About one person in ten is left-handed, and Friday, August 13, 2027 is their day: International Left-Handers Day. A British club put it on the calendar.
Left-Handers Day on August 13
August 13 never moves. Britain’s Left-Handers Club has held its event on that date since 1992.
Two Origin Stories, and a Long Prejudice
The Left-Handers Club, formed in 1990, launched the first International Left-Handers Day on August 13, 1992, according to the club’s official site.
An older claim credits Dean Campbell, founder of Lefthanders International, with proposing the day in the U.S. in 1976. Detroit station WXYZ repeated that account in 2022.
That claim remains unconfirmed. The club says it has no further information on it and that Campbell had no role in its event.
Why lefties needed a day
Left-handed people were at times branded “unclean” or even witches, Smithsonian Magazine notes. In medieval Europe, writing with the left hand could bring accusations of being possessed by the devil.
Everyday hassles never fully went away. Lefties still struggle with desks, spiral notebooks and scissors, Smithsonian adds.
How many lefties there are
A 2020 meta-analysis in Psychological Bulletin gives the best count. It pooled 200 studies covering 2,396,170 people.
Its best estimate is that 10.6% of people are left-handed. The figure ranged from 9.34% under the strictest definition to 18.1% under the loosest one.
Another 9% or so are mixed-handed, using different hands for different tasks.
Marietta Papadatou-Pastou of the National and Kapodistrian University of Athens led the work with Silvia Paracchini of St Andrews. She called it “a definitive answer to a long-standing, heated debate.”
What decides handedness
Brain asymmetry is the root. Lefties’ right hemisphere tends to lead hand control, and that asymmetry starts in the womb, a 2024 study in Nature Communications explained.
Researchers combed the genes of more than 350,000 people in the UK Biobank. Rare variants of a gene called TUBB4B were 2.7 times more common in lefties, though they appear in under 1% of people.
Genes aren’t the whole story. Clyde Francks, one of the researchers, said most left-handedness arises “simply due to random variation” as the brain develops.
Humans stand out among animals. Chimpanzee groups split about 50/50, while people lean roughly 90/10 toward the right hand. Polar bears show a paw preference, too.
Life in a Right-Handed World
Awareness is the point. The Left-Handers Club wants people to understand both the advantages and the disadvantages of being left-handed.
Beyond the date, the British club passes members’ views to manufacturers, runs an advice line and promotes research.
Lefties have plenty of famous company. WXYZ’s list included Barack Obama, Justice Ruth Bader Ginsburg and Babe Ruth. At least six earlier presidents were lefties too, Smithsonian noted.
Left-Handed Ideas for International Left-Handers Day
- Hold a left-versus-right match, a classic club event.
- Host a left-handed tea party, another tradition the club promotes.
- Write with your other hand for a few minutes to feel what lefties deal with.
- Check whether your office has left-handed scissors and notebooks.
- Look up the 2020 Psychological Bulletin meta-analysis and its 10.6% estimate.
Frequently Asked Questions
Why do definitions of left-handedness vary?
Researchers sort people differently. Some count only consistent left-hand users, while others include anyone who doesn’t strongly favor the right.
Is there a medical term for left-handedness?
WXYZ described “sinistrality” as the medical term.
Which universities took part in the big study?
Athens, Oxford, Bristol, Ruhr University Bochum and St Andrews.
Have other genes been linked to handedness?
Yes. A 2013 PLOS Genetics paper tied a gene called PCSK6, and a network of related genes, to body and brain asymmetry.
Sources
- Left Handers Day – Official Site (Left-Handers Club)
- WXYZ Detroit – International Left-Handers Day Is August 13 (2022)
- National and Kapodistrian University of Athens – World’s Biggest Study of Left-Handedness (2020)
- Smithsonian Magazine – Why Are Some People Left-Handed? (2013)
- Smithsonian Magazine – Rare Genetic Variants Linked to Left-Handedness (2024)