Behavioral Interventions- Differential Reinforcement Page 1

Behavioral Interventions-Differential Reinforcement Page | 1

Behavioral Interventions

Differential Reinforcement

Differential Reinforcement: Introduction

Differential reinforcement is probably the most fundamental and most important principle in applied behavior analysis (ABA). Interestingly, it is also one of the most misapplied. These lectures will point out why differential reinforcement is basic to understanding ABA, how it is often misapplied, and provide examples of how parents, teachers and others can use it to effectively construct and support learning among students with autism spectrum disorders (ASD).

Differential Reinforcement – What Is It?

It’s better to shape up the behavior than to ship out the student.

Let’s begin with an example.

Dana is a 12-year-old student with Asperger Syndrome attending the seventh grade at East Middle School. Mr. Rollins, has developed a strategy to support Dana’s learning in his science classroom. Each time Dana walks away from her group at the lab table, Mr. Rollins will escort Dana back to the group.Each time Dana is working with her lab mates, she will receive a coupon that she can “cash in” after class for a technology magazine she likes.

The purpose of his is to teach Dana to discriminate when she will receive reinforcement (that is, the coupon) and when she will not. Mr. Rollins is using a strategy called differential reinforcement. That is Dana will learn to tell the difference (will discriminate) between which behaviors will get reinforcement and which behaviors will not.

Differential reinforcement means that reinforcement is provided for behaviors when these behaviors occur at certain times and places, whereas reinforcement is not provided when the behaviors do not occur during other times and places (Wolery & Fleming, in Bailey & Wolery, 1992). In our example above, Dana received differential reinforcement when she was working with her lab mates, but no reinforcement during the times when she was away from her lab mates.

Differential Reinforcement – Basic Principles

Introduction

Alan is 11 years old and attends Ridgewood Middle School. Although he likes science, he has difficulty staying with his group and working on the lab assignments. In fact, Alan generally has a lot of difficulty interacting with his peers throughout the day. His individualized education plan (IEP) states “Alan needs to learn how to initiate and maintain conversation with his peers.” This lesson will demonstrate a possible strategy to support Alan in these interactions.

1. What is differential reinforcement?

A basic principle in understanding differential reinforcement and how we learn in most situations is the concept of discrimination. Basically, discrimination is a process for behaving one way in one situation and behaving in a completely different way in another situation. Like the example in Lesson 1 with Dana at East Middle School, discrimination involves understanding that certain things and events occur in some situations (Dana receives a coupon only when she is with her group) but do not occur in other situations (Dana does not receive a coupon when she is not with her group). Thus discrimination is the ability to tell the difference between environmental events (Alberto & Troutman, 1995).

Discrimination typically develops as a result of differential reinforcement. Most of the behaviors we demonstrate in our daily lives are the result of differential reinforcement. We stop our car at red lights and proceed through the intersection on green lights; we grab our umbrella before going outside in the rain; we answer the phone when it is ringing; we initiate conversation with those whom we wish to talk, and so on. Differential reinforcement is making the discrimination regarding when reinforcement will be obtained (i.e., proceeding safely through an intersection at a green light; remaining dry when we use an umbrella when its raining, etc.) and when reinforcement will not be obtained (i.e., having an accident in the intersection if we proceed through it on a red light, getting drenched if you forget your umbrella, etc.). Reinforcement for Dana was in the form of coupons when she was working with her group. She only received the coupons when she was working with her group..

In the example of Alan and his reluctance to engage his peer in conversation, we are going to use a differential reinforcement procedure. Unlike Dana who received her coupons simply for “working” with her peers (e.g., no specific behaviors were identified), Alan will receive reinforcement (he will receive checkmarks as it has already been determined they are important to him) only when he is engaged in specific conversation with his peers. That is, whenever Alan is talking with his peers about the science lesson, he will receive a checkmark from his teacher. When he is not in conversation with his peers (or the conversation is not about science), he will not receive a checkmark.

The purpose of this procedure is to teach Alan what behaviors are “appropriate” and what behaviors are not; that is, when he will receive his checkmark and when he will not. In the case of the science group, the IEP determined that talking with his peers during the lab assignment is an appropriate behavior. Thus, “talking with his peers during the lab assignment” has been targeted as a specific behavior that will receive reinforcement. Unlike in Dana’s situation where any behavior involving “working with her group” would receive reinforcement, in Alan’s case only the specific behavior of talking with his lab mates would receive reinforcement.

In both situations, reinforcement was provided only when certain behaviors were performed and not provided at other times when those behaviors were not performed. For example, whenever Dana was away from her group, she received no reinforcement. Whenever Alan was not talking with his lab mates, he received no checkmarks. Conversely, whenever Dana was with her peers and working together on the assignment, she received her coupon. When Alan was talking with his peers about the lab assignment, he received his checkmark.

The teachers in both classrooms had to set up a data collection system that monitored when each student received reinforcement. In the two examples, each time the teacher saw the student engaged in the desired behaviors, he would simply record on a piece of paper that the reinforcement was given. Similarly, whenever the students engaged in the undesired behaviors (walking away from the group or not engaging peers in conversation), the teacher would record this on the same piece of paper.

What could go wrong?

When using differential reinforcement, it is vitally important to understand some very fundamental things. First, it is important to have identified several reinforcers for the student (see earlier lesson on Determining Reinforcers). Second, it is important to have identified the behaviors you want to reinforce. In Alan’s situation, the behavior of “talking with his peers during a lab assignment” had already been identified in his IEP. For Dana, “working with her peers” was likewise defined earlier. In both cases, the teachers knew under what conditions reinforcement would be provided, and under what conditions it would not be provided. Third, it is important to identify how frequently the reinforcement will be provided. This is an important decision, since a too frequent use of reinforcement will result in the student getting tired of the reinforcement (satiation). In later lessons, we will explore the more complicated uses of differential reinforcement.

Differential Reinforcement of Other Behavior (DRO)

In previous section, we cautioned that the too frequent use of reinforcement may lead to growing tired of the reinforcement, resulting in a loss of reinforcement effectiveness (a situation known as satiation). In some situations, it does not make sense to give reinforcement every time the desired behavior occurs. Indeed, learning to perform a particular behavior requires that the behavior often be performed in the absence of reinforcement. Thus, a critical aspect of teaching involves arranging a schedule as to when to use of reinforcement and how often. There are three primary methods to do this. This section teaches us about the first one.

Example:

Claire is a 4-year-old child who has a diagnosis of autism. She attends a preschool program operated by the local school district. Every morning, Claire enters the classroom and for the first half hour engages in solitary play with the instructional materials on the floor mat. After about 20 minutes and as the other children are playing, Claire often tries to take the materials the other children are playing with. If they refuse to give them up, Claire hits them. She engages in this behavior of hitting pretty routinely in the mornings. When it happens, Ms. Pucket, her teacher, has to intervene and remove Claire to the other side of the classroom. This angers Claire and causes her to engage in even more severe displays of hitting. Ms. Pucket and the classroom aides don’t know what to do. They have tried giving her other materials. They have tired talking to her. They have even tried having her play in the corner by herself. But Claire is intent on taking the materials away from her peers.

What’s going on here?

In trying to explain Claire’s behavior, It may be that she is interested in her peers and wants to interact with them, but does not have the necessary social skills to do so in a manner that the other children find reinforcing. Or, maybe she does not know how to obtain new materials from the shelves and sees the materials her peers are playing with as “reasonable” choices for her. At this point in our analysis, all we know is (a) what she is doing, (b) how her peers respond, and (c) what the teacher does both prior to and after Claire’s response of hitting.

1. Definition

Differential Reinforcement of Other Behavior (DRO) is a procedure where positive reinforcement is provided only when the target behavior is not displayed for a specified period of time. Thus, when using a DRO procedure, reinforcement is provided for the zero occurrence of the target behavior (it is sometimes also called differential reinforcement of zero rates of behavior.) In future lectures we will discuss differential procedures for the gradual reduction of target behavior. But, in DRO, reinforcement is provided when there is no occurrence of the undesired behavior for a specified period of time.

DRO is perhaps the simplest of all behavior reduction procedures. You are merely reinforcing the absence of any misbehavior. All you do is determine whether or not the undesired target behavior occurred during a specified interval of time. If it occurred, reinforcement is withheld. If the target behavior did not occur, reinforcement is provided at the end of the designated interval. In either case, DRO involves differential delivery of reinforcement for not displaying certain predetermined target behaviors.

There are two advantages of using a DRO procedure:

1. It is easy for teachers to use in most classrooms and school settings.
2. You are working directly with the undesired target behavior by reinforcing its absence.

However, there are also two distinct disadvantages to using a DRO procedure:

1. DRO procedure is not designed to teach and/or increase any particular appropriate behavior. It merely reinforces the absence of certain behaviors.
2. When using a classic DRO procedure, you run the risk of reinforcing undesired behaviors since reinforcement is given at the end of an interval provided that the targeted undesired behavior has not occurred. This leaves you open to reinforcing other types of inappropriate behaviors.

2. Variations when using a DRO procedure

There are at least three variations to keep in mind when using DRO. First, reinforcement is made contingent on the non-occurrence of the target behavior throughout the specified period of time. For example, reinforcement is given only when Claire does not hit her peers during any 8-minute period of time (see #3B below for determining how to specify this interval). In another example, when using DRO for not getting out of his seat, John is told, “If you do not get out of your seat during our English lesson (40 minutes long), you can be at the head of the lunch line.” If the student meets this contingency (if Claire does not hit her peers, or if John does not get out of his seat during English), the reinforcer will be given. Delivery of a reinforcer is made only after no instances of the target behavior occur during the entire interval.

Second, in many instances, it is desirable to break down sessions into smaller intervals of time. For example, it may be desirable to reinforce Claire every 5 minutes for not displaying the target behavior of hitting. Similarly, we may want to reinforce John during the English lesson rather than wait until the end of the period. Or, in the case of Dana in Lecture 1, the teacher provided coupons to Dana (reinforcement) each time he saw her working with her peers during the science lesson. In these situations, it may be wise to provide reinforcement during smaller intervals of time within the period.

Third, the teacher may want to use DRO for completing specified academic work. For example, if a student is completing an in-class writing assignment, the teacher may give a sticker or a happy face on her paper only when it is handed in with no doodles (a pre-determined target behavior).

3. How to use DRO effectively

Although DRO is a relatively simple procedure to use, there are four issues to consider to ensure its effectiveness. All involve how often to schedule reinforcement.

1. Baseline data must be obtained not only to keep track of how often the target behavior is occurring, but also to decide how often the DRO procedure should be scheduled. Selection of a proper time interval is absolutely critical, and should be established by collecting data and not set arbitrarily. During baseline, the time between responses of the undesired behavior is recorded and a slightly smaller interval should be selected to determine when to give the reinforcement.
   For example, Claire’s teacher—Ms. Pucket—collected baseline data for three days. She recorded the time of day when Claire entered the classroom and the time of day when she hit the, on average, Claire went 15 minutes before she hit one of her peers. Thus, the schedule for the DRO was set at every 8 minutes, an interval about half as short as the average baseline level.
2. A criterion for increasing the DRO interval should be established. Suggestions include:
3. Start at a small enough interval so that the student can earn more reinforcement for not engaging in the target behavior than for displaying it. Typically, this interval should be one half as short as the average baseline level.
4. Lengthen the interval over time. This decision should be based upon the data being collected indicating the success the student is having at each interval length.
5. Two other decisions need to be made prior to implementing a DRO:
6. a. Whether to reset the DRO interval following a response occurrence or to wait until the next scheduled interval, and

b. Whether to respond to the undesired behavior in any other way or just ignore it.

In Claire’s situation, the teacher clearly cannot ignore the hitting and, therefore, must respond in some manner. This risk here is that Claire may be obtaining some reinforcement from the teacher’s intervention, thus potentially minimizing the effectiveness of the DRO.

1. As noted above, one limitation of a DRO procedure is that if properly implemented, you may inadvertently reinforce behaviors that are undesirable. For example, Claire may scream first to get the attention of a peer. Or, she may knock over materials that a peer was playing with. In either case, so long as she did not hit a peer, Claire would receive reinforcement at the end of the specified interval. Thus, a fourth rule may apply.
2. A decision must be reached before the intervention is begun that outlines whether reinforcement will be given regardless of which behaviors (other than the target) are displayed, or whether reinforcement will be withheld when certain other inappropriate behaviors occur during the interval.

In the above example, it may be determined ahead of time that any aggressive behaviors will result in the interval being extended without reinforcement (see #3 above). So, if the target behavior is “hitting,” and during the interval Claire pushes her peer, she would not receive reinforcement during that interval. The problem is that Claire may not receive sufficient reinforcement during the interval to allow discrimination to occur as to when and under what condition she will receive reinforcement. Thus, the DRO procedure may lose its effect.

We will address this issue in the next lecture when we talk about using another differential reinforcement procedure. Let us simplify it for Claire and assume that she does not display any other inappropriate behaviors and that a DRO is still an effective intevention.