Different regimes can be metaphorically represented by a ball-and-cup diagram. The valleys or cups represent different regimes or fundamental ways in which the system can function and be structured. A regime shift entails a shift in the current system state (represented as a ball) from one cup or valley to another. While in a particular regime, it is important to note that the system does not remain stable but fluctuates around.
Regime shifts result from a change in the dominant feedbacks. All complex systems contain many feedback loops, but these can typically evolve and combine in only a limited number of ways. Over time, a particular combination of feedbacks will tend to become dominant, leading the system to self-organize into a particular structure and function – or "regime". However, if the system experiences a large shock (eg a volcano) or persistent directional change (eg accumulation of pollutants, habitat loss) the dominant feedbacks may be overwhelmed or eroded. At some point a critical threshold may be passed where a different set of feedbacks become dominant, and the system experiences a large, often abrupt change in structure and function – or a "regime shift".
