The document describes the principles of classical and operant conditioning. It provides examples of an unconditioned stimulus (pain from a needle), conditioned stimulus (approach of a nurse), unconditioned response (screaming from pain), and conditioned response (screaming at the approach of a nurse due to past association with pain) based on a scenario of a boy receiving painful injections. It then discusses the three phase model of operant conditioning involving positive reinforcement, negative reinforcement, punishment, and schedules of reinforcement as proposed by B.F. Skinner.