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6. DRL Schedule


Movie 6.6

Movie 6.7

Now that you have seen how patterns of behaviour can be produced on tap, so to speak, we have to assess the more general lessons to be derived from such an exercise. Perhaps the most important concerns the development of an epistemology for explaining behaviour.

The value of studying schedules in the laboratory is two-fold. Firstly, they provide us with a chance to see the effects of simple environmental contingencies, and with this a chance to develop a conceptual framework based on these findings. Part of this involves a critical examination of the value of everyday language as a medium for talking about explanations. In the laboratory you can manipulate contingencies and observe their effects. You also can bring someone into the laboratory who knows nothing about contingencies and examine the language they use to explain their observations. This may provide some insight into how contingencies in the history of the observer control his/her response to the behaviour of the observed organism.

Another reason why it is important to study schedules concerns the refinement in our understanding of how to deal with complex behaviours. Although a pattern of responding on a schedule is relatively simple, it is radically more complex when compared to a single lever press. As mentioned earlier, each observation of a lever press is not to be viewed as a self-contained isolated act on the part of the observed organism but as an element in a broader pattern. This broader pattern reveals itself only when successive responses are viewed across a wider time frame. This notion of time frames is important because when you observe someone at a point in time you may not be aware of the role of this isolated act within a pattern of behaviour. However, when you extend the time frame over which the person is observed you may come to see your initial observation in a different light. This is an important point because most non-behavioural explanations are formulated in such a way that they refer to the operation of something inside the person at one precise moment to explain that observation. The general pattern of behaviour is ignored, along with the contingencies that explain the pattern.

We will examine this point in more detail after you click on the button to download a PowerPoint presentation. This exercise involves you as a participant in a simple study of schedule performance.

If you haven’t done the exercise, then go back and do it. This section will make a lot more sense if you do it. If you have done the exercise, then what follows next is your debriefing on what was happening.

There were two schedules programmed in the exercise. The simplest was FR 1. Each time you clicked on the button on the left you got immediate access to the pictures. However, in the presence of button on the right something else happened.


The schedule you were exposed to is called Differential Reinforcement of Low Rates (DRL). Movie 6.6 is an animation of how the contingencies operated. Once a 5-sec interval had started, a response that occurred before the interval was completed resulted in the clock being reset. A reinforcer was delivered only if a response occurred after the 5-sec interval had elapsed. This schedule is often used in applied settings when the goal is to reduce the frequency of a problem behaviour, because as the title of the schedule implies, this schedule controls low rates of responding. In the upper panel of the animation we see the sort of performance that happens initially on this schedule, and then we see a typical baseline performance in the lower panel. Although we don’t have data on your actual performance, you will no doubt be able to confirm, to yourself at least, that you did click a lot at the beginning of the exercise. And no doubt you got rather frustrated along the way. Now, this frustration is also important here, because it is something that only you have details on, but at the same time you now know that this behaviour arose as a consequence of the contingencies operating. In other words, even your emotional behaviour can be controlled by contingencies of reinforcement. In a more controlled study we would be able to reliably produce different feelings in the presence of each of the two different buttons (more on this later). For now, take a look at a possible analysis of your performance on the buttons in Movie 6.7.

Once it was discovered that patterns of behaviour could be designed by designing appropriate contingencies, other questions began to appear. These questions did not exist before the discovery of schedule-controlled behaviour and the experimentation needed to answer them has provided more facts about the ways organisms adapt to environmental contingencies. For example, it was noted that there was a difference in responding across schedules when reinforcers were no longer delivered, that is, when an 'Extinction' procedure was in effect. This means that different histories of reinforcement can play a crucial role in affecting behaviour in other settings. A behaviour analyst would take this finding further simply by arranging a history of reinforcement for an organism and noting what happens to its behaviour when new contingencies are introduced. Another basic finding that is characteristic of intermittent reinforcement (another term for a schedule) is that it results in organisms responding for longer in extinction than if they have only experienced continuous reinforcement. This finding could be extended simply by varying the parameters that make up the intermittent reinforcement schedule and noting the time taken to completely extinguish responding for each variation in the schedule. This finding is central to much applied work where there is an emphasis of maintenance of responding after a successful intervention.