The Effects of Initial Interval Size on the Efficacy of DRO Schedules of Reinforcement
The differential reinforcement of other behavior (DRO) is a procedure in which reinforcement is delivered if a target response does not occur for a specified interval (Kelleher, 1961; Lane, 1961; Reynolds, 1961). It has been studied both in laboratory and applied settings, the latter primarily because it is a nonaversive procedure that can reduce some inappropriate behavior. It is often used in classrooms to manage various disruptive behaviors, perhaps most commonly when teachers tell students they will be rewarded if they are good for the class period or school day.
In general, laboratory studies have not been concerned with whether DRO reduces behavior but rather with what factors make it effective or ineffective. Some of these studies have shown the following results:
1. A schedule in which the interval is fixed is more effective than a schedule in which it varies (Reuter & LeBlanc, 1972).
2. DRO is more effective when the interval is initially small and gradually increased than when it is initially large (Repp & Slack, 1977; Topping, Larmi, & Johnson, 1972).
3. Postponing reinforcement for an interval greater than the DRO interval is more effective than postponing reinforcement for an interval equal to the DRO value (Uhl & Garcia, 1969).
DRO is also a well-known procedure in applied work, although the results of its use have been mixed. In some studies, it has proved effective when used alone or with other procedures (e.g., Barton, Brulle, & Repp, 1986; DeCatanzo & Baldwin, 1978; Deitz, Repp, & Deitz, 1976; Dwinell & Connis, 1979; Lutzker, 1974; Myers, 1975; Repp, Barton, & Brulle, 1983; Repp, Deitz, & Speir, 1975; Tarpley & Schroeder, 1979). In other studies, however, it has been ineffective (e.g., Corte, Wolf, & Locke, 1971; Foxx & Azrin, 1973; Harris & Wolchik, 1979).
There could be many reasons for the disparity in these results, for example, the strength of the reinforcer used to reward the student for not engaging in the inappropriate behavior, or the events maintaining the behavior to be reduced. Speculating post hoc about these reasons would not seem to be a productive undertaking, because many variables change across studies (e.g., behaviors, subjects, settings, and reinforcement histories). A more productive approach would seem to be the one followed by the laboratory researchers. This approach directly compares variables within a single study so that we can learn how to use DRO more effectively in classrooms and other settings.
Such an approach has been followed in one set of studies concerning DRO. These studies (Barton et al., 1986; Repp et al., 1983) have compared two types of DRO schedules. In one, labeled momentary DRO (MDRO), reinforcement is delivered if the target behavior is not occurring at the moment the interval ends (Harris & Wolchik, 1979). MDRO is being used in classrooms when teachers "catch" students not behaving inappropriately (e.g., the moment the bell rings or lessons are completed, or when teachers look up from their desks). In the other procedure, whole-interval DRO (WDRO), reinforcement is delivered if the target behavior has not occurred throughout the whole interval. WDRO is being used in classrooms when teachers reward students who have not behaved inappropriately for a whole period (rather than for any specific moment in the period, which would be MDRO). Results have shown that MDRO, when used alone, is ineffective at reducing inappropriate behavior, but effective at maintaining a reduction that was achieved through WDRO. Thus, one variable associated with the effectiveness of DRO has been identified.
A second variable that seems to be important is the size of the DRO interval. Previous laboratory work has shown that DRO is more effective when its initial interval is small than when it is large. …