Behavioral momentum theory states that resistance to change of operant behavior is governed by the Pavlovian stimulus-reinforcer relation in a given discriminative stimulus situation. That is, higher reinforcer rates in the presence of a discriminative stimulus result in a stronger stimulus-reinforcer relation and, thereby, greater resistance to change. Within the momentum-based quantitative framework of resistance to change, the construct relating persistence to pre-disruption reinforcer rates is termed “behavioral mass.” All research on which momentum theory is based has examined resistance to change following prolonged exposure to stable reinforcer rates in multiple schedules of reinforcement. Thus, at present little is known about the time frame over which behavioral mass accumulates or the manner by which newly experienced stimulus reinforcer relations are incorporated into mass when these rates change. The experiments described in this dissertation aimed to clarify these facets of the construct. Chapters 1 and 2 provide a detailed overview behavioral momentum theory and resistance to change. Topics discussed include quantitative models of resistance to change, clinical implications of resistance-to-change research, some notable limitations of behavioral momentum theory, and extensions of the theory to account for diverse behavioral outcomes. A recently published study is presented in Chapter 3 that aimed to determine how resistance to change and behavioral mass of pigeons’ key pecking adapts in the face of stimulus-reinforcer relations that change across time during baseline. Results suggest that resistance to change is a function of recently experienced stimulus-reinforcer relations and that behavioral mass depends most heavily on these recent experiences. The experiment described in Chapter 4 extended the findings reported in Chapter 3 by examining whether behavioral mass changes during operant extinction. Pre-exposure to extinction in an alternative multiple-schedule component decreased resistance to extinction of target-component key pecking relative to conditions without pre-exposure to extinction. Between-condition differences in extinction were well accounted for quantitatively by either variation in behavioral mass or changes in the magnitude of factors that are assumed to disrupt responding during extinction. Chapter 5 offers an integrative discussion of this research and emphasizes theoretical implications, practical applications, and areas for future research.

Behavioral momentum theory (BMT) provides a theoretical framework for studying the persistence of behavior when challenged. The typical experimental arrangement to study persistence involves reinforcing a behavior according to a multiple schedules design. Unique schedules of reinforcement are programmed to each component. When steady-state responding occurs, the schedules of reinforcement are disrupted by a challenge condition (e.g., extinction, distraction, or prefeeding). The multiple schedules component that maintains the greatest level of responding during disruption is described as being more persistent. Basic research has shown that rate of reinforcement is a reliable predictor of persistence. The multiple schedules component associated with the higher rate of reinforcement persists longer than the multiple schedules component associated with the lower rate of reinforcement during disruption. Applied researchers have recently begun translating BMT to problems of social significance. The success of these initial translations suggests that relations between other dimensions of reinforcement and persistence should be studied. The current two-experiment study investigated the effect of quality of reinforcement on the persistence of task completion. Three participants with a history of engaging in problem behavior to escape from demands participated in Experiment I. After showing the conditions under which participants would and would not allocate away from a work task to engage with a preferred item, a baseline measure of task completion was obtained. Task completion was then reinforced with attention or tangibles within a multiple schedules design. Orange tokens signaled access to tangible reinforcement and yellow tokens signaled access to attention reinforcement. After steady-state responding occurred, preference for attention and tangibles was assessed within a concurrent schedules design. Extinction was then implemented to disrupt task completion within each component of the multiple schedules design. Results showed modest differences in the persistence of task completion with task completion in the multiple schedules component associated with the delivery of the more preferred reinforcer persisting longest. The modest differences in persistence were smaller than what has previously been shown in the literature. Thus, a follow-up experiment was conducted to evaluate the effect of reinforcer potency on the persistence of task completion. Three participants with a history of engaging in problem behavior to escape from demands participated in Experiment II. After identifying relatively more and less preferred stimuli with a multiple stimulus without replacement (MSWO) preference assessment, a unit price analysis was conducted to evaluate the potency of these two items within a concurrent schedules design. Task completion was then reinforced with the more and less potent reinforcers according to a multiple schedules design. After showing steady-state responding, task completion was disrupted by extinction. Results clearly showed greater persistence of task completion under the component associated with the delivery of the more potent reinforcer for two of three participants. Results from both experiments are discussed in terms of their conceptual and applied implications.

Um comportamento é dito mais resistente à mudança quanto menor for a alteração observada diante de modificações ambientais. Assim, estudos sobre resistência à mudança têm investigado a alteração do comportamento após a inserção de algumas operações que podem mudar comportamento que está em curso (evento perturbador). Essa proposta pode ser eficaz em investigações voltadas aos efeitos do consumo de drogas, como por exemplo, o etanol, que estimula determinadas áreas do Sistema Nervoso Central, responsáveis por possíveis alterações no valor reforçador de estímulos. O presente trabalho teve como objetivo avaliar se a presença do etanol acarretaria em alguma alteração diferencial nas condições com diferentes taxas de reforço e se sua presença e ausência poderiam ser caracterizadas como um evento perturbador. O Experimento I constou de duas partes. Na primeira parte foi analisada a função do etanol como evento perturbador. Dez ratos autoadministravam por via oral (gelatina) etanol (ET) 10% ou maltodextrina (MALTO) antes de sessões experimentais de treino de pressão à barra sob um esquema múltiplo VI 15 s-VI 45s. Na segunda parte, a pressão à barra foi colocada em extinção, mas as condições de autoadministração das substâncias foram mantidas para observar o efeito do etanol sobre a resistência à mudança dessa resposta. O Experimento II teve como objetivo avaliar o efeito da retirada de ET depois de intoxicações aguda e crônica. O experimento constou de duas partes. Na primeira, uma única dose de 20% de ET foi administrada por gavagem a ratos (n=9) previamente treinados sob o esquema múltiplo VI-VI; após 12 e 36 horas da administração, a resposta de pressão a barra sob o esquema múltiplo VI-VI foi observada. Na segunda parte, os mesmo ratos autoadministraram a cada 12 horas gelatina de ET a 10% por 21 dias; após 12 e 36 horas da administração, a resposta de pressão a barra sob o esquema múltiplo VI-VI foi novamente estudada. Os resultados do Experimento I indicaram que as doses consumidas de ET (10g/Kg) não tiveram função de evento perturbador. Quando houve algum efeito de queda ou aumento das taxas de respostas, esse não foi observado apenas no componente correlacionado com maior taxa de reforço, mas sim em ambos. Quanto à administração de ET na resistência à mudança empregando-se extinção como evento perturbador, não se obteve qualquer alteração. Contudo, quando a análise foi voltada à administração da gelatina, fosse com MALTO ou ET, houve diferentes efeitos em relação à fase de linha de base. Na primeira fase do Experimento II (retirada após intoxicação aguda) foi observado que a retirada do etanol teve efeito de evento perturbador apenas para sessões após 12h, mas não após 36h. Na segunda fase (retirada após a administração crônica) não houve efeito de retirada: os ratos continuaram se comportando de maneira semelhante aos dias com etanol. A retirada do etanol somente após a administração aguda apresentou tal efeito, que pode ser explicado devido ao efeito rebote de sua remoção do organismo, que foi observado somente após poucas horas do término do consumo (12 horas). Esse efeito rebote parece ter sido alterado pela taxa de reforço estabelecida nas condições do presente experimento (menos alterada ix na condição com maior taxa de reforço). Essa diversidade de resultados pode ter sido em função das diferenças entre consumo agudo e crônico ou por diferenças nas vias de administração empregadas / A behavior is considered resistant to change as the smallest change is observed before environmental modifications. Therefore, studies on resistance to change have investigated the change in behavior after the administration of some operations which can change the behavior in course (disrupting operation). This approach can be effective regarding investigations related to the effect of drug consumption such as ethanol, which stimulates specific areas in the Central Nervous System responsible for modifications in the reinforcement value of reinforcing stimuli. Thus, the purpose of the present study was to evaluate if the presence of ethanol would bring on any differential alteration in the reinforcement value of conditions with different rates of reinforcement and if its presence could be seen as a disruptive operation. Experiment I consisted of two parts. In the first, the function of ethanol as a disruption operation was analyzed. Ten rats self-administered orally (gelatin) ethanol (ET) 10% or maltodextrin (MALTO) before trial sessions of bar pressing training under a multiple VI 15 s-VI 45 s schedule. On the second part, the bar pressing was in extinction, but the conditions of the self-administration of the substances were maintained to observe the effects of ethanol on the resistance to change of this response. The purpose of Experiment II was to evaluate the effects of ET withdrawal after acute and chronic intoxications. The experiment was divided into two parts. On the first, a single dose of 20% ET was administered by force feeding to rats (n=9) previously trained under multiple schedules VI-VI; after 12 and 36 hours of the administration, the response bar pressing under the schedule VI-VI was observed. On the second part, the same rats self-administered every 12 hours ET gelatin at 10% for 21 days; after 12 and 36 hours of administration, the response bar pressing under the multiple schedule VI-VI was assessed. The results from Experiment I indicated that the consumed doses of ET (10g/Kg) did not function as a disrupting operation. When there was some effect or increase in response rates, it was not only observed in components co-related to a higher reinforcement rate, but in both. Regarding the administration of ET related to resistance to change when employing extinction as a disruption operation, there was no alteration. Nonetheless, when the analysis was directed to the administration of the gelatin either with MALTO or with ET there were different effects related to the baseline phase. On the first phase of Experiment II (withdrawal after acute intoxication) ethanol withdrawal had the effect of a disrupting operation only during sessions after 12hr, but not after 36hr. On the second phase (withdrawal after chronic administration) there was no effect of the withdrawal: rats continued to behave on the same way as they did on the days with ethanol. The ethanol withdrawal only presented such an effect after the acute administration which can be explained due to the rebound effect of its removal from the organism, which was observed only a few hours after the end of the consumption (12 hours). This rebound effect seems to be changed through the reinforcement rate established on the conditions of the present xi Experiment 2 (unless changed in the condition with the highest rate of reinforcement). The same results were not observed after the end of the chronic administration of the ethanol. This difference in results could be due to the differences between acute and chronic consumption or the differences in the methods of administration employed

Um comportamento é dito mais resistente à mudança quanto menor for a alteração observada diante de modificações ambientais. Assim, estudos sobre resistência à mudança têm investigado a alteração do comportamento após a inserção de algumas operações que podem mudar comportamento que está em curso (evento perturbador). Essa proposta pode ser eficaz em investigações voltadas aos efeitos do consumo de drogas, como por exemplo, o etanol, que estimula determinadas áreas do Sistema Nervoso Central, responsáveis por possíveis alterações no valor reforçador de estímulos. O presente trabalho teve como objetivo avaliar se a presença do etanol acarretaria em alguma alteração diferencial nas condições com diferentes taxas de reforço e se sua presença e ausência poderiam ser caracterizadas como um evento perturbador. O Experimento I constou de duas partes. Na primeira parte foi analisada a função do etanol como evento perturbador. Dez ratos autoadministravam por via oral (gelatina) etanol (ET) 10% ou maltodextrina (MALTO) antes de sessões experimentais de treino de pressão à barra sob um esquema múltiplo VI 15 s-VI 45s. Na segunda parte, a pressão à barra foi colocada em extinção, mas as condições de autoadministração das substâncias foram mantidas para observar o efeito do etanol sobre a resistência à mudança dessa resposta. O Experimento II teve como objetivo avaliar o efeito da retirada de ET depois de intoxicações aguda e crônica. O experimento constou de duas partes. Na primeira, uma única dose de 20% de ET foi administrada por gavagem a ratos (n=9) previamente treinados sob o esquema múltiplo VI-VI; após 12 e 36 horas da administração, a resposta de pressão a barra sob o esquema múltiplo VI-VI foi observada. Na segunda parte, os mesmo ratos autoadministraram a cada 12 horas gelatina de ET a 10% por 21 dias; após 12 e 36 horas da administração, a resposta de pressão a barra sob o esquema múltiplo VI-VI foi novamente estudada. Os resultados do Experimento I indicaram que as doses consumidas de ET (10g/Kg) não tiveram função de evento perturbador. Quando houve algum efeito de queda ou aumento das taxas de respostas, esse não foi observado apenas no componente correlacionado com maior taxa de reforço, mas sim em ambos. Quanto à administração de ET na resistência à mudança empregando-se extinção como evento perturbador, não se obteve qualquer alteração. Contudo, quando a análise foi voltada à administração da gelatina, fosse com MALTO ou ET, houve diferentes efeitos em relação à fase de linha de base. Na primeira fase do Experimento II (retirada após intoxicação aguda) foi observado que a retirada do etanol teve efeito de evento perturbador apenas para sessões após 12h, mas não após 36h. Na segunda fase (retirada após a administração crônica) não houve efeito de retirada: os ratos continuaram se comportando de maneira semelhante aos dias com etanol. A retirada do etanol somente após a administração aguda apresentou tal efeito, que pode ser explicado devido ao efeito rebote de sua remoção do organismo, que foi observado somente após poucas horas do término do consumo (12 horas). Esse efeito rebote parece ter sido alterado pela taxa de reforço estabelecida nas condições do presente experimento (menos alterada ix na condição com maior taxa de reforço). Essa diversidade de resultados pode ter sido em função das diferenças entre consumo agudo e crônico ou por diferenças nas vias de administração empregadas / A behavior is considered resistant to change as the smallest change is observed before environmental modifications. Therefore, studies on resistance to change have investigated the change in behavior after the administration of some operations which can change the behavior in course (disrupting operation). This approach can be effective regarding investigations related to the effect of drug consumption such as ethanol, which stimulates specific areas in the Central Nervous System responsible for modifications in the reinforcement value of reinforcing stimuli. Thus, the purpose of the present study was to evaluate if the presence of ethanol would bring on any differential alteration in the reinforcement value of conditions with different rates of reinforcement and if its presence could be seen as a disruptive operation. Experiment I consisted of two parts. In the first, the function of ethanol as a disruption operation was analyzed. Ten rats self-administered orally (gelatin) ethanol (ET) 10% or maltodextrin (MALTO) before trial sessions of bar pressing training under a multiple VI 15 s-VI 45 s schedule. On the second part, the bar pressing was in extinction, but the conditions of the self-administration of the substances were maintained to observe the effects of ethanol on the resistance to change of this response. The purpose of Experiment II was to evaluate the effects of ET withdrawal after acute and chronic intoxications. The experiment was divided into two parts. On the first, a single dose of 20% ET was administered by force feeding to rats (n=9) previously trained under multiple schedules VI-VI; after 12 and 36 hours of the administration, the response bar pressing under the schedule VI-VI was observed. On the second part, the same rats self-administered every 12 hours ET gelatin at 10% for 21 days; after 12 and 36 hours of administration, the response bar pressing under the multiple schedule VI-VI was assessed. The results from Experiment I indicated that the consumed doses of ET (10g/Kg) did not function as a disrupting operation. When there was some effect or increase in response rates, it was not only observed in components co-related to a higher reinforcement rate, but in both. Regarding the administration of ET related to resistance to change when employing extinction as a disruption operation, there was no alteration. Nonetheless, when the analysis was directed to the administration of the gelatin either with MALTO or with ET there were different effects related to the baseline phase. On the first phase of Experiment II (withdrawal after acute intoxication) ethanol withdrawal had the effect of a disrupting operation only during sessions after 12hr, but not after 36hr. On the second phase (withdrawal after chronic administration) there was no effect of the withdrawal: rats continued to behave on the same way as they did on the days with ethanol. The ethanol withdrawal only presented such an effect after the acute administration which can be explained due to the rebound effect of its removal from the organism, which was observed only a few hours after the end of the consumption (12 hours). This rebound effect seems to be changed through the reinforcement rate established on the conditions of the present xi Experiment 2 (unless changed in the condition with the highest rate of reinforcement). The same results were not observed after the end of the chronic administration of the ethanol. This difference in results could be due to the differences between acute and chronic consumption or the differences in the methods of administration employed

Behavioral momentum theory provides a conceptual framework for the study of the recurrence of previously extinguished operant behavior. Commonly referred to as treatment relapse, this is the failure to maintain treatment gains (e.g., reductions in challenging behavior) when there is a change in conditions under which these gains were achieved. One treatment relapse paradigm previously examined in basic and applied research is reinstatement. Reinstatement of challenging behavior has been shown to occur when functional reinforcers are delivered on a fixed-time schedule following extinction of challenging behavior. Although examinations appropriate behavior have applied value, analyses of reinstatement have been conducted almost exclusively with challenging behavior. During the current study, a reinstatement methodology was applied to communicative responses with five children diagnosed with developmental disabilities who exhibited comorbid communication deficits, as well as challenging behavior maintained by positive reinforcement. In the first phase of the reinstatement evaluation, each child received functional communication training (FCT) within a positive reinforcement context within a two-component multiple schedule design with each schedule paired with a distinct communicative response. After achieving steady-state responding in the first phase, in which all participants were independently emitting both communicative responses, all appropriate communication was placed on extinction in the second phase. Extinction continued until rates of appropriate communication were at or near zero. In the third phase, positive reinforcement was delivered and the recurrence of appropriate communication was evaluated. For two of five participants, communicative responding recurred following the fixed-time delivery of the functional reinforcer, indicating a successful demonstration of reinstatement. For three of five participants, communicative responding recurred prior to the delivery of fixed-time reinforcement, indicating that an alternative recurrence phenomenon likely occurred. These results suggest that reinstatement methodologies can be applied to cases in which FCT treatment failures have occurred to efficiently restore clinical gains for some participants. Implications for clinical practice and future directions of this line of research are discussed.

Interventions based on a token economy effectively reduce problematic behavior. Yet, treatment gains deteriorate once an intervention is discontinued. It is important to better understand the persistence of behavior maintained by token reinforcement in simple experimental procedures. A Pavlovian association with primary reinforcement is said to endow neutral stimuli (e.g., coins, poker chips, lights, signs, stickers, etc.) with their own function to strengthen behavior as conditioned reinforcers. Behavioral momentum theory suggests that resistance to change under conditions of disruption is the appropriate measure of response strength. However, some animal studies have suggested that conditioned reinforcement may not affect resistance to change of a response. Here, a novel token reinforcement procedure was developed to investigate the resistance to change of responding maintained by token reinforcement. Pigeons responded on a key to produce tokens displayed on a touchscreen monitor in two signaled token-production components. Tokens accumulated over the two production components prior to a common exchange component where pecks to the tokens on the touchscreen produced food reinforcement. Resistance to change of responding maintained by different rates of token reinforcement was assessed by disrupting baseline token-production responding with presession feeding. Token reinforcement rates had inconsistent effects on baseline token-production response rates. However, small effects of token reinforcement rate on resistance to change were found. Results provide weak support for a response-strengthening account of conditioned reinforcement and insightful directions for future studies of token reinforcement in related procedures.

Interventions based on a token economy effectively reduce problematic behavior. Yet, treatment gains deteriorate once an intervention is discontinued. It is important to better understand the persistence of behavior maintained by token reinforcement in simple experimental procedures. A Pavlovian association with primary reinforcement is said to endow neutral stimuli (e.g., coins, poker chips, lights, signs, stickers, etc.) with their own function to strengthen behavior as conditioned reinforcers. Behavioral momentum theory suggests that resistance to change under conditions of disruption is the appropriate measure of response strength. However, some animal studies have suggested that conditioned reinforcement may not affect resistance to change of a response. Here, a novel token reinforcement procedure was developed to investigate the resistance to change of responding maintained by token reinforcement. Pigeons responded on a key to produce tokens displayed on a touchscreen monitor in two signaled token-production components. Tokens accumulated over the two production components prior to a common exchange component where pecks to the tokens on the touchscreen produced food reinforcement. Resistance to change of responding maintained by different rates of token reinforcement was assessed by disrupting baseline token-production responding with presession feeding. Token reinforcement rates had inconsistent effects on baseline token-production response rates. However, small effects of token reinforcement rate on resistance to change were found. Results provide weak support for a response-strengthening account of conditioned reinforcement and insightful directions for future studies of token reinforcement in related procedures.

Several variables have been shown to influence resistance to change including rate, magnitude, and delay to reinforcement (Nevin, 1974). One variable that has not been studied with humans concerns the evaluation of resistance to change with unconditioned and conditioned reinforcers. In Experiment 1 (Resistance to Extinction Assessment), 5 participants' behaviors were reinforced during a baseline phase on a mult VI 30 s VI 30 s schedule with either a conditioned (i.e., token) or unconditioned reinforcer (i.e., food). Following equal reinforcement rates across components, extinction was introduced as a disruptor. All participants showed greater resistance to extinction in the component associated with conditioned reinforcers than unconditioned reinforcers. In Experiment 2 (Varied Distractors Assessment), 4 participants experienced a baseline phase the same as Experiment 1 (i.e., mult VI 30 s VI 30 s). Each participant was then exposed to prefeeding and distraction as disruptors in separate analyses. Results showed that behaviors were more resistant to distraction with conditioned than unconditioned reinforcers, similar to Experiment 1. However, when prefeeding disrupted responding, greater resistance to change was observed with unconditioned reinforcers than conditioned reinforcers. Implications of the results are discussed.

Attentional biases occur with various psychological disorders, including drugaddiction and anxiety. Conditioned reinforcement likely plays a role in maintainingattentional biases to stimuli associated with reinforcement for unwanted behavior. Theobserving-response procedure is considered a model of attending as reflected byresponding maintained by conditioned reinforcement. Effects of primary reinforcement on the persistence of observing have been studied in the framework of behavioral momentum theory. Studies have shown observing-responses to be more resistant tochange in contexts arranging relatively higher rates of primary reinforcement. Recently, behavioral momentum theory has been extended to describe the effects of primary reinforcement context in relapse phenomena. The present thesis aimed to extend research on the resistance to change of observing to animal models of relapse. Pigeons responded on a two-component multiple schedule of observing-response procedures. In a rich component, observing responses produced stimuli correlated with a high rate of variableinterval (VI) food reinforcement (Rich S+). In a lean component, observing responses produced stimuli correlated with a low rate of VI food reinforcement (Lean S+). Following stable performance, responding was extinguished by removing food and S+ presentations. After extinction, relapse was assessed by reinstatement tests consisting of response-independent presentations of food or S+. Replicating earlier results, observingand food-key responding was more resistant to extinction in the Rich component. Food reinstatement had no systematic effect on extinguished food- and observing-key responding. However, S+ reinstatement resulted in relapse of extinguished observingand food-key responding. Relapse during S+ reinstatement was greater in the Rich component than the Lean component. Reinstatement of responding by S+ presentations resulted in a greater overall increase in responding on the food-key relative to the observing-key. This result suggests that an important functional relationship between the presence of S+ stimuli and increased rates of primary reinforcement for food key responding remained intact during extinction. The results show that observing is susceptible to relapse, and the magnitude of relapse depends on baseline primary reinforcement rate in a context.

Behavioral momentum theory proposes that the persistence of behavior when exposed to disruptors provides an appropriate measure of the strength of behavior. Basic research has consistently demonstrated that behaviors that occurred in a context with higher overall rates of reinforcement (rich contexts) were more persistent than other behaviors that have occurred in a context with relatively lower rates of reinforcement (lean contexts). More surprisingly, behavioral momentum theory goes on to assert that this greater persistence in richer contexts is found even when rate of responding is lower in the rich context, and when the greater richness is due to noncontingent reinforcement or reinforcement for alternative responses. If behavioral momentum effects documented in laboratory settings are manifested in applied settings, these procedures may be used to increase the persistence of desirable behaviors or decrease the rate of problem behavior while simultaneously increasing its persistence. However, research on behavioral momentum has primarily been conducted by basic researchers using basic preparations. A key component of research on behavioral momentum is the presence of different contexts (typically signaled by color cues) each associated with a different rate of reinforcement. It is currently unclear if behavioral momentum effects are common in applied settings and if so, what variables determine context in applied settings. Thus, translational research should be conducted to examine the extent to which behavioral momentum theory accurately predicts behavior in applied settings while making systematic extensions to the established basic procedures. The purpose of the current study was to make one such extension that may be particularly important for replication of behavioral momentum research in applied settings. Two therapists functioned as two contexts with each participant to examine the effects of two interventions (i.e., contingent reinforcement with or without additional noncontingent reinforcement). Across participants, different patterns of results were found. In addition, participant responding was only partially disrupted during extinction and distraction phases, suggesting the procedures did not arrange a strong test of behavioral momentum theory. Because extinction did not reduce responding to very low levels, tests of reinstatement do not allow for clear conclusions to be drawn. In addition, patterns of responding did not clearly indicate participants were discriminating contexts. Several potential reasons for the lack of strong effects are discussed and suggestions for follow-up research are presented.