Most people around the world are right-handed. This also seems to be true in history. In 1799, scientists studied works of art made at different times. Most of the people shown in these works were right-handed, so the scientists guessed that right-handedness had always been common through history. Today, only about 10% to 15% of the world's population are left-handed.
Why are there more right-handed people than left-handed ones? Scientists now know that a person's two hands each have their own jobs. This is because of the different work of the two sides of the brain. The right side of the brain, which makes a person's hands and eyes work together, controls the left hand. The left-side of the brain, which controls the right hand, is the centre for thinking and doing problems. These findings show that more artists should be left-handed, and studies have found that left-handedness is twice as common among artists as among people in other jobs.
No one really knows what makes a person become right-handed instead of left-handed. Scientists have found that almost 40% of the people become left-handed because their main brain is damaged when they are born. However, this doesn't happen to everyone, so scientists guess there must be another reason why people become left-handed. One idea is that people usually get right-handed from their parents. ①If a person does not receive the gene (基因) for right-handedness, he / she may become either right-handed or left-handed according to the chance and the people they work or live with.
Though right-handedness is more common than left-handedness, people no longer think left-handed people are strange or unusual. A long time ago, left-handed children were made to use their right hands like other children, but today ②they don't have to.
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