Stimulusย Discriminationย occurs when an organism learns to respond differently to two or more stimuli based on whether reinforcement is available. In this process, aย discriminative stimulus (SD)ย signals the availability of reinforcement, while the absence of the SD, or the presence of anย S-delta (Sโ), signals that reinforcement is not available.
Example
A student raises their hand in class (SD) because they know the teacher will call on them and provide attention (reinforcement). However, when the teacher is not in the room (S-delta), raising their hand will not result in attention, so theย behaviorย of hand-raising decreases in that situation. This showsย stimulusย discrimination between when the teacher is present versus absent.