The momentum of human behavior in a natural setting

Response-dependent point loss and response force as disrupting operations on behavioral resistance to change in humans

Behavioral momentum theory (BMT) provides a theoretical and methodological framework for understanding how differentially maintained operant responding resists disruption. A common way to test operant resistance involves contingencies with suppressive effects, such as extinction or prefeeding. Other contingencies with known suppressive effects, such as response-cost procedures arranged as point-loss or increases in response force, remain untested as disruptive events within the BMT framework. In the present set of three experiments, responding of humans was maintained by point accumulation programmed according to a multiple variable-interval (VI) VI schedule with different reinforcement rates in either of two components. Subsequently, subtracting a point following each response (Experiment 1) or increasing the force required for the response to be registered (Experiments 2 and 3 decreased response rates, but responding was less disrupted in the component associated with the higher reinforcement rate. The point-loss contingency and increased response force similarly affected response rates by suppressing responding and human persistence, replicating previous findings with humans and nonhuman animals when other types of disruptive events (e.g., extinction and prefeeding) were investigated. The present findings moreover extend the generality of the effects of reinforcement rate on persistence, and thus BMT, extending the analysis of resistance to two well-known manipulations used to reduce responding in the experimental analysis of behavior.

Persistence of effort in apathy

The syndrome of apathy has generated increasing interest in recent years as systematic evaluations have revealed its high prevalence and strong negative impact on quality of life across a wide range of neurological and psychiatric conditions. However, although several theoretical models have been proposed to account for various aspects of the condition, understanding of this syndrome is still incomplete. One influential model has proposed that apathy might be described as a quantitative reduction of goal-directed behaviour in comparison to an individual's prior level of functioning. Persistence of activity defined as the capacity to continue with a task - sometimes in the face of setbacks, high levels of difficulty or fatigue - is a crucial but understudied aspect of goal-directed behaviour. Surprisingly, it has not been investigated yet in the context of apathy. Here, we provide an overview of theoretical and experimental aspects of persistence in effort that might assist to develop methods for the investigation of persistence in human behaviour, particularly within the pathologic context of apathy.

Resistance to change, of behavior and of theory

The persistence of operant behavior when disrupted tends to be positively related to how often reinforcers were delivered in the past. Behavioral momentum theory describes this finding as the outcome of Pavlovian processes. That is, the relation between discriminative stimuli and reinforcers that were delivered in their presence strengthens behavior, thereby making it more likely to persist. If only the story were that simple. A growing number of findings challenge the basic tenets of behavioral momentum theory. Some even call into question whether Pavlovian relations contribute to persistence in the first place. In this paper, I will review behavioral momentum theory and some of the data that have been problematic for the theory. I will argue that despite these very real challenges, the theory provides important utility not only to basic analyses of response persistence but also to clinical interventions directed at long-term reductions in problem behavior. It, for example, has set the stage for the development of alternative conceptual analyses of resistance to change, two of which will be highlighted for readers. Moreover, behavioral momentum theory may tell us something important about the reasons it continues to have an influence on the field, despite the challenging data that deter it.

Procedures for determining and then modifying the extinction component of multiple schedules for destructive behavior

As a component of reinforcer schedule thinning following functional communication training, multiple schedules of reinforcement produce desirable rates and patterns of communication responses as an alternative response to destructive behavior. However, reinforcement schedule thinning is a gradual process that can take many sessions to obtain therapeutic goals. The desired outcome is that manding occurs only during signaled intervals of reinforcement with a sufficiently lean terminal schedule of reinforcement availability and low rates of destructive behavior. The purposes of this study were to (a) evaluate an assessment for informing the initial duration of extinction for alternative responding, (b) evaluate the utility of competing stimuli during extinction for alternative responding, and (c) assess a method for fading the availability of competing stimuli. With these procedures, all 4 participants experienced terminal schedules of reinforcement with rapid, robust reductions in destructive behavior soon after baseline. We discuss the implications and directions for future research.

Behavior Momentum Theory and Humans: A Review of the Literature

Behavioral Momentum Theory (BMT) is often described as analogous to Newton's (1687) laws of motion. That is to say, similar to an object in motion continuing in motion unless acted upon by a force, responses occurring in a static environment will continue to occur at the same rate, unless presented with a disruptor (Nevin, Tota, Torquato, & Shull, Journal of the Experimental Analysis of Behavior, 53, 359-379, 1990). When evaluating response rates through a behavioral momentum framework, responding continuing after a change in reinforcer conditions is said to persist. Previous research conducted with nonhuman animals indicates greater response persistence following conditions with either higher reinforcer rates or higher reinforcer magnitudes (Nevin, Journal of the Experimental Analysis of Behavior, 21(3), 389-408, 1974; Nevin et al., Journal of the Experimental Analysis of Behavior, 53, 359-379, 1990). Although BMT's implications extend across human and nonhuman species, this literature review attempts to provide practitioners and researchers information regarding response persistence across various conditions with human participants.

Relational Density Theory: Nonlinearity of Equivalence Relating Examined through Higher-Order Volumetric-Mass-Density

We propose relational density theory, as an integration of stimulus equivalence and behavioral momentum theory, to predict the nonlinearity of equivalence responding of verbal humans. Consistent with Newtonian classical mechanics, the theory posits that equivalence networks will demonstrate the higher order properties of density, volume, and mass. That is, networks containing more relations (volume) that are stronger (density) will be more resistant to change (i.e., contain greater mass; mass = volume * density). Data from several equivalence experiments that are not easily interpreted through existing accounts are described in terms of the theory, generating predictable results in most cases. In addition, we put forward the higher-order properties of relational acceleration and gravity, which follow directly from the theory and may inspire future researchers to evaluate the seemingly self-organizing nature of human cognition. Finally, we conclude by describing avenues for real-world translation, considering past research interpreted through relational density theory, and call for basic experimental research to validate and extend core theoretical assumptions.

Resistance to change as function of different physical-effort requirements in humans

The effects of different physical-effort requirements on behavioral resistance to change were examined with undergraduate students engaging in a computer task for points exchangeable for money. In Baseline, button pressing was maintained on a multiple variable interval (VI) 45-s VI 45-s schedule of reinforcement with two physical-effort requirements: 10 N in the Low-Effort Component and 50 N in the High-Effort Component. In Test, button pressing was disrupted by a multiple extinction (EXT) EXT schedule plus anagrams as a concurrent task for five participants. For other two participants, button pressing was disrupted only by a multiple EXT EXT in one test, and both disruptors were implemented together in the second test. Baseline and Test conditions were replicated in an ABAB design. Resistance to change was greater in the presence of discriminative stimuli associated with the Low-Effort Component to six participants during the first test and to four participants during the second test. The present findings suggest differences in physical-effort can contribute to differences in resistance to change.

Baseline reinforcement rate and resurgence of destructive behavior

Concepts from behavioral momentum theory, along with some empirical findings, suggest that the rate of baseline reinforcement may contribute to the relapse of severe destructive behavior. With seven children who engaged in destructive behavior, we tested this hypothesis in the context of functional communication training by comparing the effects of different baseline reinforcement rates on resurgence during a treatment challenge (i.e., extinction). We observed convincing resurgence of destructive behavior in four of seven participants, and we observed more resurgence in the condition associated with high-rate baseline reinforcement (i.e., variable-interval 2 s in Experiment 1 or fixed-ratio 1 in Experiment 2) compared to a low-rate baseline reinforcement condition. We discuss the implications of these results relative to schedules of reinforcement in the treatment of destructive behavior and strategies to mitigate resurgence in clinical settings.

Delivering alternative reinforcement in a distinct context reduces its counter-therapeutic effects on relapse

Delivery of alternative reinforcers in the presence of stimuli previously associated with reinforcement for target behavior increases the susceptibility of target behavior to relapse. To explore contingencies that might mitigate this counter-therapeutic effect, we trained pigeons on a procedure that entailed extinction of previously reinforced target-key pecking, access to a distinct stimulus context contingently on refraining from target behavior (differential-reinforcement-of-other-behavior; DRO), and reinforcement of alternative-key pecks (differential-reinforcement of alternative behavior; DRA) in that context. This DRO-DRA treatment was compared with standard DRA in successive conditions, counterbalanced across pigeons. Target behavior extinguished more rapidly in the Standard-DRA condition. When alternative reinforcement was discontinued, however, there was less resurgence after DRO-DRA than after Standard DRA. In a third condition, the DRO contingency was suspended so that the former DRA stimuli were not presented (DRO-NAC), and resurgence was greater than in the Standard-DRA and DRO-DRA conditions. Reinstatement produced by response-independent reinforcers was small and similar across conditions. Subsequent reacquisition of target-key pecking under baseline reinforcement conditions was faster following DRO-NAC than Standard-DRA or DRO-DRA. These findings suggest that DRO-DRA might serve as a useful method in clinical settings for reducing problem behavior while minimizing the threat of posttreatment relapse.

Additional free reinforcers increase persistence of problem behavior in a clinical context: A partial replication of laboratory findings

Behavioral momentum theory is a quantitative framework used to characterize the persistence of behavior during response disruptors as a function of baseline stimulus-reinforcer relations. Results of several investigations have shown that alternative reinforcement can increase the resistance to change of a target response during extinction. In the present study, concomitant variable-interval fixed-time schedules of reinforcement for problem behavior were employed to simulate naturalistic situations involving the superimposition of response-independent reinforcers on a baseline schedule of reinforcement for problem behavior, as in the common use of noncontingent reinforcement treatments. Resistance to change of problem behavior was assessed during postsession periods of extinction by comparing response rates in extinction following sessions with and without additional reinforcer deliveries arranged by fixed-time schedules. For 2 out of 3 participants, problem behavior tended to be more resistant to extinction following periods in which additional fixed-time reinforcers were delivered. These results are discussed in terms of potential effects of noncontingent reinforcement on problem behavior when the intervention is discontinued or implemented without good treatment integrity.

Tony nevin: The embrace of translational work by a basic scientist

Here I summarize John A. "Tony" Nevin's evolution as a translational author. All of his publications were classified by title and content as being primarily experimental analysis of behavior or translational. Translational works were subtyped as interpretative, descriptive research, or experimental research. During the first 20 years of his publication career, Tony published exclusively experimental analysis of behavior work. In 1982, he began a series of interpretative translational analyses on topics of significant social importance. These interpretative papers translated behavioral science into logical accounts of issues of war and peace, for example, and performed quantitative analyses of available data to show that social behavior, even at the level of the group or society, conforms to predictions based on established behavioral principles. Tony began experimental translational research in 1990, first to establish whether his analysis of behavioral momentum generalized to humans. Several experimental studies later addressed the persistence of clinically relevant behavior and treatment relapse. The objective descriptions of Tony's publication patterns are punctuated with anecdotes from our 32-year collaboration and friendship.

The Role of Contingencies and Stimuli in a Human Laboratory Model of Treatment of Problem Behavior

Behavioral momentum theory posits a paradoxical implication for behavioral interventions in clinical situations using Differential Reinforcement of Alternative Behavior (DRA): When alternative reinforcers are presented within the same context as the problem behavior, the added reinforcers may decrease the frequency of the behavior but also increase its persistence when the intervention ends. Providing alternative reinforcers in a setting that is distinctively different from that in which the target behavior occurs may avoid or reduce this increase in persistence. The present experiment compared behavioral persistence following standard DRA versus DRA in a different context that was available after refraining from target behavior (Differential Reinforcement of Other Behavior, DRO). We arranged a human laboratory model of treatment intervention using computer games and token reinforcement. Participants were five individuals with intellectual disabilities. Experimental phases included (a) an initial multiple-schedule baseline with token reinforcement for target behaviors A and B, (b) an intervention phase with alternative reinforcement using a conventional DRA procedure for A and a DRO-DRA procedure for B, and (c) an extinction phase with no interventions and no tokens. Response rates as proportion of baseline in the initial extinction phase were greater for A than for B for three of five participants. Four participants whose response rates remained relatively high during the extinction phase then received a second extinction-plus-distraction test with leisure items available. Response rates were greater for A than for B in three of four participants. The results indicate that DRO-DRA contingencies may contribute to reduced post-intervention persistence of problem behavior.

Basing assessment and treatment of problem behavior on behavioral momentum theory: Analyses of behavioral persistence

The connection, or bridge, between applied and basic behavior analysis has been long-established (Hake, 1982; Mace & Critchfield, 2010). In this article, we describe how clinical decisions can be based more directly on behavioral processes and how basing clinical procedures on behavioral processes can lead to improved clinical outcomes. As a case in point, we describe how applied behavior analyses of maintenance, and specifically the long-term maintenance of treatment effects related to problem behavior, can be adjusted and potentially enhanced by basing treatment on Behavioral Momentum Theory. We provide a brief review of the literature including descriptions of two translational studies that proposed changes in how differential reinforcement of alternative behavior treatments are conducted based on Behavioral Momentum Theory. We then describe current clinical examples of how these translations are continuing to impact the definitions, designs, analyses, and treatment procedures used in our clinical practice.

Quantitative models of persistence and relapse from the perspective of behavioral momentum theory: Fits and misfits

We review quantitative accounts of behavioral momentum theory (BMT), its application to clinical treatment, and its extension to post-intervention relapse of target behavior. We suggest that its extension can account for relapse using reinstatement and renewal models, but that its application to resurgence is flawed both conceptually and in its failure to account for recent data. We propose that the enhanced persistence of target behavior engendered by alternative reinforcers is limited to their concurrent availability within a distinctive stimulus context. However, a failure to find effects of stimulus-correlated reinforcer rates in a Pavlovian-to-Instrumental Transfer (PIT) paradigm challenges even a straightforward Pavlovian account of alternative reinforcer effects. BMT has been valuable in understanding basic research findings and in guiding clinical applications and accounting for their data, but alternatives are needed that can account more effectively for resurgence while encompassing basic data on resistance to change as well as other forms of relapse.

Persistence and resistance to extinction in the domestic dog: Basic research and applications to canine training

This review summarizes the research investigating behavioral persistence and resistance to extinction in the dog. The first part of this paper reviews Behavioral Momentum Theory and its applications to Applied Behavior Analysis and training of pet dogs with persistent behavioral problems. I also highlight how research on Behavioral Momentum Theory can be applied to the training of detection dogs in an attempt to enhance detection performance in the presence of behavioral disruptors common in operational settings. In the second part of this review, I highlight more basic research on behavioral persistence with dogs, and how breed differences and experiences with humans as alternative sources of reinforcement can influence dogs' resistance to extinction of a target behavior. Applied Behavior Analysis and Behavior Momentum Theory have important applications for behavioral treatments to reduce the persistence of problem behavior in dogs and for the development of enhanced training methods that enhance the persistence of working dogs. Dogs can also be leveraged as natural models of stereotypic behavior and for exploring individual differences in behavioral persistence by evaluating breed and environmental variables associated with differences in canine persistance.

Toward a general theory of momentum-like effects

The future actions, behaviors, and outcomes of objects, individuals, and processes can often be anticipated, and some of these anticipations have been hypothesized to result from momentum-like effects. Five types of momentum-like effects (representational momentum, operational momentum, attentional momentum, behavioral momentum, psychological momentum) are briefly described. Potential similarities involving properties of momentum-like effects (continuation, coherence, role of chance or guessing, role of sensory processing, imperviousness to practice or error feedback, shifts in memory for position, effects of changes in velocity, rapid occurrence, effects of retention interval, attachment to an object rather than an abstract frame of reference, nonrigid transformation) are described, and potential constraints on a future theory of momentum-like effects (dynamic representation, nature of extrapolation, sensitivity to environmental contingencies, bridging gaps between stimulus and response, increasing adaptiveness to the environment, serving as a heuristic for perception and action, insensitivity to stimulus format, importance of subjective consequences, role of knowledge and belief, automaticity of occurrence, properties of functional architecture) are discussed. The similarity and ubiquity of momentum-like effects suggests such effects might result from a single or small number of mechanisms that operate over different dimensions, modalities, and time-scales and provide a fundamental adaptation for perception and action.

Teaching Children with Severe Disabilities to Utilize Nonobligatory Conversational Opportunities: An Application of High-Probability Requests

Two children with severe disabilities who used electronic communication aids were taught to extend conversations as a result of implementation of an intervention strategy based on high-probability request sequences. Both participants had been selected as a result of the discrepancy between their propensity to respond to obligatory conversational bids (e.g., a question such as “What did you do at recess?”) and their propensity to refrain from responding to nonobligatory conversational bids (e.g., comments such as “I played kickball at recess”). Both learners' conversational maintenance skills improved as a result of the procedure. Educational implications are discussed.

Behavioral Momentum Theory: a Tutorial on Response Persistence

Behavioral momentum theory (BMT) provides an integrative framework for evaluating the strength of a response when it contacts a disruptor, such as the discontinuation of reinforcement (i.e., extinction). Grounded in Newtonian physics, BMT distinguishes response rate (behavioral velocity) from response strength or persistence (behavioral mass). Behavioral velocity is affected by response-reinforcer contingencies, whereas behavioral mass is affected by stimulus-reinforcer contingencies (Nevin and Wacker 2013). We describe the determiners of behavioral mass, as well as common sources of disruption that are used to measure behavioral mass. Learning activities are embedded throughout this discussion to help readers better understand BMT and its implications for practice across a range of contexts.

Relations between rate of negative reinforcement and the persistence of task completion

Research has shown that differential reinforcement of alternative behavior (DRA) can be an effective intervention to address problem behavior maintained by negative reinforcement emitted by young children. However, few studies have evaluated the variables that are related to long-term maintenance (i.e., persistence) of treatment effects. Research on behavioral persistence predicts that the rate of reinforcement provided for a target behavior is correlated with its persistence when challenged. There were 2 purposes of the current investigation. First, we evaluated the effects of the rate of negative reinforcement on the persistence of task completion. Second, we applied the findings regarding rate of reinforcement to a treatment context for 3 participants who engaged in destructive behavior that was reinforced by escape from demands. Results were evaluated within a multielement design and indicated that the rate of negative reinforcement had a moderate influence on the persistence of task completion. These results contribute to the existing literature by extending analyses of persistence to treatment contexts.

Pavlovian conditioning enhances resistance to disruption of dogs performing an odor discrimination

Domestic dogs are used to aid in the detection of a variety of substances such as narcotics and explosives. Under real-world detection situations there are many variables that may disrupt the dog's performance. Prior research on behavioral momentum theory suggests that higher rates of reinforcement produce greater resistance to disruption, and that this is heavily influenced by the stimulus-reinforcer relationship. The present study tests the Pavlovian interpretation of resistance to change using dogs engaged in an odor discrimination task. Dogs were trained on two odor discriminations that alternated every six trials akin to a multiple schedule in which the reinforcement probability for a correct response was always 1. Dogs then received several sessions of either odor Pavlovian conditioning to the S+ of one odor discrimination (Pavlovian group) or explicitly unpaired exposure to the S+ of one odor discrimination (Unpaired group). The remaining odor discrimination pair for each dog always remained an unexposed control. Resistance to disruption was assessed under presession feeding, a food-odor disruptor condition, and extinction, with baseline sessions intervening between disruption conditions. Equivalent baseline detection rates were observed across experimental groups and odorant pairs. Under disruption conditions, Pavlovian conditioning led to enhanced resistance to disruption of detection performance compared to the unexposed control odor discrimination. Unpaired odor conditioning did not influence resistance to disruption. These results suggest that changes in Pavlovian contingencies are sufficient to influence resistance to change.

Behavioral momentum and accumulation of mass in multiple schedules

Behavioral momentum theory suggests that the relation between a discriminative-stimulus situation and reinforcers obtained in that context (i.e., the Pavlovian stimulus-reinforcer relation) governs persistence of operant behavior. Within the theory, a mass-like aspect of behavior has been shown to be a power function of predisruption reinforcement rates. Previous investigations of resistance to change in multiple schedules, however, have been restricted to examining response persistence following protracted periods of stability in reinforcer rates within a discriminative situation. Thus, it is unclear how long a stimulus-reinforcer relation must be in effect prior to disruption in order to affect resistance to change. The present experiment examined resistance to change of pigeon's key pecking following baseline conditions where reinforcer rates that were correlated with discriminative-stimulus situations changed. Across conditions, one multiple-schedule component arranged either relatively higher rates or lower rates of variable-interval food delivery, while the other component arranged the opposite rate. These schedules alternated between multiple-schedule components across blocks of sessions such that reinforcer rates in the components were held constant for 20, 5, 3, 2, or 1 session(s) between alternations. Resistance to extinction was higher in the component that most recently was associated with higher rates of food delivery in all conditions except when schedules alternated daily or every other day. These data suggest that resistance to change in multiple schedules is related to recently experienced reinforcer rates but only when multiple-schedule components are associated with specific reinforcer rates for several sessions.

Task Sequencing for Students With Emotional and Behavioral Disorders

We reviewed studies utilizing task sequencing to improve academic outcomes for children with emotional and/or behavioral disorders (EBD) in educational settings. Task sequencing interventions included high-probability, high-preference, and task interspersal interventions. Although task sequencing is commonly used in research, a synthesis of recent applications in educational settings for students with EBD is absent. Systematic searches of electronic databases and ancestral references identified 11 studies meeting inclusion criteria. These 11 studies were reviewed and analyzed for (a) participant characteristics, (b) experimental design, (c) type of academic outcome as the dependent variable, (d) intervention description, (e) certainty of evidence and research quality, and (f) reported student academic outcomes. Implications for continued applied practice and future research are discussed.

Behavioural Momentum: Implications for Clinical Practice

Behavioural momentum refers to the tendency for reinforced behaviour to persist when conditions are altered. Research on persistence with pigeons as subjects has suggested that response rate under steady-state conditions and its persistence when conditions are altered are independent aspects of behaviour, with response rate determined by response-reinforcer contingencies and persistence determined by stimulus-reinforcer contingencies. These results have been replicated with humans in a natural setting, and may therefore be relevant to clinical practice. The following prescriptions are suggested by the research results: (a) To eliminate undesirable behaviour, it is not sufficient to reinforce alternative behaviour in the same setting because this may actually enhance persistence of the undesired response; change to a new setting may also be necessary; (b) to establish desirable behaviour, the behaviour should be reinforced frequently, and to make it persistent, both the therapeutic and natural environments should be highly correlated with reinforcement.

A New Frontier: Integrating Behavioral and Digital Technology to Promote Health Behavior

Modifiable behavioral risk factors such as cigarette smoking, physical inactivity, and obesity contribute to over 40 % of premature deaths in the USA. Advances in digital and information technology are creating unprecedented opportunities for behavior analysts to assess and modify these risk factors. Technological advances include mobile devices, wearable sensors, biomarker detectors, and real-time access to therapeutic support via information technology. Integrating these advances with behavioral technology in the form of conceptually systematic principles and procedures could usher in a new generation of effective and scalable behavioral interventions targeting health behavior. In this selective review of the literature, we discuss how technological tools can assess and modify a range of antecedents and consequences of healthy and unhealthy behavior. We also describe practical, methodological, and conceptual advantages for behavior analysts that stem from the use of technology to assess and treat health behavior.

Modeling the effects of sensory reinforcers on behavioral persistence with alternative reinforcement

Problem behavior often has sensory consequences that cannot be separated from the target response, even if external, social reinforcers are removed during treatment. Because sensory reinforcers that accompany socially mediated problem behavior may contribute to persistence and relapse, research must develop analog sensory reinforcers that can be experimentally manipulated. In this research, we devised analogs to sensory reinforcers in order to control for their presence and determine how sensory reinforcers may impact treatment efficacy. Experiments 1 and 2 compared the efficacy of differential reinforcement of alternative behavior (DRA) versus noncontingent reinforcement (NCR) with and without analog sensory reinforcers in a multiple schedule. Experiment 1 measured the persistence of key pecking in pigeons, whereas Experiment 2 measured the persistence of touchscreen responses in children with intellectual and developmental disabilities. Across both experiments, the presence of analog sensory reinforcers increased the levels, persistence, and variability of responding relative to when analog sensory reinforcers were absent. Also in both experiments, target responding was less persistent under conditions of DRA compared to NCR regardless of the presence or absence of analog sensory reinforcers.

Behavioral resistance to haloperidol and clozapine

Using a procedure to assess behavioral resistance to change, the effects of two drugs (haloperidol and clozapine) were compared to each other and to the effect of response-independent food delivered between multiple-schedule components. Using rats as subjects, responding in one component was maintained on a variable-interval 30-s schedule, whereas responding in another component was maintained on a variable-interval 30-s schedule that operated concurrently with a variable-time 30-s schedule. Consistent with previous findings, responding in the component with the greater overall amount of reinforcement displayed the greater resistance to response-independent food delivery. Similarly, increasing the dose of haloperidol or clozapine increased the overall extent of disruption (relative to baseline levels), with the greatest disruption occurring to responding in the component associated with the smaller overall amount of food reinforcement. Thus, as with the disruption caused by alterations in reinforcement conditions, the extent of disruption to reinforced responding caused by haloperidol and clozapine is specifically dependent upon baseline reinforcement conditions rather than baseline response rates.

Tolerance to cocaine's effects following chronic administration of a dose without detected effects on response rate or pause

To observe tolerance to drug effects on operant behavior, the dose that researchers have often selected for chronic administration is one that disrupts, but does not abolish, responding. Some evidence suggests that tolerance may develop after chronic administration of relatively smaller doses. The purpose of the present experiment was to assess systematically effects of chronic administration of a dose without detected effect on responding. Specifically, response rates and post-reinforcement pauses of five pigeons key pecking under a three-component multiple fixed-ratio schedule of food reinforcement were observed under chronic cocaine administration. We evaluated the effects of a range of doses (1.0 mg/kg to 17.0  mg/kg) during acute administration. The largest dose that failed to alter responding acutely then was administered chronically (1.0  mg/kg for 1 pigeon, 3.0  mg/kg for 3 pigeons, and 5.6  mg/kg for 1 pigeon). After 30 consecutive sessions of chronic administration, smaller and larger doses occasionally were substituted for the chronic dose. Pigeons then received pre-session saline administration for 30 consecutive sessions, and the post-chronic effects of the series of doses on responding were determined. All subjects developed tolerance to doses of cocaine that initially had caused large decreases in rate, with the magnitude of the effects varying across components of the multiple schedule and subjects. Specifically, tolerance generally was greatest in the components with smaller ratios. Following post-chronic saline administration, tolerance was usually diminished. Overall, the results demonstrate that under these conditions, repeated experience with disruptive effects of cocaine on food-maintained responding is not a necessary factor in the development of tolerance.

Enhancing the application and evaluation of a discrete trial intervention package for eliciting first words in preverbal preschoolers with ASD

This study evaluates the effectiveness of an intervention package including a discrete trial program (Rapid Motor Imitation Antecedent Training (Tsiouri and Greer, J Behav Educat 12:185-206, 2003) combined with parent education for eliciting first words in children with ASD who had little or no spoken language. Evaluation of the approach includes specific intervention targets and functional spoken language outcomes (Tager-Flusberg et al., J Speech Lang Hear Res 52:643-652, 2009). Results suggest that RMIA, with parent training, catalyzes development of verbal imitation and production for some children. Three of five participants acquired word production within the DTT framework and achieved milestones of early functional spoken language use (Tager-Flusberg et al., J Speech Lang Hear Res 52:643-652, 2009). The implications of these findings for understanding the role of discrete trial approaches to language intervention are discussed.

The Persistence-Strengthening Effects of DRA: An Illustration of Bidirectional Translational Research

We summarize a series of bidirectional research studies that demonstrate the persistence-strengthening effects of differential reinforcement of alternative behavior on problem behavior. We model a possible solution to this problem with rats followed by replication with a human clinical population. The importance of coordinated basic and applied research to stimulate new behavioral technologies is emphasized.

Behavioral momentum theory: equations and applications

Behavioral momentum theory provides a quantitative account of how reinforcers experienced within a discriminative stimulus context govern the persistence of behavior that occurs in that context. The theory suggests that all reinforcers obtained in the presence of a discriminative stimulus increase resistance to change, regardless of whether those reinforcers are contingent on the target behavior, are noncontingent, or are even contingent on an alternative behavior. In this paper, we describe the equations that constitute the theory and address their application to issues of particular importance in applied settings. The theory provides a framework within which to consider the effects of interventions such as extinction, noncontingent reinforcement, differential reinforcement of alternative behavior, and other phenomena (e.g., resurgence). Finally, the theory predicts some counterintuitive and potentially counterproductive effects of alternative reinforcement, and can serve as an integrative guide for intervention when its terms are identified with the relevant conditions of applied settings.

Contextual influences on resistance to disruption in children with intellectual disabilities

Training context can influence resistance to disruption under differing reinforcement schedules. With nonhumans, when relatively lean and rich reinforcement schedules are experienced in the context of a multiple schedule, greater resistance is found in the rich than the lean component, as described by behavioral momentum theory. By contrast, when the schedules are experienced in separated blocks of sessions (i.e., as single schedules), resistance is not consistently greater in either component. In the current study, two groups of 6 children with intellectual disabilities responded to stimuli presented in relatively lean or rich components. For both, reinforcers were delivered according to the same variable-interval reinforcement schedule; additionally, the rich component included the delivery of response-independent reinforcers. The Within group was trained on a multiple schedule in which lean and rich components alternated regularly within sessions; the Blocked group was trained on two single schedules in which sessions with either the lean or rich schedule were conducted in successive blocks. Disruption tests presented a concurrently available alternative stimulus disrupter signaling the availability of tangible reinforcers. All 6 Within participants showed greater resistance to disruption in the rich component, consistent with behavioral momentum theory. By contrast, there was no consistent or significant difference in resistance for Blocked participants. This finding is potentially relevant to the development of interventions in applied settings, where such interventions often approximate single schedules and include response-independent reinforcers.

Resistance to extinction and behavioral momentum

In the metaphor of behavioral momentum, reinforcement is assumed to strengthen discriminated operant behavior in the sense of increasing its resistance to disruption, and extinction is viewed as disruption by contingency termination and reinforcer omission. In multiple schedules of intermittent reinforcement, resistance to extinction is an increasing function of reinforcer rate, consistent with a model based on the momentum metaphor. The partial-reinforcement extinction effect, which opposes the effects of reinforcer rate, can be explained by the large disruptive effect of terminating continuous reinforcement despite its strengthening effect during training. Inclusion of a term for the context of reinforcement during training allows the model to account for a wide range of multiple-schedule extinction data and makes contact with other formulations. The relation between resistance to extinction and reinforcer rate on single schedules of intermittent reinforcement is exactly opposite to that for multiple schedules over the same range of reinforcer rates; however, the momentum model can give an account of resistance to extinction in single as well as multiple schedules. An alternative analysis based on the number of reinforcers omitted to an extinction criterion supports the conclusion that response strength is an increasing function of reinforcer rate during training.

Resistance to disruption in a classroom setting

Substantial experimental evidence indicates that behavior reinforced on a denser schedule is more resistant to disruption than is behavior reinforced on a thinner schedule. The present experiment studied resistance to disruption in a natural educational environment. Responding during familiar activities was reinforced on a multiple variable-interval (VI) 7-s VI 30-s schedule for 6 participants with developmental disabilities. Resistance to disruption was measured by presenting a distracting item. Response rates in the disruption components were compared to within-session response rates in prior baseline components. Results were consistent with the predictions of behavioral momentum theory for 5 of 6 participants.

Evaluation of resistance to change under different disrupter conditions in children with autism and severe intellectual disability

Translational research inspired by behavioral momentum theory in the area of developmental disabilities has shown effects in individuals over a range of functioning levels. In the current study, behavioral momentum was assessed in 6 children diagnosed with autism and severe intellectual disability. In a repeated measures design, participants were exposed to relatively rich versus lean reinforcement contingencies in a multiple schedule with food reinforcers. This was followed by exposure to each of four disrupting conditions: prefeeding, presentation of a concurrent alternative stimulus, presentation of a movie, and the presence of a researcher dispensing response-independent reinforcers on a variable-time schedule. Consistently greater resistance to disruption in the component with the richer schedule occurred with the alternative stimulus disrupter but not with the other disrupters. These results suggest parameters that may be more (or less) effective if behavioral momentum inspired techniques are to be exploited in therapeutic environments.

The effects of constant versus varied reinforcers on preference and resistance to change

Previous research has demonstrated that factors such as reinforcer frequency, amount, and delay have similar effects on resistance to change and preference. In the present study, 4 boys with autism made choices between a constant reinforcer (one that was the same food item every trial) and a varied food reinforcer (one that varied randomly between three possible food items). For all 4 boys, varied reinforcers were preferred over constant reinforcers, and they maintained higher response rates than constant reinforcers. In addition, when a distraction (a video clip) was introduced, responding maintained by varied reinforcers was more resistant to distraction than responding maintained by constant reinforcers. Thus, the present experiment extended the generality of the relation between preference and resistance to change to variation in reinforcer quality.