Left-handed people are said to be good at complex reasoning, resulting in a high number of lefty Noble Prize winners, writers, artists, musicians, architects and mathematicians. According to research published in the American Journal of Psychology, lefties appear to be better at divergent thinking.
In their analysis of 144 handedness and brain laterality studies—accounting for a total of nearly 1.8 million individuals—University of Oxford psychologists Marietta Papadatou-Pastou, PhD, and Maryanne Martin, PhD, found that males are about 2 percent more likely to be left-handed than females.
Most of the current research suggests that left-handedness has an epigenetic marker—a combination of genetics, biology and the environment. Because the vast majority of the population is right-handed, many devices are designed for use by right-handed people, making their use by left-handed people more difficult.
While some reasons for the differences in thinking and functioning may be genetic and anatomical, left-handedness is behavioral as well. Things left-handers do differently are often influenced by the societal implications of having a dominant hand that differs from the general public.
Wright and Hardie (2012) found that left-handers reported higher levels of state anxiety but there was no difference in trait anxiety. They also demonstrated that when Trait Anxiety was controlled for, left-handers still showed a higher level of state anxiety compared to right-handers.
“When we're left-handed, our right brains are usually dominant, and that's where creativity and intuition are centered. So it's often easier for us to be creative than logical.
It's linked to a risk of mental health problems
Studies have also found links between non-right-handedness and dyslexia, attention deficit hyperactivity disorder, and some mood disorders.
However, post-hoc exploration of their and other sets of data has shown that there is an apparent tendency for left-handedness to be more prevalent in the period March-July than in the period August-February. The present work tested this seasonal hypothesis prospectively among university students.
McManus which found that the Netherlands has one of the world's highest prevalences of left-handedness at 13.23 percent. The United States isn't far behind with a rate of 13.1 percent while neighboring Canada has 12.8 percent. Elsewhere, rates of left-handedness are far lower and China is a good example.
-Counting how many people are left-handed is more difficult than it looks, because of variations in preference and skill from task to task and because of left-handers having been forced to write with their right hand, but the best estimate we have is that roughly 10% of the world population is left-handed.
The Royal Family's Handedness
Texts indicate that Queen Elizabeth II is right-handed, and some of her relatives, such as her great-grandmother Queen Victoria, her dad King George VI, her mum the Queen Mum, and her grandson, William, are left-handed.
A study in The Journal of Nervous and Mental Disease suggested that those who are left-handed are more prone to negative emotions. It also found that when processing emotions, lefties have a greater imbalance in activity between the left and right brains.
A 1967 study by Douglas found no evidence to correlate mathematical ability with left-handedness or ambidexterity. The study compared the people who came in the top 15% of a mathematics examination with those of moderate mathematical ability, and found that the two groups' handedness preferences were similar.
Clearly, being left-handed is not without its disadvantages.
However, left-handedness does not rise to the level of being a disability. The Social Security Administration has a list of all conditions which qualify as disabilities. This listing is commonly known as the “Blue Book”.
Browse through a list of history's most famous left-handers and you are likely to see Albert Einstein's name. You may even see people tying Einstein's genius to his left-handedness.
Left-handed and ambidextrous people are more susceptible to negative emotions, including anger. A small study published last year in the Journal of Nervous and Mental Disease found that the brains of lefties process emotions differently than those of righties, with more communication between the brain's two halves.
In support of this, many studies have found that left-handed men are overrepresented among modern professional fighters, but studies typically find no difference in fighting success between left and right-handed fighters.
Lefties--or at least relatives of lefties--may be better than right-handed people at remembering events, according to a new study. Since the mid-1980s, scientists have known that the two brain hemispheres of left-handers are more strongly connected than those of right-handers.
THIS STUDY TESTED WHETHER LEFT-HANDED JUVENILES ARE OVERREPRESENTED AMONG VIOLENT JUVENILE OFFENDERS AND FOUND THAT LEFT-HANDED OFFENDERS SCORED LOWER THAN RIGHT-HANDERS ON THE VIOLENCE SCALE.
According to a small study published in the Journal of Nervous and Mental Disease, lefties are more prone to having negative emotions. In addition, they seem to have a more difficult time processing their feelings. Again, this seems to be related to the brain-hand connection.
Left-handedness and longevity
In addition, some diseases associated with left-handedness are relatively rare and there is no evidence that left-handedness is associated with increased risk of common diseases such as malignancy, cerebrovascular and cardiovascular diseases.