- Researchers have identified, for the first time, the genetic differences between right-handed and left-handed people.
- In left-handed people, both sides of the brain tend to communicate more effectively.
- This means that left-handed people may have superior language and verbal ability.
- The research may also shed new light on the role that brain development plays in neurological disorders .
Left-handed people are by far in the minority when it comes to handedness.
This means that everything from computer mice to scissors to musical instruments are typically designed for right-handers.
But while life might be full of minor irritations for the southpaws of the world, their handedness might carry an advantage.
New research identifies, for the first time, the genetic differences between left-handers and right-handers.
As it turns out, one of those differences suggests that left-handed people have better verbal skills.
Researchers from the University of Oxford in the United Kingdom published their findings in the journal Brain earlier this month.
To understand the data, it’s helpful to know the difference between the left and right sides of the brain.
In short, the left side of the brain is associated with logical tasks and language while the right side performs more creative or abstract calculations.
“Each function, behavior, cognition, mood, somatic sensation, all of that, requires multiple areas of the brain to work as a network,” explained Paul Mattis, PhD, a neuropsychologist at Northwell Health’s Institute for Neurology and Neurosurgery in Manhasset, New York.
“This connectivity is what allows a behavior, action, or thought to occur and exist. If you lose this connectivity between areas, things don’t work as efficiently, or functions are lost,” Dr. Mattis told Healthline.
Researchers in this recent study looked at the DNA of 400,000 people from the UK Biobank, a long-term genetic study of health data from hundreds of thousands of volunteers.
Professor Gwenaëlle Douaud, PhD, joint senior author of the study and fellow at Oxford University’s Wellcome Centre for Integrative Neuroimaging, told Healthline that this huge health database provides invaluable data to researchers.
“Thanks to the amazing resource that is the UK Biobank, it is the first time that left-handedness has been shown to be driven by the complex interplay of many genes that contribute to brain organization, particularly in the regions dedicated to language,” she wrote.
To interpret the data, researchers zeroed in on four regions of the brain that are associated with handedness.
Dr. Douaud says it was a pleasant surprise to find that the genetic variants related to left-handers were closely tied to areas of the brain associated with language and verbal skills.
“We were surprised to find that three of our four genetic variants associated with handedness were actually related to genes that play an active role in brain development and organization,” Douaud wrote. “These genes were associated with what we call the cytoskeleton, or the cells scaffolding, which helps guide the construction and functioning of the cells in the body.”
From there, researchers looked at brain imaging from about 10,000 people, finding that differences in the cytoskeleton associated with handedness could actually be visibly detected.
The biggest takeaway was that, in left-handed people, the left and right sides of the brain work more effectively with one another. This means that lefties may have inherently better verbal and language skills, although this hasn’t been proven.
“Language tends to be primarily associated with the left hemisphere and in the right-handers, the researchers showed the typical association with the left hemisphere, the language-dominant hemisphere,” Mattis said. “Whereas the left-handers showed a greater connection between the language areas in the left hemisphere and the analogous areas in the right hemisphere, which typically isn’t the side associated with language.”
The findings are deemed significant, but they’ve also opened up an intriguing set of questions.
For starters, does the brain synergy in a left-handed person truly give them better language abilities?
“We need to assess whether this higher coordination of the language areas between left and right sides of the brain in the left-handers actually give them an advantage at verbal ability,” wrote Douaud. “For this, we need to do a study that also has in-depth and detailed verbal ability testing.”
Douaud also notes that while the UK Biobank comprises an enormous amount of scientific data, it would be interesting to confirm their findings with larger samples from around the world.
The research also shows that handedness may be associated with a higher or lower likelihood of developing neurological disorders.
“These areas, or genes, are also associated with neurodevelopment,” Mattis said. “The study shows a connection between handedness assumed to be at least partially genetic, and disorders also thought to be developmentally related to brain development.”
“I think the next step is something they mentioned: trying to relate these genetic factors, and factors which are related to handedness, with other aspects of an individual — in particular, cognition or thinking,” he said.