In reality, it is due to infant mortality rates. Once you make it past a certain age (10-15 years) your life expectancy shoots up into the 40-60's easily. However, when you average the population out, those infant deaths tank the average life expectancy.
I'm not surprised they glossed over this, most researchers do, because they don't want to go into infantile deaths, disease spread during child birth, still births, etc.
Not only is it a complex topic, but it's fraught with political and religious ideology. When my history and anthropology professors started talking about it, certain folks of a particular religious bent almost immediately started trying to correct them about it.
I am annoyed by these slips every time because they make it seem as if we live so much longer since hunter-gatherer times... Modern medicine reduced early age mortality, sure, but funny enough it did not do much to increase max lifespan (and especially healthy lifespan).
To add to your comment about modern medicine. Keep in mind that when you isolate out infant mortality, you get an average life span of roughly 60-ish in ancient times.
Present day mortality is closer to 85+ for the G7 countries and 75+ for other fairly well developed countries. That's a 25 year increase! Given those statistics, I would say modern medicine is actually doing quite a bit to improve life expectancy into your golden years!
There can be an ideological bent to try and label Rome (and by relation Catholicism) as being unclean and ungodly because it does not protect its young. Or even more extreme, suggest that their children die regularly because they are godless and that history proved it.
I hope I don't need to explain why this is very much an extremist point of view, but I'll say so regardless so that HN mods or other folks don't label me as being political/religious here.
In my history class, a religious argument of "my children are more godly and history proves it by the deaths" broke out between a group of very devout Orthodox, some Catholic folks, and some Muslim folks. All of them were trying to use the infant mortality rate as proof of some or the other's faith of god in their children. It got very weird, very fast. The professor had to break up the argument.
This happened in Alberta, the "religious zealotry" capital of Canada. Lots of religious conservatism here.
If you don't mind clarifying just a bit. What types of religious folks would get upset about a professor in a course (for a scientific discipline they presumably want to do well in no less) describing the very real history of terrible infant mortality across pretty much all premodern cultures and societies? Why would this even be a problem for them? Daily life in the past was known to be very harsh, even the bible itself (among other religious texts) alludes to that constantly.
> Researchers Gurven and Kaplan have estimated that around 57% of hunter-gatherers reach the age of 15. Of those that reach 15 years of age, 64% continue to live to or past the age of 45. This places the life expectancy between 21 and 37 years.[54] They further estimate that 70% of deaths are due to diseases of some kind, 20% of deaths come from violence or accidents and 10% are due to degenerative diseases.
But even that aside, it is definitely not what the guy in video literally said, which is quote "their lifespans would have only been around 35 years", 5:22. By the way, I had to sit through 6 unskippable 10-second ads to tell you the timestamp (2 ads every time I scrub around).
Edited for brevity
Huh, does uBlock Origin not work for blocking ads on YouTube anymore?