What does spontaneous recovery refer to in classical conditioning?

Spontaneous recovery in classical conditioning refers to the sudden reappearance of an extinguished conditioned response after a period of rest following extinction. When a conditioned response has been extinguished, the subject no longer exhibits that response to the conditioned stimulus. However, after some time has passed without any exposure to the conditioned stimulus, the conditioned response may unexpectedly return when the stimulus is presented again.

This phenomenon suggests that extinction does not completely erase the learned associations; rather, it suppresses the conditioned response, which can later resurface. This highlights the complex nature of learning processes, emphasizing that memories and learned behaviors may still linger even after they seem to have been removed.

The other options represent different concepts in learning and conditioning, such as the initial phase of learning, a gradual decrease in responses, and observational learning, but they do not capture the essence of spontaneous recovery.