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| International Symposium - Processes Involved in Equivalence Class Formation |
| Saturday, May 26, 2007 |
| 2:30 PM–3:50 PM |
| Del Mar AB |
| Area: EAB/VBC; Domain: Theory |
| Chair: Louise A. Mchugh (University of Wales, Swansea) |
| Discussant: Philip N. Chase (West Virginia University) |
| Abstract: In the equivalence literature much debate has surrounded the issue of how new stimuli join equivalence classes. Two opposing arguments have been put forward. One argument suggests that new members become equivalent to old ones due to their common history of reinforcement that was established during training. While others propose that the structural network of connections among class members may reflect performances that indicate differing degrees of relatedness among stimuli. The three papers in the current symposium will present theoretical and empirical papers on the emergence of nodal distance in equivalence class formation. Paper 1 will provide an overview of the nodal distance literature. Paper 2 presents empirical evidence on the effect of equal numbers of training and testing trial types on equivalence class formation. Results indicate that nodal distance among class members may be due to training structure. Finally, paper 3 presents a study that compares the effects of three processes, word frequency, time of acquisition and reinforcement in the formation of equivalence classes. Findings implicate level of reinforcement as critical in their formation. Together these papers will help inform our understanding of equivalence class formation. |
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| Stimulus Interchangeability and Nodal Distance Effects in Equivalence Classes: An Integrated Account. |
| LANNY FIELDS (Queens College, City University of New York) |
| Abstract: By definition, stimuli in equivalence classes are interchangeable or substitutable for each other. By implication, they should be equally related to each other. Under certain testing conditions, however, responding occasioned by the stimuli or the stimulus relations are inverse functions of the nodal distance that separates the stimuli in the class. In these cases, the stimuli are not interchangeable, substitutable or equally related to each other. After reviewing the data that support both positions, an account will be proposed that integrates both sets of findings. |
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| The Effect of Equal Numbers of Training and Testing Trial Types on the Formation of Equivalence Class Formation. |
| TING WANG (University of Wales, Swansea), Robert Whelan (University College Dublin), Louise A. Mchugh (University of Wales, Swansea) |
| Abstract: Saunders and Green (1999) suggested that the gradual acquisition of a simple discrimination might be a function of frequency of stimulus presentation during testing of equivalence classes. The current study aimed to test this hypothesis, by comparing performance on a series of conditional discrimination tasks with equal numbers of training and testing trial types. Twelve healthy adults participated in this study. Each of the participants were trained and tested on two five-member equivalence classes. Findings indicated that there was no significant difference amongst the response time in each derived trial type across testing. The results of this experiment indicate that differential acquisition of simple discriminations may be due to training structure. The suggestion that nodal distance effects may be a by-product of the experimental procedures employed is discussed. |
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| The Effects of Word Frequency, Time of Acquisition and Reinforcement on Equivalence Class Formation. |
| LOUISE A. MCHUGH (University of Wales, Swansea), Robert Whelan (University College Dublin), Ting Wang (University of Wales, Swansea) |
| Abstract: Three processes have been implicated in the formation of equivalence classes; reinforcement, word frequency and time-of-acquisition. 128 participants were trained using a match-to-sample procedure to relate two equivalence classes, while level if reinforcement, word frequency and time-of-acquisition were systematically manipulated. Subsequently, these participants were exposed to a lexical decision task involving these equivalence classes while reaction times were recorded. Typically faster reaction times emerge when semantically related pairs are presented. Findings indicated that the fastest reaction times between members of equivalence classes emerged in high reinforcement conditions. The importance of history of reinforcement for equivalence class formation is discussed. |
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