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EAB Monday Afternoon Session |
Monday, May 28, 2012 |
12:00 PM–2:00 PM |
Exhibit Hall 4AB (Convention Center) |
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1. Individual Differences in Effects of Exercise on Smoking in the Human Laboratory |
Area: EAB; Domain: Basic Research |
ALLISON KURTI (University of Florida), Jesse Dallery (University of Florida) |
Abstract: A single bout of exercise can decrease cigarette cravings and withdrawal, and increase the delay to ad libitum smoking. The present study used a laboratory analogue of smoking and a within-subjects design to assess individual differences in the relation between exercise and smoking. Participants experienced 20-min of exercise and 20-min of leisure activities across four sessions in an ABAB design. To assess individual differences in effects of exercise on smoking, a median split distinguished participants as responders (exercise increased delay > 1-min relative to control sessions) or non-responders (exercise increased delay < 1-min relative to control sessions). Responders waited 30.2-min longer to smoke after exercise relative to control sessions, and smoked 2.4 cigarettes per session. Non-responders waited 0.4-min longer to smoke after control relative to exercise sessions, and smoked 3.8 cigarettes per session. Responders also displayed lower resting heart rates, initiated smoking at a later age, and smoked fewer cigarettes per day than non-responders. These results suggest that exercise increases the delay to ad libitum smoking in the human laboratory, although there are substantial individual differences in the magnitude of this effect. Future research should identify characteristics that predict, or conditions that enhance, the efficacy of exercise to reduce smoking. |
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2. Prevalence and Difficulty Effects on Vigilance in a Baggage Screening Task |
Area: EAB; Domain: Applied Research |
JY LIN (Santa Clara University), Christina Rothans (Santa Clara University), Matthew C. Bell (Santa Clara University) |
Abstract: The Vigilance Reinforcement Hypothesis (VRH) predicts that a higher prevalence rate of target items (e.g., knives or guns) will function as reinforcement for baggage screening behavior and increase vigilance. Previous studies (Hogan et al., 2009; Wolfe, Horowitz, & Kenner, 2005) have explored this issue but not with more complex schedules, nor has there been much investigation of additional levels of difficulty in the visibility of the targets (easily-detected & difficultly-detected targets). In Experiment I, each experimental session included two different prevalence rates, 5% and 30%, but only one level of difficulty, easy targets or hard targets. The purpose was to examine the effects of prevalence rate on vigilance. Our prediction was that vigilance would be higher in conditions with higher prevalence rates of targets regardless of difficulty level, but that overall vigilance in conditions with easy target presentations would be greater than in conditions with hard target presentations. Preliminary data suggest that vigilance was greater in the conditions with easy target presentations. The mean hit rate was M=98% for the easy target condition and 62% in the hard target condition. In Experiment II, experimental sessions incorporated the same prevalence rate of targets (either 5% or 30%) across two different levels of difficulty of target visibility, easy and hard targets. Order of target difficulty was counterbalanced, allowing us to investigate order effects. We predicted that vigilance would improve for hard target performance when it followed practice with easy targets, independent of prevalence rate. Contrary to our prediction, there appears to be no effect of order in the 30% condition (hit rate in the hard condition was M = 71% and in the easy condition it was M = 96%) and degraded performance for the hard target condition when it follows an easy target condition (hard first hit rate M = 65% and hard following easy hit rate M = 0%). These initial findings have implications for training screeners. |
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3. A Behavioral Model of Pathological Human Avoidance: Quantifying Key Behaviors and Examining the Temporal Dynamics of Approach and Avoidance Behavior |
Area: EAB; Domain: Basic Research |
KAY TREACHER (University of North Texas), Sandy Magee (University of North Texas), Michael W. Schlund (University of North Texas) |
Abstract: Many forms of clinical pathology are characterized by four distinct interrelated dysfunctional behaviors (DBs): (a) increased attention to negative events (vigilance), (b) over-appraisal of stimuli as threatening (appraisal), (c) heightened negative emotion (anxiety/stress) and (c) excessive amounts of avoidance (avoidance). We developed an approach-avoidance model to quantify DBs, examine relations among DBs and examine variables that affect DBs. Within the model, approach responding was maintained by reinforcing button pressing on a fixed-ratio schedule with money. Pressing a concurrently available observing button (vigilance) produced an avoidance button and threat meter. Instructions stated that the meter displayed the current threat of losing money (0=none, 100=definite) and the level increased over time, but avoidance button presses could reduce the level. Results from ten subjects showed our instructions about threat were effective in modulating DBs. Increasing threat was associated with increases in vigilance and subsequent avoidance. Threat level was also associated with reported stress/anxiety. Decreasing threat level prompted switching from avoidance back to approach. Loss magnitude (1 cent, 40 cents) did not modulate behavior. However, increasing the cost of avoidance (FR2 to FR40) did increase threat tolerance for some subjects. This behavioral model provides a framework for examining variables that fuel pathological forms of avoidance. |
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4. Effects of Reinforcement History and Satiation Levels on Resistance to Change |
Area: EAB; Domain: Basic Research |
Raquel Alo (Universidade de Sao Paulo), JOSELE ABREU-RODRIGUES (Universidade de Brasilia), Alessandra Souza (University of Zurich) |
Abstract: The effects of different reinforcement histories and satiation levels on resistance to change were investigated in four experiments. After a history of exposure to a mult FR DRL schedule, the effects of two different levels of prefeeding upon resistance to change were evaluated, during the Test, with the same schedule and same schedule-correlated stimuli (Experiment 1); a mult FI FI schedule (Experiment 2); the same schedule, along with stimuli reversals (Experiment 3); and a mult EXT EXT schedule (Experiment 4). The three general findings were: (a) responding during the Test was at least initially a function of the stimulus correlated with each component schedule of the history-building Baseline; (b) a history of exposure to the FR schedule was associated with less resistance to prefeeding than a history of exposure to the DRL schedule; and (c) increases in the satiation level entailed decreases in response rates that, in most cases, implied less resistance to the contingency changes effected. The exceptions to these effects revealed that resistance to change was affected not only by the reinforcement histories and satiation levels, but also by the specific contingency modification of the Test condition. |
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5. Memory Deficits in a Transgenic Model of Comorbid Alzheimer's Disease and Diabetes |
Area: EAB; Domain: Basic Research |
DAVID E. TOSTO (West Virginia University), Michael A. Winser (West Virginia University), Tiffany L. Glover (West Virginia University), Stephen L. Deweese (West Virginia University), Kevin M. Knowlan (West Virginia University), John M. Grizzanti (West Virginia University), Miranda Reed (West Virginia University) |
Abstract: Diabetes is both a risk factor for Alzheimers disease, and a comorbidity that hastens dementia. The purpose of this study was to determine whether diabetes would exacerbate the learning and memory deficits observed in the tauP301L mouse model of Alzheimers disease. To induce diabetes, tau mice were injected with streptozotocin (STZ), which destroys the pancreatic islets of Langerhans. Weekly glucose measurements were taken to ensure hyperglycemia following STZ injections. After six weeks, mice were run through an autoshaping procedure. During the first experimental session, a tone (80 db) was presented on a variable-interval schedule) and maintained until either a nosepoke occurred or 15 seconds elapsed at which time sweetened milk is delivered. The session continued for two hours or until 20 reinforcers were earned. Seven days later a retention session was run, identical to that of the first session. We predict diabetes will exacerbate the learning and memory deficits observed in Alzheimers mice. |
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6. Performance Differences Between Adolescent and Adult Mice in an Incremental Repeated Acquisition of Behavioral Chains Task |
Area: EAB; Domain: Basic Research |
DEREK POPE (Auburn University), Andrew Shen (Auburn University), Blake A. Hutsell (Auburn University), M. Christopher Newland (Auburn University) |
Abstract: In a variety of species, adolescence is associated with abnormalities in decision-making, perseveration, and sensitivity to change that may leave the organism vulnerable to its environment. The present study assessed differences between adolescent BALB/c mice (n=10) at approximately postnatal day (PND) 35, and adult mice (n=11) at approximately PND 70, on an Incremental Repeated Acquisition (IRA) procedure. Lever pressing was autoshaped using presentations of sweetened condensed milk in modified rat chambers containing three levers. Subjects were required to perform the same response chain during each experimental session. The chain began with a single response (e.g., right lever press) then incremented up to a six-link response chain as behavior met arranged criteria (6-3-3-3-3 consecutive correct sequences). Dependent measures included a weighted sum of reinforcers earned per link, termed progress quotient (PQ), max chain length, response rate, and number of correct and incorrect responses. Adolescent mice acquired the IRA task with comparable speed to adults, but had lower overall response rates, maximum chain lengths, PQs, and correct responses. In addition, adolescent mice made substantially more errors on the rear lever, regardless of chain length, which may indicate insensitivity to changing contingencies, perseverative responding, or deficits in spatial learning. [Supported by ES003299] |
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7. Neural Correlates of Behavior Change: Temporal Dynamics of Brain Activation Associated With Changes in Reinforcement Rate During Schedule Changes |
Area: EAB; Domain: Basic Research |
SANDY MAGEE (University of North Texas), Michael W. Schlund (University of North Texas) |
Abstract: Behavior change prompted by changes in reinforcement conditions is supported by regulatory processes distributed throughout a prefrontal-striatal-parietal executive network. However, little is known about the relationship between temporal dynamics of the network and fluctuations in reinforcement rate. Using functional magnetic resonance imaging (fMRI) and free-operant methods, we tracked changes in brain activation during transitions from fixed-ratio reinforcement (RF) to extinction (EXT), where reinforcement rates decreased, and EXT to RF, where reinforcement rates increased. Both mixed and multiple schedules were used. Changes in reinforcement rate during both transitions prompted positive phasic responses in a prefrontal-parietal network, the insula and thalamus. However, the EXT to RF transition prompted positive phasic responses only in reward-sensitive striatal region. Furthermore, the RF to EXT transition prompted negative phasic responses only in ventral frontal regions sensitive to value and contingency. These results highlight regional plasticity and synchronization of a network important for supporting adaptive behavior change. |
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8. Assessing Influential Dimensions of Reinforcers on Choice in Children With Overweight |
Area: EAB; Domain: Applied Research |
ARIEL VITE SIERRA (Universidad Nacional Autonoma de Mexico), Alejandra Cavita (Universidad Nacional Autonoma de Mexico), Anayeli Hernandez (Universidad Nacional Autonoma de Mexico) |
Abstract: We examined how reinforcer rate, quality, delay, and response effort combined to influence in the choices of 10 children with overweight or obesity, to explore the viability of an assessment derived from the matching theory for determining differential responsiveness to those reinforcer and response dimensions. The students were given two concurrent sets of math problems that were equal on two dimensions but competed on two other dimensions (e.g., one set yielded higher rate and lower quality reinforcement than the other). Competing dimensions were counterbalanced across the six conditions of the initial baseline phase, permitting assessment of each dimension on time allocation. Time allocated to each of the problems within sets was differentially affected by the reinforcer and/or response dimensions, with allocation patterns varying across students. The results are discussed in the context of implications for the design of treatments and extrapolations from basic research on matching. |
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9. Pigeon Within Session Preference Reversal Using a Concurrent-Chains Procedure |
Area: EAB; Domain: Basic Research |
EMMA BEEBY (University of Otago), Geoff White (University of Otago) |
Abstract: Two experiments offered pigeons choices between small and large rewards using a concurrent-chains procedure with differing durations of delay (red and green trials) from the time of choice. It was hypothesized that the pigeons would initially prefer the small rewards delivered after short delays. However, it was also predicted that once the delay length increased for the green trials the pigeons preference would reverse, preferring the larger later reward. In Experiment 1, the difference between red and green trials was initially short 3 s, and this increased to a longer duration (10-s) for Condition 2 of the experiment. Four of the five pigeons showed within-session preference reversal, acting impulsively in red trials and self-controlled in green trials. In Experiment 2, the delays until reinforcement were increased or decreased by 1, 2, 4, 6, 8, 10, 12, and 15-s. Pigeons in the ascending group did demonstrate a gradual, steady increase in preference for the larger reward as the delay until reinforcement increased on green trials. Pigeons in the descending group did not show this pattern on green trials, and did not become more self-controlled with longer delays. These results show that pigeons can demonstrate within-session preference reversal using a concurrent-chains procedure. |
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10. The Effects of Fines on Cooperation in a Four-Person Prisoner's Dilemma Game |
Area: EAB; Domain: Basic Research |
ZACHARY H. MORFORD (University of Nevada, Reno), Traci M. Cihon (University of North Texas), Sigrid S. Glenn (University of North Texas) |
Abstract: Cooperation is an important area of investigation for behavior analysis. The Prisoners Dilemma game (PDG) provides a useful scenario for studying cooperation in a behavior analytic paradigm. The PDG can be coupled with the concept of the metacontingency to investigate how various contingency arrangements support and promote cooperation in a group. Players in this experiment participated in a PDG and, in some conditions, were given the ability to fine other players but could not talk. The goal of this experiment was to investigate how players ability to fine one another affected the players patterns of cooperation, and whether fining itself was affected by the addition of a shared group consequence. The data show that participants cooperated in some conditions, but the fines did not seem to affect players rates of cooperation. |
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11. Exploring Body Weight and Intrinsic Value Related to Exercise in Rats |
Area: EAB; Domain: Basic Research |
JENNIFER BRINEGAR (University of Central Arkansas) |
Abstract: Human and animal research shows an intrinsic relationship between body weight and voluntary activity. Modeling Activity-Based Anorexia, food-deprived rats consistently show that activity increases as weight decreases. This effect was explored in 8 food-deprived, Sprague-Dawley rats as potentially mediated by intrinsic value of activity. Running wheel activity rates were recorded for free-fed weight, reduction to 90% of free-fed weight, and 80% of free-fed weight. As expected, activity increased as weight decreased. Further, significant differences appeared in the trends of individual run rates when compared across all trials. These individual trends were expressed as varied rates of running, with extreme high and low run rates prevalent throughout all three weight conditions. The rewarding nature of exercise itself might serve to predict these trends in individual rats and reveal potential indicators for the development of Activity-Based Anorexia. |
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12. Demographic Differences in the Discrimination of Slight Differences in the Human Body Shape |
Area: EAB; Domain: Basic Research |
Diana Alejandra Gonzalez Garcia (Universidad Nactional Autonoma de Mexico), LAURA ACUNA (Universidad Nactional Autonoma de Mexico) |
Abstract: Members of different groups of people differ in their ability to discriminate subtle stimulus differences. The participants in this study were 56 men and 86 women that differed in age (18 to 90 years old) and in social class (low and middle). To determine possible differences in the thresholds of the subgroups, a constant, normal shape silhouette of either a man or a woman was presented on a screen next to a comparison silhouette of the same sex slightly deformed on a random basis. The participants task was to adjust the different parts of the comparison silhouette to match the sample. For most parts of the man and woman silhouettes, men were more sensitive to body shape than women. For most parts of the man silhouette, people younger that 50 were more sensitive to body shape than women while for the woman silhouette there were no age differences. For both, men and women silhouettes middle-class participants were more sensitive to body shape than those of the lower class. Results showed that as in previous psychophysics investigations discriminative ability varies between groups, in this case defined by the demographic differences of the same-nationality group. |
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13. Percent Body Fat Predicts Sensitivity to Hypothetical Outcomes for Food |
Area: EAB; Domain: Basic Research |
KELSIE HENDRICKSON (Idaho State University), Aarica Burke (Idaho State University), Jennifer Stoll (Idaho State University), Bradley D. Gossett (Idaho State University), Erin B. Rasmussen (Idaho State University) |
Abstract: Obese individuals endorse more impulsive decisions than healthy-weight individuals, but few studies model behavioral patterns of food choice. The current study examined impulsive choice patterns in two hundred eighty-six university students using the delay and probability discounting procedures. Participants made hypothetical choices between (a) 10 dollars after one of several different delays or a smaller amount of money available immediately; (b) 10 bites of food after one of several delays or a smaller number of bites available immediately; (c) $10 at one of several probabilities or a smaller amount of money to be received for sure; and (d) 10 bites of food at one of several probabilities or a smaller number of bites to be received for sure. For the food choices, 50 obese participants (BMI = 30) were compared to 103 healthy-weight participants (BMI = 18.5-24.9). Percent body fat (PBF) was also calculated for upper (37.1%, n = 55) and lower (20.5%; n = 54) quartiles. Results indicated that PBF, but not BMI, predicted delay and probability discounting for hypothetical food, but not for money. These results replicate Rasmussen et al. (2010)’s study, but extends it by controlling for variables that have been suggested to impact discounting (e.g., IQ). |
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14. Further Evaluation of Delay Fading to Teach Self-Control |
Area: EAB; Domain: Basic Research |
Shelly Moore Murawski (University of North Carolina Wilmington), Nathan Gibson (University of North Carolina Wilmington), Christine E. Hughes (University of North Carolina Wilmington), RAYMOND C. PITTS (University of North Carolina Wilmington) |
Abstract: The present experiment evaluated effects of a fading procedure on self-control choice. Rats chose between larger and smaller reinforcers. Using a procedure similar to the one described by Terrace (1963), both when and how the delay to the larger reinforcer was introduced was manipulated. Rats in the early-progressive group were exposed to a gradual increase in the delay, whereas rats in the early-constant group were exposed to an immediate, abrupt increase in the delay. Rats in the late-progressive and late-constant groups were exposed to the same training contingencies as their early counterparts, but only after over 100 sessions with a 0-s delay. Rats in the progressive groups chose the larger reinforcer more often than did rats in the constant groups. Whether or not the delay fading was introduced early or late had relatively little effect on choice. After training, all rats were exposed to a delay-discounting procedure. The primary effect of the progressive training appeared to be a bias for the side associated with the larger reinforcer, rather than a general tolerance for delay. |
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15. A Comparison of Peri-Adolescent and Adult Performance on a Two-Choice Serial Discrimination Reversal Task |
Area: EAB; Domain: Basic Research |
ANDREW SHEN (Auburn University), Derek Pope (Auburn University), Blake A. Hutsell (Auburn University), M. Christopher Newland (Auburn University) |
Abstract: Relatively few studies have assessed reversal learning in peri-adolescent animals. The present study compared peri-adolescent and adult performance on a two-choice, response-initiated, spatial discrimination reversal task (SDR). Subjects were peri-adolescent and adult BALB/c mice (n=9, n=7). Peri-adolescents were obtained at approximately postnatal day (PND) 30; adults were obtained at PND 50. Peri-adolescents began autoshaping at PND 35 while adults began at PND 64. Then subjects were assigned to a starting lever (left or right) in original discrimination (OD) training. A subject had to press a rear lever to initiate a trial, and then chose the appropriate front lever. OD sessions were 60 trials. Correct front lever-presses were reinforced under an FR 1 for sweetened condensed milk. Criterion for a reversal was 85% correct choices (51/60) for three consecutive sessions. Following criterion, the lever associated with the reinforcement contingency reversed. There were age-related differences in performance on the SDR task. During OD, peri-adolescent subjects showed increased commission and omission errors than adults. Correct responding in OD stabilized and peri-adolescents met criterion after 9-10 sessions, while adults met criterion within three to six sessions. In subsequent reversals, compared with adults, peri-adolescents failed to initiate trials (omissions) more frequently and latencies to initiate trials on the rear lever were higher for peri-adolescents. |
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16. Reinforcer Type Modulates Strain Differences in a Spatial Discrimination Reversal Procedure |
Area: EAB; Domain: Basic Research |
CRAIG W. CUMMINGS (Auburn University), Benjamin Campbell (Auburn University), Blake A. Hutsell (Auburn University), M. Christopher Newland (Auburn University) |
Abstract: Three genetically divergent strains of mice (DBA/2, C57BL/6 & BALB/c) were examined in a spatial discrimination reversal (SDR) procedure. In the SDR, two front levers were inserted into the chamber after a trial-initiation response occurred on a rear lever. Presses at only one of the front levers led to reinforcer presentation (sweetened condensed milk or sucrose pellet). In the pellet groups neither DBA/2 nor C57BL/6n met reversal criterion of 85% accuracy on 3 consecutive sessions so they received a reversal after 20 sessions and stable performance. This was because they failed to initiate a trial (omission errors) and not because they pressed the wrong lever (commission errors). For all strains, commission errors (incorrect front lever responses) were high on the first 3 sessions immediately following the initial reversal. For DBA/2 and BALB/c commissions declined with subsequent reversals. C57BL/6 showed more commission errors across reinforcers, especially with pellets. Trial-initiation latencies were higher across all strains in the pellet group. However, all strains demonstrated a decrease in trial initiation latencies across reversals for both reinforcer types, i.e., there were fewer omission errors with milk. Overall, milk seemed to equalize performance across strains while pellets seemed to amplify strain differences. [supported by ES017448]. |
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17. Reinforcer Quality Overcomes Strain Differences in Behavior Under an Incremental Repeated Acquisition-Performance Procedure |
Area: EAB; Domain: Basic Research |
BENJAMIN CAMPBELL (Auburn University), Craig W. Cummings (Auburn University), Blake A. Hutsell (Auburn University), M. Christopher Newland (Auburn University) |
Abstract: Inbred mouse strains provide a unique tool for uncovering genetic influences over operant behavior, and whether environmental variables can overcome them. To determine these differences, we used an incremented repeated acquisition-performance (IRA-P) procedure, which required an animal to complete increasingly elaborate chains for food presentation (e.g, up to a 6-link chain) with all sequences for each chain being the same in all sessions. We tested three strains of mice (DBA/2, C57BL/6 and BALB/c) on two different reinforcers (milk and sucrose). We compared the performance of each strain on three measures: maximum chain length, response rate and progress quotient (PQ), which quantifies progress through the chain as the total responses participating in a reinforced chain divided by the total reinforcers earned. The PQ measure showed that with sucrose reinforcers the BALB/c mice were superior to DBA/2 and C57BL/6 mice, which performed similarly to each other. With milk, however, C57BL/6 improved to perform similarly to BALB/c, but DBAs continued to perform poorly. Response rates were higher with milk reinforcers but varied independently of PQ and maximal chain length. We conclude that some genetic differences in stimulus control can be overcome by changing the reinforcer used to establish and maintain behavior. [supported by ES017448]. |
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18. Hedonic Scaling in the Rat |
Area: EAB; Domain: Basic Research |
JOSEPH D. MINTZ (University of Alaska Anchorage), Eric S. Murphy (University of Alaska Anchorage), Mikaela Mulder (University of Alaska Anchorage), Alyssa Hoskie (University of Alaska Anchorage), Shea Lowery (University of Alaska Anchorage), Rebecca Hoyman (University of Alaska Anchorage), Eric Regan (University of Alaska Anchorage) |
Abstract: The purpose of our study was to explore different methods of quantifying reinforcer value in four food-deprived rats. The rats were given free access to all possible pairs of purified, chocolate, grain and banana flavored 45-mg food pellets for five minutes. We used Case V of Thurstones (1927) Law of Comparative Judgment to derive interval-level preference scales from amount consumed and time allocated. The scales were highly reliable, Cronbach's alpha = 0.97, ICC = 0.93, and the scaled values correlated significantly with the calorie density of the reinforcers, r(30) = 0.86, p < 0.001. Our analysis revealed significant difference between the rates of consumption of each reinforcer, but there was no difference between the amount consumed or time allocated between subjects. The mean amount of time allocated to the environment as a function of trial was best approximated by a logarithmic decay function, suggesting habituation to the testing environment. The mean amount of time allocated to the environment also varied significantly as a function of reinforcer pair. Our study indicates Thurstonian scaling can be used to quantify reinforcer quality and may be adapted to leading models of choice behavior, such as the generalized matching law (e.g., Baum, 1974). |
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19. Issues in Operant Learning in Rattlesnakes |
Area: EAB; Domain: Basic Research |
CHRIS VARNON (Oklahoma State University), David Craig (Oklahoma State University), Aaron Place (Northwestern Oklahoma State University), Charles Abramson (Oklahoma State University) |
Abstract: Although the general principles of learning are thought to be fundamental across species, some groups of animals are not well represented in the literature. Snakes are one such group that have received little attention. A lack of replicated research has left us with no reliable methods to study operant learning in snakes. This is unfortunate considering the benefit of understanding the behavior of venomous snake species, and the phylogenetic relationship between reptiles and the more frequently studied birds and mammals. The present research explores potential responses that may be used to demonstrate learning, potential reinforcers for behavior, and the general methodology needed to study rattlesnake learning. Initial results have shown that the seemingly ubiquitous rattle response of rattlesnakes may not be a practical response in many experiments due to difficulty measuring lower volume rattles, an inability to truly shape the rattle, and difficulties reliably eliciting the rattle. Results are discussed in relation to other potential responses, such as lever presses, that may be more suitable for investigations of operant learning. |
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20. Area Under the Curve as a Measure of Temporal Control in Peak-Interval Procedures |
Area: EAB; Domain: Basic Research |
MIRARI ELCORO (Armstrong Atlantic State University), James W. Diller (Eastern Connecticut State University) |
Abstract: The study of temporal control has used a variety of quantitative indices, including the quarter life (QL), and the index of curvature (IC). The present project applied Area Under the Curve (AUC), a measure previously used to describe delay discounting functions (e.g., Myerson, Green & Warasuwitharana, 2001) to the analysis of data obtained from rats and pigeons in a peak interval procedure. In general, the AU C adequately reflected the changes in behavior resulting from several manipulations. The calculation of AUC is described, with comparisons to other quantitative indices such as the QL and IC. Additionally, we examined the variation of the AUC according to bin size. The application of AUC to describe temporal control of behavior potentially advances the quantitative analysis of temporal control of behavior. |
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21. Temporal and Probability Discounting of Real and Hypothetical RewardsDuring One Week |
Area: EAB; Domain: Basic Research |
ALEXIS MATUSIEWICZ (University of Maryland), Anne E. Carter (Virginia Tech Carilion School of Medicine and Research), Reid D. Landes (University of Arkansas), Richard Yi (University of Maryland) |
Abstract: Temporal discounting (TD) and probability discounting (PD) refer to the reduction in the subjective value of outcomes as a function of delay and uncertainty, respectively. Elevated measures of discounting are associated with a variety of maladaptive behaviors. Confidence in the validity of these measures is imperative. The present research examined (1) identity of discounting measures when rewards hypothetical or real, and (2) their 1-week stability. Previous research has partially explored these issues, however, this work has employed the relatively low threshold of nonsigificant difference rather than the more compelling threshold of statistical eqivalence. The current study addressed these questions by collecting TD and PD measures from 28 healthy adults using real and hypothetical $50 rewards during each of two experimental sessions, one week apart. Analyses using area-under-the-curve measures revealed a general pattern of statistical equivalence, indicating identity between real/hypothetical conditions as well as 1-week stability for TD and PD. Exceptions are identified and discussed. |
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