Why is almost everyone right-handed? A new study connects it to bipedalism • Hacker News Board

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

#91

Post by lurquer » Tue, May 19, 2026, 9:22 PM UTC

The ‘study’ is fluff.

Paraphrase: Amongst primates there is a correlation between brain size and bipedalism with handedness… (unless you exclude humans, in which case there isn’t.)

That’s like saying: “Alongst animals there is a correlation between height and neck length… unless you exclude giraffes, in which case there isn’t.”

If a correlation disappears when you remove one datapoint, then the correlation was not really a broad pattern across the dataset. It was mostly a story about that one datapoint.

I mean, I get it… you gotta publish something. But, geesh… this is beyond stupid.

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

#92

Post by Pay08 » Tue, May 19, 2026, 9:33 PM UTC

bkjelden wrote: post #28

jvanderbot wrote: post #27

Earlier quoted context omitted.

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'm otherwise a lefty but I use computer mice right handed, because when I first started using a computer in elementary school all of the computer labs were set up right handed.

Weirdly enough, I don't know why I use the mouse right-handed. I was forced into doing it in any particular way, and beside the fact that I was already an adult when I learned of the existence of left-handed mice, I can't think of any reason why I'd naturally gravitate towards right-handed mouse use.

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

#93

Post by js2 » Tue, May 19, 2026, 9:40 PM UTC

skyberrys wrote: post #74

The article didn't really help me understand what it was about bipedalism that resulted in a right handed preference. Also in my family left hand dominates, we are a cluster of left handed people. My theory is if any child wants help with fine motor control the help is provided by a left hand to a left hand.

The original paper is titled "Bipedalism and brain expansion explain human handedness". It doesn't seek to explain why we have a right-handed preference specifically (vs left-handed), but rather why humans have such a strong handedness preference compared to ancestors who had only a mild right-handed preference.

IOW, why handed vs ambidextrous, not so much why left-handed vs right-handed.

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

#94

Post by thaumasiotes » Tue, May 19, 2026, 9:42 PM UTC

scythe wrote: post #16

Freak_NL wrote: post #10

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.

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.

> Here's my five minute lunchtime hypothesis: it's because the heart is on the left.

Your hypothesis can't possibly be correct, because the only premise is false.

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

#95

Post by js2 » Tue, May 19, 2026, 9:44 PM UTC

dagi3d wrote: post #67

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

Same which makes me very poor at sports. I write right-handed. For anything sports related (riding a board, throwing a ball, golf, batting, bowling, etc) I'm leftie. My dad is left-handed, mother is right-handed. I have wondered if I should've been a left-handed writer and was corrected either explicitly or just by the environment to write right-handed.

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

#96

Post by thaumasiotes » Tue, May 19, 2026, 9:44 PM UTC

rolph wrote: post #53

stackghost wrote: post #49

Earlier quoted context omitted.

>if you really want to kill someone you stab them through the sternum, kind of dead center, not where they hold their hand when performing patriotism. Noted, thanks.

even this is wrong, a penetrating weapon aimed for the heart is applied below the sternum at roughly the positionof the 3rd shirt button, and thrust upward at shallow angle topass behind the manubrium, and is then levered into a pommel upward position so as to lacerate the heart

Well, yes, the point of the solid bone plate right in front of your heart is to block stabbings. And it works!

If you had a weapon that wasn't bothered by the presence of the sternum, and you wanted to stab the heart, you'd go right through the sternum.

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

#97

Post by busyant » Tue, May 19, 2026, 9:45 PM UTC

emporas wrote: post #77

scythe wrote: post #16

Earlier quoted context omitted.

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.

That's a long time hypothesis of mine as well, but I think it stems from being stung or bitten by venom. If venom is injected into the bloodstream, it is desirable to be injected as far away from the heart as possible. Some centimeters might not sound much, but over millions of years, the cumulative effect might be that 1% of human population every 10.000 years gets genetically optimized to hold their heart at a more…

Interesting!

Handedness is probably not (often) captured in healthcare records, but I'm wondering if epidemiologists could mine insurance claims (or some other data rich resource) to see if there's a correlation with serious outcomes (death, hospitalization, etc.) from venom and handedness.

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

#98

Post by thaumasiotes » Tue, May 19, 2026, 9:48 PM UTC

Pay08 wrote: post #85

senko wrote: post #80

Earlier quoted context omitted.

Left-to-right writing systems are optimized for right-hand use. Two examples: * if you're left-handed, your hand smudges over the ink before it dries. There are various contortions that some left-handed people do (hover the hand or wrap it around from above) - right handed ones don't need any of that. * stroke patterns, as usually learnt in school, result in pushing away if left handed, vs drawing to, if you're right…

Right-to-left languages don't make writing much easier. It certainly helps, but at least anecdotally, it's overstated how much more easy (how much easier? English is confusing) it is.

Chinese was traditionally written top-to-bottom, and I can see that making it more a matter of taste which hand you painted with.

Today it's always left-to-right, though.

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

#99

Post by colkassad » Tue, May 19, 2026, 9:55 PM UTC

I always faced left when riding a skateboard back in the day, otherwise known in skater parlance as being "goofy-footed". Facing right felt as difficult as writing with my left hand. I always wondered whether that was just the way I first rode a skateboard and it stuck, but if that was the case, I would expect the distribution of which skateboarders face which way to be about even. But goofy-footed riders are in the minority. I'm right-handed as well. I wonder what's up with that.

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

#100

Post by rolph » Tue, May 19, 2026, 9:57 PM UTC

thaumasiotes wrote: post #96

rolph wrote: post #53

Earlier quoted context omitted.

even this is wrong, a penetrating weapon aimed for the heart is applied below the sternum at roughly the positionof the 3rd shirt button, and thrust upward at shallow angle topass behind the manubrium, and is then levered into a pommel upward position so as to lacerate the heart

Well, yes, the point of the solid bone plate right in front of your heart is to block stabbings. And it works! If you had a weapon that wasn't bothered by the presence of the sternum, and you wanted to stab the heart, you'd go right through the sternum.

the risk is one of being unable to extract the weapon expediently.

there is an unacceptable risk of having to abandon it.