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Thursday, June 15, 2017

Are left-handed people more gifted than others? Our study suggests it may hold true for maths | The Conversation UK - Science + Technology

Photo: Giovanni Sala
"People who have an extreme preference for using their right hand may be worse at maths, according to new research" argues Giovanni Sala, PhD Candidate - Cognitive Psychology, University of Liverpool and Fernand Gobet, Professor of Decision Making and Expertise, University of Liverpool.

Photo: The corpus callosum. 
 Life Science Databases(LSDB)/wikipedia, CC BY-SA

The belief that there is a link between talent and left-handedness has a long history. Leonardo da Vinci was left-handed. So were Mark Twain, Mozart, Marie Curie, Nicola Tesla and Aristotle. It’s no different today – former US president Barack Obama is a left-hander, as is business leader Bill Gates and footballer Lionel Messi.

But is it really true that left-handers are more likely to be geniuses? Let’s take a look at the latest evidence – including our new study on handedness and mathematical ability.

It is estimated that between 10% and 13.5% of the population are not right-handed. While a few of these people are equally comfortable using either hand, the vast majority are left-handed.
Hand preference is a manifestation of brain function and is therefore related to cognition.

Left-handers exhibit, on average, a more developed right brain hemisphere, which is specialised for processes such as spatial reasoning and the ability to rotate mental representations of objects.

Also, the corpus callosum – the bundle of nerve cells connecting the two brain hemispheres – tends to be larger in left-handers. This suggests that some left-handers have an enhanced connectivity between the two hemispheres and hence superior information processing. Why that is, however, is unclear. One theory argues that living in a world designed for right-handers could be forcing left-handers to use both hands – thereby increasing connectivity. This opens up the possibility that we could all achieve enhanced connectivity by training ourselves to use both hands.

These peculiarities may be the reason why left-handers seem to have an edge in several professions and arts. For example, they are over-represented among musicians, creative artists, architects and chess players. Needless to say, efficient information processing and superior spatial skills are essential in all these activities.

Handedness and mathematics 
But what about the link between left-handedness and mathematical skill? Unsurprisingly, the role played by handedness in mathematics has long been a matter of interest. More than 30 years ago, a seminal study claimed left-handedness to be a predictor of mathematical precociousness. The study found that the rate of left-handedness among students talented in mathematics was much greater than among the general population.

However, the idea that left-handedness is a predictor of superior intellectual ability has been challenged recently. Several scholars have claimed that left-handedness is not related to any advantage in cognitive skills, and may even exert detrimental effects on general cognitive function and, hence, academic achievement.

For example, one study discovered that left-handed children slightly under-performed in a series of developmental measures. Also, a recent review reported that left-handers appear to be slightly over-represented among people with intellectual disabilities. Another large study found that left-handers performed more poorly in mathematical ability in a sample of children aged five to 14.

Source: The Conversation UK 

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