Final answer:
Unlearned response generalization refers to the tendency to respond to stimuli similar to the conditioned stimulus. An example is a dog salivating to similar sounds after being conditioned to salivate to the sound of a bell.
Step-by-step explanation:
In classical conditioning, unlearned response generalization due to physical similarity of responses refers to the tendency of an organism to respond to stimuli that are similar to the conditioned stimulus. For example, if a dog has been conditioned to salivate to the sound of a bell, it may also salivate to similar sounds, such as the ringing of a phone or the chiming of a doorbell.