Post-childhood, few of us spend much time thinking about which hand we write with. The classroom novelty of left-handedness wears off during the teen years, and by adulthood few people think twice about it. However, the hand you write with may say more about you than you ever expected.
In Western countries around 10 per cent of the population are left handed, and ambidextrous people– those who can write comfortably with both their right and left hands – are very uncommon. In China, Japan and other Asian countries the percentage of left-handed people is far lower.
History have favoured right-landed people, and often villainised or even feared left-handedness. In the Middle Ages, people believed that the devil was left-handed, and in the 1900s American doctors believed that people who wrote with their left hands were more likely to have mental disorders, and teachers would often encourage left-handed students to switch hands.
By examining patterns of wear and tear on ancient tools and measuring the arm bones of early human skeletons, researches have concluded that right-handed people have vastly outnumbered left-handed people since the Stone Age. Researchers have also found that other primates such as apes show preferences for right or left handedness.
A 2019 study identified differences in the DNA of left and right-handed people, concluding that genetic makeup is a determining factor in whether or not people are left-handed. In fact, by the second trimester, foetuses already show a strong preference for sucking one thumb over the other, suggesting that handedness is determined before birth. However, during early childhood many children are likely to switch between their hands for different tasks, so their handedness may not be clear until later in childhood.
Some studies have suggested that students who are left or mixed handed may be more likely to struggle in the classroom. Students who are left-handed, mixed-handed or ambidextrous were more likely to display symptoms of ADHD. According to WebMD, children who swapped back and forth between dominant hands were twice as likely to have dyslexia.
An upper hand
However, some research suggests that left-handed people may have the upper hand – mind the pun – in some areas. One study analysed the brain scans of 9000 participants and found that the areas of the brain that process language in the left and right hemispheres worked together better in left-handed people. Some research has found that left-handed children are more likely to be in gifted programs and to perform higher on verbal reasoning tests. Left-handed people are also overrepresented in creative professions.
Chris McManus from University College London argues that left-handed people make up more than their fair share of high achievers in his book Right-Hand, Left-Hand. Professor McManus wrote in the Scientific American, “Left-handers’ brains are structured differently from right-handers’ in ways that can allow them to process language, spatial relations and emotions in more diverse and potentially creative ways. Also, a slightly larger number of left-handers than right-handers are especially gifted in music and math … Similarly, studies of adolescents who took tests to assess mathematical giftedness found many more left-handers in the population.”
Left-handers also seem to have an edge over right-handed folk when it comes to sports and athletic abilities. In sports like boxing and fencing, when a left-handed strike may surprise their opponents, left-handed people seem to have an advantage.
One study in the UK found a link between regions of the brain associated with handedness and those areas associated with personality, restlessness, neuroticism and mood swings. There is also a well-established link between left-handedness and schizophrenia. Some research has also found that left-handers are overrepresented among those with lower cognitive skills and mental impairments. Left-handed people are twice as likely to have an intellectual disability than other people.
Some research has found that as we age, we become less and less dependent on our dominant hand.
Are you left or right-handed? Do you agree with these observations? Do you find yourself becoming less dependent on your dominant hand as you get older?
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