«EVALUATIONS OF DELAYED REINFORCEMENT IN CHILDREN WITH DEVELOPMENTAL DISABILITIES By JOLENE RACHEL SY A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL ...»
EVALUATIONS OF DELAYED REINFORCEMENT IN CHILDREN WITH
JOLENE RACHEL SY
A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA© 2011 Jolene Rachel Sy To my parents, who taught me to value education and enjoy life
ACKNOWLEDGMENTSI thank my mentor, Dr. Tim Vollmer, for his excellent suggestions, valuable feedback, and years of support. I would not be who I was today without his guidance. I also would like to thank my committee members: Dr. Brian Iwata, Dr. Darragh Devine, and Dr. Hazel Jones for their comments and suggestions on this project. Finally, I would like to thank Dr. Jesse Dallery for his feedback on this project.
I could not have gotten here without support from my dear family and friends. I thank them for the years and years of love and understanding.
TABLE OF CONTENTSpage ACKNOWLEDGMENTS
LIST OF FIGURES
LIST OF ABBREVIATIONS
CHAPTER 1 INTRODUCTION
Recommendations About the Necessity of Reinforcement Immediacy
Laboratory Studies of Delayed Reinforcement
A Summary of Laboratory Studies
Innovative Methods Used to Evaluate Delayed Reinforcement
The Effects of Delayed Reinforcement on Human Behavior
Variables that May Influence Delayed Reinforcement
Responses During the Delay
Number of Alternatives Targeted at One Time
2 HUMAN OPERANT EVALUATIONS OF DELAYED REINFORCEMENT............... 23
Subjects and Setting
Experiment 1A: Procedure
Experiment 1A: Results and Discussion
Experiment 1B: Procedure
Experiment 1B: Results and Discussion
Experiment 1C: Procedure
Experiment 1C: Results and Discussion
3 THE EFFECTS OF DELAYED REINFORCEMENT ON DISCRIMINATIONACQUISITION DURING CONDITIONAL DISCRIMINATION TRAINING............... 63 Conditional Discrimination Training
Subjects and Setting
Target Responses and Data Collection
Conditional discrimination training
Experiment 2A: Procedure
Experiment 2A: Results and Discussion
Experiment 2B: Procedure
Experiment 2B: Results and Discussion
Experiment 2C: Procedure
Experiment 2C: Results and Discussion
Experiment 2D: Procedure
Experiment 2D: Results and Discussion
4 GENERAL DISCUSSION
LIST OF REFERENCES
Rate of “correct” responses during delayed reinforcement and immediate 2-1 reinforcement conditions of Experiment 1A.
Mean rate of “correct” responses as a function of delay, during Experiment 2-2 1A and hyperbolas depicting estimated relationship between these variables... 47 Percentage of ”correct” responses during the delayed reinforcement and 2-3 immediate reinforcement conditions of Experiment 1A
Mean percentage of ”correct” responses across consecutive delays to 2-4 reinforcement during Experiment 1A.
2-5 Breakpoints obtained during the delayed reinforcement condition of Experiment 1A.
Rate of “correct” responses during delayed reinforcement and immediate 2-6 reinforcement conditions of Experiment 1B.
Mean rate of “correct” responses as a function of delay during Experiment 1B 2-7 and hyperbolas depicting estimated relationship between these variables........ 52 Percentage of “correct” responses during delayed reinforcement and 2-8 immediate reinforcement conditions of Experiment 1B
Mean percentage of “correct” responses across consecutive delays to 2-9 reinforcement during Experiment 1B.
2-10 Breakpoints obtained during the delayed reinforcement condition of Experiment 1B..
Rate of “correct” responses during delayed reinforcement and immediate 2-11 reinforcement conditions of Experiment 1C.
Mean rates of “correct” responses as a function of programmed delay during 2-12 Experiment 1C and hyperbolas depicting relationship between variables.......... 57 Mean rates of “correct” responses as a function of obtained delay between 2-13 last “correct” or “incorrect” response and reinforcment during Experiment 1C... 58 Mean rates of “correct” responses as a function of obtained delay between 2-14 last “correct” response and reinforcement during Experiment 1C
Percentage of “correct” responses during delayed reinforcement and 2-15 immediate reinforcement conditions of Experiment 1C..
Mean percentage of “correct” responses across consecutive delays to 2-16 reinforcement in Experiment 1C..
2-17 Breakpoints obtained during the tandem VI - PT schedule of reinforcement in the delayed reinforcement condition of Experiment 1C.
3-1 Percent correct across 20-s delayed reinforcement and immediate reinforcement conditions in Experiment 2A..
3-2 Percent correct across 30-s delayed reinforcement and immediate reinforcement conditions during Experiment 2A..
3-3 Percent correct across 40-s delayed reinforcement and immediate reinforcement conditions during Experiment 2A.
3-4 Percent correct across delayed reinforcement and immediate reinforcement conditions of Experiment 2B. Stimuli available during delay..
3-5 Percent correct across delayed reinforcement and immediate reinforcement conditions of Experiment 2C. Four alternatives were targeted per condition...... 80 3-6 Percent correct across conditions in which either 0-s or 30-s ITI were programmed during Experiment 2D
DD Developmental Disability; Characterized by below-average scores on tests of mental ability and limited daily living skills (e.g., communication) DRO Differential Reinforcement of Other Behavior; Reinforcement provided contingent on the absence of problem behavior for a prespecified interval FI Fixed Interval; Reinforcement provided for the first response following a constant period of time FR Fixed Ratio; Reinforcement provided following the last of a constant number of responses IRI Interreinforcement Interval; Time between successive reinforcer deliveries ITI Intertrial Interval; Time between the consumption of the reinforcer and the start of the next trial SD Discriminative Stimulus; Stimulus that signals that a particular response will produce reinforcement S S-Delta; Stimulus that signals that a particular response will not produce reinforcement PT Progressive Time; Schedule of reinforcement in which reinforcers are delivered following progressively increasing delays VI Variable Interval; Schedule of reinforcement in which reinforcement is provided for the first response following an average period of time VT Variable Time; Schedule of reinforcement in which reinforcement is provided, independent of responding, following an average interval of time
Chair: Timothy R. Vollmer Major: Psychology It is commonly recommended that reinforcers be provided immediately after behavior to establish or maintain responding (e.g., Miltenberger, 2008). These recommendations are usually provided in the absence of supporting empirical work, which is unfortunate because several laboratory experiments have found that delayed reinforcement can produce response acquisition and maintenance (e.g., Lattal & Gleeson, 1990). Relatively fewer studies with humans have isolated the effects of unsignaled, delayed reinforcement. Fewer still have evaluated unsignaled, delayed reinforcement in children with developmental disabilities (DD). Thus, the general purpose of the following experiments was to (a) examine whether delayed reinforcement could produce response maintenance in children with DD during an operant arrangement, (b) examine whether delayed reinforcement could produce discrimination acquisition in children with DD, (c) examine some of the variables that may affect the efficacy of delayed reinforcement in children with DD, and (d) examine one variable that may account for situations in which delayed reinforcement prevents acquisition. We found that delayed reinforcement produced response maintenance during three human operant arrangements. In addition, we found that 20-, 30-, and 40-s delays to reinforcement lead to discrimination acquisition for the majority of subjects.
The availability of identical responses during the delay did not prevent response maintenance for 2 out of 3 subjects or discrimination acquisition for 2 out of 3 subjects.
For 1 out of 2 subjects, discrimination acquisition was hindered when the number of responses targeted during each session was increased. These results suggest that delayed reinforcement can produce acquisition and maintenance under specific conditions. In addition, we found that longer intertrial intervals (time between delivery of a reinforcer and the presentation of the next trial) most likely do not account for cases in which discrimination acquisition fails to occur under conditions of delayed reinforcement.
Recommendations About the Necessity of Reinforcement Immediacy Several notable textbooks recommend that reinforcers be provided immediately following a response to establish or maintain behavior (e.g., Miltenberger, 2008;
Skinner, 1953). Skinner noted, “The reinforcement which develops skills must be immediate. Otherwise, the precision of the differential effect is lost.” (p.96) Likewise, Catania (2007) noted, “with both positive and negative reinforcement, immediate reinforcement is more effective than delayed reinforcement.” (p.99) Given these types of recommendations, it is not surprising that the temporal proximity between a response and a reinforcing event has been considered to be one of the most important parameters of reinforcer efficacy (Williams, 1976). Nevertheless, results from several experiments suggest that delayed reinforcement can produce response acquisition and maintenance under some conditions.
A Summary of Laboratory Studies Researchers have evaluated both signaled delays to reinforcement, which program a stimulus change immediately following a response, and unsignaled delays to reinforcement, which do not program a stimulus change following a response. Due to their pairing with delayed reinforcement, stimulus changes may begin to function as conditioned reinforcers and supplement the effects of delayed reinforcement with immediate reinforcement. Laboratory studies have found that both signaled and unsignaled delays to reinforcement can produce response acquisition (e.g., Critchfield & Lattal, 1993; Lattal & Gleeson, 1990) and maintenance (e.g., Gleeson & Lattal, 1987;
Schaal & Branch, 1988). Some of these studies program resetting delays, in which every response that occurs during the delay resets the delay interval, ensuring that obtained delays to reinforcement match programmed delays. Resetting contingencies do not allow experimenters to isolate the effects of delayed reinforcement independent of a differential reinforcement of other behavior (DRO) contingency, which requires that a given amount of time elapse since the last response before a reinforcer can be delivered. Thus, many researchers program nonresetting delays in which responses that occur during the delay do not have programmed consequences. Lattal and Gleeson found that unsignaled, nonresetting 30-s and resetting 10-s delays produced response acquisition in pigeons, and that unsignaled, resetting 10-s or 30-s delays produced response acquisition in rats.
Innovative Methods Used to Evaluate Delayed Reinforcement Given the wealth of basic research on delayed reinforcement, it is not surprising that several procedural advances have been made. These advances allow researchers to isolate the effects of delayed reinforcement. Although concurrent arrangements, in which two or more responses are available and proportional responding is measured, can be used to study relative preference for immediate reinforcement over delayed reinforcement (e.g., Dixon, Horner, & Guercio, 2003), single-operant arrangements, in which only one response is available, provide information about the absolute effects of delayed reinforcement, and several laboratory experiments have used such arrangements (e.g., Critchfield & Lattal, 1993).
Basic researchers have also created procedures that rule out the effects of (a) reinforcement rate, (b) immediate conditioned reinforcement, and (c) adventitious reinforcement. When delayed reinforcement conditions are compared with immediate reinforcement conditions, it is often the case that at least two variables differ between conditions: (a) the time between a response and a reinforcer, and (b) reinforcement rate (with delayed reinforcement sessions associated with lower rates of reinforcement). To rule out decreases in reinforcement rate as a confounding variable, reinforcement rate must be equated across delayed reinforcement and immediate reinforcement conditions. Researchers have done this by yoking interreinforcement intervals (IRI;