What is the term for a stimulus that initially does not trigger a response?

The term for a stimulus that initially does not trigger a response is known as the conditioned stimulus. In classical conditioning, a conditioned stimulus is paired with an unconditioned stimulus to elicit a conditioned response over time. For instance, if a neutral stimulus, such as the sound of a bell, is consistently associated with the presentation of food (the unconditioned stimulus), it can eventually provoke a response, such as salivation, from the subject even when the food is not present. This transformation highlights the learning process, where the previously neutral or non-responsive stimulus gains the ability to elicit a response after conditioning.

The other terms have distinct meanings in the context of conditioning and learning. An unconditioned stimulus naturally triggers a response without prior learning, while an unconditioned response is the reflexive reaction to the unconditioned stimulus. Reinforcement, on the other hand, refers to any stimulus that strengthens or increases the likelihood of a behavior, rather than being a stimulus that initially does not elicit a response. Thus, the role of the conditioned stimulus is pivotal in establishing the basis of learned behaviors through association.