I'm not sure about that, actually. The average lifespan has been pretty consistent throughout the industrial era, and the age reproduction starts is usually a function of it. Though yeah, I think most people at a suicide risk are younger. Might be a recent thing, though? Who knows.
Casual reminder that body fat percentage directly influences whether or not human ovaries do the thing, so food scarcity in earlier times would lead to a later onsent of Menstruation. Additionally, during the first few years after starting to menstruate, ovulation doesn't alwa,s takes place per se, so it's both possible and very much sensible that during the hunter-gatherer days child bearjng didn't start as early as people often think. ETA:fixed some stuff, my dysgraphia is acting up exceptionally today
The grandmother effect (or, 'older caregiver still being around to help look after grandchildren') does seem to have a positive effect on the survival of children from first-time mothers. The hypothesis, afaik, is that having someone who's been through this once before and can give tips and advice to the newbie will result in decreased infant mortality, because the first-time mother can more easily avoid mistakes that would result in the child becoming sick or dying and the first-time mother is more readily able to get breaks to rest and eat and do self-care. I don't recall where I read about it, but I think they weren't sure how much of an effect is has in the modern day, at least in developed nations, since modern medicine may have made some of it redundant. But it likely did have an effect (although they weren't sure how much or how to measure it) during the pre-industrial era that might have been more pronounced. The article I remember was more focusing on elephants, though, and how first-time elephant moms are more likely to have calves who survive their first migration when the grandmother is still alive and part of the herd, with a bit of speculation about how similar behaviour would have affected humans.
The Main issue with stuff like grandmother hypothesis is that A Lot of it hinges on assumptions, which makes me personally always super leery because i've seen where evopsych likes to take that. Fake edit: the 'gay uncle' hypothesis has a similar but even more pronounced problem.
Yeah, and we can't really...test the grandmother hypothesis, either? Or at least, there's no feasible way of testing it that I can think of which would actually pass an ethics committee. All we've got is "well, this sounds reasonable, and also some other social species that are about as intelligent as we are display this behaviour and it seems to have an impact on offspring mortality rates for them, so it makes sense for a thing that probably happened for our species too".
I wasn't thinking of, like, reproducing at twelve. I mean people in the 2000s often wait till they're thirty or more, which probably wouldn't be happening at the very early stages in humanoid evolution.
