Alearned association between two stimuli is central to

A learned association between two stimuli is central to classical conditioning.

Explanation:

The term classical conditioning refers to a form of learning in which a biologically potent stimulus is linked with a neutral stimulus, creating a new learned response in an animal or a person. This phenomenon, which has greatly impacted behaviorism, was discovered by Russian psychologist Ivan Pavlov. That's why it's also known as Pavlovian conditioning. Pavlov's experiment included a dog, whose salivation was observed. A dog would receive food and, due to the biological response to food, begin to salivate. Before feeding the dog, Pavlov began introducing a clicking metronome (a neutral stimulus), and after a few repetitions, just the sound of the metronome was enough to cause salivation, which is, in this case, a conditioned response. The metronome became a conditioned stimulus. This shows that the dog learned a new behavior.