tend to be better at sports when they are facing an opponent who is left handed but not in sports where they aren’t interacting with a competitor. The main stress hormone in the body, cortisol, can affect brain development. Cortisol has the ability to get through the placenta barrier and possibly influence the baby. Many studies have shown that traumatic and stressful life events while pregnant can increase the chance of having a left-handed child. In a study of over eight hundred Danish mother and their Danish children, all age three, Dr.Obel who is a professor at Aarhus University in Denmark and has conducted research on risk of disease and the prenatal environment, and his team observed that the mothers who had, had multiple stressful events take place during their third trimester were over three times more likely to have a child who is mixed-handed.