Comment by Eliezer
3 days ago
Poor eyesight is evolutionarily recent (not enough sunlight exposure in childhood, rare to find in hunter-gatherer societies). Baldness won't kill you.
3 days ago
Poor eyesight is evolutionarily recent (not enough sunlight exposure in childhood, rare to find in hunter-gatherer societies). Baldness won't kill you.
I'd be interested to see sources for the claim that poor eyesight is evolutionarily recent.
I strongly suspect it's more a matter of "won't kill you". Nearsightedness is far more common than farsightedness, and it's only in the last two hundred or so years that there's been any major benefit in seeing fine details at distance. The fuzzy shapes afforded by 20/80 vision are plenty enough to hunt a mammoth.
Having 20-20 vision is nice for avoiding lions and tigers, but it's a luxury spec, because movement acuity doesn't decrease linearly with nearsightedness, and movement acuity (plus traveling in groups, as prehistoric humans were wont to do) can take care of business decently-enough on its own - so I wouldn't call it "evolutionary-pressure"-nice.
> not enough sunlight exposure in childhood
Do you have any source for this? As someone born in the summer to a farming family with poor eyesight, I find it hard to believe that happened because I wasn't exposed to enough sun as an infant or child.
I've worn glasses since I was 2.
https://pmc.ncbi.nlm.nih.gov/articles/PMC6678505/
Interesting study. Myopia can definitely be caused by focusing too much on nearby things.
I just so happen to have Hyperopia with astigmatism, neither of which came from a lack of outdoor exposure. (If anything, I needed less time outside).
That's a bit of the issue I have with such a broad generalization. It's true that for some, a lack of time outdoors damaged their eyesight, it's not universally true that all or perhaps even most poor eyesight is a result of staying indoors.
Don't forget that hunter-gatherers rarely lived much beyond 30. Modern society isn't so bad :)
This is an incorrect generalization from average life expectancies that include incredibly high infant/childhood mortality.
The life expectancy cited by Wikipedia for the paleolithic is around 39 additional years for those surviving to 15.
https://en.wikipedia.org/wiki/Life_expectancy
Samson and Delilah would like to have a word with you. Also with Japanese Samurai. You loose your mythological power, leading to lost status, suicide, ...