In classical conditioning, when is learning evident?

In classical conditioning, learning is evident when a previously neutral stimulus begins to elicit a response after being paired with an unconditioned stimulus. This process highlights how associative learning occurs; the neutral stimulus transforms into a conditioned stimulus capable of producing a conditioned response. For example, if a bell (initially a neutral stimulus) is rung before food (an unconditioned stimulus) is presented to a dog, after several pairings, the dog will begin to salivate (conditioned response) at the sound of the bell alone. This shift showcases the learning that has taken place through association, which is fundamental to classical conditioning.

The other options do not accurately capture the essence of learning in this context. Ignoring a neutral response does not signify learning; instead, it indicates that no association has been made. Similarly, simply eliciting a response by a new stimulus does not necessarily reflect the learned association expected in classical conditioning, as the response could be based on other variables. Finally, the absence of unconditioned stimuli does not, by itself, demonstrate learning; it may simply reflect a lack of reinforcement for the associative behavior.