velvetpage: (Default)
velvetpage ([personal profile] velvetpage) wrote2008-07-22 07:39 am

Help! And, social anthropology intersects vaccination debates

Wikipedia is failing me, as is google at the moment, and I've had a request to explain a certain term I used a day or so ago in a community.

The term I used is "grandparent factor," though I'm not sure that's the term anthropologists use for the situation I'm thinking of. When I learned about it in anthropology years ago, it was an explanation for menopause, which traditionally happens in middle age; that is, humans become effectively infertile several decades before the end of their expected lifespan. We're the only members of the animal kingdom that experience a loss of fertility so early, so anthropologists proposed that it might be due to the grandparent factor. Less-able elderly people stayed home from the hard work of hunting and gathering, and looked after the small children who were not yet old enough to participate in that hard work, thus freeing up the parents to contribute their strength and youth to the family and community. The explanation posits that menopause is nature's way of creating an available pool of babysitters within the family, people who would have a vested interest in seeing that the children of their lineage were being cared for.

This came up in a discussion of shingles. I just found out (from [livejournal.com profile] doc_mystery - it's no end of useful having doctors on one's friends list!) that shingles is not a new infection; it's the chicken-pox virus that has been hiding out in your nervous system ever since you had chicken pox as a child, and it erupts when your immune system is somehow suppressed. The interesting part is that regular exposure to chicken pox during adulthood seems to act as a booster shot, making it less likely that the person will eventually get shingles because their body will be able to fight better, even with a depressed immune system. I see a connection there. Older people who look after young kids are going to come into regular contact with chicken pox, all things being equal, so they're going to get an additional boost to their immune systems every few years. The grandparent factor offers an increase to natural immunity from shingles.

Anyone have any links to prove I'm not pulling this out of thin air?

[identity profile] velvetpage.livejournal.com 2008-07-22 03:21 pm (UTC)(link)
Yes, the theory is that menopause developed in hunter-gatherer societies, and allowed for a level of expansion that wasn't possible when the society had to stay in places where small children could find enough to eat. It's a survival mechanism for the group as a whole. Like many other things, industrialization has changed it, by making it less likely that grandparents will want to/be able to take on that role.

The link further up the thread talks about it in a lot more detail.

(Anonymous) 2008-07-22 03:37 pm (UTC)(link)
huh. that is interesting. I'm thinking of Sarah, Abraham's wife from the book of Genesis. At 90+ she laughs at abraham when he tells her that God has promised she will conceive. She says she is past her time or child bearing but concieves anyway.

So the question is, just when did true menopause start? Eve of course, concieved indefinitely. Scripture records that she and Adam lived into the 700's I think and that they bore children for a good portion of that time.

Similarly, Noah is presumed to have gone on to have more children with his wife after the flood and he was 200ish I think?

The time line would be that Abraham and Sarah were several hundred years after Noah and it is the first mention of the cessation of fertility.

I don't know if you subscribe to the historical content of the Bible or not but regardless, it is compelling within the context of the theory of the evolution of late-life infertility to aide in rearing the younger generations while the able bodied adults worked/hunted

[identity profile] integritysinger.livejournal.com 2008-07-22 03:38 pm (UTC)(link)
that was me BTW. forgot to login

[identity profile] velvetpage.livejournal.com 2008-07-22 03:45 pm (UTC)(link)
I figured that. :) Answer is up to the original comment, but you won't get it to your email since you weren't logged in.

[identity profile] dornbeast.livejournal.com 2008-07-22 04:47 pm (UTC)(link)
Similarly, Noah is presumed to have gone on to have more children with his wife after the flood and he was 200ish I think?

As I recall, age is not as strong a barrier to fatherhood as it is to motherhood. It is still a factor, but (exaggerating a bit) the chance of fertilizing an egg doesn't approach zero until the heart rate does.

[identity profile] velvetpage.livejournal.com 2008-07-22 03:44 pm (UTC)(link)
I don't believe those ages, or necessarily those people, were historically accurate - I believe they're myths told to justify elements of early civilizations on which Judaism is built, so I wouldn't look to those scriptures for that evidence. I would use them for the anthropology of cultural myth, but that's a different topic. :)