Wikipedia
Behavioral paradigm in which organisms learn to predict aversive events
Summary
Pavlovian fear conditioning is a behavioral paradigm in which organisms learn to predict aversive events. It is a form of learning in which an aversive stimulus is associated with a particular neutral context or neutral stimulus, resulting in the expression of fear responses to the originally neutral stimulus or context. This can be done by pairing the neutral stimulus with an aversive stimulus. Eventually, the neutral stimulus alone can elicit the state of fear. In the vocabulary of classical conditioning, the neutral stimulus or context is the “conditional stimulus” (CS), the aversive stimulus is the “unconditional stimulus” (US), and the fear is the “conditional response” (CR).