3.5 Classical Conditioning

The basics of classical conditioning

Classical conditioning is a form of learning discovered by Ivan Pavlov where a neutral stimulus becomes associated with a meaningful stimulus. A neutral stimulus (NS) naturally produces no response, but after repeated pairing with an unconditioned stimulus (UCS) (which triggers an automatic unconditioned response, UCR), it becomes a conditioned stimulus (CS) that triggers a learned conditioned response (CR).

Key processes

Acquisition is the initial learning of the CS–UCS link. Extinction occurs when the CS is repeatedly presented without the UCS, weakening the CR. Spontaneous recovery is the reappearance of an extinguished CR after a rest period. Generalization occurs when stimuli similar to the CS trigger the CR, while discrimination is learning to distinguish between the CS and other similar stimuli.

Real-world relevance

Pavlov's dogs salivated (CR) to a bell (CS) after it was paired with food (UCS). Higher-order conditioning occurs when a CS is paired with a new neutral stimulus to create a second CS. Classical conditioning explains phenomena like taste aversions, phobias, and advertising associations, and applies to involuntary, reflexive behaviors.

Key terms

Classical conditioning

Learning process where a neutral stimulus becomes associated with a meaningful stimulus, eventually eliciting a similar response.

Unconditioned stimulus (UCS) vs. Unconditioned response (UCR)

UCS naturally triggers a response (UCR) without learning, e.g., food (UCS) causes salivation (UCR).

Conditioned stimulus (CS) vs. Conditioned response (CR)

CS is a previously neutral stimulus that, after pairing with a UCS, triggers a learned response (CR).

Extinction vs. Spontaneous recovery

Extinction: CR fades when CS is presented without UCS. Spontaneous recovery: CR reappears after a rest period.

Generalization vs. Discrimination

Generalization: responding to stimuli similar to CS. Discrimination: responding only to the exact CS, not similar ones.

Try an AP-style question

In classical conditioning terms, the dog was the…

1. reinforcer
2. conditioned stimulus
3. unconditioned response
4. unconditioned stimulus