1) The process of changing a behaviour that involves interactions between responses and environmental events whose effects depend upon the processes of reinforcement.

2) The strengthening of a particular behavior. In respondent conditioning repeated pairing of a neutral stimulus with a stimulus which already elicits a response results in the neutral stimulus gaining control over that response in a new reflex. In operant conditioning a kind of response becomes more likely in a particular situation when similar responses in similar situations have been reinforced.

3) The term conditioning is used to describe both operant and respondent behavior. It refers to a change in the frequency or form of the organism's behaviour as a result of the influence of the environment. In operant conditioning the frequency of a performance changes as an organism interacts with the environment. In respondent conditioning, a neutral stimulus comes to elicit a response as a result of pairing it with an unconditioned stimulus.