9:48 PM
@James or they turn into a different kind of smart people.
@James im not sure that's an answerable question. How do you tease apart local tech levels (defined/discovered how?) from nation-wide tech levels?
The approximate tech levels in a modern US town are absurdly high because of all the imported technology. However, one could easily argue that the Cambridge, MA had way higher tech levels because of MIT alone.
Then there's the problem of legible knowledge like degrees or patents vs illegible knowledge like crazy good cooking or a green thumb or farming or blacksmithing.
Inhabitants stuck on an island will become highly optimized for those circumstances.