First civilizations - common factors?

[Rodion Romanovich]

Ok, but if slavery was to cover lack of workers, then the slaves would just create more work because they mean more mouthes to feed? So could the real reason for slavery actually have been that people didn't want to do their share of the work? Divided on enough people, a single person's refusal to work becomes a lighter burden. Or is that what you meant? The ants example is interesting, but not really comparable because ants are insects, who can reproduce in large numbers and where droners are common - in slow reproduction animals a completely different ethics and morals system is needed for survival. For example there's this insect that eats the male after mating - such behavior isn't really possible among most slow reproduction animals, especially not humans who get one child per birth normally - then population would be halfed every generation. But perhaps human beings are able to lighten morals because they're nowadays reproducing faster?

The pologamy aspect is interesting, but hasn't the trend rather has gone towards monogamy than from it? So there were reasons for going towards polygamy as you wrote above - but why then going towards more monogamy as so many civilizations have?

Also some have mentioned that even early neolitic societies had better survival rates, but IIRC they DID have lower survival rate for a long time before getting better than hunting societies. Can anyone point in the direction of some relevant study about the subject? Even if they did have lower rates for a while that doesn't at all contradict common sense because given enough groups of people the chances that one or two will try something strange is quite large, but their settled lifestyle could give an advantage relative to other humans (notice: not relative to nature), and when also farming methods improved, they also got an advantage relative to nature, so to say.