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| Int'l Symposium - Stimulus Control |
| Tuesday, May 31, 2005 |
| 9:00 AM–10:20 AM |
| International South (2nd floor) |
| Area: EAB; Domain: Basic Research |
| Chair: Anthony DeFulio (University of Florida) |
| Abstract: Stimulus control refers to the systematic influence of an antecedent stimulus on the probability of occurrence of a response. Stimulus control research has historically included a wide range of topics. Much of the experimental activity in psychophysics, equivalence, signal detection, and memory has been dedicated to answering questions about the ways in which antecedent stimuli relate to behavior. The present symposium is a sampling of current work in the area of stimulus control. The authors will present on diverse topics, including numerosity, transposition, generalized identity matching, and equivalence relations. The goal of this symposium then, is to gather scientists with diverse yet common interests to facilitate both problem solving and question asking. |
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| Counting, Timing, and Stimulus Control: Control of Pigeons’ Key Pecking by Numerical Properties of Stimuli |
| ANTHONY DEFULIO (University of Florida), Timothy D. Hackenberg (University of Florida) |
| Abstract: Pigeons’ key pecks produced food according to both a fixed-interval (FI) 24 s schedule of reinforcement and a fixed-number (FN) 12 schedule in which the first peck after the twelfth in a series of events (flashes of light) produced food. Key colors served as schedule-correlated stimuli. Inter-trial intervals followed each reinforcer delivery. Flashes occurred at three different rates during both FI and FN trials, for a total of six trial types. Trials were blocked within each session such that all 10 of each trial type occurred consecutively. Within each block, eight trials terminated with reinforcer delivery and two trials continued for 100 s and terminated without reinforcer delivery (empty trials). Peak rates of responding on empty trials were used as indices of temporal or numerical control. Results indicate no effect of flash rate on performance during FI trials, and differential performance across different flash rates on FN trials. The subjects were exposed to additional conditions in which flash rate changed within trials, and in which particular flashes were omitted. The entire series of conditions were then replicated with an additional spatial cue correlated with food availability. The implications for numerical control in non-human token systems are discussed. |
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| Transposition in Pigeons and People Using Multiple-Pair Discrimination Training |
| OLGA LAZAREVA (University of Iowa), Michelle Miner (University of Iowa), Edward Wasserman (University of Iowa), Michael Young (Southern Illinois University, Carbondale) |
| Abstract: We studied transposition in pigeons and human adults. In training, subjects were exposed to a single training pair, to two training pairs, or to four training pairs along the size dimension. Testing included stimulus pairs that, according to theoretical simulations, distinguished absolute from relational accounts of transposition. Both pigeons' and people's relational responding rose from one- to two- to four-pair training, although the increase was more evident for pigeons. The similarity of the testing stimuli to one another also affected relational responding: transposition increased with highly dissimilar stimuli. Using post-experimental questionnaires, we evaluated people's awareness of the task and found no measurable relationship between awareness and relational responding. We conclude that multiple-pair discrimination training enhances relational responding in both pigeons and people. Such relational responding may not require verbalization of the relationship between the paired stimuli. |
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| Are Extended Observing and Choice-Response Requirements Sufficient for the Development of Generalized Identity Matching in Pigeons? |
| YUSUKE HAYASHI (University of North Texas), Manish Vaidya (University of North Texas) |
| Abstract: Wright (1997) suggested that programming extended sample observing-response requirements (e.g., FR20) in identity matching trials led to performances describable as generalized identity matching. However, his procedure consisted of several unconventional features: stimuli were color cartoons, stimuli were presented on and responses were detected by a touch screen laid out horizontally, and the reinforcer was delivered on top of the correct comparison stimulus which stayed on for 8” as the subject ate. In the current study, four naïve pigeons learned three conditional relations with an FR20 programmed on the sample and a response-initiated FI 8-s on the comparison keys followed by tests with novel stimuli in a standard Skinner box with hues as stimuli. Although some suggestive evidence of generalized identity matching was found in the tests with novel stimuli, none of the birds showed as high accuracy with the novel stimuli as that with the training stimuli. This suggests that while extended sample observing and choice-response requirements may be necessary, they are not sufficient to produce generalized identity matching in pigeons. |
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| Can Differential Sample-Response Patterns Become Members of Acquired Equivalence Classes? |
| PETER URCUIOLI (Purdue University), Karen M. Lionello-DeNolf (E.K. Shriver Center, University of Massachusetts Medical School) |
| Abstract: Differential sample responding is known to provide additional cue for choice in pigeons’ matching-to-sample. The experiments we will report ask whether or not two distinct sample-response patterns will join separate acquired equivalence classes if, in training, each pattern serves as one sample in a many-to-one (comparison-as-node) relation. Transfer-of-control assessments of the type commonly used to assess acquired equivalence in non-human animals revealed little or no evidence for class formation that included these response patterns as members, even though the differential patterns provided a cue for comparison choice. |
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