Are you a southpaw, mollydooker or dreaded cacky-hander? Chances are, either you or someone you know writes, eats or plays sport with their left hand and has suffered these taunts.
Much superstition and fear has historically surrounded left-handed people. They’ve been burnt as witches, beaten, shunned as marriage partners and endured having their ‘wrong’ hand tied behind their backs to encourage use of the ‘right’ one.
This discrimination is carried through many languages – ‘gauche’ meaning both ‘awkward’ and ‘left’ in French and in Italian, the word is ‘sinistra’. Sounds sinister, doesn’t it?
Even everyday tools most of us take for granted like scissors, can openers and computer mice have an inherent bias and can be difficult for left-handers to manoeuver, not to mention the indignity of your pen smudging as you write.
As a left-hander encountering an unsuitable implement, your choices are usually to muddle through, swap to your weaker hand, modify your technique (often with uncomfortable and painful consequences) or to locate a rare and expensive left-handed version.
The news is not all bad, however. Many lefties are justifiably proud of their point of difference and revel in the positives. Aside from purported talents in art, mathematics and music, they have a distinct advantage in sports like tennis, fencing and baseball and may have better reaction times playing computer games and driving in traffic.
There are also many famous figures among their ranks, including Joan of Arc, Isaac Newton, Leonardo da Vinci, Paul McCartney, Queen Victoria, Lewis Carroll, Marie Curie, Gandhi and Martina Navratilova.
In addition to these left-handed qualities, there is significant debate in the scientific community when it comes to links to various health problems. The exact causes of handedness itself remain a mystery, although it’s thought to be a mixture of genetics and environmental factors, and it’s still unknown how this affects the body and mind. Here we examine a selection of the health claims surrounding left-handedness.
Some left-handers are more likely to: Suffer an early death
Studies have suggested lefties don’t tend to live to a ripe old age. However, there is conflicting evidence, variably pronouncing there is no relationship at all, that only women suffer a higher mortality rate or even that lefties actually live longer.
It has been observed that as the population ages, the percentage of left-handed survivors decreases from 10 per cent of young adults to only one per cent of 80-year-olds. Theories abound to explain this phenomenon, including:
• Lefties have the same life expectancy, but older generations were forced to switch hands or don’t like the stigma of admitting they are left-handed.
• Left-handers are more accident-prone due to the awkwardness of adapting to right-handed implements.
• Whatever causes left-handedness also causes health complications. Yikes!
Some left-handers are more likely to: develop breast cancer
Worryingly, one health risk for female lefties may be an increased incidence of breast cancer. A 16-year study conducted in the Netherlands found before menopause, left-handed women have double the risk of developing the cancer compared with their right-handed counterparts.
This is the case even after adjusting for differences in family and reproductive history, smoking and socio-economic status. Strangely, the risk was greater for thin left-handers with a BMI of 25 or less than for those whose BMI was above 25.
Researchers believe exposure to steroid hormones when these women were in the uterus may at least partially account for both their hand preference and elevated cancer risk.
The good news is, after menopause left-handers had no increased risk of the disease.
Some left-handers are more likely to: develop schizophrenia
One in 100 people worldwide is schizophrenic, a psychiatric condition which can cause hallucinations, paranoid delusions, disorganised speech and thinking, and dysfunctional behaviour in its sufferers.
Experts suspect a combination of genetics, viral infections, problems in childbirth, drug use and poverty cause the illness. In 2007, an Oxford University-led team found a gene with the cute and cuddly name LRRTM1, which appears to increase the odds of both left-handedness and schizophrenia.
The gene seems to be inherited from your father’s side and affects the symmetry of the brain, a factor in schizophrenia. Luckily, not all left-handers have the gene and even if you do, the vast majority of carriers won’t ever develop a problem.
Scientists are still investigating the causes of schizophrenia, but the discovery of this gene is a significant leap in our understanding of the link between your hand preference and schizophrenia.
Some left-handers are more likely to: become alcoholic
The truth of this not entirely complimentary claim is still uncertain.
Several studies have looked at the issue, but came up with conflicting results. Some experts think lefties may be biologically predisposed to drinking an unhealthy amount or the stress of an unfriendly right-thinking world drives them to drink.
One larger study of over 25,000 people from 12 countries found lefties aren’t more prone to alcoholism, but do drink more often on average. However, the fact the participants were all over 50 years old and the findings being based on them filling in a survey casts doubt on this conclusion.
Hard-drinking lefties could have kicked the bucket before reaching that age or might not have come clean about their partying past when smudging ink across their survey answers.
Some left-handers are more likely to: be born from older mothers
The rumour of lefties generally being delivered by older mums has been around for donkey’s years, but the jury is still out on whether it’s really true.
Experts arguing for the theory say older mothers (aged 30 years or over) tend to have more birth complications such as premature babies, low birth weight and breech delivery and that these are linked to left-handedness in the children.
Other experts claim no association between parents’ ages and left-handed babies has been found, or even that younger mothers tend to have left-handed children.
One explanation could be that the oldest mothers’ tend to die from birth complications, altering results in some studies. This could mean that while it’s far from a sure bet, if you’re wanting to add a new generation of left-handers to the family delaying pregnancy for several years may well help nature along. Ultimately though, some things in life are best ‘left’ to chance.
Some left-handers are more likely to: be dyslexic
An estimated five to 10 per cent of the population has dyslexia, including actors Tom Cruise and Whoopi Goldberg. The learning disability impairs your ability to read, speak and spell.
It’s thought higher exposure to testosterone in the womb creates a more ‘male’ brain by suppressing development of the left side usually responsible for linear reasoning and certain language functions such as grammar and vocabulary.
If this occurs, there is greater likelihood you’ll be left-handed and have ‘male’ brain impairments like dyslexia and stuttering. It may also explain why there are more male lefties than female.
While a recent breakthrough has comefirmed a gene, PCSK6 to its friends, which links handedness and reading difficulties, further study will help us better understand the relationship.