Summary: Stimulus control is the goal of nearly every acquisition program: the learner does the right thing in the presence of the right cue, and not otherwise. This page covers the SD and the S-delta, how discrimination training establishes the difference, why targets are rotated randomly and positions counterbalanced, and the failure mode that costs more programs than any other, which is a learner who scores 95% while attending to something you never meant to teach.
Every program in this section ends in the same place. It is not enough that the learner can do the skill. They have to do it when the situation calls for it, and not when it does not. A learner who says "dog" to every animal has not learned to tact a dog. A learner who washes their hands beautifully but only when you say the full verbal prompt has not learned to wash their hands.
That is what stimulus control means, and building it deliberately is what discrimination training is.
What stimulus control actually is
A behavior is under stimulus control when it reliably occurs in the presence of a specific stimulus and not in the presence of others.
Both halves matter, and the second half is the one people forget. Responding in the presence of the cue is easy to see and easy to celebrate. Not responding in the absence of the cue is the part that proves the learner has actually discriminated anything.
That's the free preview of Stimulus Control and Discrimination Training. The complete guide, plus all 851 practice questions and 3 full exams, is in the study pack and the book.