Final answer:
Dogs salivating to a dim light after being conditioned to salivate to a bright light exhibit stimulus generalization, where they respond to similar stimuli as they would to the original conditioned stimulus.
Step-by-step explanation:
When dogs that have learned to salivate at the sight of a bright light also salivate when a dim light is shown, this is an example of stimulus generalization. This means they are showing the conditioned response to stimuli that are similar to the conditioned stimulus. In contrast, stimulus discrimination would occur if the dogs learned to respond only to the specific bright light associated with food and not to other similar stimuli. Extinction would be observed if the dogs stopped salivating to the light after repeated presentations without food. Spontaneous recovery can occur after a conditioned response has been extinguished and then, following a rest period, the response suddenly reappears when the conditioned stimulus is presented again.