After conditioning has taken place, the salivation exhibited by a dog in…

Concept

In classical conditioning a stimulus that at first evokes no relevant reaction — the neutral stimulus — is repeatedly paired with an unconditioned stimulus, which naturally evokes an unconditioned response. After enough pairings the once-neutral stimulus becomes a conditioned stimulus, and the reaction that this learned signal now evokes on its own is called the conditioned response.

Application

Mapping Pavlov's experiment onto those four terms:

1. Food placed before the dog is the unconditioned stimulus, and the salivation it triggers is the unconditioned response; neither one needs any training.

2. Before training the bell is the neutral stimulus: by itself it produces no salivation.

3. The bell is sounded and food follows, trial after trial, until the dog learns the association and the bell becomes the conditioned stimulus.

4. Once conditioning is complete the bell alone makes the dog salivate. That salivation is produced by a learned signal rather than by food, so it is the conditioned response.

Cross-check

The stem supplies both markers of a learned reaction — "after conditioning has taken place" and "in the absence of food" — which separates it from the innate reaction and from the pre-training vocabulary:

• Unconditioned response: in this experiment it is the salivation elicited directly by food placed in the mouth; it appears without any training, so with no food present there is no unconditioned stimulus here to elicit it.

• Involuntary reflex: the general name for an innate reflex arc such as blinking or the knee-jerk, which is wired in rather than built up by pairing.

• Neutral response: "neutral" is applied to the stimulus during the pre-training phase; it is not a category of response in this framework.

Result

The salivation a conditioned dog shows to the bell alone is the conditioned response.