Definition: In classical conditioning, a previously neutral stimulus that comes to elicit the conditioned response. Customarily, in a conditioning experiment, the neutral stimulus is called a conditioned stimulus when it is first paired with an unconditioned stimulus.

Quite Simply...


  • It is a conditioned stimulus only during the acquisition period (during conditioning).
  • The formerly neutral stimulus becomes the conditioned stimulus.
  • Stimulus previously listed as the neutral stimulus, produces conditioned response after training.
  • Something that was neutral becomes a conditioned stimulus.

Examples of Conditioned Stimulus (CS)...


  • When someone is calling for their dog, they may ring a bell (CS) for the dog to respond and come (CR).
  • The smell of your favorite food is the (US) and if a sound is made every time you smell it, then that sound will become the (CS).
  • The random word in the Lemon Powder Day experiment originally did not produce the UCR of salivation until the experiment was performed, where the random word became the CS by causing salivation (CR).
  • You walk home the same route everyday, you get attacked by a dog on your normal route (US), now when you walk by the place you were attacked (CS) you become paranoid (CR).

See Also


  • Pavlov - experimenter
  • Behavioral Learning - forms of learning that can be described in terms of stimuli and responses
  • Classical Conditioning - form of behavioral learning in which a previously neutral stimulus acquires the power to elicit the same innate reflex produced by another stimulus
  • Lemon Powder Day - students get cups with lemon powder in them and pick a cue word, and when the cue word is said students must stick their finger in the lemon powder and put their finger in their mouth as quickly as possible
  • Aquisition Period - The initial learning stage in classical conditioning, during which the conditioned response comes to be elicited by the conditioned stimulus

Additional Resources


  1. http://psychology.about.com/od/cindex/g/condstim.htm