Amos, nicely turned.
Mrrzy, with all due respect, not all human societies are at the same level of complexity. A simple hunger-gatherer society with no visible leadership is worlds apart, complexity-wise, from a society with permanent classes based on economic and career path factors, an established, multi-layered government, standing laws, etc.
This is not to say the one is "primitive" and the other something else (what exaclty is the opposite of "primitive," anyway?). While it is true that the simpler one can often "evolve" into more and more complex ones, the complex ones can also be turned back into simpler ones due to disease, war, etc.
Is one superior to the other? Well that obviously depends on whom you ask.
For a really good look at human societies, both from a historical perspective and from a complexity-scale standpoint, please see Guns, Germs and Steel (I forget the author's name; easily found on Amazon.)