In this country, those who were on the bleeding (literally!) edge of the frontier were certainly not risk-averse. They were at much greater risk, and knew it, than those even a few miles back, much less those in the well-settled (and theoretically less resource-rich) areas.
I think we are on different pages. I am not looking at how Homo sapiens evolved r/K. It was there from way back before they were even monkeys, and is there in every other species. When I mention the migration, there is no written history about it.
When I say the migration, I am looking at how a primitive monkey-like creature, which had evolved r/K millions of years back, would carry the r and K-mindsets as a few members first evolved into Homo Sapiens, lost body hair, began running down prey in the daylight, and exploded in number. From there, once fully migrated, I am looking at how these mindsets would be evolved to find and exploit resource availability, and flee from risk and violence.
“In fact, I know of no case anywhere in recent millenia, with exception of the expansion of the Polynesians across the Pacific, where a group expanded into “unpopulated” territory. “
Yes, that is what this post is about, actually. Spreads occur in two directions, from an ecological perspective. Forward, into similar areas - unpopulated, but with similar or greater resource availability (again, this is back before history entered the picture). Think invasive species. Or laterally, into a new niche - a new environment, not as hosptiable for some reason, and probably requiring some adptation. Obviously we have not moved forward in a long time, but we did at one point, and it would have favored r way back then, and that is probably where the ball started rolling.
I am not saying r has functioned as pure r for a long time, or that is has been related to the migration for a long time, especially once everywhere was populated, and the only migration was lateral, which as you note, will not favor r. r does still have the migratory urge, though it will depend on resource availability, and competition avoidance. Combined, (ie violence and limited resources at home, free resources, foreign lands, and no violence abroad), I think Libs would almost universally migrate out.
My case is, r likely began in Africa as r, when we first began to spread. Probably functioned that way after the bottleneck as well. It may have offered some advantage when we met Neanderthals, since in addition to free resources, it seems to crop up in other mammals epigenetically, due to stressful early rearing experiences. A model where the less capable as children, grew up to be highly fecund, prone to migrate, less sexually selective, open to out-groups, and prone to get kicked out of the group, would produce a steady flood of r’s being thrown up against the more K Neanderthal, constantly. Competitive Exclusion would indicate a less capable model, thrown against a more capable specimen, in sufficient numbers constantly, would wear them down over time. Might even have something to do with the interbreeding, since r is associated with diminished sexual selectiveness (read the two posts in my sidebar on homosexuality and Liberalism).
Oer time, it likely adapted to persist in groups through social manuevering, and be expressed variably in response to resource variability.
Once agriculture hit, you have free resource availability, not associated with migration. It would have adapted. As groups grew, it became more of a socially manipulative psychology which would emerge orgnaically when resources grew plentiful. From there, r was a strategy designed to exploit resource availability, and avoid competition.
“In this country, those who were on the bleeding (literally!) edge of the frontier were certainly not risk-averse. “
As this post ended, I made a point that our nation’s founding, by colonists spreading into a land with very spread out, low resource availability, would favor the strategy which goes with that, which is more Libertarian, and which is more in line with the American Ideal.
Again, r’s will spread and migrate, if doing so will score them free resource availability, which is what they are really after. If not, this post makes the case you will get a more Libertarian, live and let live psychology. Our Republic was built by men who sought out this environment, and that is why it appeared as it did.