The interactions have a fairly short-range. There are loops in the interactions. Complex systems are open systems. Complex systems operate under conditions far from equilibrium. Complex systems have histories.
Individual elements are ignorant of the behavior of the whole system in which they are embedded.
Postmodern societies have millions of agents operating within them at any one time. In a postmodern society, the interactions between agents and and mechanisms of the societal system are extremely rich and diverse. Social relationships in postmodern society are non-linear and asymmetrical with respect to power. It is within these asymmetrical power relationships that people operate as teachers, students, consumers, and citizens. Individuals interact on local levels.