ABSTRACT
Instrumental learning is concerned with the effects of an animal’s responses on that environment, whereas classical conditioning deals with the detection of regularities in the environment. Animals can also learn to make different instrumental responses to different stimuli. Instrumental behavior can be shaped by a process of selective reinforcement so as to produce novel responses. The four best known schedules of reinforcement are: fixed ratio, fixed interval, variable ratio, and variable interval. Positive reinforcement consists of the presentation of a reward or the removal of an aversive stimulus. Negative reinforcement involves removal of a reward or presentation of an aversive stimulus. If a response is followed by the removal of an aversive stimulus it is positively reinforced; this is escape learning. The avoidance response removes the buzzer; removal of an aversive stimulus is positively reinforcing, and so the avoidance response continues to be strengthened even in the absence of shock.
