Why are about 90% people worldwide Right-handed? what causes Left-handedness & ambidexterity?

I'm completely left handed for writing or painting. For everything else either hand will do most of the time. I use a right handed guitar and right handed scissors.

Originally posted by unityemissions

Originally posted by RandomEsotericScreenname
reply to post by BiggerPicture

 

I think lefties have a better connection between brain hemispheres, but that is just a theory.

Not theory, it's true. On average, the corpus callosum is 11% larger than righties.

We share this with females, but have larger brains, too..score!!

edit on 29-4-2012 by unityemissions because: (no reason given)

Cool, I never knew it was a fact, just figured that with my super connected brain hemisphere powers, lol.

i cannot answer the reason 'Why' a greater portion of people tend to favor the right hand side


all i can submit is that my Mother...all of her learning in Catholic schools
was forced by the Nuns to sit on their right hands so that the youngsters had to Learn cursive and math problems written out with their Left hand...

She was born in 1922, and had her Catholic schooling from 1928-1940...but she also learned Short-Hand in the 12 years of required education... which got her 'Personal Secretary' positions in the business world


right or left handed is a learned or trained kind of thing imho

Wanna hear something kinda crazy? I never knew this until this thread made me curious. This is from Wiki:

Of the seven most recent U.S. Presidents, four, including Barack Obama, have been left-handed, while a fifth is said to have been ambidextrous: Ronald Reagan, who was left-handed by birth,[31][32][33] became president after he defeated left-handed candidate George H. W. Bush in the Republican primary election. Four years earlier, Reagan had lost the Republican presidential primary to incumbent left-handed President Gerald Ford. George H. W. Bush succeeded Reagan and later ran for re-election against left-handers Bill Clinton[34] and Ross Perot.[33] Clinton's second term opponents included Perot, and Bob Dole who had become left-handed when his right arm was paralyzed in combat 50 years earlier. Left-handed then-Senator Obama defeated left-handed Senator John McCain in his race for the presidency.

Being a conspiracy site, I figured I would have heard this before. Considering one out of ten people are lefties, what are the odds of all these presidents and primary hopefuls being left handed?

reply to post by BiggerPicture


I reckon people just automatically go with what they feel comfortable with as a kid, what feels natural to them. the rest are due to injuries that required the use of the opposing side in order to function.

a lot of people just stick with using the right side because they are comfortable with it and use to it and have no need to start using the left. but if we really wanted to with practice we could all be left sided as well.

when i was younger a torn muscle in my thigh weakened my right leg (shooting leg) and it hurt when i shot the ball, but i did'nt want to stop playing, so i spent a couple of days just shooting a ball against a wall as hard as i could with my left foot and each time the ball came back shooting instantly again with my left, no second touches. to start with there were mis-kicks and wonky shots but the more i did it the better i got.

by the time my right leg had properly healed i was two footed which worked to my advantage and improved my abilities especially when controlling the ball, i recommend trying to teach yourself being both sided with hands or feet, it can give you an edge in certain circumstances and especially if you play sports.

Originally posted by Shoonra
It was discovered, about 20 years ago, that in utero one of the baby's arms sticks out of the placenta and sort of pushes or strokes the amnioatic sac around. It appears - I don't know if there has been a thorough census of pregnancies for this - that approx 90% of the time it's the fetus's right arm that pokes through. I do not know if anyone has established that the dominant hand in childhood is that the same that was poking through in utero but it seems plausible.

thats neat to know, had no idea!

. one of my mom's most repeated newborn stories about me is that since the day i was born i would always twirl my left ear with my left hand.

it turns out my left earhole and lobe are bigger, i think from the messing with my left ear so much back then

I'm a fellow southpaw and if it wasn't for my mother I would have ended up right handed. I've always used my left hand for almost everything excluding bowling using scissors and a few other things. In kindergarden my teacher started teaching me to write with my right hand my mother noticed this and set up a meeting with my teacher... she told the teacher to stop trying to make me right handed. IIRC the teacher was trying to make things eaiser for me or some bullcrap line. this was in the early 90's and i've heard reports of teachers doing this in 2008 (which makes no sense at all) Apparently the myth persists that we're all ebil ebil people!! :p

Being left-handed, I do everything with my left hand apart from hold a cigarette (for some reason?). I can't for the life of me do anything constructive with my right hand. I also think it is definately true that left handers are much more creatively minded than our poor right-handed brethren.

It's all a bit weird really.

Write left handed, play darts, snooker and pool, throw, bowl at cricket left handed yet I bat at cricket right handed, play golf with my right hand, play bass guitar right handed, (badly it must be said) and even predominantly pick my pint glass up with my right hand.

I think the batting and golf thing is because when I was a toddler my father would try to teach me the rudiments of batting etc whilst standing over me.
I was bought a right handed bass guitar so that's how I played.
I more or less was left to learn the other's myself so used my naturally dominant left hand.

As a slight aside, Phil Mickelson is probably the best know left handed golfer is known as Lefty.
He learnt to play golf by copying his father standing opposite him and trying to replicate everything he did, more or less like a mirror image.
He has become one of the greatest golfers ever.
He is right handed at everything else he does.

Perhaps the brain and body can be taught to do many things.

I have no idea what initially determines the dominant hand but it does seem to involve genetics and environment etc.

It is also strange that left handed people seem to be disproportionately successful in various fields.

I'm a lefty In my case I can hear a little better and see stuff coming before others but that could just be me. I kick with my left leg write with my left hand but bat right handed. Stuff like batting was taught to me by a right handed person so that's why I bat right. Same goes for some other things but I am still very dominate with my left hand. Or should I say left side. live love laugh

I'll just leave this comic up here

i.imgur.com...

I don't know what the facts are, but it seems to me all of the lefties I've ever known have been very talented.

My best friend growing up is a lefty, he's an amazing guitarist (plays right hand guitar)

My daughter is a lefty, she is turning into a great pianist and violinist as well. (she's 11)

My son is 26 months, and it's hard to tell if he's a left or righty. He can use either hand to eat, or to throw, but uses his right to draw. We'll see how things go, maybe he'll be one of you awesome ambidextrous folks. His grampa on mom's side is ambidextrous and he's a talented guy too..

So I have no idea what causes it, but as I said, I think lefties might have an advantage in some areas over us clumsy righties.

My Daughter is Ambidextrous and very intelligent for a 6 year old.

She is now at the age where she is playing sports (teeball) and we had to just pick a hand for throwing and catching when buying her a mitt.

At first she favored the left a tiny bit over the right hand, but because of everything being made for right handed people she (computers as a big example), and her watching how other kids do thing, she has moved to favor the right hand a little more.

It is very interesting watching her do certain things though, because one second she is using one hand, and the next she is using the other.

I believe I may have been born Left handed, but because in the early 80's and was raised in my very young child years as a ward of the state, I was forced to do everything with my right hand over my left.

It seemed being left hand was bad.

I write with my right hand and growing up I threw with my right, but as an adult I can see how I probably should have been left handed, and was forced right handed.

I have paperwork from prior to my adoption where a state agency that was helping me had written about how I would use my wrong hand to color with or throw or what not.

So if you force a lefty to be a righty and they learn to develop themselves as right handed, while ignoring the left, would it cause some development problems and possibly hamper a childs learning ablility?

reply to post by TinkerHaus


I would have to agree with that. I can remember being in elementary school and noticing that the smartest kids were left handed.

It actually made me jealous and made me wish I was left handed, because I struggled in school.

As a youngster when I was playing table tennis or tennis I would swap the bat / racket between hands rather than play a backhand stroke....it made no difference as I was crap with both hands.

reply to post by RandomEsotericScreenname


I have 4/5 lefthanded children. Though predominantly right handed, and in the past tested extremely neutral for left/right hemisphere, now due to chronic fatigue/thyroid, I'm very right hemisphered. It hasn't carried over to my hand dominance though. But I do see my children as very right hemisphered too.

I find these two contrasting studies on being ambidextrous quite interesting.

ambidextrous kids have more mental problems

Children who are ambidextrous, using either hand with the same ease, may be more likely to have mental health, language and academic problems than their peers, according to a new study.

Gifted child study

48.9% (of exceptionally gifted and intellegent children) were ambidextrous at some period of their development.

So My theory, with an ambidextrous child, you need to work to develop both sides of the brain, not just one. But society (especially in the past) has forced the development of the left side of the brain (right hand), causing the ambidextrous and left handed (if forced to against their natural tendency) children to have development and academic problems because it is going against their natural tendencies. (I doubt any study has been done though to prove or disprove my theory)

The brain is a marvelous thing and how it develops is far from being able to comprehend and understand, no matter how much science is put into it.

reply to post by BiggerPicture


I am left-handed,rh- and carry a gene for producing 6 fingers.

I almost forgot...I can do the vulcan salute with both hands.

Left handed, green eyes, and I recently found two four leaf clovers one on march 19 and one yesterday, so I've got a triple whammy going on right now