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Why is almost everyone right-handed? A new study connects it to bipedalism

ox.ac.uk

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Re: Why is almost everyone right-handed? A new study connects it to bipedalism

#61

Post by taeric »

Technolithic wrote: post #59
taeric wrote: post #37

I am curious at what age hand preference develops. And can you exert any influence on that development? In particular, I would expect the influences to be somewhat counter intuitive. With things like having to use the left hand to hold a caregiver's hand in early walking preferencing the right for accessory use. At infant ages, it would be neat to see if preference of holding a baby on a side influences things.

The introduction of this article makes reference to a couple of papers (e.g. https://doi.org/10.1038/s41598-017-16827-y ) that handedness is observable in utero but cautions small sample sizes for these studies.

Right, my question was more meant for how well established that is. And if it is open to influence. My searches made it look like it was not positive that handedness was fixed until a bit later. Still before formal schooling, but not necessarily in babies.

Re: Why is almost everyone right-handed? A new study connects it to bipedalism

#62

Post by Stevvo »

I taught English in China 20 years ago. Of the thousands of students I taught, none wrote with their left hand.

"There are no left-handed in China" might sound as ridiculous as "There are no gays in Uganda".

However of those thousands of students, none had messy hand writing. In any class in Europe or the US, around 10% of students have messy writing. Suspiciously equivalent to the supposed number of left-handed students.

Re: Why is almost everyone right-handed? A new study connects it to bipedalism

#63

Post by NickC25 »

jvanderbot wrote: post #27
NickC25 wrote: post #14

What does it say for mixed-handed folks like myself (different skillsets per hand - in other words, throw and write with different hands)? What about cross-dominance (different body parts differ on dominant side - in other words, a right-handed person being left-foot dominant)? I've been told that it's effectively a mental illness if discovered during childhood (as is ambidexterity). Yet I can't help but think that i…

You were probably a left-handed person who was taught to write/use tools with their right hand in kindergarten. I got this treatment too.

I don't know - my grandmother (father's mom) was fully left handed. My dad writes left handed but everything else right handed.

I am left handed for fine motor skills (writing, fork/knife) but throw righty and play single handed sports with my right (except for table tennis which i can do either hand at a good level). I can play two handed sports (hockey, lacrosse, golf) pretty much with either hand with little issue. Right footed, but can kick with my left pretty confidently.

Re: Why is almost everyone right-handed? A new study connects it to bipedalism

#64

Post by PeterWhittaker »

krater23 wrote: post #7

Didn't I understood the text or is the 'why' not really part of it? I expected more than a vague 'because it slightly existed and then hands are free to do things and brains got bigger'. I miss the point.

They don't discuss a "why", so much as present data on the "how" and "when". If this work is valid and reliable, then it will be up to later research to propose and test hypotheses as the why.

In a nutshell, the paper basically says that the lateralization that led to the predominance of right-handedness occurred around the time humans became bipedal and around the time of neuroanatomical expansion, possibly related to bipedalism.

In other words, before these two changes, we used all four limbs for locomotion and had no preference for either forelimb for grasping. Then one or two things happened and right-handedness predominated. It seems that that neuroanatomical expansion took over the areas of the brain that previously allowed our left hands to be as capable as our right hands.

I write "one or two things happened" because it wasn't clear to me from the paper whether the neuroanatomical expansion that led to lateralization was necessary to and part of bipedalism, i.e., caused by our locomotion bits taking over other parts of the brain to manage our balance, or whether it was merely coincident with it.

Interesting questions asked and answered, more research needed.

Re: Why is almost everyone right-handed? A new study connects it to bipedalism

#65

Post by booleandilemma »

scythe wrote: post #58
booleandilemma wrote: post #50

Earlier quoted context omitted.

I wonder why you're getting downvoted? Even if it turns out you're completely wrong it's still an interesting point and something I never even considered before.

Sometimes I think people downvote me because they're frustrated that I didn't engage further. After twenty years of Internet discussions, I'm a little burned out and I tend to fire and forget.

You might enjoy this: https://serjaimelannister.github.io/hn-words/

Re: Why is almost everyone right-handed? A new study connects it to bipedalism

#66

Post by TitaRusell »

Stevvo wrote: post #62

I taught English in China 20 years ago. Of the thousands of students I taught, none wrote with their left hand. "There are no left-handed in China" might sound as ridiculous as "There are no gays in Uganda". However of those thousands of students, none had messy hand writing. In any class in Europe or the US, around 10% of students have messy writing. Suspiciously equivalent to the supposed number of left-handed stud…

My father was left handed like me and he got in trouble from teachers.

It's possible that Chinese will one day obtain individuality and freedom and they can write left handed. That would kill the one last advantage the West has.

Re: Why is almost everyone right-handed? A new study connects it to bipedalism

#68

Post by AnotherGoodName »

dagi3d wrote: post #67

I am right handed but left handed for some very specific things such as playing pool or hockey

Same but i feel many sports are weird in that i’ve never been convinced that there’s a particularly natural right or left handedness to them.

Eg. For pool does the more dextrous hand need to push the cue or does it line up and guide the front of the cue? I can see tradeoffs each way and the front hand is certainly not just limp when playing.

Hockey is similar. The top or the bottom hand being the more dextrous probably has tradeoffs but I don’t see either grip as being more or less natural for handedness. I don’t play hockey but play golf and cricket which have similar grips and am similar there to you too.

Re: Why is almost everyone right-handed? A new study connects it to bipedalism

#70

Post by [deleted] »

AnotherGoodName wrote: post #68
dagi3d wrote: post #67

I am right handed but left handed for some very specific things such as playing pool or hockey

Same but i feel many sports are weird in that i’ve never been convinced that there’s a particularly natural right or left handedness to them. Eg. For pool does the more dextrous hand need to push the cue or does it line up and guide the front of the cue? I can see tradeoffs each way and the front hand is certainly not just limp when playing. Hockey is similar. The top or the bottom hand being the more dextrous probab…

[deleted]
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