[Martin_Silenus]

> Their right handed writing was an artifact of that culture.

Sure. But that does not define a person as a right-handed writer. That's precisely why I wrote "individual's ABILITY to write with their right hand".

[nitwit005]

If you can't write with your left hand, because you never learned to do so, and you can with your right hand, you're a right handed writer. That's the only form of writing you can do.

Yes, the underlying handedness is independent of culture, but the actual ability is cultural.