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The Science of Handedness
Hugh Pickens writes "Representing only 10 percent of the general human population, scientists have long wondered why left-handed people are a rarity. Now a new study suggests lefties are rare because of the balance between cooperation and competition in human evolution and a mathematical model was developed that predicts the percentage of left-handers by sport based on each sport's degree of cooperation versus competition. 'The more social the animal—where cooperation is highly valued—the more the general population will trend toward one side,' says study author Daniel M. Abrams. 'The most important factor for an efficient society is a high degree of cooperation. In humans, this has resulted in a right-handed majority.' If societies were entirely cooperative everyone would be same-handed, but if competition were more important, one could expect the population to be 50-50 because cooperation favors same-handedness—for sharing the same tools, for example while physical competition favors the unusual. In a fight, for example, a left-hander would have the advantage in a right-handed world. The mathematical model accurately predicted the number of elite left-handed athletes in baseball, boxing, hockey, fencing, and table tennis (PDF)—more than 50 percent among top baseball players and well above 10 percent (the general population rate) for the other sports. For other sports like football or hockey where team cooperation is paramount, it is ideal for all individuals to possess the same handedness. For example, in football, blocking schemes are often designed to protect a quarterback's blind side. As a result, it is beneficial for all quarterbacks on the roster to possess the same handedness to minimize variations of the offensive sets. 'The accuracy of our model's predictions when applied to sports data supports the idea that we are seeing the same effect in human society.'"
Why isn't everyone left-handed? That too would be beneficial in a cooperative society (shared tools). Maybe millions of years ago, the left-handed tribes died out. (Maybe they called themselves Neandertals.)
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Single bevel axes are 'handed'.
I imagine optimizing the grip would also cause some handedness as well.
Just a few years ago, a Canadian study using baseball stats (because they tracked handiness closely) concluded that lefties were far more likely to die, ( http://www.nejm.org/doi/full/10.1056/NEJM199110033251412) this was later shown to have suffered a seemingly paradoxical sampling error (not controlling adequately for those that didn't die). Then there was another study that concluded that left-handedness was likely the result of anoxia in the womb ( http://www.sciencedirect.com/science/article/pii/002839327390050X). It was discounted for similar sampling error problems. Neurological "wiring error"; perhaps a mutation with few consequences; advantages in the mathematical world (presumably via having a screwy mindset); Language disadvantages; Language *advantages*; high proportion of left-handed (possibly suppressed) American presidents http://www.anythingleft-handed.co.uk/presidents.html (Clinton, Bush, Obama ... ). So... run a elaborate predator/prey model applied to sports and see an advantage for the 10% that are different; sounds like rediscovery of Perato distribution to me, http://en.wikipedia.org/wiki/Pareto_distribution I'm just not convinced that there's been a proper scientific approach to this issue to date, and until then i'm still stuck with a twisted spine in most college classrooms.
I'm the child of two right-handed people - and I'm neither, I'm one of the 1% ambidextrous people - but I prefer to write with my left hand.
Unicode killed the ASCII-art *
In a perfect world we would all be ambidextrous -- being able to use BOTH hands would make things much simpler.
Yeah, one could take over when the other got tired.
Sheesh, evil *and* a jerk. -- Jade
I'd give my right arm to be ambidextrous!
are like the wolves amongst you right-handed sheep, right!!!!???
I'm not ENTIRELY convinced, what about situations where it is advantageous for people to have opposite handedness for optimal cooperation? There seems to be a built-in assumption here that different-handed assortments of people will always have more problems working together. I'm not sure there's a practical way to test this as a general thing though.
I agree, the theory is weak.
Using sports as a model for why handed-ness exists is putting the cart before the horse. That Baseball was able to capitalize on left handed pitchers throwing to much more common right handed hitters is a rather late innovation in the annals of human endeavor.
Further, very few tools existed in historical times where handedness mattered at all. A wrench or a hammer or a spear have no handedness. Only much later were tools invented to meet the needs of the majority or users, which is why there was a tendency to put controls on power tools on the right.
The whole thesis mistakes cause for effect, suggesting tools and games we invented had something to do with what made us what we are. Whether our ancestors threw the spear, or picked the berry right or left handed couldn't have mattered at all.
Sig Battery depleted. Reverting to safe mode.
All I can say is that I'm left-handed. Both my parents are right-handed and so are both my brothers.
No, it wasn't actually...
"Cooperation favors same-handedness—for sharing the same tools, for example. Physical competition, on the other hand, favors the unusual. In a fight, a left-hander would have the advantage in a right-handed world."
This is simply taken axiomatically as a starting point for the study. I see no indication that it was determined by any sort of analysis. I'm not even sure such an analysis is feasible. You'd have to know what activities people carried out in prehistoric times, how, and what the value of cooperation was for each one. There could be various advantages and disadvantages of same or opposite handedness depending on the activity, etc. The entire concept of their study rests ENTIRELY on the validity of this same-handedness is better for cooperation proposition. I'm not saying it is untrue, but without demonstrating it to be true and to what degree I cannot see how any meaningful conclusions can be drawn.
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You joke, but that was literally true for me w/ regards to handwriting. Then one day my second grade teacher saw me switching hands and freaked out. She made me sit on my left hand for the rest of the year and had the colossal gall to tell me that someday I'd thank her for it. When my doctor learned about it at my next annual physical, he was pissed off beyond belief. He didn't cuss, but he kept muttering about "superstitious morons" and "subjecting kids to the prejudices of idiots", or words to that effect.
Fortunately the only thing impacted was my handwriting. Fifty years later my left-handed writing still looks like a first-grader while my right-handed writing got arrested at a second grade level. But I'm one heck of a typist, when I played soccer I did equally well on either left or right wing, I'm popular at dinner parties because I can accommodate whoever I am seated next to without bumping elbows, and my wife thinks I'm a very versatile fellow.
FTA:
Representing only 10 percent of the general human population, scientists have long wondered why left-handed people are a rarity.
Wow, I never knew that scientists made up ten percent of the population. Yay us.
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I have (fraternal) twin sons. One is right handed, one left handed.
-- Alastair