Handed 🤌

"When I was first learning to write, my letters and words ran from right to left, reversed as if in a mirror. 

"Being left-handed, I was imitating the hand strokes of my right-handed teachers instead of reversing their strokes to replicate the letters. 

"I gradually got the hang of writing in the correct direction, but it still feels natural for me to mirror-write. 

"I have a mirror-written childhood diary. Leonardo da Vinci, another lefty, did that too.

"Being left-handed is mostly no big deal. It is annoying how ink smudges under my hand. And I did once have to jump out of the way of a circular saw that I was holding backward; indeed, left-handers have more accidents while operating machinery. 

"That aside, overall, I enjoy being left-handed. It grants entry into a smug little club, whose members —10% of the human population —carry the secret knowledge that we are overrepresented among U.S. presidents, famous artists and musicians, and top athletes.

"But our difference hasn’t always been welcome. My 91-year-old Texan grandmother remembers starting out left-handed (she, too, has examples of mirror-writing from early childhood) before being forced to switch, a common practice in much of the world until about the 1970s.

"That we can fully retrain our hands (and brains) reinforces how little it matters which hand naturally dominates. And that’s part of what makes the circumstance so mysterious. If it makes no material difference, then why am I left-handed? Or perhaps more pertinently: Why are 90% of people right-handed?

"Ultrasound studies indicate that a fetus’s dominant hand is decided before its brain even connects to its limbs. 

"We start flailing one arm around much more than the other starting about 10 weeks post-conception, as a fishlike fetus the size of a kidney bean. The movements are entirely reflexive, yet the arm that flails more predicts future handedness with a high level of accuracy."