What happens when the conditioned stimulus is presented repeatedly without reinforcement?

When the conditioned stimulus is presented repeatedly without reinforcement, extinction occurs. In classical conditioning, extinction happens when the association between the conditioned stimulus and unconditioned stimulus is weakened or eliminated. This process takes place when the conditioned stimulus is presented alone, leading to a decrease in the conditioned response over time.

For example, if a dog has been conditioned to salivate at the sound of a bell because it has been repeatedly paired with food, but then the bell is rung multiple times without presenting food, the dog will eventually stop salivating at the sound of the bell. This indicates that the expectation of food has diminished, demonstrating extinction of the learned response.

In contrast to extinction, concepts like generalization and discrimination relate to the responses to different stimuli rather than the weakening of an association, while habituation involves a decrease in response to a stimulus after repeated exposure, but it is not the result of a learned association being broken. Thus, the phenomenon described in the question aligns clearly with the concept of extinction.