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Abstracts | Publications | Grants Fantino: Nonoptimal and Counterintuitive Choice Madden: Impulsivity: Discounting the Benefits of Drug Abstinence Hackenberg: Quantification of Species Differences in Adaptive Choice Serna: A Stimulus Control Analysis of Attending Title: Nonoptimal
and Counterintuitive Choice We propose work with adults, children and pigeons. According to delay-reduction theory (DRT), the effectiveness of a stimulus as a conditioned reinforcer may be predicted most accurately by the reduction in length of time to primary reinforcement correlated with its onset compared to the length of time to primary reinforcement measured from the onset of the preceding stimulus. One set of proposed experiments would provide new tests regarding the issue of whether when the strength of a stimulus as a conditioned reinforcer is enhanced by correlating that stimulus with greater delay reduction, that enhancement carries over, at least temporarily, to a new context. The proposed experiments develop two ways of correlating a stimulus with greater delay reduction and propose two methods to assess strength of conditioned reinforcement in a new context. A counterintuitive prediction derived from DRT is that differences in delay to reward and not ratios of delay to reward should control choice when subjects are choosing between two schedules of reward as the outcomes, at least in the well-established concurrent-chains procedure. According to most theories, choice between two outcomes with different delays to reward is governed by the ratios of the delays, not by the differences between them. We propose to test the conditions under which ratios and/or differences control choice with two different choice procedures. We also propose to continue investigating the conjunction fallacy, displayed when subjects report that the conjunction of two events is more rather than less likely to occur than one of the events alone. We have developed a behavioral approach to the study of the fallacy that would permit us to investigate critical variables affecting its occurrence. This work takes us naturally to further investigation of pigeons', human adults' and children's response to novel compound stimuli. Together with our proposed research on problem solving these experiments would help clarify the role of rule-governed (instructed) and contingency (or experience)-shaped behavior on learning. Our interest in the factors governing reasoning in humans and non-humans extends to the sunk cost effect, a maladaptive economic behavior involving an increased tendency to persist in an endeavor once an investment has been made. The present aim is to develop a pigeon analog of the sunk-cost effect and to explore several variables that may contribute to the development and/or the persistence of commitment in the pigeon. Back to Grants List (top of page) Title: Impulsivity:
Discounting the Benefits of Drug Abstinence Back to Grants List (top of page) Title: Quantification
of Species Differences in Adaptive Choice The aim of the present research is to develop a method by which adaptive choice in humans and other animals can be systematically compared. Several lines of evidence suggest that humans and other animals often behave differently when confronted with choices involving short-term versus longer-term outcomes. More specifically, delayed outcomes appear to decrease in value more sharply in nonhuman animals than in humans, suggesting perhaps that the processes governing adaptive choices in humans and other animals are fundamentally different. Another possibility is that human-animal disparities in adaptive choice reflect differences in the ways in which humans and other animals have typically been studied. The present research was designed to explore this latter possibility by examining the choice patterns of pigeon and human subjects under more closely analogous laboratory conditions than has been attempted in prior research. This work grows out of some recent research in the investigator's laboratory, which shows that modifying the procedures used with pigeons in ways that more closely approximate those used with humans results in performance that is more "human-like." The present research extends this approach in several significant ways, including the use of procedures that permit detailed quantitative information. By eliminating key procedural differences which have plagued prior cross-species comparisons, the present research will help in distinguishing genuine from superficial species differences in adaptive choice. This will provide important information on the continuity of choice patterns across species, and on the degree to which principles discovered in the animal laboratory can be extended to fairly complex human activity. In identifying factors contributing to adaptive choice, this research may also provide a starting point for developing effective self-management techniques in humans. Back to Grants List (top of page) Title: A
Stimulus Control Analysis of Attending This project is a five-year study of stimulus control acquisition in individuals with severe to moderate intellectual disabilities. The program will focus on attending and its role in effecting transfer of control within and across stimulus dimensions. Despite years of research in many laboratories, no satisfactory process-level account has emerged to explain stimulus control development and transfer. As a consequence, the many successes and too-frequent failures of transfer-based teaching programs are only poorly understood. The research program will help in developing a general theoretical account of transfer, a general theory of stimulus control acquisition, and a more effective, better understood teaching technology for people with intellectual disabilities. The empirical foundation for the project derives from a series of methodological studies that have been conducted over the past five years, as well as other basic research studies, conducted in Shriver laboratories and others. Those methodological studies sought reliable procedures for teaching individuals with mental retardation to relate physically dissimilar stimuli (e.g., a picture and a corresponding printed word). The findings have clarified the nature of the problem we face and have led us to reconsider longstanding assumptions about stimulus control development and transfer. For example, do the gradual stimulus changes in transfer programs produce gradual changes in stimulus control or does transfer occur in a different manner than previously assumed? Are failures of programmed teaching procedures due to stimulus control transfer failures or merely to the wrong type of transfer? Are the variable outcomes of transfer procedures inevitable or can we develop a principled approach to reduce that variability? We believe that the theoretical and methodological foundation now exists to begin to answer these and other longstanding questions about stimulus control transfer and stimulus control development more generally. Answering those questions will advance not only theory but also our ability to teach people with intellectual disabilities more effectively. Research-to-practice studies are included to validate key principles and procedures in applied settings. |
