 All right, everybody, let's talk about matching law. Matching law is actually pretty complex. It's one of the more advanced basic conceptual foundations of behaviorism. If you come back and you take the RAT lab or if you take a more advanced course in behavior analysis, we will be coming back to talking about matching law. But essentially what we're looking at here is a way of quantifying responses, a way of showing that behavior will change relative to the amount of reinforcement available to it. Essentially what I'm showing you on screen here on the left is an example of Hernstein's matching law. It shows that when you have different behaviors and different rates of reinforcement, you can see that different rates of responses occur. The graph here is showing you that if you have perfect matching and you have two different responses, each of which have a level of reinforcement available that if you perfectly allocate your responding to the amount of reinforcement available, you have what's called matching. You match the amount of reinforcement or you match your responses to the amount of reinforcement available. That's pretty confusing. We make it a little bit easier. Think about a simple creature, rat, pigeon in an operant chamber. Say they're presented with what I'm showing you on here is a photo of two different levers and they can press the left lever, which is on what's called a fixed ratio five schedule or it means that for every five times they press that lever. They're gonna earn a reinforcer versus an FR25 schedule, which means that every 25 times they press that lever, they're gonna earn a reinforcer. Now, you can see one lever, the left lever, the FR5 lever is gonna pay off after you press the lever five times. The other lever, the FR25 lever, pays off if you press it 25 times, which means you have to work five times as hard to get the same reinforcer. So where's responding gonna go? Which lever is the organism gonna push? Well, you might be inclined to say they're only gonna press the left lever. That's actually false. What's interesting, again, going back to Hernstein's matching law, this equation that I'm showing you on screen and what we know from basic experimental literature is the organism is gonna press both levers. But what you're gonna see is five times as much responding on the left lever as you see on the right lever. You're gonna see five times more work here on the left side where it pays off really well. You're still gonna see some responses on the right lever, but about five times as few, because again, it requires five times as much work to pay off. And this has all been very complex and very difficult and like, why are we even talking about this? Well, the reason that we're talking about this is because when you're using differential reinforcement clinically, you have to understand matching law and you have to understand this adage that behavior goes where reinforcement flows. What that means is if you want one behavior to increase, you have to make that behavior pay off a lot better, a lot faster, a lot bigger. You have to make the reinforcer for that behavior bigger compared to everything else that the organism could be doing, right? Let's think about this from a simple differential reinforcement using extinction to try to decrease the rate of a response kind of paradigm. If you have a learner, if you have a client, if you have a loved one, if you have someone that you're trying to decrease the rate of a response and you want that rate of the response to be zero, well, what are you gonna do? How do you make sure that the levers are paying off? Well, you wanna make sure that one lever, one behavior doesn't contact reinforcement. You wanna make sure that you are using extinction with fidelity on that one lever. Whatever the target behavior is, you're trying to decrease, do not reinforce it. No way, no how, never. And you wanna make sure the other lever is gonna pay off. In fact, pay off well. You especially wanted to pay off well if this is a new behavior, the person's never done it before, or if they have a long history with that problem behavior that you're not reinforcing anymore. So you have to make sure that the lever on the left, the problem behavior, that it doesn't pay off. And you want that lever on the right, the new behavior, the harder behavior, the brand new thing we're trying to teach to replace the behavior that it pays off like gangbusters that it is easier or faster or produces more reinforcement than that old problem behavior we're trying to decrease. I want you to know about matching law because this is one of the foundational principles that many applied behavior analysts don't understand very well. And behavior goes where the reinforcement flows. So if you wanna make sure that your client is engaging in the desirable behavior, the replacement behavior that you're trying to get an increase in to decrease another different undesirable behavior, you wanna make sure you're paying it off but you also wanna make sure you're paying it off well because this is very simple, very basic foundational understanding of human behavior. So let me know if you guys have any questions about this and I look forward to seeing you guys next time.