For centuries, left-handedness has been shrouded in mystery, with some cultures even viewing it with suspicion. But science is shedding light on this fascinating quirk that affects 9.2% of the world’s population. Delve into the latest research and discover the surprising things science reveals about left-handed people.
There Are 708 Million Lefties In The World
Left-handedness is a fascinating trait, and scientists are still unraveling the reasons behind it. An estimated 708 million people around the world are left-handed. This translates to roughly 9.2% of the global population (as of 2019). Researchers arrived at this figure by analyzing data from a massive study involving over 2.3 million people.
Genetics Plays A Role
Left-handedness has a complex genetic link. While children of lefties are more likely to be left-handed themselves, most aren’t. Researchers suggest numerous genes (up to 40) might be involved, with recent studies highlighting a possible role for the MAP2 gene in brain development and handedness.
Men Are More Likely To Be Left-Handers
Studies suggest men are about 2% more likely to be left-handed than women. The cause remains a puzzle, but researchers suspect hormones or societal pressures might be at play. Further studies are needed to unravel the specifics.
Handedness Develops In The Womb
Even before birth, babies might be showing signs of their future handedness. Studies using ultrasounds have observed that by 15 weeks, a whopping 90% of fetuses favor sucking their right thumb. This strong preference points to the idea that handedness is rooted in how the brain develops in the womb, even before birth.
Early Life Factors Influence Left-Handedness
It’s not just genes. While genetics play a part in left-handedness, a Dutch study revealed other surprising factors. Birth weight, multiple births, season of birth, breastfeeding, and even sex can influence handedness. This suggests the environment and even cultural attitudes have a role in shaping this unique trait.
25% Preschoolers Are Unsure Of Their Handedness
Not all preschoolers have a clear dominant hand yet. A questionnaire study found that most 3-year-olds were right-handed, but a significant portion (25%) showed mixed hand use for different tasks. This suggests that handedness is still developing for some children at this age.
Left-Handedness Isn’t Always Linked To Left-footedness
Handedness isn’t the only way our bodies show a preference for one side! We also have “footedness,” your go-to foot for kicking a ball or grabbing with your toes. While footedness and handedness are related in most people, not every left-hander is a left-footer. A study found that out of 1026 felt-handers, 59% were left-footed, 25% were mixed-footed, and only 17% were right-footed.
Animals Can Also Be Left-Handed
Just like humans, many animals show paw preference. Studies suggest 36-46% of cats and 31-53% of dogs favor their left paws. Interestingly, this trait seems more common in our animal companions compared to humans, where only about 10% are left-handed. Even chimps and gorillas show handedness, with a surprising twist – they might favor their left paw for some tasks and their right for others.
Lefties Communicate And Perceive Differently
A UK study found genes linked to left-handedness also affect brain structure. The study identified four genetic regions associated with left-handedness when they analyzed the genomes of approximately 400,000 people from the UK Biobank (including 38,332 left-handers). Left-handers showed stronger connections between language areas in both hemispheres, hinting at potential differences in communication and perception.
Ultrasounds Increase Odds of Left-handedness
Prenatal ultrasounds might be linked to a slight uptick in left-handedness. A study found that children exposed to ultrasounds in the womb were more likely to be left-handed, though the effect was small. This trend held for both genders but appeared stronger for boys with earlier ultrasounds. More research is needed to confirm this intriguing possibility.
Twins Have A Higher Chance Of Being Lefties
Twins do have a slightly higher chance of being left-handed compared to singletons. An analysis of 19 studies found that 15.09% of identical twins and 12.08% of non-identical twins are left-handers. The overall frequency of left-handedness is about 9% in the general population. Interestingly, even among identical twins, about 20 to 25% do not share the same handedness. So, while genetics play a role, it does not guarantee that both twins will have the same handedness.
Left-handers Have An Advantage In Sports
Lefties may have a hidden edge in sports like tennis, boxing, and baseball. Because they’re less common, right-handed opponents might be less prepared for their moves, giving them a surprise advantage. Studies even show lefties scoring more goals in water polo.
Left-Handedness and Mental Health
While lefties may shine in sports, research suggests a possible link to mental health. Studies show higher rates of schizophrenia and PTSD in left-handed individuals. Scientists believe brain development differences underlying left-handedness might be a factor.
Lefties are Quicker Thinkers
Left-handed individuals often exhibit faster connections between the right and left hemispheres of the brain, leading to quicker information processing. A 2006 Australian study in Neuropsychology found that left-handers performed better on tasks assessing inter-hemispheric transfer time. This cognitive advantage could benefit them in activities like video games and sports.
Left-Handers Have A Creative Edge
Left-handers may have a creative edge. Studies suggest their brains are wired differently, allowing them to form unique connections between ideas. This “outside the box” thinking could be due to a more diverse neural network. While not all left-handers are creative geniuses, research shows they tend to excel at divergent thinking, a key component of creativity.