โ How Rare Is Being Left-Handed? 10% of People
The Science of Handedness
Handedness is influenced by genetics, prenatal environment, and brain lateralization. The LRRTM1 gene has been linked to left-handedness, but it's not a simple one-gene trait. Left-handed people often show more bilateral brain activity, which may contribute to creativity and spatial reasoning.
Left-Handedness by Region
Rates of left-handedness vary modestly by region, partly due to cultural pressure. In Western countries with low cultural stigma, rates hover around 10โ12%. In some East Asian and Middle Eastern countries where left-handedness has been historically discouraged, reported rates drop to 3โ6%.
Ambidexterity: Even Rarer
True ambidexterity โ performing all tasks equally well with both hands โ is estimated at only about 1% of the population, making it significantly rarer than left-handedness. Most people called 'ambidextrous' are actually cross-dominant (preferring different hands for different tasks).
Frequently Asked Questions
About 10% globally, though this varies by region and cultural factors.
Around 1900, Left-Handers Were Down to About 3%
The rate hasn't always been close to 10%. Chris McManus and colleagues estimated 19th-century rates from a 1953 BBC viewer survey and other historical data, adjusting for left-handers' greater willingness to answer handedness surveys. Their best estimate (Laterality, 2010) is that the rate was probably around 10% in the 18th century. It then fell to a low of about 3% among people born between 1880 and 1900 and rose again in the 20th century. The rebound shows up in living memory too. The 1986 National Geographic smell survey asked 1,177,507 Americans aged 10 to 86 which hand they wrote and threw with. About 14% of younger men and 12% of younger women reported some left-hand preference, compared with about 6% of the oldest respondents (Gilbert and Wysocki, Neuropsychologia, 1992). The usual explanation is schooling, not ageing. Children who started out using their left hand were often made to write with their right, and that pressure eased as the century went on.
Where “Left-Handers Die Nine Years Sooner” Came From
That shifting rate also created a well-known myth. In 1991 Diane Halpern and Stanley Coren surveyed relatives of people who had died in 1989 in two southern California counties. They reported that the left-handers had died about nine years younger. But people who died that year included many born around 1900, when few people were recorded as left-handed. The younger people who died came from generations where left-handedness was common. That alone makes the left-handers younger on average, even if handedness has no effect on lifespan. Lauren Julius Harris made this argument in a 1993 critique and concluded that the case for shorter left-handed lives could not be sustained. A six-year study of 3,774 older adults in East Boston found no link between handedness and death (Salive and colleagues, American Journal of Public Health, 1993). A 2023 modelling study in Archives of Public Health assumed that left- and right-handers die at the same ages. Adding only the historical change in handedness rates still produced a 9.3-year gap among US deaths in 1989. Among people born in the same year, the gap was under half a year.
Why Studies Report Anywhere From 9% to 18%
Even today there's no single rate, because studies define it differently. A 2020 Psychological Bulletin review by Papadatou-Pastou and colleagues combined 200 studies of 2,396,170 people. In studies that sorted people into right-, mixed- and left-handers, the left group made up 9.3%. In studies that counted everyone who wasn't right-handed, the figure was 18.1%. The best overall estimate was 10.6%. The way handedness was measured mattered too: asking about writing hand gave about 9.3%, questionnaires 10–13%, and watching people do tasks about 15%. Men were slightly more often left-handed than women (11.6% vs 9.5%). The 2021 genome-wide association study of handedness found similar variation for ambidexterity. About 1.3% of women and 2% of men in UK Biobank said they were ambidextrous, compared with 2.6% and 3.5% of 23andMe customers.
No Single “Left-Handed Gene”
Genes play a part, but a modest one. In 54,270 Australian and Dutch twins and their siblings, additive genetic effects explained about a quarter of the variation in handedness (Medland and colleagues, Neuropsychologia, 2009). A 2021 genome-wide study (Cuellar-Partida and colleagues, Nature Human Behaviour) combined data on 1,766,671 people from UK Biobank, 23andMe and the International Handedness Consortium. It found 41 regions of the genome linked to left-handedness and 7 linked to ambidexterity. The results pointed to the central nervous system and to microtubules, the protein scaffolding inside cells, rather than to the hands. The two traits were only weakly related genetically (a correlation of 0.26), which suggests they are mostly shaped by different genes. The same study re-tested LRRTM1, announced in 2007 as the first potential genetic influence on handedness to be identified. That link came from dyslexic siblings and didn't appear in a separate twin-based sample. In the 2021 study, the variants from that report weren't even nominally significant. Common genetic variants explained only about 3–6% of the variation, so no genetic test can predict which hand a child will use.