A demonstration of incorporating discriminative stimuli into an AAC device during functional communication training

Functional communication training (FCT) is an effective intervention for teaching communication responses and reducing challenging behavior. One limitation of FCT is that frequent reinforcement may be impractical or impossible in many situations. Recently, Mitteer et al. published a tutorial in the journal AAC that provided video models on how to implement an empirically supported strategy for thinning reinforcement during FCT, known as FCT with discriminative stimuli, when teaching with an augmentative and alternative communication (AAC) device. However, no study has empirically evaluated the approach described in that tutorial. This paper details a case study using several single-case experimental designs to teach a non-vocal autistic adult who did not use speech to communicate requests only when reinforcement was signaled to be available by the color of the AAC icons. We demonstrated the efficacy of this approach with unique pairs of discriminative stimuli for tangible and edible items, thinning reinforcement for each stimulus class independently. We then rapidly transferred stimulus control to new icons and integrated both classes of stimuli into a single AAC grid. This first demonstration of embedding discriminative stimuli into an AAC device represents a promising advancement for individuals who do not use speech and may not readily respond to delay or denial cues.

A comparison of RIRD within chained and multiple schedules in the treatment of vocal stereotypy

Slaton and Hanley (2016) compared the effects of multiple and chained schedules on stereotypy and item engagement for 2 individuals who exhibited automatically maintained motor stereotypy. Contingent access to motor stereotypy (i.e., chained schedules) was more effective than time-based access (i.e., multiple schedules) at reducing motor stereotypy, increasing item engagement, and establishing stimulus control for both participants. We systematically replicated Slaton and Hanley with 2 participants by a) targeting vocal stereotypy, b) including response interruption and redirection as a treatment component across conditions, c) conducting sessions in the natural environment with teaching assistants as change agents, and d) conducting an analysis of the effective treatment component(s). Chained schedules were more effective for 1 participant, whereas both treatments were effective for the other participant. The component analysis showed that different components were necessary for effective treatment for each participant.

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.

On the Efficacy of and Preference for Signaling Extinction in a Multiple Schedule

Previous basic research has shown that signaling the extinction component of a compound schedule can be aversive and nonpreferred. However, such discriminative stimuli are common when thinning schedules of reinforcement in practice, and they provide several advantages to clinicians. A limitation of previous applied studies on different arrangements of discriminative stimuli is that researchers have used identical stimuli to signal the availability of reinforcement across conditions that do and do not signal extinction, often doubling exposure to the stimulus signaling the availability of reinforcement. The present experiments corrected this limitation by comparing multiple-schedule arrangements that do and do not signal extinction when unique stimuli signal each component across conditions. Results from three participants indicated that both multiple-schedule arrangements were similarly efficacious when teaching the successive discrimination. However, response patterns differed when testing under a concurrent-operants arrangement, suggesting different patterns of preference across various multiple-schedule arrangements.

Formative applications of ongoing visual inspection for trial-based functional analysis: A proof of concept

Trial-based functional analysis (TBFA) possesses many strategic advantages which make it an ideal candidate for adoption in applied settings. Notwithstanding, some aspects of the analysis remain underdeveloped, including structured guidelines for interacting with obtained data reliably in formative and summative ways. The purpose of this study was to adapt existing ongoing visual-inspection (OVI) criteria to match the idiosyncrasies of TBFA and then to assess their practical utility in applied settings. Thus, we first drafted OVI criteria appropriate for trial-based FA (i.e., TB-OVI). Then, we trained 5 caregivers to conduct TBFAs of their children's challenging behavior and to react to their data as they obtained it, using the TB-OVI criteria as their guide. Finally, we validated interpretations of TBFA outcomes based on TB-OVI criteria through effective intervention. Across 5 participants and 7 opportunities, function-based interventions successfully eliminated challenging behavior.

A Bayesian time-to-event pharmacokinetic model for phase I dose-escalation trials with multiple schedules

Phase I dose-escalation trials must be guided by a safety model in order to avoid exposing patients to unacceptably high risk of toxicities. Traditionally, these trials are based on one type of schedule. In more recent practice, however, there is often a need to consider more than one schedule, which means that in addition to the dose itself, the schedule needs to be varied in the trial. Hence, the aim is finding an acceptable dose-schedule combination. However, most established methods for dose-escalation trials are designed to escalate the dose only and ad hoc choices must be made to adapt these to the more complicated setting of finding an acceptable dose-schedule combination. In this article, we introduce a Bayesian time-to-event model which takes explicitly the dose amount and schedule into account through the use of pharmacokinetic principles. The model uses a time-varying exposure measure to account for the risk of a dose-limiting toxicity over time. The dose-schedule decisions are informed by an escalation with overdose control criterion. The model is formulated using interpretable parameters which facilitates the specification of priors. In a simulation study, we compared the proposed method with an existing method. The simulation study demonstrates that the proposed method yields similar or better results compared with an existing method in terms of recommending acceptable dose-schedule combinations, yet reduces the number of patients enrolled in most of scenarios. The R and Stan code to implement the proposed method is publicly available from Github ( https://github.com/gunhanb/TITEPK_code).

Effects of schedule type and terminal-link duration on choice in concurrent chains

Four pigeons responded in a three-component concurrent chains procedure in which the terminal-link schedules were either both fixed-interval (FI FI), both variable-interval (VI VI), both mixed-interval (MI MI) or variable-interval fixed-interval (VI FI). Across components within sessions, overall terminal-link duration was varied while schedule types were varied across conditions. For the conditions with homogeneous schedules, the strongest preference was obtained with FI FI, intermediate with MI MI, and weakest with VI VI. Preference increased with overall terminal-link duration for all schedules, but the increase was more rapid for VI FI. The hyperbolic value-added model (HVA) and cumulative decision model (CDM) were fitted to the choice data and accounted for 83.9% and 76.1% of the variance, respectively. However, deviations from both models' predictions were systematic. A modification of the CDM, which assumed that reinforcers delivered after variable delays were more effective, improved the fit of the model and substantially reduced the systematic deviations in residuals. Comparable modifications of HVA produced only limited improvement. Results show that preference in concurrent chains with homogeneous terminal links depends on the degree of variability in reinforcer delays, and that the CDM can provide an excellent account of results across different terminal-link schedules.

A multicomponent approach to thinning reinforcer delivery during noncontingent reinforcement schedules

We evaluated a noncontingent reinforcement procedure that involved initially providing three subjects with signaled, continuous access to the functional reinforcer for aggression and slowly increasing the amount of time subjects were exposed to the signaled unavailability of the reinforcer. Additionally, alternative potential reinforcers were available throughout the sessions. Results showed immediate and substantial reductions in aggression for all three subjects. The clinical utility of this intervention is discussed, and future research directions are recommended.

A preliminary investigation on improving functional communication training by mitigating resurgence of destructive behavior

Despite the effectiveness and widespread use of functional communication training (FCT), resurgence of destructive behavior can occur if the functional communication response (FCR) contacts a challenge, such as lapses in treatment integrity. We evaluated a method to mitigate resurgence by conducting FCT using a multiple schedule of reinforcement prior to extinction. After functional analyses of 2 boys' destructive behavior and treatment with FCT (Study 1), we compared levels of resurgence during an extinction challenge either after a typical FCT sequence or after exposure to schedule thinning in the context of a multiple-schedule arrangement (Study 2). Results for both participants suggested that schedule thinning using discriminative stimuli in a multiple schedule mitigated the resurgence of destructive behavior.

Multiple schedules in practical application: Research trends and implications for future investigation

Researchers began studying multiple schedules in basic laboratories, but recent advances have extended research on multiple schedules to a wide variety of socially significant applications, especially during the last decade. Applied researchers have used multiple schedules to (a) promote stimulus control over high-rate appropriate behaviors, (b) thin the schedule of reinforcement following functional communication training, and (c) obtain stimulus control over problem behaviors maintained by automatic reinforcement. In the current paper, we reviewed 31 studies with 147 applications identified through a search of the applied literature on multiple schedules. Using these studies, we (a) reviewed the empirical literature on multiple schedules, (b) recommended multiple-schedule procedures that serve as best practice guidelines for applied behavior analysts, (c) identified the generality and boundaries of current knowledge about the effectiveness of multiple schedules, and (d) critically analyzed the literature to provide directions for future multiple-schedule research.

Evaluation of multiple schedules with naturally occurring and therapist-arranged discriminative stimuli following functional communication training

Many studies have shown that (a) functional communication training (FCT) is effective for reducing problem behavior, and (b) multiple schedules can facilitate reinforcer schedule thinning during FCT. Most studies tha have used multiple schedules with FCT have included therapist-arranged stimuli (e.g., colored cards) as the discriminative stimuli (S(D) s), but recently, researchers have evaluated similar multiple-schedule training procedures with naturally occurring S(D) s (e.g., overt therapist behavior). The purposes of the current study were to compare the effects of arranged and naturally occurring S(D) s directly during (a) acquisition of discriminated functional communication responses (FCRs) and (b) generalization of discriminated FCRs when we introduced the multiple schedules in novel contexts in which the naturally occurring stimuli were either relatively easy or difficult to discriminate. Results showed that (a) 2 of 3 participants acquired discriminated responding of the FCR more rapidly with arranged than with naturally occurring stimuli, (b) 2 of 3 participants showed resurgence of problem behavior , and (c) 2 of 3 participants showed greater generalization of discriminated responding to novel contexts with arranged stimuli than with naturally occurring stimuli. We discuss these results relative to the conditions under which naturally occurring and arranged S(D) s may promote rapid and generalized treatment gains.

An evaluation of a three-component multiple schedule to indicate attention availability

Students may engage in high rates of social approach responses at inappropriate times throughout the school day. One intervention that has been used to teach students appropriate and inappropriate times to access attention is a multiple schedule of reinforcement. In this study, we evaluated the efficacy of a multiple schedule that indicated when attention was available or not available in a bilingual preschool classroom during small-group instruction. Results showed that the intervention was effective in bringing students' social approaches under stimulus control.

Functional communication training during reinforcement schedule thinning: An analysis of 25 applications

Two principal goals of functional communication training (FCT) are (a) to eliminate destructive behavior and (b) to establish a more acceptable, yet functionally equivalent, communication response (FCR). A related and critically important goal is to thin the schedule of reinforcement for the FCR to levels that can be reasonably managed by caregivers. Researchers have described several approaches to thinning FCT reinforcement schedules. We summarize the results of 25 consecutive applications (among 20 cases) in which schedule-thinning procedures employed discriminative stimuli to signal when the FCR would and would not produce reinforcement (i.e., using multiple schedules, response restriction, or chained schedules). Results suggest that schedule-thinning procedures that use discriminative stimuli can maintain the effectiveness of FCT while they minimize the need for punishment or other supplemental procedures.

Using multiple schedules during functional communication training to promote rapid transfer of treatment effects

Multiple schedules with signaled periods of reinforcement and extinction have been used to thin reinforcement schedules during functional communication training (FCT) to make the intervention more practical for parents and teachers. We evaluated whether these signals would also facilitate rapid transfer of treatment effects across settings and therapists. With 2 children, we conducted FCT in the context of mixed (baseline) and multiple (treatment) schedules introduced across settings or therapists using a multiple baseline design. Results indicated that when the multiple schedules were introduced, the functional communication response came under rapid discriminative control, and problem behavior remained at near-zero rates. We extended these findings with another individual by using a more traditional baseline in which problem behavior produced reinforcement. Results replicated those of the previous participants and showed rapid reductions in problem behavior when multiple schedules were implemented across settings.

The several roles of stimuli in token reinforcement

Three experiments were conducted with pigeons to identify the stimulus functions of tokens in second-order token-reinforcement schedules. All experiments employed two-component multiple schedules with a token-reinforcement schedule in one component and a schedule with equivalent response requirements and/or reinforcer density in the other. In Experiment 1, response rates were lower under a token-reinforcement schedule than under a tandem schedule with the same response requirements, suggesting a discriminative role for the tokens. In Experiment 2, response rates varied systematically with signaling functions of the tokens in a series of conditions designed to explore other aspects of the temporal-correlative relations between tokens and food. In Experiment 3, response rates were reduced but not eliminated by presenting tokens independent of responding, yoked to their temporal occurrence in a preceding token component, suggesting both a reinforcing function and eliciting/evocative functions based on stimulus-food relations. Only when tokens were removed entirely was responding eliminated. On the whole, the results suggest that tokens, as stimuli temporally correlated with food, may serve multiple stimulus functions in token-reinforcement procedures--reinforcing, discriminative, or eliciting--depending on the precise arrangement of the contingencies in which they are embedded.

Effects of a signaled delay to reinforcement in the previous and upcoming ratios on between-ratio pausing in fixed-ratio schedules

Domestic hens responded under multiple fixed-ratio fixed-ratio schedules with equal fixed ratios. One component provided immediate reinforcement and the other provided reinforcement after a delay, signaled by the offset of the key light. The components were presented quasirandomly so that all four possible transitions occurred in each session. The delay was varied over 0, 4, 8, 16, and 32 s with fixed-ratio 5 schedules, and over 0, 8 and 32 s with fixed-ratio 1, 15 and 40 schedules. Main effects of fixed-ratio value and delay duration were detected on between-ratio pauses. Pauses were longer when the multiple-schedule stimulus correlated with a delayed-reinforcer component was presented, with the longest pauses occurring at the transition from a component with an immediate reinforcer to one with a delayed reinforcer. Pause durations were shortest during immediate components. Overall, both the presence or absence of a delay in the upcoming component, and the presence or absence of a delay in the preceding component affected pause length, but the upcoming delay had the larger effect. Thus changes in delay had similar effects to past reports of the effects of changes in response force, response requirement, and reinforcer magnitude in multiple fixed-ratio fixed-ratio schedules.

Response strength in extreme multiple schedules

Four pigeons were trained in a series of two-component multiple schedules. Reinforcers were scheduled with random-interval schedules. The ratio of arranged reinforcer rates in the two components was varied over 4 log units, a much wider range than previously studied. When performance appeared stable, prefeeding tests were conducted to assess resistance to change. Contrary to the generalized matching law, logarithms of response ratios in the two components were not a linear function of log reinforcer ratios, implying a failure of parameter invariance. Over a 2 log unit range, the function appeared linear and indicated undermatching, but in conditions with more extreme reinforcer ratios, approximate matching was observed. A model suggested by McLean (1991), originally for local contrast, predicts these changes in sensitivity to reinforcer ratios somewhat better than models by Herrnstein (1970) and by Williams and Wixted (1986). Prefeeding tests of resistance to change were conducted at each reinforcer ratio, and relative resistance to change was also a nonlinear function of log reinforcer ratios, again contrary to conclusions from previous work. Instead, the function suggests that resistance to change in a component may be determined partly by the rate of reinforcement and partly by the ratio of reinforcers to responses.

Resistance to change and preference for variable versus fixed response sequences

In Experiment 1, 4 pigeons were trained on a multiple chain schedule in which the initial link was a variable-interval (VI) 20-s schedule signalled by a red or green center key, and terminal links required four responses made to the left (L) and/or right (R) keys. In the REPEAT component, signalled by red keylights, only LRLR terminal-link response sequences were reinforced, while in the VARY component, signalled by green keylights, terminal-link response sequences were reinforced if they satisfied a variability criterion. The reinforcer rate for both components was equated by adjusting the reinforcer probability for correct REPEAT sequences across sessions. Results showed that initial- and terminal-link responding in the VARY component was generally more resistant to prefeeding, extinction, and response-independent food than responding in the REPEAT component. In Experiment 2, the REPEAT and VARY contingencies were arranged as terminal links of a concurrent chain and the relative reinforcer rate was manipulated across conditions. For all pigeons, initial-link response allocation was biased toward the alternative associated with the VARY terminal link. These results replicate previous reports that operant variation is more resistant to change than operant repetition (Doughty & Lattal, 2001), and show that variation is preferred to repetition with reinforcer-related variables controlled. Behavioral momentum theory (Nevin & Grace, 2000) predicts the covariation of preference and resistance to change in Experiments 1 and 2, but does not explain why these aspects of behavior should depend on contingencies that require repetition or variation.

Reinforcement schedule thinning following functional communication training: review and recommendations

This paper extends the Tiger, Hanley, and Bruzek (2008) review of functional communication training (FCT) by reviewing the published literature on reinforcement schedule thinning following FCT. As noted by Tiger et al. and others, schedule thinning may be necessary when the newly acquired communication response occurs excessively, to the extent that reinforcing it consistently is not practical in the natural environment. We provide a review of this literature including a discussion of each of the more commonly used schedule arrangements used for this purpose, outcomes obtained, a description of methods for progressing toward the terminal schedule, and a description of supplemental treatment components aimed at maintaining low levels of problem behavior during schedule thinning. Recommendations for schedule thinning are then provided. Finally, conceptual issues related to the reemergence of problem behavior during schedule thinning and areas for future research are discussed.

Extended pausing by humans on multiple fixed-ratio schedules with varied reinforcer magnitude and response requirements

We conducted three experiments to reproduce and extend Perone and Courtney's (1992) study of pausing at the beginning of fixed-ratio schedules. In a multiple schedule with unequal amounts of food across two components, they found that pigeons paused longest in the component associated with the smaller amount of food (the lean component), but only when it was preceded by the rich component. In our studies, adults with mild intellectual disabilities responded on a touch-sensitive computer monitor to produce money. In Experiment 1, the multiple-schedule components differed in both response requirement and reinforcer magnitude (i.e., the rich component required fewer responses and produced more money than the lean component). Effects shown with pigeons were reproduced in all 7 participants. In Experiment 2, we removed the stimuli that signaled the two schedule components, and participants' extended pausing was eliminated. In Experiment 3, to assess sensitivity to reinforcer magnitude versus fixed-ratio size, we presented conditions with equal ratio sizes but disparate magnitudes and conditions with equal magnitudes but disparate ratio sizes. Sensitivity to these manipulations was idiosyncratic. The present experiments obtained schedule control in verbally competent human participants and, despite procedural differences, we reproduced findings with animal participants. We showed that pausing is jointly determined by past conditions of reinforcement and stimuli correlated with upcoming conditions.

Developing stimulus control of the high-rate social-approach responses of an adult with mental retardation: a multiple-schedule evaluation

We evaluated a multiple schedule in which the extinction (S-) components were signaled overtly by a black lanyard and the reinforcement (S+) components were not correlated with any programmed stimuli in developing stimulus control over the high-rate social-approach responses of an adult with mental retardation. Responding was consistently low in the presence of the S- and consistently high when the lanyard was absent (i.e., the S+ condition). Component durations were thinned successfully to a level that was manageable for caregivers.

Discriminated functional communication: a procedural extension of functional communication training

A limitation associated with communication-based interventions for problem behavior is the potential for requesting reinforcement at high rates. Multiple-schedule arrangements have been demonstrated to be effective for controlling rates of responding (Hanley, Iwata, & Thompson, 2001). In the current study, we extended previous research by teaching individuals to attend to naturally occurring discriminative stimuli (e.g., caregiver behavior) instead of arbitrary stimuli (e.g., picture cards). Following successful treatment with functional communication and extinction, 2 participants were taught to request attention differentially based on whether the caregiver was engaging in a variety of "busy" (e.g., talking on the phone) or "nonbusy" (e.g., reading a magazine) activities. Following training, each participant engaged in communication primarily when caregivers were engaged in nonbusy activities.

Stimuli, reinforcers, and the persistence of behavior

This article reviews evidence from basic and translational research with pigeons and humans suggesting that the persistence of operant behavior depends on the contingency between stimuli and reinforcers, and considers some implications for clinical interventions.

Changeover delay effects on topographically tagged discriminative behavior

In a multiple variable-interval extinction schedule, pigeons' responses on an operant key were differentially reinforced in the presence of discriminative stimuli located on a signal key. Changeover delays of zero, one, two, or four seconds specified the time following a signal-key response within which an operant-key response was not reinforced. Systematic reduction of signal-key response rates with increasing changeover-delay duration indicated that signal-key responding was largely maintained by reinforcement of adventitious signal-key/operant-key response chains.