Association for Behavior Analysis International

The Association for Behavior Analysis International® (ABAI) is a nonprofit membership organization with the mission to contribute to the well-being of society by developing, enhancing, and supporting the growth and vitality of the science of behavior analysis through research, education, and practice.


35th Annual Convention; Phoenix, AZ; 2009

Event Details

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Symposium #396
Behavior in Variable Environments: Dynamics of Behavior in Choice and Stimulus-Control Procedures
Monday, May 25, 2009
10:30 AM–11:50 AM
North 226 AB
Area: EAB; Domain: Experimental Analysis
Chair: Raymond C. Pitts (University of North Carolina Wilmington)
Discussant: Douglas Elliffe (University of Auckland)
Abstract: Behavior readily adapts to rapidly changing contingencies. For example, several studies have shown that response allocation in concurrent schedules can adapt to session-to-session, or within-session, changes in the ratio of reinforcement rates, amounts, and/or delays. After sufficient exposure to rapidly changing environmental conditions, behavior becomes relatively sensitive to the current contingencies, and relatively insensitive to contingencies prevailing in previous conditions. In this symposium, we explore further the dynamics of behavior under rapidly changing contingencies. Data investigating effects of unsignaled, within-session, changes in reinforcement parameters under concurrent variable-interval schedules (e.g., reinforcement rate and reinforcement magnitude), and data investigating effects of session-to-session changes in contingencies controlling a temporal discrimination, will be presented.
Choice in a Variable Environment: Do Findings Depend on Level of Aggregation?
ANDREW M RODEWALD (University of North Carolina Wilmington), Christine Hughes (University of North Carolina Wilmington), Raymond C. Pitts (University of North Carolina Wilmington)
Abstract: Davison, Baum and colleagues have reported data from a series of studies in which reinforcer ratios, arranged via concurrent variable-interval (VI) schedules, varied unpredictably within sessions. Data aggregated over several sessions indicated that: a) response allocation within a given component was sensitive to the arranged reinforcer ratio for that component, b) preference for an alternative increased with successive reinforcers obtained via that alternative, and, c) each reinforcer presentation produced a brief “preference pulse” for the just productive alternative. It was suggested that reinforcers guide, rather than strengthen behavior. The current experiment was a replication of one condition of the Davison and Baum (2000) study. Each session consisted of seven components in which concurrent VI schedules were arranged; the programmed reinforcer ratios (L:R) ranged from 27:1 to 1:27. Components were unsignaled, their order within each session was randomly determined, and each lasted 10 reinforcers. When aggregated over a large number of sessions (e.g., 35), the data were similar to those reported by Davison and Baum (2000). Several characteristics of performance (e.g., preference pulses) were preserved when the data were aggregated over fewer sessions. Finally, sensitivity to the rapidly changing conditions was acquired in relatively few sessions.
Effects of Relative Amount and Rate of Food on Preference
CARLOS F. APARICIO (University of Guadalajara-CUCS-Neuroscience), Raymond C. Pitts (University of North Carolina Wilmington), Craig Cummings (University of North Carolina Wilmington), Christine Hughes (University of North Carolina Wilmington), William M. Baum (University of California, Davis)
Abstract: Recent research showed that control over local choice by extended variables proved to be true not only of relative food rate but also relative amount. In these studies either a constant overall rate of food delivery or a food-rate ratio provided by two alternatives changed across seven components within daily sessions and food-amount ratio changed across phases. Short- and long-term effects of food deliveries on preference were found with no evidence indicating that control of preference became more local as food amount varied, suggesting that variations in the amount and frequency of food act in similar ways to control preference. We assessed the generality of these findings with eight rats responding in concurrent schedules. The food-amount ratio provided by two levers changed across seven components within daily sessions and three food-rate ratios changed across phases. Results showed that preference separated across components, more responses occurred on the large-amount-of-food lever than on the small-amount-of-food lever. More local analysis of visits to the levers between food deliveries and preference pulses following food deliveries will be conducted to find out whether or not a mathematical model based on a linear-operator equation accounts for these results.
Rapid Changes in Bias in Simple and Complex Temporal Discrimination in Rats
BLAKE A. HUTSELL (Southern Illinois University-Carbondale), Eric A. Jacobs (Southern Illinois University-Carbondale)
Abstract: In the present study, we sought to extend the rapid acquisition methodology to signal detection procedures. Specifically, we investigated changes in bias when relative reinforcer frequency for correct responses varied across sessions according to a pseudorandom sequence (Hunter & Davison, 1985). In Experiment 1, four rats responded in a two-stimulus, two-response detection procedure employing temporal stimuli (short vs. long houselight presentations). Relative reinforcer frequency varied according to a 31-step pseudorandom binary sequence and stimulus-duration difference varied over two levels across conditions. In Experiment 2, three rats responded in a five-stimulus, two-response detection procedure employing temporal stimuli. Relative reinforcer frequency was varied according to a 36-step pseudorandom ternary sequence. Results of both experiments were analyzed according to a behavioral model of detection (Davison & Nevin, 1999). The model was extended to incorporate the effects of current and previous session reinforcer frequency ratios on current session performance. Similar to findings in concurrent schedules, effects of relative reinforcer frequency were highest in the current session; however, effects of previous sessions were evident. Generally, the results indicate that bias can come under control of frequent changes in relative reinforcer frequency in both simple and complex detection procedures.



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