Hacker News Reader

Comment by jayd16 | Hacker News Reader

This doesn't really make sense does it? There's only really evolutionary pressure up to the end of your child rearing years, no?

View on HN

Humans are double-viviparous species, meaning average grandparent lives past its grandchild's puberty. Humans are also atricial. These traits are shared by elephants, whales and dolphins too. However, humans are the only animal species those are triple-viviparous in occasions, meaning great-grandparent lives past its great-grandchild's puberty.

Human's average lifespans have been a lot shorter throughout history.

Average isn't that relevant. It's driven down by early childhood deaths & childbirth deaths (but after a point - menopause - childbirth deaths end).

Infectious disease killed many before old age. Antibiotics are a pretty recent invention.

Yeah, but the impact isn't that great.

According to Our World In Data [1] a 20-year-old would expect to live to 60 in 1850 (before penicillin), versus to 80 now.

[1] https://ourworldindata.org/life-expectancy#it-is-not-only-ab...

That's still long enough for a person to see their grandchildren reach and cross puberty.

Especially in a world where kids were born when the parent was in late teens or early 20s, rather than now when average age is 28 and pushing higher.

This means first grandchildren in early 40s (rather than late 50s), and first great grandchildren by mid 60s (rather than mid 80s)

And infectious disease was probably a much smaller problem for hunter gatherers living in small groups, which has been the case for the vast majority of our evolutionary history.

Historical average is relevant. I have an 18 year old cat. It's an aberration. We evolved under specific pressures. Only recently, have we removed specific age gates.

Should be context dependent. New parents benefit a lot from their own elder family members giving them advice on the basics; in an environment with less information (i.e. no internet), the advantage vs. people with no parents or family to help would have been substantial. So unless we expand the definition of “child-rearing years”, I think it could go either way.

for any amount of food, it's better to have an adult rather than an elder, for any particular gene.

So a truly optimal age system would have no old age at all, you will just die off after your children are self-sustaining.

> There’s only really evolutionary pressure up to the end of your child rearing years, no?

No, at least according to some anthropologists and evolutionary biologists. For example see the Grandmother Hypothesis https://en.m.wikipedia.org/wiki/Grandmother_hypothesis

Reply on news.ycombinator.com