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Experimental Analyses of Conditional Discrimination Learning and Equivalence Class Formation |
Monday, May 30, 2005 |
10:30 AM–11:50 AM |
Boulevard C (2nd floor) |
Area: EAB; Domain: Basic Research |
Chair: Manish Vaidya (University of North Texas) |
Discussant: Richard W. Serna (E.K. Shriver Center, University of Massachusetts Medical School) |
Abstract: The symposium is organized around three papers dealing with conditional discrimination learning and equivalence class formation. Thre first paper asks if stimuli that are treated similarly in one context will also appear to be equivaelent in other, unrelated contexts. The second experiment asks whether human subjects can acquire a conditional discrimination in which a brief tone serves as the comparison stimulus. The third paper looks at the effects of extended observing-response requirements on titrated delays in a titraing-delay-matching-to-sample procedure. |
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The Role of Common Stimulus Functions in the Development of Equivalence Classes |
KIRSTY MACIVER (University of North Texas), Manish Vaidya (University of North Texas) |
Abstract: The extension of stimulus functions across equivalence class members has been reported for reinforcing, discriminative, and eliciting stimulus functions among others. In this study, we ask if having learned a common response in the presence of several distinct stimuli will produce equivalence-like organization among those stimuli. Eight college students were exposed to training designed to teach nine simple discriminations, assigning each of three functions to a different set of three arbitrary visual stimuli. For seven of eight participants, three 3-member contingency classes resulted. When the same stimuli were presented in a match-to-sample procedure under test conditions, four participants demonstrated equivalence-consistent responding, matching all stimuli from the same contingency class. Test performance for two of the remaining three participants was systematically controlled by other identifiable variables, and was unsystematic for a final participant. For one participant, exposure to a different testing preparation yielded equivalence-consistent performance where the match-to-sample test had not. These data have implications for increasing our understanding of the ways in which equivalence classes may develop and maintain cohesiveness outside the laboratory context. |
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Tone-Letter Conditional Discrimination Learning with Typical College Students |
JOSEPH L. CERMAK (University of North Texas), Manish Vaidya (University of North Texas) |
Abstract: Although conditional discrimination procedures have served as a prevalent preparation for the investigation of a host of interesting behavioral phenomena with typically developing human subjects (e.g., concept formation and equivalence relations), our understanding of the development of conditional discriminations in this population remains incomplete. One reason for this lack of understanding may be the rapid manner in which typically developed adults acquire conditional discrimination performance. In this study, we sought to retard the development of conditional discriminations in typically developed adults in order to observe and describe the development of conditional relations more precisely. Toward this end, four subjects were taught eight conditional relations simultaneously in which tones served as sample stimuli and lowercase English letters served as comparison stimuli. Three of the four subjects acquired the conditional discrimination with some difficulty. Generalization tests with one subject suggested that the physical relation among sample stimuli was important and, by implication, that control over comparison-stimulus choices (within trial) extended beyond the current trial. |
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Effects of Extended Sample-Observing Response Requirements on Titrating Delay in a Matching-to-Sample Procedure with Pigeons |
BRIAN D. KANGAS (University of North Texas), Manish Vaidya (University of North Texas) |
Abstract: Laboratory lore suggests that requiring multiple response to sample stimuli facilitates the acquisition of conditional discrimination performance. The precise nature of this relation, however, is not well understood. What, for example, is the nature of the function relating sample-observing response requirements to improvements in the rate at which conditional discriminations are acquired? Traditional measures such as percent of correct trials are inadequate for such questions because of a ceiling effect – performance cannot improve past 100% correct. In the current study, we used a titrating-delay-matching-to-sample (TDMTS) procedure to parametrically examine the effects of extended sample observing-response requirements on conditional discrimination performance. Four pigeons worked on a successive matching-to-sample procedure in which the delay between sample offset and comparison onset was continually adjusted as a function of the pigeon’s performance accuracy. The number of responses required (FR 1, 2, 4, 8, and 16) to produce the comparison array was manipulated across conditions. Results show that all subjects are able to withstand longer delays between sample offset and comparison onset as observing-response requirements increase. In addition, preliminary results suggest a curvilinear function across FR values plotted against steady-state delays. |
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