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| The Role of Stimuli and Responses |
| Thursday, November 29, 2001 |
| 1:00 PM–1:50 PM |
| Palladian Refectory Hall |
| Area: EAB |
| Chair: Deirdre Beebe Fitzgerald (Eastern Connecticut State University) |
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| The Relation of the CS to Behavior is Fundamental in the Pavlovian Procedure |
| Domain: Applied Behavior Analysis |
| ROCIO VEGAS (Universidad Central de Venezuela), John W. Donahoe (University of Massachusetts at Amherst) |
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| Abstract: The Pavlovian procedure commonly studies learning by varying the temporal relation between the conditioned stimulus (CS) and the unconditioned stimulus (US). However, when the CS-US relation is varied, the relation between the CS and the unconditioned response (US) necessarily changes as well. Thus, the effects on conditioning that are attributed to the relation between the two stimuli are inevitably confounded with any effects of the temporal relation between the CS and the UR. A new conditioning preparation used water - or air-puff-elicited throat movements in restrained pigeons to assess the contribution of the relation of the CS to the UR in the Pavlovian procedure. Because the UR in this preparation has a substantial latency and duration, the relation of the CS to the US and UR could be independently manipulated. A series of experiments demonstrated that CS--UR overlap is sufficient to produce conditioning and that the CS need not precede either the US or the UR in order for conditioning to occur. These results support the relation of the CS to US-elicited behavior as the critical variable in the acquisition process in a Pavlovian arrangement and promotes a unified view of conditioning in Pavlovian and operant procedures. |
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| Dissociating the Three-Term Contingency: The Role of the Response |
| Domain: Applied Behavior Analysis |
| IVER H. IVERSEN (University of North Florida) |
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| Abstract: In spite of its popularity, the three-term contingency is not well researched. Does the subject learn about the stimulus or does the subject learn about the response? In other words, does a subject learn that the stimulus signals reinforcement and that the absence of the stimulus signals absence of reinforcement, or does the subject learn to emit a certain response to the stimulus and withhold that response when the stimulus is absent? Rats were trained with food reinforcement to press a lever when a light turned on; pressing was not reinforced in the absence of the light (inter-trial intervals were 60 s). When the discrimination was acquired with prompt pressing when the light turned on and absence of pressing when the light was absent, the contingency was shifted to another response while the original stimulus was the same. Thus, when the light turned on pressing another lever now produced the food while pressing the original lever merely turned the stimulus off. Pressing the new lever was acquired quickly during the light. However, the rats also pressed the new lever at a high rate when the light was absent. Thus, the rats had to acquire the discrimination again when a new response was introduced; the rats had not leaned that absence of the light "signaled" no reinforcement. When the contingency was switched back to the original response the rats quickly switched the response. Interestingly, the rats immediately switched back to absence of responding during the absence of the light. This shows that the S-delta function of a stimulus is response specific. Additional responses were introduced in subsequent phases of the experiment while keeping the stimulus the same. In each case, the rats went through extinction of the new response in the absence of the light. The rats apparently never learned that the absence of the light signaled absence of reinforcement; instead the rats had to lean that the absence of the light was an S- delta for each response. Apparently the rats had to acquire the discrimination anew each time a new response is introduced even though the stimulus was kept the same. The results illustrate some of many complexities involved in the "simple" three-term contingency and suggest that rats do in fact no learn that stimuli "signal" reinforcement or absence of reinforcement. |
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