Learning: relatively prominent change in behaviour or knowledge, resulting from experience. Classically conditioned a baby to be afraid of animals by having him play with a rat and banging a gong near him. Classical (pavlovian) conditioning: occurs when 2 different stimuli come to be associated with one another, no action required on part of learner. Operant (instrumental) conditioning: animal of person operates on environment to produce particular results. Classical conditioning: neutral stimulus comes to elicit a reflexive response, becomes associated with a stimulus that already produces that response. Unconditioned stimulus (ucs), unconditioned response (ucr), conditioned stimulus (cs), conditioned response (cr) Acquisition: gradual formation of an association between conditioned and unconditioned stimulus. Cs-ucs pairings lead to increased learning such that the cs can produce the ucs. Extinction: a process in which the conditioned response is weakened when the conditioned stimulus is repeatedly presented without the unconditioned stimulus. If cs presented without ucs, cr eventually extinguishes.