Approximately 10 percent of the population are left-handed. While that is not nearly a majority, it is still significant. Despite this, they are often (if not always) excluded from studies in neuroscience.
According to Science Daily, left-handed and right-handed people have different brains and genes from each other, and this can cause difficulty with results for brain studies. In order to reduce variance in data, only right-handed people are included in research.
However, research has found that including left-handed people can be informative. “Left-handed individuals represent a substantial portion of the human population and therefore left-handedness falls within the normal range of human diversity; thus, it is important to account for this variation in our understanding of brain functioning. We call for neuroscientists and neurogeneticists to recognize the potential of studying this often-discarded group of research subjects,” said Willems et al. in an article published in 2014.
“One of our studies from 2009 clearly shows why research into left-handed people is so vital”, said Willems. “According to the textbooks, facial recognition takes place in the right half of the brain. Our research revealed that the same process takes place in both halves of the brain in the case of left-handed people, but with the same final outcome. That is a fundamental difference. And left-handed people might process other important information differently as well. The minimal amount of research into this is, in my view, a missed chance for the neurosciences.”
Now, Lyam Bailey, a doctoral student in psychology and neuroscience, is accepting left-handed people for his studies.
“A lot of [left-handed people] are incredibly frustrated at how few studies they can participate in,” Bailey, who conducts research at Dalhousie University in Canada, told Vice.
“It’s been thought that it’s just best to play it safe, be careful and exclude left-handers,” Bailey said. “That kind of mindset has become very deeply ingrained in cognitive neuroscience.”
Bailey says that left-handed people should be included in studies, as it would lead to interesting findings about how it influences brain functions.
“It can have an impact on some functions of the brain, not all. But that should prompt further inquiry into how it affects other cognitive functions.”