 Hey everyone, welcome back. It's Veronica Howard. So this time around we're going to talk about differential reinforcement. Differential reinforcement is one of those really foundational principles of behavior and when we're talking about changing the rates of behavior, especially changing the rates of behavior relative to one another, when we're looking at two different responses and trying to maybe increase one or decrease one with respect to the level of the other, typically we're talking about differential reinforcement. So let's talk about some of the very basic vocabulary here. This is just an introduction. When we talk about differential reinforcement we mean it's a procedure involving two or more physically different behaviors. One of those behaviors will be reinforced, the other is going to be extinguished. Now this is Miller's definition, the other behavior is extinguished, but I want you to bear in mind that when we talk about differential reinforcement we could be looking at a combination of reinforcement and extinction, or we could be looking at a combination of reinforcement and another behavior deceleration technique like punishment. What matters is that one behavior is going to be reinforced and another behavior is in some way going to be decreased through extinction or through punishment. That's differential reinforcement. When we're looking at examples of different behaviors what I want you to bear in mind is that when we mean different they can be different in very subtle ways. We mean that you're going to have different muscles involved. It can be very, very simple, very small distinctions. Examples that Miller talks about could be maybe using the same muscles faster or slower. So if I'm trying to teach a person to speak for instance, if I'm trying to teach a person how to have a conversation with other people and they're talking like this in their conversation and I want them to talk a little faster because I'm from the east coast and we talk really fast in the east coast. If I'm trying to increase the speed of their behavior then I'm probably looking at using all the same muscles and apertures of speaking but at different paces, different rates. If I'm trying to get a person maybe to live 20 pounds rather than 15 pounds, same muscles, different strengths, different requirements. It can be also small in terms of subtle differences and where are you moving your body? Where are those muscles going? Am I maybe moving my arm over here versus over there? Using muscles in slightly different ways can be an example of this and this is something that coaches, like physical sport coaches often do and it can be things like pronouncing things in a slightly different way. I'm going to post a link to some optional materials about looking at different accents. This is one of my favorite things to look at. Looking at different ways that people pronounce things is an example of differential reinforcement because it's again, it's all the same muscles and all the same aperture of your mouth and how you produce sound but those subtle differences are just pronouncing them in slightly different ways, maybe moving the tongue to one side or another. This is differential reinforcement. Other things that we would not consider differential reinforcement will come back to. Things you want to look for are things like are you reinforcing one behavior and not reinforcing other behaviors, physically different behaviors. This can be not reinforcing in terms of extinction. This could be placing it on a punishment schedule. Are you decreasing another response? But always be looking carefully. Make sure that you don't have a situation where you're talking about behavior in different places, different contexts or different times with different people because context differences, teaching you to raise your hand in one class but not raise your hand in another class, that's a different procedure. Teaching people to do stuff in the presence of one person and not another person is the same behavior. It's just different contexts and that's a different procedure we're going to learn later in the course. That distinction is important because the way you go about teaching them are different. Let's look at some examples. If you see a scenario where one behavior, this is indicated on screen with the behavior superscript one or B1, one behavior is contacting reinforcement and the rate of that behavior increases. The other behavior is contacting no reinforcement. The rate of that behavior decreases relative to the other. Is this differential reinforcement? I would say yes. This is an example. This is a perfect textbook Miller example of differential reinforcement. Let's do one that's maybe a little harder. If you've got one behavior contacting reinforcement and that behavior increases but behavior two contacts no reinforcement and remains unchanged, is this differential reinforcement? I would actually say yes. This is differential reinforcement as well because what we're looking for is a relative increase of one behavior compared to another. That can be reinforcing one behavior seeing that increase but this remains unchanged. It can be this behavior continues to be reinforced but the other decreases in the rate of reinforcement so that rate decreases. Differential reinforcement can look like a lot of different things. Let's move on. Looking at another example, like I said, behavior one is contacting reinforcement but we see that that behavior remains unchanged in its rate but behavior two is no longer reinforced and we see a decrease in the rate of responding. Is this differential reinforcement? Again, I say yes because one behavior is increasing relative to another or one behavior is maintaining while another decreases. Again, we're just looking at relative changes in the rate of response to the other behavior as a result of differential reinforcement. That is a little confusing so go back and watch that again if you're having any difficulty. What we're looking for is when a behavior is reinforced, do we see an increase relative to another or when a behavior is decreased, do we see that drop in rate relative to another that maintains? All of these can be differential reinforcement. Like I said, we also have another procedure that's not differential reinforcement. We're going to learn it in Unit 3 where we look at behaviors happening in different places, different contexts, different times with different people, different locations. For example, maybe I reinforce an employee for clocking in at 7.55 but don't reinforce them for clocking in at 8.10. This is not differential reinforcement because the behavior of clocking in whether that's with a touch pad or using the old punch card system, these are not different behaviors. They're just occurring at different times, different contexts. We haven't learned this yet. We're going to come back to that Unit 3. This has just been a very brief introduction to differential reinforcement. I really encourage you to check out some of the other videos that we're going to talk about in this unit, especially matching law, other examples of differential reinforcement. Let me know if you guys have any questions.