LONDON - Left-handed people once suffered prejudice - the word "sinister" from the Latin for left came to mean "evil" or "unlucky".

But a study has found that sinistrality - which affects up to 15 per cent of the population and is more common in men than women - is linked with quicker thinking when doing tasks such as playing computer games or sport.

Australian researchers have shown that connections in the left and right-hand side of the brains, or hemispheres, are faster in left-handed people.

The study published in the journal Neuropsychology says the faster transformation of information in the brain makes left-handers more efficient when dealing with multiple stimuli.

Dr Nick Cherbuin, of the Australian National University, measured transfer time between the two sides of the brain by measuring reaction times to white dots flashed to the left and right of a fixed cross. He then compared this with how good participants were at carrying out a task to spot matching letters in the left and right visual fields which would require them to use both sides of the brain at the same time. "Extreme" left-handers were 43 milliseconds quicker at spotting matching letters across the right and left visual fields than right-handed people.

"These findings confirm our prediction of increasing efficiency of hemispheric interactions with increasing left-handedness," said Dr Cherbuin.

He said people tended to use both hemispheres for tasks which were fast or hard and which required interpretation.

Chartered psychologist Dr Steve Williams said left-handed people tended to be better at using both sides of the brain. "It's certainly interesting. It's always been said that left-handers are different from right-handers in that they are less consistent with their left-handedness."

He said the research seemed to be consistent with prior research showing that left-handers used both sides of the brain for language, meaning they were more bicerebral. They become faster at it because they are having to use both sides of the brain more.

This can have benefits for naturally left-handed sports players. In football, being able to kick with either foot is a huge asset, because each foot like each hand is under opposite-side control. Left-handers also tend to have better backhands in tennis.

Between eight and 15 per cent of the population are left-handed with identical twins more likely to be so than the rest of the population.

Theories behind the reasons for left-handedness include exposure to higher levels of testosterone before birth while some claim ultrasound scans may affect the brain of the unborn child, causing more left-handedness.