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Why are most humans right-handed? The answer may lie in how we learned to walk

20 points by gmays 3 hours ago | 20 comments

Freak_NL 50 minutes ago

So why are us southpaws a rarity? The article and the linked research paper both point to bipedalism and bigger brains as the cause, and the paper vaguely seems to hint at selective pressures leading to the right hand getting favoured by the majority of the population, but why?

The question from the headline is excellent, if only it was actually answered.

scythe 21 minutes ago

Here's my five minute lunchtime hypothesis: it's because the heart is on the left. As human behavior demanded increasing precision from the hands, being a little farther from the heartbeat was a slight advantage.

gherkinnn 7 minutes ago

Wikipedia on Situs Inversus (visceral organs are mirrored, heart on the right, liver on left) [0], mentions mixed results regarding handedness. There would be a load of other confounding factors here and I know nothing about medicine.

0 - https://en.wikipedia.org/wiki/Situs_inversus

gpm 14 minutes ago

If this was the case wouldn't it be easier to measure the pulse in peoples left wrists? Which doesn't seem to be a thing?

yawpitch 11 minutes ago

Here’s my multiple years of anatomy classes response: the heart isn’t on the left. The aorta is, sure, but the vena cava is on the right. Also people with situs inversus (essentially all organs flipped laterally from “normal”) aren’t obviously more prone to left-handedness.

hypnodrones 23 minutes ago

I would be interested in studies into impact of left hemisphere importantce on the right hand usage, possibly the more sophisticated and "logical" usage of our hands pressured it as well.

yawpitch 15 minutes ago

One of many articles out there debunking the pop-psych mythology around brain lateralization: https://themindcompany.com/blog/left-brain-right-brain-myth

hypnodrones 2 minutes ago

Thanks! Although I understand there is still some specialization in each of the hempispheres, which could influence it, but I probably went too strong with my imagination here.

NickC25 25 minutes ago

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 it is not a mental illness, but rather something else.

tejohnso 11 minutes ago

In order to present it as a mental illness there would have to be some kind of negative effect, wouldn't there? These differences you mention don't stand out as harmful or even disadvantageous.

krater23 53 minutes ago

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.

stackghost 49 minutes ago

Actual study here: https://journals.plos.org/plosbiology/article?id=10.1371/jou...

My take is that when they added extra factors to the Bayesian model, the plot was such that humans were no longer outliers.

Whether or not that's scientifically rigorous, or even interesting, I leave to others to determine.

jnakano89 41 minutes ago

[dead]

foofyter 25 minutes ago

[flagged]

raggi 2 hours ago

Why are, Oxford.

Freak_NL 58 minutes ago

'Everyone' is treated as singular (aside from 'everyone are' sounding completely wrong).

3form 12 minutes ago

I think that's the case for all the "every <noun>". "Every human is a person", for example. This would make sense, to put it in programming terms - the verb applies to an element in an array of people, not the array itself (which would be plural): for every single human, that human is a person.

cwnyth 55 minutes ago

Confidently incorrect.

darenr 55 minutes ago

No, grammatically "everyone" is an indefinite pronoun. a single collective unit.

stackghost 52 minutes ago

Is that a British thing? Nobody in North America uses "everyone are"

shagie 19 minutes ago

https://www.britannica.com/dictionary/eb/qa/Everybody-Has-or...

> The words everybody and everyone are pronouns that describe a group of people, but grammatically they are singular. The last part of each word is a singular noun: body and one.

https://en.wikipedia.org/wiki/Encyclopædia_Britannica

> Though published in the United States since 1901, the Britannica has for the most part maintained British English spelling.

exe34 50 minutes ago

It's not.