Right-handers, but not left-handers, are biased to select their dominant hand

March 8, 2011

The vast majority of humans – over 90% – prefer to use their right hand for most skilled tasks. For decades, researchers have been trying to understand why this asymmetry exists. Why, with our two cerebral hemispheres and motor cortices, are we not equally skilled with both hands? A study from the University of Aberdeen in the UK, published in the April 2011 issue of Cortex, suggests that the explanation may stem from actions that require us to use both hands at the same time, which may bias right-handers toward choosing their right hands.

Gavin Buckingham, now a postdoctoral researcher at the Centre for Brain and Mind at the University of Western Ontario in Canada, and his PhD supervisor Dr. David Carey, asked left- and right-handed participants to reach first toward a pair of targets with both hands at the same time and, immediately afterwards, toward a new single target with only their closest . Just before they began the reach, subjects were given a short vibratory pulse on one of their hands, giving them a clue about where the new target would appear, and hence which hand should perform this second portion of the reach. On a small proportion of trials, the pulse was given to the wrong hand, which meant that subjects had to restrain the reach with this incorrectly-cued hand in order to make the reach with the correct hand.

The right-handed subjects had far greater trouble dealing with this incorrect cue when it was given to their right hands, making more mistakes and taking longer to successfully inhibit the reaches, almost as if the right hand was already pre-selected to carry on during the bimanual reach. The left-handed subjects showed no such asymmetries, suggesting that they are less inherently biased to select one hand over the other.

These findings build on a series of studies from the same researchers which have indicated that right-handers have their attention largely directed at their right hands during bimanual tasks. "One explanation for these data is that hand choice is related to hemispheric specialisation for speech and language" says Dr Carey. "Many left-handed people have "right-handed" brains, which weakens the typical bias towards choosing their dominant left hand."

Explore further: Left and Right Hands Rely on Different Senses

More information: The article is "Asymmetries in motor attention during a cued bimanual reaching task: Left and right handers compared" by Gavin Buckingham, Julie C. Main, David P. Carey, and appears in Cortex, Volume 47, Issue 4 (April 2011) http://www.sciencedirect.com/science/journal/00109452

Related Stories

Left and Right Hands Rely on Different Senses

October 20, 2006

Sometimes, the right hand really may not know what the left hand is doing. It turns out that each of them relies on a different set of sensory inputs to control its movement.

Amputees can experience prosthetic hand as their own

December 11, 2008

Scientists at Karolinska Institutet and Lund University in Sweden have succeeded in inducing people with an amputated arm to experience a prosthetic rubber hand as belonging to their own body. The results can lead to the ...

In double transplant, left hand works first

April 7, 2009

(AP) -- When patients had both hands transplanted, their brains re-established connections much more quickly with the left hand than the right, a team of researchers in France reports.

Good and bad in the hands of politicians

July 29, 2010

"In laboratory tests, right- and left-handers associate positive ideas like honesty and intelligence with their dominant side of space and negative ideas with their non-dominant side," says Daniel Casasanto of the Max Planck ...

Recommended for you

How the finch changes its tune

August 3, 2015

Like top musicians, songbirds train from a young age to weed out errors and trim variability from their songs, ultimately becoming consistent and reliable performers. But as with human musicians, even the best are not machines. ...

Machine Translates Thoughts into Speech in Real Time

December 21, 2009

(PhysOrg.com) -- By implanting an electrode into the brain of a person with locked-in syndrome, scientists have demonstrated how to wirelessly transmit neural signals to a speech synthesizer. The "thought-to-speech" process ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Mar 09, 2011
Not necessarily inherent. It could be that left handers living in world created around the convenience of right handers encounter an advantage in being able to readily use either hand that is not encountered by right handers.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.