Escape learning is learning an action that terminates an already-present aversive event. If making the response becomes more likely because it ends the event, the contingency is negative reinforcement. It differs from avoidance learning, in which an action prevents or postpones the event before it begins.
For example, compare a response that stops an ongoing unpleasant sound with one that prevents the sound after a warning cue. The physical response could be identical while its relation to the event differs. A yoked control can receive the same event timings without controlling them, separating exposure from controllability. Classic learned-helplessness experiments used such differences in prior controllability to study later escape performance. [ref]
Failure to escape traumatic shock by Martin Seligman and others. 1967, experimental comparison of controllable and uncontrollable prior exposure
Performance also depends on sensory, motor and motivational conditions, not learning alone. New to topics? Read the docs here!