What term describes a stimulus in the presence of which a given behavior has not produced reinforcement in the past?

• A. Stimulus Delta
• B. Discriminative Stimulus
• C. Motivating Operation
• D. Establishing Operation

Answer: (A)

A stimulus delta is a signal that reinforcement will not follow a given behavior in its presence. This means the organism learns to withhold the response when that stimulus is present because the past history shows no reinforcement for that behavior in that context. For example, if pressing a lever never produces food when a particular light is on, that light functions as an SΔ for lever pressing. This differs from a discriminative stimulus, which signals that reinforcement is available for the behavior. The other terms describe changing the value or effectiveness of reinforcement rather than marking a specific context where reinforcement has not occurred, so they don’t fit the definition as precisely.