Social grooming is great for group cohesion. But that's others you know, not total strangers. Monkeys don't have to constantly deal with strangers.

Last I checked at least, monkeys also don't build cities.

You can learn how to build a city. You can't learn how to build acquaintances with everyone in that city.

I'm not sure how to address the idea that prior acquaintance is a requirement for speaking to anyone, or being spoken to.

I remain unconvinced this is other than an impoverished way of looking at the world. If anything, it seems much more to me now also a self-impoverishing one.

That's not the claim, the claim is that "prior acquaintance" is a pretty big part of social grooming.

I'm just saying to be slow to use monkey habits as a reference when critical pieces are so different. I'm not particularly arguing about what humans should do. Merely pointing out that the human situation is more unique than previously implied.

I didn't introduce the figure, only riffed on it to try to make my point more clear. If it's become a distraction, we should indeed discard it. That said, unique or no, I don't think a situation in which no one is willing to speak to or be spoken to by anyone they don't recognize is one that's especially ordinary for this species either. Certainly it has been anything but in my lifetime, and not only for happening to grow up in a place that wasn't Boston or Seattle.

One of the things I've loved about Baltimore for the quarter century I've lived here has been exactly that it differed in this, but lately that hasn't seemed very much to be the case, and that bothers me, especially to see happen in such a relatively short time.

I'm not inclined to haste in accepting it as normal, especially in the wake of a pandemic that seems to have significantly accelerated a process of cultural disintegration in at least the US. Things were not like this at all five years ago, and it legitimately frightens me that people seem to struggle to remember that, because it means I have to wonder what else may have come to be thought normal five years hence.