Why Is Right-Handedness More Common Than Left-Handedness?

[Pego]

I'm ambidextrous, one of my children is ambidextrous and one is exclusively left handed :shock: 8-)

The hand you right with is what your handedness is, regardless how handy (klutzy) you are with either.

Who wrote that rule?

It's not a rule, it's a simple observed fact. All right-handers are left hemisphere dominant. About 50% of left-handers are also left hemisphere dominant.

[BisonHurdler]

To go along with Pego, I don't have numbers, but in school we were taught that right brain dominant people are much rarer than Left-handed folks. Ergo, many many left-handed folks are also left brain dominant.

[Marlow]

[All right-handers are left hemisphere dominant.

ALL? Really? I know some pretty flaky right-handed artsy types, who MUST be right-brained!!! :twisted:

[TrackDaddy]

I see guys

But what does that have to do with which hand you write with?

I ask because based on your statements it doesn't sound like hemisphere dominance dictates it.

Why is handwriting a factor and strength isnt?

For example, like Track Family I too am ambidextrous.

I write with my left hand. But that's about all I use it for.

My strongest arm, hand, leg are my right ones. That is I throw, kick and punch righthanded. I consider my dominant hand to be the right one.

How or why would only writing with the left hand trump all that?

[Pego]

But what does that have to do with which hand you write with? I ask because based on your statements it doesn't sound like hemisphere dominance dictates it. Why is handwriting a factor and strength isnt?

Let me try to explain a rather complicated neuroanatomy briefly.
What we commonly refer to as "speech" is, in fact, language. Writing (any, handwriting, typing) is part of the language function just as the speech or reading. Listening and reading is language comprehension, speeking and writing is the expressive language. The primary center for this is the gyrus of Heschl in temporal lobe, which is located about 95% of the time in the left hemisphere. The way the motor system is constructed, the left hemisphere controls the right side of the body and vice versa. So, you write with the right hand, you have the left hemisphere as dominant. Left hand and it is 50-50. "Ambidextrous", you really cannot be sure, but I am betting on the left.
As far as the strength is concerned, you use your dominant arm a lot more, so it gets bigger by greater use. Tennis players are a classic example.

ALL? Really? I know some pretty flaky right-handed artsy types, who MUST be right-brained!!!

A common reference of "right-brained" does not refer to cerebral dominance. It is a completely different concept. A fascinating reading would be Roger Sperry's work on split brains.

[AthleticsInBritain]

[All right-handers are left hemisphere dominant.

ALL? Really? I know some pretty flaky right-handed artsy types, who MUST be right-brained!!! :twisted:

Where do i fit in? Left-handed father, ambidextrous grandfather, both left-brain dominant. I'm right brain dominant, was apparently born left-handed but "forced" at school to use right hand instead, so I'm right handed by learning.

One interesting point (to me anyway) is that my after a disabling stroke, my father learnt to use his right hand virtually as proficiently as his left for writing, etc and is presumably now ambidextrous after recovering use of the left side of his body.

I'm sure the MD's on here will know this, but I'm convinced that you can train either hand to be as good at everyday tasks as the other.

[JRM]

Who wrote that rule?

My guess is that is how neurologists define it.

As to why, I'm not aware of a simple genetic component, so it might well be due to a stochastic event during early development. X-inactivation works this way too which is why each calico cat has a different pattern.

In the particle physics world, there are two types of particles that interact differently: we call them left-handed and right-handed. That is, you can have a "left-handed electron" and a "right-handed electron". It turns out that the universe today only contains left-handed ones -- or rather, than left-handed are much more common than right-handed ones.

The reason given is that, sometime long ago, there were equal amounts of both. But somewhere along the line, something happened to make the righties disappear (a process called "symmetry breaking"). Daisy's explanation is a similar process in the biological world.

[Pego]

[All right-handers are left hemisphere dominant.

ALL? Really? I know some pretty flaky right-handed artsy types, who MUST be right-brained!!! :twisted:

Where do i fit in? Left-handed father, ambidextrous grandfather, both left-brain dominant. I'm right brain dominant, was apparently born left-handed but "forced" at school to use right hand instead, so I'm right handed by learning.

One interesting point (to me anyway) is that my after a disabling stroke, my father learnt to use his right hand virtually as proficiently as his left for writing, etc and is presumably now ambidextrous after recovering use of the left side of his body.

I'm sure the MD's on here will know this, but I'm convinced that you can train either hand to be as good at everyday tasks as the other.

The cerebral dominance of your father is easy to determine. With his stroke, if he lost some language abilities, his cerebral dominance was right, if he did not, it was left.

Yours is statistically 50-50.

Some people can train the non-dominant side after a stroke the way you describe, but it's pretty rare. I have not seen a lot of it. But then, I've only been a neurologist for 43 years :wink: .

[AthleticsInBritain]

I can't remember if he had any damage to his language function with the stroke where he lost the use of/control of large parts of the left hand side. He could still talk to a minor degree, but the muscles in the face were affected. I suppose I'm trying to say that his cognitive abilities weren't damaged, but the physical ability to speak was? Aren't the two things controlled by different areas of the brain?

Plus, he's had more than one stroke (three I think), so the fact that he's walking, talking and driving, playing golf and swimming while being an active member of the British Legion (our veteran's association) is probably very unusual!

[Pego]

I can't remember if he had any damage to his language function with the stroke where he lost the use of/control of large parts of the left hand side. He could still talk I think, but the muscles in the face were affected, so it's difficult to tell. Plus, he's had more than one stroke (three I think), so the fact that he's walking, talking and driving, playing golf and swimming while being an active member of the British Legion (our veteran's association) is probably very unusual!

I am almost certain, your father's dominant hemisphere is left. Yours is, likely, too .

[AthleticsInBritain]

But I want to be right brain dominant! I'm artistic, and flaky, and I took this test on Facebook that said I was so I must be! :lol: I still use my knife and fork the wrong way round. :lol:

Can you be right-brain-dominant and right-handed?

There's a whole sort of left-handed liberation movement that objects to the latin - sinister and the negative connotations that have come to be attached to the word. The most famous leftie, of course, must be Ned Flanders, with his leftorium.

[Pego]

But I want to be right brain dominant! I'm artistic, and flaky, and I took this test on Facebook that said I was so I must be! :lol: I still use my knife and fork the wrong way round. :lol:

Can you be right-brain-dominant and right-handed?

There's a whole sort of left-handed liberation movement that objects to the latin - sinister and the negative connotations that have come to be attached to the word. The most famous leftie, of course, must be Ned Flanders, with his leftorium.

I don't like to be dogmatic with an unequivocal NO, let's just say, the odds for it are infinitesimal. I've never heard of it.

[AthleticsInBritain]

Thanks for your comments Pego. I find it an interesting subject and it's been good to have the benefit of your experience!

[Brian]

I heard a person is left-handed if their parents did it standing up when they were conceived.


--Inspired by the wisdom of Michael Kelso,
That '70's Show.

[Halfmiler2]

I'm ambidextrous, one of my children is ambidextrous and one is exclusively left handed :shock: 8-)

The hand you right with is what your handedness is, regardless how handy (klutzy) you are with either.

I have to disagree with that rule. I write as a righty because the good Sisters taught me that way and the school desks were made for righties back then anyway. But at age eight, I determined that in sports I was a natural lefty. I became a switchhitter in baseball, throw lefty, kick a football lefty, use starting blocks as a lefty, etc. There is no doubt that my brain considers me lefthanded.

The above saved me in grad school when I broke my lefty finger going after a sinking line drive but could still write my final exams righthanded. :wink:

By the way, the only subject I ever flunked in school was penmanship in the 4th Grade - righthanded.