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| Current Human Operant Research on Stimulus Equivalence, Self Control, and Schedule Control |
| Saturday, May 28, 2005 |
| 4:00 PM–5:20 PM |
| Boulevard B (2nd floor) |
| Area: EAB; Domain: Basic Research |
| Chair: Michael Johnston (University of Nevada, Reno) |
| Abstract: This symposium will be comprised of current research in human operant areas of study. These include investigations of some basic methodological elements of human operant research in general, as measured by responding on Fixed Interval schedules of reinforcement. In addition, the important issue of choice from the perspective of the self control and impulsivity will be presented. Finally, additional research on stimulus equivalence from it’s efficacy as part of an assessment tool, to the nature of stimulus classes involved will be discussed. |
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| How Schedule History and Type of Consequence Affect Human Responding on an FI Schedule |
| MICHAEL JOHNSTON (University of Nevada, Reno), Linda J. Parrott Hayes (University of Nevada, Reno) |
| Abstract: Experimental work conducted with animals tends to show regularity in terms of schedule controlled behavior. The results of human operant work shows much more variability and are often disparate from animal patterns. One potential explanation for this lies in the methodological differences between human and animal experiments. That is, the use of appetitive schedules of reinforcement with food-deprived animals is a highly relied upon methodology that delivers a very predictable result. However, given the wide variety of methodologies used in human operant literature, and the wide variety of results obtained, perhaps some of the discrepancies between human and animal performance may be due to these methodological incongruities. The present study employed a systematic investigation of human operant methods in a search for potentially more efficacious types of antecedents, responses, and consequences, without ignoring the role of motivation (i.e., establishing operations) in an attempt to investigate the role of these methodological variables and their effects on schedule-controlled behavior. By varying these types of elements, data indicates an important contribution of the methodology used in a human operant setting and this approach may help explain some of the differences between humans and animal responding on certain schedules of reinforcement. |
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| Self-Control and Impulsivity Demonstrated by Humans in the Laboratory Setting |
| RACHEL S. F. TARBOX (Center for Autism and Related Disorders), Jonathan J. Tarbox (University of Nevada, Reno), Patrick M. Ghezzi (University of Nevada, Reno) |
| Abstract: The purpose of the current investigation was to further examine the conditions under which humans engage in self-control and impulsivity. A computerized program was designed in which digital videos (DVDs) were used as the consumable reinforcer and a procedure was developed that eliminates the inter-trial interval (ITI) but that equalizes the overall magnitude of reinforcement available for the two alternatives. In one experiment the effects of eliminating the ITI were evaluated. In a second experiment the effects of varying the absolute delay to and duration of reinforcement while still equalizing the overall magnitude of reinforcement were evaluated. Results demonstrated that the inclusion of an ITI produced self-control, whereas the removal of an ITI produced impulsivity. Additionally, as the absolute values of delay and duration increased, preference shifted. These results suggest a number of potentially significant implications. First, unlike previous investigations, self-control with the use of consumable reinforcers was shown. Second, impulsivity was demonstrated in humans when the overall magnitude of reinforcement available for the impulsive alternative was no greater than the overall magnitude of reinforcement for the self-control alternative. Third, results depicted the only demonstration to date of individuals switching from impulsive to self-controlled choice with equal magnitudes of reinforcement. |
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| An Examination of the Relations between ABLA Performance, Language Ability and Within Modal Stimulus Equivalence |
| MARIANNE L. JACKSON (University of Nevada, Reno), W. Larry Williams (University of Nevada, Reno) |
| Abstract: Six participants, all with moderate to severe mental retardation, were selected for participation based on their performance on the Assessment of Basic Learning Abilities (ABLA). Three participants demonstrated the ability to make visual, auditory and auditory-visual discriminations, and performed significantly better on measures of functional language abilities. Three more participants performed less well on tests of functional language abilities and demonstrated some ability to make visual discriminations, but not auditory discriminations. Visual discrimination abilities varied from the ability to imitate, to make positional discriminations, simple discriminations and conditional discriminations. All six participants were trained in all relevant baseline discriminations required to form four, three member equivalence classes. Training of these relations was conducted in a comparison-as-node format, using a computer and a touch screen. Equivalence relations were tested with each participant and results are discussed in relation to ABLA performance and language ability. We consider the implications of this study for what is known about pre-requisite skills required for the demonstration of positive outcomes on equivalence tests. |
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| Substitution of Stimulus Functions as a Means to Distinguish Among Different Types of Functional Classes |
| DIANA M. DELGADO (University of Nevada, Reno), Linda J. Parrott Hayes (University of Nevada, Reno) |
| Abstract: A functional class refers to a circumstance in which multiple forms of responding are controlled by singular stimulus conditions, as exemplified in the formation of concepts and categories. The conditions under which functional classes are established have been studied extensively by way of simple and conditional discrimination procedures. The classes established by these procedures are more representative of conceptual repertoires than categorical repertoires, however. Hence it appears that there is more than one type of functional class and not all of these types are established equally well by standard conditional discrimination procedures. An alternative to these procedures is thereby investigated in which proximal relations among stimuli, supplemented by specific contextual conditions; provide the basis for their organization into classes capable of exerting singular control over multiple responses, as entailed in functional classes of the categorical type. It is argued that a process of substitution of stimulus functions is needed to distinguish among functional classes of different varieties. |
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