Final answer:
Stimulus discrimination occurs in classical conditioning when an organism learns to respond differently to various stimuli that are similar.
Step-by-step explanation:
In classical conditioning, stimulus discrimination occurs when two stimuli are clearly different and one brings on a conditioned response but the other one does not. This means that the organism has learned to respond differently to various stimuli that are similar.
For example, in Pavlov's experiments with dogs, the dogs discriminated between the basic tone that sounded before they were fed and other tones, because the other sounds did not predict the arrival of food. Similarly, a cat named Tiger discriminated between the sound of the can opener and the sound of the electric mixer, not coming to the kitchen for food when the electric mixer was going. The ability to discriminate between stimuli is important for animals and humans to respond appropriately to different situations.