Your shaping CA: What to watch for

Revised on 9/30/14

In order to get credit for your shaping CA, there are a few details that you have to be careful about. Shaping is a natural extension of differential reinforcement (or punishment) because, in effect, it's a connected series of differential reinforcement (or punishment) contingencies. That means that the behaviors in each phase have to be members of the same response class. And that means they're pretty similar to each other, except for the differences along the chosen dimension that get reinforced (or punished).

In the case of shaping using reinforcement, as the frequency of the behavior during a particular phase becomes more frequent, there are naturally some variations in how it's performed. Once the frequency stabilizes at a new, higher level, the performance manager watches for variations in occurrences of the behavior that are a little bit closer to the desired terminal behavior. The next phase begins when these variations become the only occurrences that are reinforced. After a while, these once-rare variations become the most common form of the behavior, and occasionally new variations appear that are even closer to the terminal behavior.

So the occurrences of the behavior during subsequent phases must overlap with each other. Another way to think about it is that the behavior in the earlier phase naturally "flows into" the behavior in the next phase. Still another way to think about it is that the behavior that's going to be reinforced in the next phase must occur occasionally during the present phase. Think about this as you put together and revise your CAs. The behavior you're thinking of describing in the next phase ... Is it a behavior that you see occasionally in the present phase? If not, then change the behavior you're thinking of describing in the next phase.

One more detail to be careful of: Your description of the behavior that gets extinguished in the 2nd phase should be identical to your description of the behavior that was reinforced in the 1st phase, and your description of the behavior that gets extinguished in the 3rd phase should be identical to your description of the behavior that was reinforced in the 2nd phase. You won't see that in all of the examples in the textbook, but this is the way you should do it.

Note that it's often appropriate to indicate "N/A" as the behavior being extinguished in the 1st phase. That's because during the 1st phase, there was no previous phase during which there was a behavior that was being reinforced. Therefore, you can't describe a behavior, so you say "N/A" instead.