What is classical conditioning in psychology?

Definition

Classical conditioning is a learning process first described by Ivan Pavlov. It occurs when a neutral stimulus becomes associated with a meaningful stimulus, eventually eliciting a similar response. In essence, an organism learns to connect two stimuli so that the first predicts the second.

• Unconditioned stimulus (US): Naturally elicits a response (e.g., food).
• Unconditioned response (UR): Natural reaction to the US (e.g., salivation).
• Neutral stimulus (NS): Does not elicit the response initially (e.g., bell).
• Conditioned stimulus (CS): Previously neutral, now triggers response after association (e.g., bell after pairing with food).
• Conditioned response (CR): Learned response to the CS (e.g., salivation to bell).

Worked Example: Pavlov's Dogs

Step 1: Before Conditioning

• Food (US) $\rightarrow$ Salivation (UR)
• Bell (NS) $\rightarrow$ No salivation

Step 2: During Conditioning

• Bell (NS) + Food (US) $\rightarrow$ Salivation (UR)
• This pairing is repeated several times.

Step 3: After Conditioning

• Bell (now CS) $\rightarrow$ Salivation (now CR)

Summary Table:

Stimulus	Response
Food (US)	Salivation (UR)
Bell (NS)	No response
Bell (CS)	Salivation (CR)

Mathematical Representation:

If $NS + US xrightarrow{\text{repeated pairings}} UR$, then $NS \to CS$ and $CS \to CR$.

Takeaways

• Classical conditioning links a neutral stimulus to a reflexive response through association.
• Repeated pairings are necessary for the neutral stimulus to become conditioned.
• This process explains many learned behaviors, from phobias to advertising effects.