Roughly 1 in 10 people are left-handed, and there has always been a bit of mystery surrounding this minority group.
Throughout history, left-handedness has been accused of being a sign of evil, wickedness, unluckiness, insanity, illness, and shortened life spans.
More recently, myths around left-handedness have tended to swing in the opposite direction, claiming that lefties are more creative, intelligent, and successful.
But the truth, as usual, is more complex and interesting than either of these overly-simplified extremes.
The Development of Handedness
As early as 15 weeks after conception, fetuses in the womb show a preference for using one hand over the other. They will tend to move one arm more than the other (usually the right arm) and will suck on one thumb more than the other (usually the right thumb).
The less common manifestation of left-handed preference in the womb has been linked with several factors, including exposure to higher testosterone levels, genetics, and prenatal stress.
By the age of 2 or 3, as the toddler begins to explore and engage with the world around them, handling toys, tools, and utensils in more controlled ways, their handedness will usually be apparent.
The Asymmetrical Brain
The human brain is not quite perfectly symmetrical. The brain’s two hemispheres are not exact mirror images of each other, and there are some subtle differences in how they process information and the functions they perform.
But these differences are often exaggerated, oversimplified, and misunderstood.
You might hear claims that “left-brained” people are more logical, analytical, and factual, while “right-brained” people are more creative, intuitive, and emotional.
Despite the common belief that the brain’s left hemisphere controls logical, linear thinking, and the right hemisphere controls creative, non-linear thinking, the reality is that most thinking involves many parts of the brain working together.
It’s often pointed out that gifted musicians, artists, chess players, and mathematicians have a slightly higher representation of left-handedness than the general population. This may be true, but the difference seems small, and it’s unlikely to be entirely due to handedness itself.
Left-Handedness and Intelligence
There have been several studies looking at the relationship between handedness and intelligence.
There appears to be no statistically significant difference in the overall IQ of left-handers or right-handers.
When measuring specific types of thinking, intelligence, and cognitive abilities, there may be some noticeable differences in the performance of left-handers and right-handers. For example, left-handers seem to excel in some tests of divergent thinking, which is a type of thinking that allows for the generation of new ideas and solutions.
But it’s essential to keep in mind that these differences are minor, and the results of different experiments often conflict with one another. Left-handers are not generally more intelligent – or less intelligent – than right-handers.