Left-handedness: A Few Facts Worth Knowing
Nov 02, 2015 10:50 AM EST | By A. M.
"Handedness seems to be determined very early on in fetal development, when a lot of other things about your future are being determined as well," Psychology professor Ronald Yeo of the University of Texas-Austin says.
Some aspects of being left-handed have been found to have an effect on an individual's health and personality. A few facts about left-handedness are listed here.
1. The genes of it
Dr. Yeo explains that genes only play a role in the determination of an individual's handedness 25% of the time. While, left-handedness can show up in a family line, this happens less frequently than the inheritance of other traits as height or intelligence. Experts believe this trait is generally randomly determined.
2. Pregnancy stress link
A Swedish research in 2008 of mothers and their 5-year old offsprings revealed that mixed-handed or left-handed children came from mothers who were stressed or depressed in pregnancy. Maturity in the mothers' age and low birth weight were also seen to possibly result to left-handedness in the child.
A British study, on the other hand, suggested that babies in the womb of very stressed pregnant women tended to touch their face more with the left hand rather than the right.
3. Common among twins
A Belgian research in 1996 revealed that 21% of fraternal and identical twins are left-handed.
4. Not automatically right-brained
Cognitive and Affective Neuroscience Laboratory director Gina Grimshaw of the University of Wellington clarifies that 98% of right-handers are left-brained just as 70% of left-handers.
"... for the most part, left-handers do not differ obviously from right-handers. They certainly don't have reversed brains."
5. May indicate a propensity for different thinking
"For left-handed people, implicitly, they think good stuff is on the left and bad stuff is on the right, even though consciously, explicitly, everything in language and culture is telling them the exact opposite," says the lead author of a 2009 Stanford University research.
6. Has added advantage in sports
Most experts agree that the left-handed individuals' skill in adjusting to asymmetry typifies better skills in one-on-one sports.
7. Makes better fighters
Research theories suggest that the left-hook of left-handed individuals offer an element of surprise and enable them to fare well in violent situations and societies.
8. Creativity link is a myth
The link may have grown from a study in 1995 where left-handed men displayed divergence in thinking more than right-handed men, which suggested a tendency to explore problem-solving options outside of readily available ones.
9. Not a guarantee for artistry
A study in 2013 by Gina Grimshaw and her associates indicated no difference between left-handed and right-handed individuals in five personality measures used for testing. Mixed-handers, on the other hand, displayed more introvertedness.
10. Has increased protection against ulcers and arthritis
A 2005 study links left-handedness to lower rates of arthritis and ulcers.
On the whole, Yeo qualifies, "The differences between righties and lefties are really rather subtle, and of much greater scientific interest than any kind of practical use."
"We shouldn't assume much about people's personalities or health just because of the hand they write with. And we certainly shouldn't worry about lefties' chances of success: After all (as of 2015), five of our last seven U.S. presidents have been either left- or mixed-handed."