Classical Conditioning

Classical Conditioning

Classical conditioning is a type of learning in which a stimulus acquires the capacity to evoke a reflexive response that was originally evoked by another stimulus. As experimented by Ivan Pavlov, classical conditioning can be exemplified by the classic example of a dog’s salvation by associating food with a particular noise.

PHASE 1: Before Conditioning

The neutral stimulus (NS) in this example would be the bell’s tone because it does not invoke a response from the dog. Initially, the NS has no relation or way of associating food to the bell. Therefore, there is no salivation response when the dog hears the bell. On the other hand, the unconditioned stimulus (UCS), the food, directly results in the unconditioned response (UCR), the natural response of the dog salivating.

  • NS ⇨ no response (bell)
  • UCS (food) ⇨ UCR (salivation): natural reflex


PHASE 2: Acquisition (the unconditioned stimulus (UCS) and conditioned stimulus (CS) are paired repeatedly).

In phase two, the NS begins to transform into the conditioned stimulus (CS) because it is presented with the UCS (food). The dog is now associating that the particular tone is heard when he or she is receiving food, which then the dog elicits the natural UCR response (salivate).

  • NS (bell) ⇨ UCS (food) ⇨ UCR (salivation)
  • Pairing NS with UCR


PHASE 3: After Conditioning

Because the dog is reinforced by consistently hearing the tone with the food, the tone itself will result in salvation for food. Ultimaitely, the NS becomes the CS and causes the learned or reflexive Conditioned Response (CR) of salivating.

  • NS becomes CS: CS ⇨ CR


See Also



John B. Watson

Ivan Pavlov


Operant Conditioning



Dyce, J. (2008, July 24). Power Point: Principles of Behavior Change. Retrieved from: