The big question is: What makes humans more prone to right-handedness? Of all the creatures on earth, research shows that only humans prefer one hand with such an overwhelming majority. Animals do show hand (paw) preference, but the distribution is 50/50. Humans, in all cultures, countries and racial groups, favor the right hand by about 90%.
The jury is still out on this question, and research is currently inconclusive. I may end up asking more questions than I answer on this topic!
It may be easier to say what a lefty is NOT:
Left-handers are not the mirror image of right-handers
- Currently, studies show that the brain organization of left-handers can vary, compared to that of right-handers.
- Most lefties are not as fully left-handed as righties are right-handed. They are more accurately described as “mixed-handed.”
- This vagueness can occur due to societal influence on doing certain things right-handed, such as in some sports. It isn't always been easy to find a left-hander's baseball mitt, or golf clubs, so sometimes lefties will use (or be forced to use) the path of least resistance and learn to do things right-handed.
- Even aside from such restrictions, lefties often do some things right-handed naturally.
Left-handers are not all “brain-damaged."
As writer Rik Smits explains on his website (in the "curiosities" section, under the "ration book" image):
"Since there are nine times as many natural righthanders as there are lefthanders, the chance of an embryo becoming lefthanded by trauma is nine times as high as the opposite chance. The very rare traumatic righthanded then disappears into an ocean of natural righthanders, never to be spotted for what he really is, whereas the nine time larger group of traumatic lefthanders joins the 10% minority of lefthanders. As a result, they are conspicuously (but still only just measurably) present in every study of a group of sufferers from a variety of impairments induced by braindamage [sic], such as (probably) dyslexia."
Can we determine what does cause left-handedness? We'll continue now with an examination of some of the theories that have been put forth.
