Pavlovian Classical Conditioning

Pavlovian Classical Conditioning refers to a learning procedure in which a biologically potent stimulus (e.g. food) is paired with a previously neutral stimulus (e.g. a bell). It also refers to the learning process that results from this pairing, through which the neutral stimulus comes to elicit a response (e.g. salivation) that is usually similar to the one elicited by the potent stimulus. These basic facts, which require many qualifications, were first studied in detail by Ivan Pavlov through experiments with dogs. Together with operant conditioning, classical conditioning became the foundation of behaviorism, a school of Psychology which was dominant in the mid-20th century and is still an important influence on the practice of psychological therapy and the study of animal behavior. Classical conditioning is the basic learning process, and its neural substrates are now beginning to be understood.

Classical conditioning occurs when a conditioned stimulus is paired with an unconditioned stimulus. Usually, the conditioned stimulus (CS) is a neutral stimulus (e.g., the sound of a tuning fork), the unconditioned stimulus (US) is biologically potent (e.g., the taste of food) and the unconditioned response (UR) to the unconditioned stimulus is an unlearned reflex response (e.g., salivation). After pairing is repeated (some learning may occur after only one pairing), the organism exhibits a conditioned response (CR) to the conditioned stimulus when the conditioned stimulus is presented alone. The conditioned response is usually similar to the unconditioned response (see below), but unlike the unconditioned response, it must be acquired through experience and is relatively impermanent.In classical conditioning, the conditioned stimulus is not simply connected to the unconditioned response; the conditioned response usually differs in some way from the unconditioned response, sometimes significantly.

Little Albert Experiment
The Little Albert experiment was a controlled experiment showing empirical evidence of classical conditioning in humans and operant conditioning in humans. The study also provides an example of stimulus generalization. It was carried out by John B. Watson and his graduate student, Rosalie Rayner, at Johns Hopkins University. The results were first published in the February 1920 issue of the Journal of Experimental Psychology.

After observing children in the field, Watson hypothesized that the fearful response of children to loud noises is an innate unconditioned response. He wanted to test the notion that by following the principles of the procedure now known as "classical conditioning", he could use this unconditioned response to condition a child to fear a distinctive stimulus that normally would not be feared by a child (in this case, furry objects).