It’s widely believed that humans basically lived in <200 person tribes that didn’t interact with each other too much before agriculture, so one might wonder how anything got any amount of adoption.
I thought people exchange between adjacent tribes was common, which makes me suspect that the amount it time it takes to transfer innovations is actually not that long?
Yes, but: a ~200 person tribe still limits the total amount of know-how that can a given tribe can remember and pass down, and then the next tribe over has to remember most of it redundantly, rather than specializing in something else.
I thought people exchange between adjacent tribes was common, which makes me suspect that the amount it time it takes to transfer innovations is actually not that long?
Yes, but: a ~200 person tribe still limits the total amount of know-how that can a given tribe can remember and pass down, and then the next tribe over has to remember most of it redundantly, rather than specializing in something else.
Sure; I’m not sure what fraction of the relevant innovations were additions instead of replacements (which might not impact total memory burden much).