Discriminative Stimulus Control Research Articles

Control of Transition Time by the Likely Future as Signalled from the Past in Children with ASD

The signaling perspective offers an alternative to the Skinnerian view of understanding behavior. The signaling effects of reinforcers have predominantly been explored in the laboratory with nonhuman subjects. To test the implications of this view for applied behavior analysis, we contrasted the effect of discriminative stimulus versus reinforcer control in children with autism spectrum disorder (ASD). We aimed to determine whether the duration of their transitions from one reinforcer context to another is controlled by their most recent past or the likely future based on more extended past experience. Reinforcer context (rich, moderate, or lean) was signaled in the first condition. We observed that transition times to the leaner reinforcer were longer than those to the richer. The reinforcer context was unsignaled in the second condition. The differences between transition times disappeared in the second condition. The difference in durations of transitions to signaled and unsignaled reinforcer densities suggests that behavior is primarily controlled by signals of likely future reinforcers as extrapolated from extended past experience rather than strengthened by the most recent event.

Intraverbal Assessment for Persons with Aphasia or Other Acquired Brain Injury.

An intraverbal assessment was administered to older adults with aphasia, using a hierarchy of questions that required increasingly complex verbal discriminative stimulus control. Five categories of errors were defined and analyzed for putative stimulus control, with the aim to identify requisite assessment components leading to more efficient and effective treatments. Evocative control over intraverbal error responses was evident throughout the database, as shown by commonalities within four distinct categories of errors; a fifth category, representing a narrow majority of errors, was less clear in terms of functional control over responses. Generally, questions requiring increasingly complex intraverbal stimulus control resulted in weaker verbal performance for those with aphasia. A new 9-point intraverbal assessment model is proposed, based on Skinner's functional analysis of verbal behavior. The study underscores that loss or disruption of a formerly sophisticated language repertoire presents differently than the fledgling language skills and errors of new learners, such as typically developing children and those with autism or developmental disabilities. Thus, we would do well to consider that rehabilitation may require a different approach to intervention than habilitation. We offer several thematic topics for future research in this area.

The role of dorsomedial striatum adenosine 2A receptors in the loss of goal-directed behaviour.

Adenosine A2A receptors (A2AR) in the dorsal striatum have been implicated in goal-directed behaviour. While activation of these receptors with several methods has resulted in an insensitivity to outcome devaluation, particular explanations for how they disrupt behaviour have not been explored. We both confirm a role for A2A receptors in goal-directed responding and evaluate additional behavioural aspects of goal-directed control to more fully understand the role of A2A receptors in instrumental behaviour. To examine the effects of the adenosine A2A agonist CGS-21680 in the DMS on response-outcome encoding, updating representations of outcome value and on the ability to inhibit behaviour when reward is not available. Male rats were trained to lever press for food reward. The A2AR agonist CGS-21680 was infused into the dorsomedial striatum either before an outcome devaluation test, prior to training with two distinct response-outcome associations or prior to a test of discriminative stimulus control over instrumental performance. Intra-DMS administration of CGS-21680 impaired sensitivity to outcome devaluation. CGS-21680 treatment did not impair acquisition of specific response-outcome associations, selective control of responding based on the presence of stimuli that signaled when reward was or was not available, discrimination between stimuli or lever choices nor did it influence the effect of devaluation on the amounts of food eaten in a consumption test. CGS-21680 impairs the ability to modulate responding based on recent changes to outcome value, an effect that is not accounted for by impairments in behavioural inhibition, discrimination, encoding the specific outcome of a response or the effectiveness of specific satiety.

Grounding applied animal behavior practices in the experimental analysis of behavior.

Some of the earliest applications outside the laboratory of principles derived from the experimental analysis of behavior (EAB), such as the pioneering work of Keller and Marian Breland, involved animals. This translational tradition continues to the present as EAB-related behavior principles are applied with increasing frequency to behavior management and training practices with animals in nonlaboratory settings. Such translations, and those populations to which they are applied, benefit from a rigorous experimental analysis of practices that are promulgated in popular outlets. These translations both affirm the generality of those principles and serve as goads for laboratory and field research that can further articulate extant principles, develop new ones, and refine methods of application and assessment. This review considered several areas of basic EAB research and contemporary applied animal behavior (AAB) practices in relation to one another: (1) response establishment and maintenance, (2) response reduction and elimination, (3) chaining and conditioned reinforcement, and (4) discriminative stimulus control. Within each topic, a selection of processes and procedures in both EAB and AAB work were reviewed in relation to one another.

The Effects of a Procedure to Decrease Motor Stereotypy on Social Interactions in a Child With Autism Spectrum Disorder.

Repetitive and stereotypic motor movements and vocal behavior are among the diagnostic characteristics of autism spectrum disorder (American Psychiatric Association, 2013, Diagnostic and Statistical Manual of Mental Disorders [5th ed.]. Washington, DC: Author). Motor stereotypy can interfere with the acquisition and demonstration of many adaptive skills and may socially stigmatize individuals, limiting the development and maintenance of peer relationships. The current study evaluated the effects of a differential reinforcement procedure used to establish discriminative stimulus control over the rate of motor stereotypy. In the second experimental phase, the child was taught a multistep self-management program using the differential reinforcement procedure. The data indicate that the procedure was effective in decreasing the rate of motor stereotypy across all evaluated settings for an increased duration. Although motor stereotypy was not completely eliminated by the procedure, a large reduction in rate was observed, as well as a large increase in the initiation of and response to social interactions. The findings are discussed in terms of social validity and the establishment and transfer of stimulus control.

Extension of the stimulus control produced by three procedures for teaching pseudowords discrimination

Abstract This study investigated the effects of pseudoword discrimination training that either required or didn’t require selection responses upon control by stimulus elements and recombination of elements, and upon stimulus observation. Eight undergraduate students were exposed to two conditions with discriminative training and stimulus control test. Condition SEL required selecting the S+, and condition OBS only required observation. Test results suggest that selection responses did not affect control by the elements or the recombination of elements in the pseudowords. Four participants presented restricted stimulus control. This control was extended in the additional DOR condition, which required differential observation of the elements, and was accompanied by increases in S+ observation. Increased stimulus control, promoted by the DOR, should still be evaluated independently of previous teaching conditions.

Can the discriminative stimulus effects of nicotine function concurrently as modulatory opponents in operant and pavlovian occasion setting paradigms in rats?

Nicotine promotes interoceptive changes in the nervous system. Such interoceptive stimuli play important roles in modulating addictive behavior. Operant and Pavlovian stimulus control modulate responsiveness to environmental stimuli related to drug-seeking and self-administration. Nicotine functions as a discriminative stimulus in modulating operant behavior as well as Pavlovian feature stimuli in modulating the conditional responding (CR) to exteroceptive CS→US contingencies. Elucidation of the interaction of these interoceptive stimulus control functions is vital for a comprehensive understanding of nicotine use/abuse, which might lead to better behavioral treatment strategies. This experiment evaluated the interaction among Pavlovian feature positive (FP) and feature negative (FN) effects of nicotine on concurrently occurring operant SD and SΔ effects. Sixteen rats were trained in a Pavlovian and operant bidirectional contingency paradigm, using nicotine (0.3 mg/kg) and non-drug (saline) states as interoceptive cues for operant discriminative stimulus conditions (SD and SΔ) as well as Pavlovian FP and FN for a light-CS, either leading to a shared food pellet outcome or non-outcome. Nicotine and saline sessions were intermixed. For one group of rats (n = 8), nicotine served as an SD for lever pressing (variable interval 60 s) and simultaneously functioned as an FN for CS-light→noUS relation on the same sessions. On intermixed sessions, saline served as the SΔ for lever pressing (non-reinforced) and FP, during which the 8-sec light preceded delivery of the food pellet (variable time ITI = 60 s). For the other group (n = 8) nicotine served as the SΔ (lever pressing non-reinforced) and FP for the CS, with saline serving in the reverse roles. Consecutive brief non-reinforcement tests revealed that: A) rates of lever pressing were significantly greater in SD than SΔ with nicotine and saline suggesting strong operant discriminative stimulus control; B) FP responding to the light CS with nicotine and saline was evident; and C) FN suppression of the CR with nicotine was not evident but weak under saline. These data suggest that nicotine can function as an interoceptive context that hierarchically can enter into concurrently opposing modulatory relations in Pavlovian and operant drug discrimination procedures.

Ethanol→Nicotine & Nicotine→Ethanol drug-sequence discriminations: Conditional stimulus control with two interoceptivedrug elements in rats.

Self-administration of ethanol (E) and nicotine (N) occurs frequently in tandem orders (i.e., N→E vs. E→N) and thereby produces differing interoceptive profiles of subjective effects in humans. If the interoceptive stimulus characteristics of N→E differ from E→N, it is possible that such differences contribute to their co-dependence. The rationale for the present investigation was to determine whether ethanol, when preceded or followed by nicotine, produces different discriminative stimulus effects in rats. In two experiments, using a one-manipulandum operant drug discrimination procedure, rats were trained to discriminate temporal sequential administrations of ethanol (1.0g/kg) that was followed or preceded by nicotine (0.3mg/kg). Sessions alternated between food-reinforcement sessions on a variable interval 30-sec schedule (i.e., SD) and non-reinforcement sessions (i.e., SΔ). In Experiment 1, administrations of ethanol were followed or preceded by a 10-min interval of nicotine. Training sessions took place 10min following the second drug injection. Four groups of rats were trained to discriminate only one sequence from sequential administrations of saline, and each drug sequence was counterbalanced across groups for their roles as SD or SΔ. There was robust stimulus control. N→E and E→N functioned equally well as SD or SΔ. Experiment 2 used two groups of rats. For one group, the E→N sequence functioned as the SD and the N→E sequence functioned as the SΔ. The drug sequences were counterbalanced for the other group. Brief non-reinforcement tests revealed significantly greater responding during the SD sequence compared to the SΔ sequence for both groups. These results suggest that different drug sequences of ethanol followed or preceded by nicotine established reliable discriminative stimulus control over operant responding, potentially because of characteristic differences in the overlapping pharmacokinetic profiles of the NE compound. The results are discussed in terms of: 1) conditional stimulus control among two interoceptive drug states; and 2) the clinical modulation of human alcohol consumption and tobacco smoking.

Intraverbal Training for Individuals with Autism: The Current Status of Multiple Control

Teaching complex intraverbal responding to children with autism spectrum disorder (ASD) can be challenging and often requires careful programming. Divergent and convergent multiple control are particularly important elements to incorporate into intraverbal training programs, as well as procedures to ensure responding is under control of both discriminative and conditional vocal verbal stimuli. The current study systematically reviewed research articles on intraverbal training methods for individuals with ASD published and available from 2005 to 2016. The purpose of the review was to assess the extent to which divergent and convergent control was incorporated into training and to determine whether systematic instruction ensured correct verbal conditional discriminations. Thirty-six studies met inclusion criteria and were included in this reviewed. A total of 5 studies taught intraverbal responding under divergent control and 21 taught responding under convergent control. Two studies sufficiently described procedures to ensure accurate verbal conditional discriminations across trials. The results highlight the need for additional research on systematic teaching procedures for complex intraverbal repertoires.

The ability for cocaine and cocaine-associated cues to compete for attention

In humans, reward cues, including drug cues in individuals experiencing addiction, are especially effective in biasing attention towards them, so much so they can disrupt ongoing task performance. It is not known, however, whether this happens in rats. To address this question, we developed a behavioral paradigm to assess the capacity of an auditory drug (cocaine) cue to evoke cocaine-seeking behavior, thus distracting thirsty rats from performing a well-learned sustained attention task (SAT) to obtain a water reward. First, it was determined that an auditory cocaine cue (tone-CS) reinstated drug-seeking equally in sign-trackers (STs) and goal-trackers (GTs), which otherwise vary in the propensity to attribute incentive salience to a localizable drug cue. Next, we tested the ability of an auditory cocaine cue to disrupt performance on the SAT in STs and GTs. Rats were trained to self-administer cocaine intravenously using an Intermittent Access self-administration procedure known to produce a progressive increase in motivation for cocaine, escalation of intake, and strong discriminative stimulus control over drug-seeking behavior. When presented alone, the auditory discriminative stimulus elicited cocaine-seeking behavior while rats were performing the SAT, but it was not sufficiently disruptive to impair SAT performance. In contrast, if cocaine was available in the presence of the cue, or when administered non-contingently, SAT performance was severely disrupted. We suggest that performance on a relatively automatic, stimulus-driven task, such as the basic version of the SAT used here, may be difficult to disrupt with a drug cue alone. A task that requires more top-down cognitive control may be needed.

Configurations of the interoceptive discriminative stimulus effects of ethanol and nicotine with two different exteroceptive contexts in rats: Extinction & recovery

Interoceptive states interact with exteroceptive contexts in modulating operant behavior, which is maintained by its consequences. Evaluating discriminative stimulus control by overlapping interoceptive and exteroceptive configurations (gestalts) and the contribution of each modality may be clinically important for understanding aspects of relapsing behavior (e.g., drug abuse). With rats, the current investigation used a completely counterbalanced one-manipulandum operant drug discrimination procedure that established discriminative stimulus control between nicotine (0.3mg/kg) in one exteroceptive context and EtOH (1.0g/kg) in a differing exteroceptive context. One combined interoceptive–exteroceptive condition occasioned sessions of food reinforcement (SD) and the other counterbalanced condition occasioned sessions of non-reinforcement (SΔ). Each stimulus modality contributed to discriminative control, but to lesser extents than the combined intero–exteroceptive compound configurations (Experiments 1 & 2). In Experiment 1, responding was extinguished in the interoceptive stimulus conditions alone in a neutral exteroceptive context, but then renewed by reconfiguring the drugs with the exteroceptive contexts, and reversed in the opposing exteroceptive contexts. In Experiment 2, responding was extinguished in the interoceptive and exteroceptive contexts separately. Reconfiguration of the full intero–exteroceptive compound configurations did not promote recovery. These results suggest that interoceptive and exteroceptive discriminative control can be methodologically configured in modulating operant behavior during acquisition, extinction, and recovery of behavior; however, configuring interoceptive and exteroceptive discriminative stimuli do not appear to function as unique cues that differ from each stimulus modality alone. Clinical implications are discussed.

An Analysis of an Autoclitic Analogue in Pigeons.

Using a conditional discrimination procedure, pigeons were exposed to a nonverbal analogue of qualifying autoclitics such as definitely and maybe. It has been suggested that these autoclitics are similar to tacts except that they are under the control of private discriminative stimuli. Instead of the conventional assumption of privacy, which precludes direct manipulation of the controlling variable, the autoclitic was here identified as a response that is jointly determined by its function as a modifier for the consequence of the tact and by some variable that modifies stimulus control of the tact. Following this modified conceptualization, a novel conditional discrimination procedure was developed as an analogue for establishing autoclitic-like behavior in pigeons. Under some conditions, autoclitic-like behavior was established. Methodological challenges in developing an autoclitic analogue in nonhumans are discussed, followed by a consideration of the implications of such analogues for the understanding of verbal and, more broadly, human behavior.

Signal functions in delayed discriminative stimulus control by reinforcement sources

The discriminative functions of the response-reinforcer relation may contribute to the changes in response rates that occur when reinforcement is delayed. These properties were investigated in three experiments with pigeons using a discrete-trials conditional discrimination procedure. A concurrent variable-interval schedule was arranged on two side keys during a sample component. The key peck that ended the schedule (the sample response) initiated a delay with either a stimulus present throughout the delay interval (full signal), a stimulus present only during the first second of the interval (partial signal), or no stimulus present (unsignaled delay). The delay was followed by a choice component where one alternative was reinforced if the left sample response produced the choice component and the other if the right sample response produced the choice component. Accuracy was high with a full signal; slightly lower with a partial signal; and lowest without a signal. The results parallel the effects of similar delays programmed in conventional reinforcement schedules. This in turn suggests a possible discriminative effect of the response-reinforcer relation in the control of behavior by (delayed) reinforcement.

The discriminative stimulus effects of a nicotine-ethanol compound in rats: Extinction with the parts differs from the whole.

Nicotine and ethyl alcohol (EtOH) interact neurophysiologically and induce internal sensory states that contribute to their coabuse. Evaluating the combined internal sensory effects of nicotine and alcohol may be important for understanding this nexus. With rats, this investigation used an operant drug discrimination procedure to establish discriminative stimulus control with a mixture of nicotine plus EtOH (NE) at doses of nicotine (0.3 mg/kg) and EtOH (1.0 g/kg) that have previously been shown to be equally salient (Gauvin & Holloway, 1993). In Experiment (Exp) 1 the NE compound mixture continued to evoke responding despite extinction of responding with nicotine and EtOH alone. In Exp 2 the NE mixture was reliably discriminated from the nicotine and EtOH elements. Experiment 3 showed that the discriminative functions of the NE mixture emerged when the nicotine and EtOH elements were combined following their initial establishment as separate discriminative stimuli; however, nicotine evoked more control than EtOH. Extinction of responding with the NE mixture impacted rates of responding with nicotine and EtOH alone. The results of the all three studies parallel findings with exteroceptive Pavlovian literature in showing that extinction of responding with the elemental parts does not appear to impact the whole-but, extinction with the whole appears to affect its parts. The multielement discriminative function of a NE mixture appears to be a "unique cue" that differs qualitatively from nicotine or EtOH alone. Associative factors related to compound conditioning (i.e., configural learning) play an important role in mediating the discriminative functions of drug mixtures.

A Preliminary Investigation of Stimulus Control Training for Worry

For individuals with generalized anxiety disorder, worry becomes associated with numerous aspects of life (e.g., time of day, specific stimuli, environmental cues) and is thus under poor discriminative stimulus control (SC). In addition, excessive worry is associated with anxiety, depressed mood, and sleep difficulties. This investigation sought to provide preliminary evidence for the efficacy of SC procedures in reducing anxiety-, mood-, and sleep-related symptoms. A total of 53 participants with high trait worry were randomly assigned to receive 2 weeks of either SC training (consisting of a 30-min time- and place-restricted worry period each day) or a control condition called focused worry (FW; consisting of instructions to not avoid naturally occurring worry so that worry and anxiety would not paradoxically increase). At post-training, SC was superior to FW in producing reductions on measures of worry, anxiety, negative affect, and insomnia, but not on measures of depression or positive affect. Moreover, SC was superior to FW in producing clinically significant change on measures of worry and anxiety. Results provide preliminary support for the use of SC training techniques in larger treatment packages for individuals who experience high levels of worry.

Control de estímulos de efectos del castigo: Determinando las variables controladoras

The study of discriminative stimulus control of responding maintained by positive reinforcement has a long-standing and dominant role in the behavioral literature. In contrast, the literature on discriminative stimulus control of response suppression by punishment is small and moribund. Investigating the form of stimulus control that develops under conditions of punishment is a topic in need of further attention for both theoretical and practical reasons. In preparations wherein stimulus control can develop (e.g., multiple schedules), at least two stimuli can come to exert discriminative control over response suppression: an antecedent discriminative stimulus (e.g., multiple-schedule stimulus) and the punisher delivery itself. We reviewed the experimental and applied literatures involving punishment and found only a few unambiguous demonstrations of operant stimulus control by an antecedent stimulus. We discuss limitations in methods, and conventions of data analysis and presentation, that preclude unambiguous conclusions regarding the establishment of antecedent stimulus control with punishment. A consideration of these limitations is important because they bear on both basic and applied issues in behavior analysis.

Variáveis controladoras dos comportamentos “trabalhar” e “estudar” em jovens: uso de relato verbal

Os objetivos deste estudo foram identificar, em relatos verbais, variáveis controladoras dos comportamentos “estudar e trabalhar” em um grupo de jovens universitários e determinar a existência de classes de operantes verbais sobre o comportamento “trabalhar”. A amostra foi composta por 107 jovens universitários entre 19-24 anos (40 jovens trabalhadores e 67 jovens não-trabalhadores), provenientes de uma universidade particular da cidade de São Paulo. Foram realizados 5 grupos para acessar os relatos verbais sob controle de estímulos discriminativos verbais. A análise de dados foi executada com o auxílio do software ALCESTE 4.5. Os resultados apontam para a emissão de tatos verbais entre os jovens trabalhadores em que o comportamento “trabalhar” se mantêm sob controle do reforçador positivo “dinheiro” e auto-regras. Uma semelhança entre os jovens trabalhadores e não-trabalhadores apontou para a função discriminativa aversiva que apresenta a concorrência entre os comportamentos de estudar e trabalhar.

Ethanol-induced alterations of c-Fos immunoreactivity in specific limbic brain regions following ethanol discrimination training

The discriminative stimulus properties of ethanol are functionally regulated by ionotropic GABA A and NMDA receptors in specific limbic brain regions including the nucleus accumbens, amygdala, and hippocampus, as determined by microinjection studies. The purpose of the present work was to further investigate potential neural substrates of ethanol's discriminative stimulus effects by examining if ethanol discrimination learning produces changes in brain regional response to ethanol. To accomplish this goal, immunohistochemistry was used to assess the effects of ethanol (2 g/kg) on c-Fos immunoreactivity (Fos-IR). Comparisons in ethanol-induced Fos-IR were made between a group of rats that was trained to discriminate the stimulus properties of ethanol (2 g/kg, IG) from water (IG) and a drug/behavior-matched control group that did not receive differential reinforcement for lever selection, which precluded acquisition of discriminative stimulus control by ethanol. In some brain regions discrimination training had no effect on ethanol-induced Fos-IR changes (caudate putamen, bed nucleus of the stria terminalis, and CA1 region of the hippocampus). In contrast, discrimination training altered the pattern of ethanol-induced Fos-IR in the nucleus accumbens (core), medial septum, and the hippocampus (dentate and CA3). These results indicate that having behavior under the stimulus control of ethanol can change ethanol-induced Fos-IR in some brain regions. This suggests that learning about the subjective properties of ethanol produces adaptive changes in how the brain responds to acute ethanol exposure.

Discriminative control of variability: Effects of successive stimulus reversals

A growing body of evidence suggests that behavioral variability can come under control of discriminative stimuli. The present experiment further examined discriminative control of variability in a novel way by using the discrimination-reversal paradigm. Eight pigeons responded under a multiple schedule of Vary and Yoke components signaled by different-colored keylights. In the Vary component, 4-response sequences that differed from the previous 10 produced food, while in the Yoke component, any 4-response sequence had a fixed probability of producing food, yoked to the prior Vary component. Following stability in this procedure, the key colors signaling the Vary and Yoke components were reversed across four successive conditions. Across the experiment, variability of keypeck sequences was higher in the Vary than in the Yoke component. Across successive reversals, the level of variability in the Vary component adapted more rapidly to the reversed contingencies, while the rate of adaptation in the Yoke component did not change systematically. These results are interpreted in terms of the different contingencies in the Vary and Yoke components. In addition, the improvement in the rate of adaptation across successive reversals in the Vary component appears consistent with a proactive interference account of discrimination-reversal performance. These results join others in suggesting that variability may be an operant dimension of behavior.

A Salience Theory of Learning and Behavior: With Perspectives on Neurobiology and Cognition

Traditional behaviorists have described behaviors fundamentally as responses to stimuli or, perhaps more liberally, as behaviors under the control of discriminative stimuli or contexts. They have held responses or behaviors to be established, strengthened, sustained, and inhibited or extinguished by contingent events: notably reinforcers, punishers, or the absence of either. In addition, they believed reinforcement acts on the response, the behavior, not on the organism. Here, and in support of Hebb’s view, we advance a contrarian view. A key principle of our framework is that species’ brains are uniquely designed to perceive and to relate stimulus events that are contiguous, salient, and relevant to adaptation. In accordance with what we here view as the constructive biases of species’ brains, stimuli are differentially organized into amalgams that reflect an exchange of salience and response-eliciting properties of component units, which are then integrated to form a basis of knowledge about the organism and its ecological niche. One can then base adaptation on overarching principles and rules, not just on simple associations. Species may create emergent behaviors with no history of specific training, and even new capacities, to service adaptation to both familiar and novel challenges.