We all know whether we are right- or left-handed. The hand that we prefer to use for actions requiring fine motor skills, such as writing, is established early in our childhood development. Some research even suggests that fetuses prefer one hand or the other while still in the womb.
Interestingly, the proportion of left-handed to right-handed people is remarkably consistent across cultural and geographic divides, with roughly one in ten people being left-handed globally. However, chimpanzees, our closest mammal relatives, also tend to prefer one hand over the other for certain tasks, but at a much more even ratio of roughly 50/50.
The underlying reasons why so few people are left-handed remain a scientific mystery, even though this ratio appears to have been constant throughout much of human evolution. Studies of Neanderthal eating habits suggest that, just as in humans, right-handers were overwhelmingly more common.
While there is clearly at least some genetic basis to this phenomenon, geneticists believe that up to 40 different genes may influence handedness but have yet to pinpoint which ones. Other factors that have been proposed to explain the discrepancy in handedness range from pregnancy stress and brain organization patterns to cooperative interaction and societal bias.
Right or left?
- Preference and skill do not always align; nearly a third of people who write with their left hand can throw a ball more accurately with their right.
- Myths suggesting that left-handed people have a shorter life expectancy than right-handers have now been debunked, with the origins of such theories shown to be based on flawed data analysis.
- Besides handedness, most people prefer using a certain side of their body in many other everyday situations. However, although just 10% of us are left-handed, 20% are left-footed, 30% are left-eyed, and 40% are left-eared.
- The test to see if you are right- or left-eyed is very simple. Hold your thumb out in front of you and look at it with just your right eye and then just your left; you’ll get a clearer picture with your stronger eye. The same is true of our ears; which ear do you naturally prefer to hold your phone to?
