Operant conditioning is a learning process whereby deliberate behaviors are reinforced through consequences. It differs from classical conditioning, also called respondent or Pavlovian conditioning, in which involuntary behaviors are triggered by external stimuli.
With classical conditioning, a dog that has learned the sound of a bell precedes the arrival of food may begin to salivate at the sound of a bell, even if no food arrives. By contrast, a dog might learn that, by sitting and staying, it will earn a treat. If the dog then gets better at sitting and staying in order to receive the treat, then this is an example of operant conditioning.