KEY POINTS:
Children who are left-handed or ambidextrous perform worse at school than right-handers, according to a study of national curriculum test results. Left-handed girls fare worse than boys, by failing to catch up with their right-handed peers during later school life.
Those who are ambidextrous from both sexes also
fail to bridge the gap in performance, according to the study carried out by researchers from the University of Bristol for the Economic and Social Research Council. The researchers, who looked at the results of more than 10,000 children, reveal that left-handers perform less well in IQ tests and tests for 11- and 14-year-olds.
"Left-handed children perform worse than right-handed ones in terms of cognitive outcomes at ages eight, 11 and 14," they conclude. "The gap between left-handed girls and right-handed girls is larger than the gap between left-handed boys and right-handed boys ... there is no sense of catching-up in non-right-handed girls.
"Mixed-handers of both genders do less well than right-handed children across a wider range of outcomes."
Left-handers' average test scores are 1 per cent below that of right-handers.
The performance of the ambidextrous students is more troubling. "Children with 'mixed-handedness' have lower development, which first appears in the early years but remains present at age 14, particularly for girls," the research says.
The study found that about 10 per cent of children were left-handed and about 7.5 per cent ambidextrous. One theory put forward for the poor performance of ambidextrous children is that they may have become mixed-handed due to lack of parental awareness of their development and less stimulation.
There is one bright spot on the horizon for left-handed boys: the research indicated there are more boy geniuses among left-handers than right-handers. Left-handed boys dominate the top and the bottom of the ability range.
OUT ON A LIMB
GEORGE BUSH SNR
The 41st president of the US, he captained his Yale University baseball team, and, as a left-handed first baseman, played in the first two College World Series (1947 and 1948).
KURT COBAIN
Usually wrote left-handed, but in time learnt how to write right-handed as well. Sometimes he would play a right-handed guitar upside down and re-string it.
OSAMA BIN LADEN
According to the FBI, he is left-handed.
MATT GROENING
The creator of The Simpsons also made his star Bart Simpson left-handed. Bart's neighbour Ned Flanders is also a leftie.
JOAN OF ARC
Was burnt at the stake in 1431 for being a heretic and a witch. History has her down as a leftie but there is some speculation about this, as she may have been depicted in this way to make her seem evil.
ANGELINA JOLIE
Had to have guns specially made so that she could reload them easily for the film Lara Croft: Tomb Raider.
MARTINA NAVRATILOVA
One of only nine left-handed players (seven men and two women) who have ever won a Wimbledon singles title.
- INDEPENDENT