August 13, 2012 Celebrating International Left-Handed Day: Relatively Condensed Histories and HypothesesWhy we shake hands with our right, why some countries drive on the right side of the road, why humans have an uneven dominant hand distribution, and more.
Once upon a time, being left-handed in virtually every culture (with the exception of ancient Incas) could lead to a one-way trip to be burned at the stake. From lacking a word for left in proto-Indo European languages, to sinistre
in Latin (sinister), skaios
in Greek (ill-omened, awkward), Ulta Haanth
in Hindi (wrong hand), gauche
in French (clumsy), links
in Germany (weak), and the meaning in English (depart, leave), discrimination and prejudice against the left-handed has a long history. Today, being left-handed doesn't necessarily mean we'll be tried as witches, but living in a dominantly right-handed world does mean we'll struggle more and are likely to die sooner: the risks of using right-handed tools, increased chance of psychiatric and immune disorders, to the basic annoyances (right-handed desks, whiteboards, ink smudges, scissors, ect). With that in mind, maybe we should instead be looking on the b_right_ side of things, yes? To do that, let us take the advice of the famous leftie Leonardo da Vinci
who said, "The noblest pleasure is the joy of understanding."What determines hand dominance?
Let's start with the interesting fact that within the primate family, only humans have the uneven ratio of hand dominance. While humanity is roughly 10% left-handed, it's an even distribution for other primates. The question is, why?
Is it a retained evolutionary advantage of a surprise left punch? Perhaps it was the advantage of being a risk-taker. This trait is quite common with the lefties of the world including Alexander the Great
and Napoleon Bonaparte
Maybe it is due to language dominance in the left brain (remembering the left side of the brain controls the right of the body). This hypothesis is strengthened by the increased likelihood of developing a stammer if you are right-brained dominant, especially if that individual is "encouraged" to be right-handed. This hypothesis is supported with individuals like Lewis Carroll
, Jimi Hendrix
, Alan Turning
, and King George VI
who were left-handed and had or developed a stammer.
Could it also be linked to higher levels of testosterone exposure in the womb? The chance of a man being left-handed is about 50% higher than that for a woman. Other animals such as cats support this theory with tom cats more likely to be left-handed, whereas female cats are more likely to be right-handed.
There is also the question of how much genetics play a role in hand dominance. The trait of being left-handed is not uncommon within the royal bloodline, like Queen Victoria
. Other family lines such as Marie Curie
show some genetic preference, with her husband, daughter, and self all being left-handed.
So what's the answer? Well, truly it's still unknown, but likely all hypothesis have validity. The real question is more, to what extent do each of these influence left-handedness? Are genetics more influential than hormone exposure? That is what is still being researched.Why are there so many influential left-handers?
In addition to the ones mentioned above, let's add a few more: Ramses the Great
, Julius Caesar
, Isacc Newton
, Mark Twain
, Friedrich Nietzsche
, Mahatma Gandhi
, Bill Gates
, and the Last Five US Presidents
. They all have very similar traits gained either from adapting to their surrounding world, a result of brain wiring, or perhaps something else. Not all have every trait, but the traits they do have seem exemplified. These traits include being intuitive, empathetic, hot-tempered, solitary, iconoclastic, experimental, and fantasist. The traits of having visual-spatial ability, lateral thinking, and being self-taught are especially prominent. So why do we shake hands with our right then? Why do many countries drive on the right-side of the road?
You may thank Julius Caesar
for the custom of a right-handed shake. It is to ensure trust as neither can now punch or stab. Why would he do this? When a person shakes the hand of say, a left-handed emperor, the dominant left-hand is left free for attack if needed.
It is Napoleon Bonaparte
who can be thanked for the practice of driving on the right-hand side of the road in Europe and European-influenced countries. During his time, right-handed horsemen held the reins in their left, their weapon in the right (or left
free to shake hands). By maintaining that traffic pass on the right, Napoleon retained the superior defensive position for himself. England was one of the coalition members against Napoleon, never following that reform nor has ever adapted that practice (unlike other coalition members).
And with that, I leave you to further consult A Left-Handed History of the World
by Ed Wright for more information. Certainly a good read! Photo was found on the flickr page of inertia186.Happy International Left-Handed Day, my fellow Lefties! #lefthanded #left #lefthandersday #history #august13