Sociobiology is the application of evolutionary theory to social behavior. It is based on the premise that some behaviors are at lease partly inherited and can be affected by natural selection.
One way of analyzing social interaction is through the social exchange theory. This model interprets society as a series of interactions that are based on estimates of rewards and punishments. According to this view, our interactions are determined by the rewards or punishments that we receive from others and all human relationships are formed by the use of a subjective cost-benefit analysis. The theory has its roots in economics as well as sociology and psychology.
Chaos theory is a field of study in mathematics, however it has applications in several disciplines, including sociology and other social sciences. In the social sciences, chaos theory is the study of complex non-linear systems of social complexity. It is not about disorder, but rather is about very complicated systems of order.
Social phenomenology is an approach within the field of sociology that aims to reveal what role human awareness plays in the production of social action, social situations and social worlds. In essence, phenomenology is the belief that society is a human construction.