Pavlov's Experiments

Core Terms & Definitions

Classical conditioning is learning to associate two events that happen together.

  • Neutral Stimulus (NS): A sight or sound that normally triggers no reaction (e.g., a tone, a light, or onion breath).

  • Unconditioned Stimulus (US): Something that automatically/naturally triggers a response without training (e.g., food or a kiss).

  • Unconditioned Response (UR): The natural, automatic reaction to a US (e.g., drooling when eating, sexual arousal).

  • Conditioned Stimulus (CS): A previously neutral stimulus that now triggers a response after being paired with a US (e.g., tone signaling food).

  • Conditioned Response (CR): The learned reaction to the CS (e.g., drooling just from hearing the tone).

Quick Memory Trick:

  • Unconditioned = Unlearned / Automatic

  • Conditioned = Learned / Trained

Pavlov’s Famous Dog Experiment

Ivan Pavlov discovered classical conditioning while studying dogs' digestion.

  1. Before Conditioning:

    • Food (US) Drooling (UR).

    • Tone (NS) No drooling.

  2. During Conditioning:

    • Tone (NS) played right before giving food (US).

  3. After Conditioning:

    • Tone (CS) alone Drooling (CR).

The 5 Key Processes of Conditioning

1. Acquisition (The Learning Phase)

  • What it is: The initial stage when a link is formed between the NS and the US.

  • Timing matters: The neutral stimulus must come shortly before the unconditioned stimulus (usually within half a second) for the brain to connect them.

  • Purpose: Helps animals survive and reproduce by reacting to cues about food, danger, and mates.

2. Extinction (Fading Away)

  • What it is: The gradual weakening of the learned response (CR) when the CS keeps happening without the US.

  • Example: Playing the tone repeatedly without giving food causes the dog to stop drooling.

3. Spontaneous Recovery (Reappearing)

  • What it is: The sudden return of a weakened learned response (CR) after a rest period.

  • Key Takeaway: Extinction doesn't erase the learned link entirely—it just suppresses it.

4. Generalization (Reacting to Similar Things)

  • What it is: Responding to new stimuli that are similar to the original conditioned stimulus (CS).

  • Examples:

    • A dog conditioned to drool to a specific tone also drools slightly to a similar-sounding tone.

    • A child scared by a moving car becomes afraid of trucks and motorcycles.

5. Discrimination (Telling Things Apart)

  • What it is: The learned ability to distinguish between the target stimulus (CS) and other irrelevant stimuli.

  • Examples:

    • Facial recognition software identifying your specific face while rejecting faces that look similar.

    • Feeling your heart race when facing a guard dog, but feeling calm near a guide dog.