Social agents are abstract models of individuals or organizations which have agency, meaning the capacity to make choices and to act independently on those choices to affect the state of their environment. In order to make choices, agents need some set of rules under which to make their choices. This set of instructions or rules can be based on some simple linear cause and effect model, what may be called an algorithm, or they may be much more complex models, what may be called a schema. With this capacity of agency comes autonomy. In their choices and actions, agents define themselves as independent from other things and thus define their own identity with associated responsibility for their actions.