ABSTRACT
This chapter introduces the notion of ‘feedback’ as the term is used in system dynamics. Feedback takes place when a change in the level of a system variable propagates around a causal loop to amplify or oppose the original change. Many aspects of the behaviour of social–ecological systems are most easily explained as feedback effects. Feedback loops can have causal impacts that lead even very simple systems to behave in unexpected and complicated ways. It is necessary for human ecologists to at least understand the basic mechanism, to have a good grasp of what types of behaviour are typical of feedback systems, and to know when a system dynamics approach is likely to be useful. A particularly important characteristic of feedback systems is that their behaviour is endogenous – that is, generated inside the system boundary.
