Negative feedback reduces the error or deviation from a goal state.
Positive feedback increases the deviation from an initial state. A flow of information back to its origin. A circular causal process in which a system 's output is returned to its input, possibly involving other systems in the loop. Positive feedback or deviation amplifying feedback increases the input and is inherently destabilizing, explosive or vicious, e.g., the growth of a city when more people create new opportunities which in turn attract more people to live there. Feedback is not the term for a response to a stimulus rather for the circularity implied in both.