This document discusses discriminated avoidance learning in humans and animals. It describes how a warning signal prompts an avoidance response to prevent or remove an aversive stimulus. The dominant two-process theory explains that classical conditioning creates a fear response to the warning signal, and operant conditioning reinforces the avoidance response because it reduces this fear. The avoidance response is maintained because it allows escape from the conditioned fear response, not because it directly prevents the aversive stimulus.