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Old 03-14-2016, 06:24 PM
Broomstick Broomstick is offline
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Join Date: Mar 2001
Location: NW Indiana
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Originally Posted by md2000 View Post
One explanation I recall reading (obviously someone being somewhat sarcastic) was that left-handedness was the brain development compensating for oxygen starvation and brain damage during birth.
While left-handedness can be a compensation for damage (people who lose their arm or are paralyzed by a stroke can learn to use the non-dominant hand for tasks that used to be done by the now missing or useless hand) it's not always. There are developmental situations where all the internal organs are a mirror image of the usual arrangement, and such people are, not surprisingly, frequently left-handed. That's not damage, that's a reversal of some early signal in the embryo.

If a lefty's brain is arranged more as a righty's that might be a case of damage compensation, but if the lefty's brain is a mirror image of the typical righty's I'd suspect it's a developmental reversal of some sort (not everything has to be reversed. Pre-birth development can be complicated). We can actually make such determinations in a living brain. When my mother (a lefty) had a stroke they did imaging that showed her brain organization was mirror to the typical righty's (which was fortunate, because if it wasn't the stroke would have been far more damaging than it was). The doc's said it was important to know these things when planning for rehab. They also said that you occasionally find a righty with a "mirror" brain, that is, their brain is a mirror image of a typical righty, which means in that case being right-handed might be a case of pre-birth damage compensation in someone who should have been a lefty!