Why are some people ambidextrous

[kevin_chen83]

Do any of you know why some people are ambidextrous? And also why are some people left- handed or right handed? Can anyone answer these questions?

[BenSon]

If I may I would like to tack on another question. Why are there more people right handed then left handed and even less ambidextrous people? Wouldn't evolution favoured the ambidextrous?

[Glider]

It comes down to brain lateralization, or more specifically, differences in brain lateralization between individuals. The stronger the hemispheric lateralization, the more 'one side' dominant we are. In about 20% of the population, the right hemisphere is more strongly lateralized leading to left-handedness. In some cases, the brain is less strongly lateralized and the greater the tendency toward being ambidextrous.

 

About 80% of the population show left hemispheric dominance and so are right handed. However, even in this group there are differences. Some some right handers are left footed or show left eye dominance, so there is a degree of variance even in a particular group, which siggests that hemispheric lateralization exists on a continuum rather than a dichotemous either - or state.

[BobbyJoeCool]

so... wouldn't that mean there is a correlation in being left handed and being "more creative" (as the right side of the brain has more creative potential and the left logic...)? Or is it just the motor part of your brain that shows "dominance" in one hemisphere?

[BobbyJoeCool]

If I may I would like to tack on another question. Why are there more people right handed then left handed and even less ambidextrous people? Wouldn't evolution favoured the ambidextrous?

 

How so? What advantage does an ambidextorous person have over a right handed person? Because a right-handed person uses the left side of their brain, and the left side of the brain is more logical... it might make sence that that person would have an advantage over one who uses less logic...

[BenSon]

How so? What advantage does an ambidextorous person have over a right handed person? Because a right-handed person uses the left side of their brain, and the left side of the brain is more logical... it might make sence that that person would have an advantage over one who uses less logic...

An amibidextrous person would have that same advantage as the right handed person and then some. Also I think being well coordinated with both hands would be an advantage.

 

`Scott

[YT2095]

actualy we prefer to be called Equimanual

 

no seriously, we do, read posts #37 and #38 here: http://www.scienceforums.net/forums/showthread.php?t=2727&highlight=equimanual

[BobbyJoeCool]

An amibidextrous person would have that same advantage as the right handed person and then some. Also I think being well coordinated with both hands would be an advantage.

 

`Scott

 

Ok, yes... but that's only the using of the hands... You're right handed because you use the left side of your brain... the "logic" side of your brain... now "equimanual" people use less of their left side (the logic side) and more of the other side (commonly associated with creativity). The problem is that creativity can get in the way of logic when used too much... And, the ability of using both hands is not a significant advantage (unless you're a sports player... you get paid more... grr.)

 

EDIT: LOL YT... equimanual... nice

[Ophiolite]

Why are some people ambidextrous?

 

Well, on the one hand.....

[BenSon]

Ok, yes... but that's only the using of the hands... You're right handed because you use the left side of your brain... the "logic" side of your brain... now "equimanual" people use less of their left side (the logic side) and more of the other side (commonly associated with creativity). The problem is that creativity can get in the way of logic when used too much... And, the ability of using both hands is not a significant advantage (unless you're a sports player... you get paid more... grr.)

I would dissagree, I think by having a balance between both halves you would get the best of both worlds. But what would I know I'm not 'equimanual';)

 

`Scott

[BobbyJoeCool]

I would dissagree' date=' I think by having a balance between both halves you would get the best of both worlds. But what would I know I'm not 'equimanual';)

 

`Scott[/quote']

 

but what if it works this way... (And I'm not sure about this). The more of the right side of your brain you use, the less of the left (ie, more creative=less logical). So, an equimanual person (such as muself) might not be as logical as a right handed person. Creativity is good and all, but the best balance might not be 50-50... as creativity helps you to see "outside the box," but most of the time, you need to think "inside the box," and that's logic. And, there are other factors that might come into play... since in the dark ages if you were left handed, you were burned at the steak because you were a demon (because you weren't "right" handed...). That would make it less common via natural selection. And various other factors that we aren't taking into account.

 

And, if I'm wrong about the whole thing, and it's just the motor cortex, the ability to use both hands is not a significant advantage. It would have been in the sword and shield days, but leftys were "demonic" back then, so they hid it and used their right hand anyway...

[YT2095]

as creativity helps you to see "outside the box," but most of the time, you need to think "inside the box," and that's logic.

 

For the love of All that`s holy (and even that which isn`t), THERE IS NO F**KIN` BOX!!!!

 

Damn I hate that cliche` !

[insane_alien]

i can write with both hands but i prefer the right. i just trained myself to write with my left hand so i'm not truely ambidextrous, or equimanula

[BobbyJoeCool]

For the love of All that`s holy (and even that which isn`t)' date=' THERE IS NO F**KIN` [b']BOX[/b]!!!!

 

Damn I hate that cliche` !

 

Yes, I know... but it's the best way to illustrate what I was trying to show (that I can think of...)

[YT2095]

i can write with both hands but i prefer the right. i just trained myself to write with my left hand so i'm not truely ambidextrous, or equimanula

 

heheheh, the REAL test is when you can write with both hands at the same time!

 

I Can do this and have been able to since I can remember, I do Mirror writing, that is that if I write a sentance with my right hand, I can do the same at the same time with my left, but the one on the left can only be read in a mirror, that includes spelling mistakes and badly drawn letters, the same works with smal pictures too or "Doodles" I can do them both the same at the same time (it`s actualy oddly "Relaxing" too, even if it`s just garbage or doodles) I CAN also do both in the same direction too at the same time, but that needs effort, but simultanious mirror writing I can do with my eyes shut

[BenSon]

since in the dark ages if you were left handed, you were burned at the steak because you were a demon (because you weren't "right" handed...). That would make it less common via natural selection. And various other factors that we aren't taking into account.

Actualy funny story, my dad went to catholic school and was left handed so they forced him to right with his right hand so now hes ambidextrous. So much for 'dark ages' huh?

 

`Scott

[RyanJ]

Actualy funny story' date=' my dad went to catholic school and was left handed so they forced him to right with his right hand so now hes ambidextrous. So much for 'dark ages' huh?

 

`Scott[/quote']

 

My friend had to learn to write with his left even though he was right handed because he broke his hand pretty badly and lost a lot of its control... not hes left handed.

 

I'm actually ambidextrous which is pretty unusuall because no-one else in my family has it.

 

Does anyone happen to know if it is genetic or envromental or a bit of both?

 

Cheers,

 

Ryan Jones

[Douglas]

I Can do this and have been able to since I can remember, I do Mirror writing, that is that if I write a sentance with my right hand, I can do the same at the same time with my left, but the one on the left can only be read in a mirror,

You gotta be shitting me!!!

[Callipygous]

it may be that some people are "equimanual" more easily, but my english teacher for freshman and sophomore year decided at some point that he wanted to be able to use both hands equally and forced himself to use his off hand till they were both as good. so id say its at least partially training.

[doG]

In my case I actually favored my left hand as a toddler but my mother forced me to use my right hand for everything. This was a common practice at the time because of the limited availability of left handed products for consumers, i.e. scissors, baseball mitts, guns, etc.. As I got older I learned that it was not very difficult to learn to do things with my left hand, a little practice and I had it. I assume this shallow learning curve is the result of me having been born favoring the left hand to begin with.

[doG]

heheheh, the REAL test is when you can write with both hands at the same time!

I saw a girl on T.V. that could write with both hands and both feet simultaneously. The show was 'Real People' or something like that.

[BobbyJoeCool]

I saw a girl on T.V. that could write with both hands and both feet simultaneously. The show was 'Real People' or something like that.

 

There's actually a condition where they have to disconnect the two sides of the brian... and it's really interesting because people who have had this operation have weird perceptions and abilities...

 

such as

 

heart

 

you probably see that as the word "heart." But someone with this "disablility" would see the words he and art, because you see he with the left eye, and right brain, and art with the right eye and left brain...

 

Another interesting thing about these people is that if you give them two sheets of paper, they can draw a triangle with one hand and a circle with the other... at the same time...

[BobbyJoeCool]

Actualy funny story' date=' my dad went to catholic school and was left handed so they forced him to right with his right hand so now hes ambidextrous. So much for 'dark ages' huh?

 

`Scott[/quote']

 

This is different... they forced him to be right handed, they didn't kill him because he was left handed...

[Glider]

so... wouldn't that mean there is a correlation in being left handed and being "more creative" (as the right side of the brain has more creative potential and the left logic...)? Or is it just the motor part of your brain that shows "dominance" in one hemisphere?

No such correlation has been shown as far as I'm aware. Both hemispheres contain motor cortices and lateralisation just determines which is dominant. As I said, there are degrees of lateralisation, so right handed people can be left footed or left eye dominant, so it's not an 'all or nothing' state. Left handed people are not necessarily left hemisphere dominant and all people use both hemispheres anyway. It's a question of degree.

 

BobbyJoeCool: These 'split-brain' patients have had the hemispheres of their brain separated by cutting through the corpus callosum (in most cases other transhemispheric tracts are left alone). This is usually done in cases of severe (life threatening) epilepsy, to prevent the cascade from passing from one hemisphere to the other.

 

These people can read well enough because the optic chiasm allows information from each eye to pass into both hemispheres. Where it gets strange is when, for example, they are choosing a dress or a suit from a wardrobe. One hand will reach for one and the other will reach for another, each hemisphere having made a separate choice.

[YT2095]

You gotta be shitting me!!!

 

No, not at all, what would be the point?

 

actualy My mother is Equimanual also, and it was her that 1`st showed me this, and so I tried and found that I could do it also with the same ease (I was only about 9 years old at the time).

 

as for writing with Feet, LOL! I have actualy tried that years ago and gave up as I got a bad cramp after about 30 seconds just trying to hold the pencil, I`ve never tried it since!