 Again, we've already talked about this. The discriminative stimulus doesn't actually control our behavior, right? It's the stimulus that signals that a reinforcer is available for a particular response. And that stimulus changes, you know, again, that stimulus can signal that one behavior is going to get reinforced. It can signal that a different behavior is going to get reinforced. It can signal about what types of reinforcers are available. It can do all sorts of things, but just remember that it's just a signal. It just tells you what's going to get reinforced. It's not like classical conditioning. In classical conditioning, the initial S, the stimulus, pulls a response out of you. It causes a reflex, right? This isn't a reflex. This is voluntary behavior. So when we think about voluntary behavior, this is how we think about it. We think about it in this three-term contingency. So the SD isn't what's actually controlling your behavior. Even though we call it stimulus control, it's not what's controlling your behavior, right? It's just a signal to say that a particular response is going to be reinforced at this time. There's other ways to look at this thing, right? We've got the S-delta stuff now. S-delta's are kind of confusing to get your head around, but here's the basic idea. They indicate that no reinforcement is available for a given behavior. It doesn't signal that punishment is available. Signals that extinction is coming, right? So S-delta's are kind of hard to think about, but I've got an example on the next page. Again, the idea is that now the stimulus is signaling, not that reinforcement is available, but signaling that extinction is going to happen. In the operant chamber, with rats and pigeons, this is pretty easy to establish because you take an S-delta, you put a signal on the wall that says any response now is not going to be reinforced. It's that simple, but in the real world, it's a little different. You can think of a broken pot machine, and so somebody sticks a sign on the soda machine that says this machine is broken. So any response that you do on that machine, you put money into it or hit the button or whatever, it's not going to get reinforced. So that sign is a signal. That's an S-delta to say that a response here is not going to get you a reinforcer. It's going to get you extinction, and that's not a good thing. So any of those signs that may signal something like that are S-delta's. Let me think of another one here. Oh, like a sign on a store, if the open sign is off, that's an S-delta to say that coming to this store is going to be extinguished. You're not going to get a reinforcer for it. There's no one's going to be here. You can't open the door, so on and so forth. So let's look at how this stuff interacts in multiple situations here. So we're going to look at both S-d's and S-delta's, and we're going to look at two different behaviors to see that sort of interaction between the behavior manager and the person that's having their behavior managed. And the idea is that the behavior manager also is getting reinforced and punished for what they're doing. So let's take a look at it here. You've got the behavior of the child, and you've got the behavior of the teacher. We're going to focus on the child first. So again, a given stimulus can serve as both, so this, an example of this whole thing, plus it's also showing you how one stimulus can mean different things depending on what's going on, even in the same context. So a given stimulus can serve as both for different behaviors in the same context. Here we go. So it's both meaning a S-delta and an S-d. So here's the first one. Look at me. All right? So there's your S-delta. It's a command. Child looks at the person. Person says, thank you. So the teacher says, thank you. I get reinforced for it. That's the behavior of the kid. Now let's see how that interacts with the behavior of the adult. So the behavior of the teacher is going to be influenced by this correction. So the kiddo fails to look. That's the result. So the child looked at the floor. So the child fails to look. So that's a discriminative stimulus to the teacher to model the appropriate behavior. So now the kid has failed to look. Now the teacher is doing this corrective procedure. So now they're going to model the appropriate behavior and the child imitates. So there is the reinforcer for the particular modeling. So you can see now that the teacher and the child are interacting with each other. So the child was the behavior of looking at the floor was extinguished, or at least it's put on extinctions, probably not gone completely. It's only one try. So again, so if we start that S-delta line, you say, look at me. Child looked at the floor. All right? No reinforcement is available. And the teacher starts a corrective procedure. So the consequence for the child is also a discriminative stimulus for the teacher to model the appropriate behavior. So then the teacher goes and does the modeling. And that is likely reinforced by the child actually imitating what the teacher did. So then you've got this sort of positive cycle that's all interacting with itself.