Everyone feels neuroscience studies are biased, no matter how representative they try to be. But Roel Willems and colleagues from the Donders Institute for Brain, Cognition and Behaviour at Radboud University Nijmegen, and Max Planck Institute in Nijmegen say studies are flawed if they don't include enough left-handed people.
Because left-handed people have different brains.
Of course, everyone has different brains, the issue in studies is whether or not the difference is meaningful and can easily be controlled for in data. The authors of a new paper in Nature Reviews Neuroscience contend that left-handed people are rarely included in neuroscience studies, not because they are only 10 percent or less of the population, but because the differences with right-handed people cause noise in the final results.
Neuroscience studies overall suffer from suspect methodology and poor grasp of statistics and if the handedness of participants is skewing results, that's even worse. If researcher can't control for that, they certain can't control for sexual orientation, gender or anything else where brains may be different.
The authors say more left-handed representation would add valuable information about brains and genes as well as about several psychiatric disorders.
Verbs that express actions ('to write', 'to throw') have opposite effects in the motor cortex of left-handed and right-handed people. This figure is taken from the article published in Nature Reviews Neuroscience on 12 February 2014. http://www.nature.com/nrn/journal/vaop/ncurrent/pdf/nrn3679.pdf
"One of our studies from 2009 clearly shows why research into left-handed people is so vital," says 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."
Data from left to right
According to Willems, the same applies to genetic research.
Schizophrenic and psychotic patients are more likely to be left-handed. Up until now little has been done with that information to clarify the genetic links with the disorders concerned.
Left-handed and right-handed people perceive actions in different ways. Left-handed people do that with the right half of the brain and right-handed people do that with the left half of the brain. This figure is taken from the article that Willems and colleagues published in 2009 in Frontiers in Human Neuroscience. http://www.frontiersin.org/human_neuroscience/10.3389/neuro.09.039.2009/full
"Databases without left-handed people are not representative for the population and in view of the large number of genetic databases currently being set up, ignoring left-handed people is not wise," says Willems. The researchers are setting up a website, www.mpi.nl/handedness, to encourage left-handed people to participate in research.
Citation: Roel M. Willems, Lise Van der Haegen, Simon E. Fisher&Clyde Francks, 'On the other hand: including left-handers in cognitive neuroscience and neurogenetics', Nature Reviews Neuroscience 2014 www.nature.com/nrn/journal/vaop/ncurrent/pdf/nrn3679.pdf
- PHYSICAL SCIENCES
- EARTH SCIENCES
- LIFE SCIENCES
- SOCIAL SCIENCES
Subscribe to the newsletter
Stay in touch with the scientific world!
Know Science And Want To Write?
- Researchers Created A Laser Bullet To See What It Would Look Like - And Here It Is
- The Strange Organic Molecules In Titan's Atmosphere
- Will Holding Thermal Printer Paper Really Send Your BPA Levels Soaring?
- The Quote Of The Week - Shocked And Disappointed
- As The Weather Changes, So Do Beliefs About Climate Change
- Moderate Pot Use By Adolescents Doesn't Hurt IQ
- Great Earthquakes Doubled In The Most Recent 10 Year Period - What That Means
- "Regardless of the merits of the research, just because it's published in PLoS ONE doesn't mean..."
- "Hi Nury, good to see you back here again after so many months away from this monster Science20..."
- "The OSX versions are all free, the all in one IOS version is not free. The developer (which I am..."
- "Anonymous, when you disagree, be civil and cite the specific sentence or quote that you disagree..."
- "I wonder how this one was genetically modified?(cartoon by Norman Thelwell) ..."
- Coffee grounds turned biofuel can heat your home
- Bill and Melinda Gates on GMOs: ‘Poor farmers should not be denied choice of life-saving tools’
- Why do foodies love organics? Because they taste like McDonald’s!
- GMO milk? An enviros dream innovation that most enviros oppose
- National Wildlife Refuge System bans on GMOs and neonics lack transparency, scientific rationale
- Want better sperm? Eat more pesticides
- New policymaking tool for shift to renewable energy
- Teens whose parents exert more psychological control have trouble with closeness, independence
- Two days later: Adolescents' conflicts with family spill over to school, vice versa
- Children in high-quality early childhood education are buffered from changes in family income
- 'Breath test' shows promise for diagnosing fungal pneumonia