1. Common Properties of Differential Reinforcement A target behavior performed in the presence of a particular stimulus is reinforced. The same behavior is not reinforced (placed on extinction) if it is performed in the absence of a stimulus.

2. Differential Reinforcement of Incompatible Behavior (DRI) DRI involves selecting and reinforcing a behavior that is topographically incompatible with the inappropriate. DRI is synonymous with the fair pair. A behavior is selected and reinforced that cannot coexist with the inappropriate behavior.

3. Differential Reinforcement of Alternative Behavior (DRA) DRA is similar to DRI in that an alternative to the inappropriate behavior is reinforced. Unlike DRI, an alternative behavior is not topographically incompatible with the inappropriate behavior. DRA takes advantage of a functional alternative.

4. Differential Reinforcement of Other Behavior (DRO) DRO involves reinforcing a child for not engaging in the inappropriate behavior. Only zero responding of the inappropriate behavior is reinforced. DRO is called “omission training” because a student is reinforced for the absence rather than the presence of behavior.

5. Steps for Applying DRO An interval of time is set. Any appropriate behavior occurring at the end of that interval is reinforced if the target behavior was not emitted during the interval. Any occurrence of the target behavior causes a return to the beginning of the interval

6. Considerations for Using DRO Because reinforcement is delivered if a student does not perform the target behavior, teachers run the risk of positively reinforcing a variety of other inappropriate behavior. Teachers may create a “behavioral vacuum” for students who do not possess a large repertoire of appropriate behaviors because DRO reinforcers the absence of behavior. DRO will only be effective if the reinforcer is as powerful as the one the student naturally obtains from performing the inappropriate behavior.

7. Differential Reinforcement of Low Rates of Behavior (DRL) Unlike DRO which requires zero responding on the target behavior, reinforcement is delivered using DRL if the inappropriate behavior is at a tolerable or desirable level. Reinforcement is provided either after a response that follows an interval of specific length or after a specified interval if the frequency of the behavior is below some established criterion.

8. Guidelines for Using DRL Baseline must be recorded in order to determine the average number of responses per full session or session intervals. This average occurrence may then serve as the initial DRL limit. Reasonably spaced criteria should be established when using successively decreasing DRL limits to avoid too frequent reinforcement and ratio strain, and so that the program can be faded out. A decision must be made as to whether or not to provide feedback to the student(s) concerning the cumulative number of responses during the session.

9. Schedules of DRO DRO Reset Schedule DRO Fixed-Interval Schedule DRO Increasing-Interval Schedule DRO Progressive Schedule

10. Interresponse Time (IRT) Calculating IRT is a way to determine an appropriate interval length for many DRO and DRL schedules. IRT refers to the time that passes between occurrences of the inappropriate behavior. This time period (or one slightly higher) becomes the initial interval that must pass without a student engaging in the inappropriate behavior in order to obtain reinforcement.

11. Calculating IRT The number of times the behavior occurs is divided by the total time a child is in school (i.e., 6 hours). This calculation will yield the number of times the behavior is performed per hour. Next, the number of times the behavior occurs per hour is divided into 60 (i.e., number of minutes in the hour). The number obtained from this calculation represents the average amount of time that passes between the child performing the inappropriate behavior.

12. An Example of Calculating IRT Kyle would poke other students 48 times during the day. His teacher wanted to completely eliminate this behavior using a DRO schedule. Therefore, she needed to determine an appropriate interval of time in which Kyle had to refrain from poking peers in order for him to obtain reinforcement. First, she divided 48 into 6—the latter number representing the total time Kyle was in school daily. This calculation indicated that Kyle poked peers 8 times per hour. Next, his teacher divided 8 into 60—the number of minutes in an hour. The number obtained, 7.5, represents the average minutes that pass between Kyle poking other students. Therefore, Kyle’s teacher set an initial interval length of 8 minutes in which he must refrain from poking peers in order to obtain reinforcement.

13. DRO Reset Schedule In the DRO reset procedure, the interval is reset every time the inappropriate behavior occurs.

14. DRO Fixed-Interval Schedule In the DRO fixed-interval procedure, the interval schedule is fixed, and reinforcement is delivered at the end of each interval during which the response does not occur. The interval time is not reset with each occurrence of the target behavior.

15. DRO Increasing-Interval Schedule In the DRO increasing-interval schedule is a way of thinning or fading reinforcement. If the specified interval passes without a target response occurring, reinforcement is delivered and the next interval could be increased by a certain amount of time.

16. DRO Progressive (DROP) Schedule In a DRO progressive (DROP) schedule, the interval size remains the same. However, the amount, or kind, of reinforcement increases as the student refrains from performing the inappropriate behavior for more and more consecutive intervals.

17. DRL-IRT Schedule The DRL-IRT schedule is one in which the target behavior is reinforced following a specified interval of time since the previous episode. The interval is determined by calculating IRT.

18. DRL-Below-Criterion Schedule The DRL-Below-Criterion schedule involves determining the average number of times the target behavior is typically exhibited during a certain interval of time. Reinforcement is delivered if the frequency of the behavior is below this baseline rate during the specified interval of time.

19. Considerations When Using Differential Reinforcement DRI and DRA both strengthen appropriate behavior. DRO does not specify what behaviors will be reinforced, thereby creating the potential for a “behavioral vacuum.” DRL is the only type of differential reinforcement technique that does not require the inappropriate behavior to be completely eliminated in order for a student to receive reinforcement. DRI, DRA, and DRL usually produce a gradual change in behavior which may not be desirable for behaviors that a re dangerous to self and others. DRO may be the technique of choice when the behavior is dangerous to self or others since it often results in rapid decreases.