Backing up a step from this, actually… how confident are we of the “no contact with each other” condition?
Speaking from near-complete ignorance, I can easily imagine how a level of contact sufficiently robust to support “hey, those guys over there are doing this nifty thing where they plant their own food, maybe we could try that!” once or twice a decade would be insufficient to otherwise leave a record (e.g., no commerce, no regular communication, no shared language, etc.), but there might exist plausible arguments for eliminating that possibility.
Well, we know pretty well that even when societies were in very close contact, they rarely adopted each other’s technology if it wasn’t already similar to what they’ve been doing.
Agriculture probably initially expanded because farmers pressed north through the continent, not because hunter-gatherers adopted the practice on their own, Scandinavian scientists say.
If in this close contact scenario agriculture didn’t spread, it’s a huge stretch to expect very low level contact to make it happen.
Backing up a step from this, actually… how confident are we of the “no contact with each other” condition?
Speaking from near-complete ignorance, I can easily imagine how a level of contact sufficiently robust to support “hey, those guys over there are doing this nifty thing where they plant their own food, maybe we could try that!” once or twice a decade would be insufficient to otherwise leave a record (e.g., no commerce, no regular communication, no shared language, etc.), but there might exist plausible arguments for eliminating that possibility.
Well, we know pretty well that even when societies were in very close contact, they rarely adopted each other’s technology if it wasn’t already similar to what they’ve been doing.
See this for example:
If in this close contact scenario agriculture didn’t spread, it’s a huge stretch to expect very low level contact to make it happen.
(nods) Yup, if that theory is true, then the observed multiple distinct onset points of agriculture becomes more mysterious.