I disagree with Goldielocks. Left-handedness is not a ‘learned’ behavior. It is genetically ingrained. When my mother was teaching me to print the alphabet before I started school, I was using either hand. I asked here which hand I should use. Mom told me to use which ever hand felt best and easiest to use. I settled on my left hand.
My lifelong friend and I studied consciousness and brains since high school. He became a REEG tech… brainwave technician. So we have read and shared a lot of research. Lefties have a larger nerve bundle connecting the two halves of the brain… “Inter-Cortical Communication” is vastly improved. Along with that goes more glial cells & synapses in the cortex.
So the result is that we are better able to fully utilize both halves of the brain, and score higher on IQ tests. Einstein was left-handed.
But we are also more prone to dyslexia… left-right symmetry mix-ups if we don’t learn to deal with that early in life. Dyslexic people are really smart…. if they learn to deal with that. All lefties have this to some extent. I do a few noncritical things right handed, but eating and writing are left hand.
I have an engineer friend who is the most perfectly ambidextrous person I have ever known. After an ID theft at his bank, he changed his check signature to a full-script signature… backwards. You had to hold it to a mirror to read the script of his name signature. Now here’s the killer…. He could do this backwards signature with EITHER HAND. They looked identical.
I did have to check his work, though. He was prone to wire a terminal strip with color codes in the wrong, reverse order. The old left-right symmetry error.