A process of learning in humans or animals via an experimental procedure, where a given stimulus produces a response other than its normal, natural or automatic one. In the CLASSICAL form developed by PAVLOV a dog learned to salivate at the sound of a bell or buzzer and not just at the presentation of food. Later, B.F.SKINNER developed a different procedure known as OPERANT CONDITIONING in which an animal’s simple response could be used as the basis for training it to engage in very complex behaviour.