Expansion into areas that aren't generally considered desirable, for one thing.
Primitive society = no air conditioning. But a hothouse climate is great for growing a lot of different fauna. A group (sub-group, faction, whatever) that can live in an uncomfortably hot area, only working at night and mostly sleeping away the day, would give you some interesting economic options.
The same applies to mining -- which even becomes safer. Pockets of flammable gas will not be immediately ignited -- no burning light sources -- and could most likely be detected before they became an issue. In addition, the work becomes somewhat less undesirable, simply because working underground in low/no lighting is less of a big deal.
I would actually expect the society to trend towards being LESS divided over day and night folks. Everyone can see in the dark. Unless they use a regimented working schedule -- a hold-over in modern times of the old sun-tied work system -- then people are going to sleep, eat, and work when it's the most efficient. This could easily lead to more fluid cycles and LOTS more 24-hour establishments.
Daytime drinking? Not a problem (or a social stigma), since it's assumed you were working during the night. Buying a fancy gown at 4am? No problem, there are multiple shifts of dress-makers.
I'd expect such a society -- given enough people -- would be far more productive than a 'standard' group of humans. People work when they want and when they're at their best and sleep whenever works for them. Farmers can work the fields day or night, improving harvests and planting cycles -- you can get the work done in fewer days, providing a better chance to get the seeds down or crops out before rains/winter/other undesirable conditions. Milling works the same way -- the river turns that wheel all night long, so let's have millers there feeding product into it all the time.
The biggest change of all is the one already mentioned... in a midevil-ish society, the hours of night are mostly dead time -- the hours of watchmen, thieves, and those with the least desirable jobs. By making that time accessible (for free, no torches or lanterns required) you've just added another 10 hours or so to the available time for all to live.
Primitive society = no air conditioning. But a hothouse climate is great for growing a lot of different fauna. A group (sub-group, faction, whatever) that can live in an uncomfortably hot area, only working at night and mostly sleeping away the day, would give you some interesting economic options.
The same applies to mining -- which even becomes safer. Pockets of flammable gas will not be immediately ignited -- no burning light sources -- and could most likely be detected before they became an issue. In addition, the work becomes somewhat less undesirable, simply because working underground in low/no lighting is less of a big deal.
I would actually expect the society to trend towards being LESS divided over day and night folks. Everyone can see in the dark. Unless they use a regimented working schedule -- a hold-over in modern times of the old sun-tied work system -- then people are going to sleep, eat, and work when it's the most efficient. This could easily lead to more fluid cycles and LOTS more 24-hour establishments.
Daytime drinking? Not a problem (or a social stigma), since it's assumed you were working during the night. Buying a fancy gown at 4am? No problem, there are multiple shifts of dress-makers.
I'd expect such a society -- given enough people -- would be far more productive than a 'standard' group of humans. People work when they want and when they're at their best and sleep whenever works for them. Farmers can work the fields day or night, improving harvests and planting cycles -- you can get the work done in fewer days, providing a better chance to get the seeds down or crops out before rains/winter/other undesirable conditions. Milling works the same way -- the river turns that wheel all night long, so let's have millers there feeding product into it all the time.
The biggest change of all is the one already mentioned... in a midevil-ish society, the hours of night are mostly dead time -- the hours of watchmen, thieves, and those with the least desirable jobs. By making that time accessible (for free, no torches or lanterns required) you've just added another 10 hours or so to the available time for all to live.