Jim Heffernan, a former Duluth News Tribune editor, posted in his blog about being left-handed.
See http://www.jimheffernan.org/2009/02/left-handed-commentary.html
I sent the the following email to him.
I’m belated catching up on your blog. The left-handed entry really caught my interest: I too am an overhanded left-handed writer.
But writing is almost the only thing I do exclusively with my left hand, except scratch my right arm:) I use tools with my right hand. If fact I can hardly pound a nail straight or saw a straight line with me left hand.
I have a hypothesis on why left-handers write over-hand.
It's how we imitate others. If we learn something side-by-side, we will imitate our teacher’s handed-ness. If we learn something face-to-face we might mirror our teacher’s handed-ness. If we watch somebody write across from us, we will place the pen in the mirror hand. But then it breaks down because we place the paper in the same direction. It is very awkward to write left-hand and underhand with the paper slanted “counter-clock-wise”.
I have noticed that fewer people say “Oh, you’re left-handed!” My inclinations is to say “But when people say that I punch them in the nose with my right hand!”
