[gottorf]

> This can’t surely have been happening when we were hunter / gatherers!

Or it did, and those people died and we no longer have any record of them. That's entirely possible, I suppose.

[davzie]

That implies might be a genetic disposition which would also imply anyone suffering today maybe shouldn’t be here if that mutation died out. I dunno, I’m a software engineer not a geneticist but I just enjoy the thought experiment