Your discrimination CA: What to watch for

When students don't get the discrimination CA right, very often it's because of what they write in the S^Δ box. In a discrimination situation, the behaver must be able to perceive (thru seeing, hearing, or any of the other senses) the difference between the S^D and the S^Δ BEFORE the target behavior is performed. So make sure you don't describe an S^Δ that the behaver can't perceive as different from the S^D until after the behavior has already been performed. An example of this mistake might be saying that the S^D is an ATM machine that has money in it, the S^Δ is an ATM that's empty, and the target behavior is punching in your code and requesting money. In this situation, the target behavior has to be performed before the behaver knows that the ATM is empty. So an empty ATM can't be an S^Δ in this case.

Think of it this way: In the case of reinforcement-based discrimination, the S^D functions like a signal that if the target behavior is performed, it will be reinforced, and the S^Δ functions like a signal that it won't be. In the case of punishment-based discrimination, the S^D signals that the target behavior will be punished and the S^Δ signals that it won't. And in order for these stimuli to function like signals, the behaver has to be able to perceive the difference between them BEFORE performing the target behavior.