Stimulus control: part II

Effects of stimulus disparity on acquisition of sight word sets: Manipulation of initial letter

Due to the prevalence of words that cannot be read phonetically in the English language, sight word instruction is required to supplement phonics instruction. In this study, we manipulated stimulus disparity in sight word sets by comparing the effects of sets of sight words with the same initial letter (3 words per set, 3 total sets) versus distributing words with the same initial letter across sets when assessing acquisition of the combined set (9 words) for 5 children who ranged from 4-6 years of age using a combined adapted alternating treatments design and pre-posttest design. All participants mastered the 3-word sets in both teaching conditions but did not master the control sets. In general, participants required more teaching sessions when the words in sets began with the same letter. These findings are consistent with stimulus disparity research demonstrating that discrimination training is generally less efficient when comparison stimuli are similar.

Response Systems, Antagonistic Responses, and the Behavioral Repertoire

While response systems are often mentioned in the behavioral and physiological literature, an explicit discussion of what response systems are is lacking. Here we argue that response systems can be understood as an interaction between anatomically constrained behavioral topographies occasioned by currently present stimuli and a history of reinforcement. “New” response systems can develop during the lifetime as the organism gains instrumental control of new fine-grained topographies. Within this framework, antagonistic responses compete within each response system based on environmental stimulation, and competition is resolved at the striatum-thalamo-cortical loops level. While response systems can be by definition independent from one another, separate systems are often recruited at the same time to engage in complex responses, which themselves may be selected by reinforcement as functional units.

Facilitating the emergence of intraverbal tacts in children with autism spectrum disorder: A preliminary analysis

Intraverbal tacts are an example of multiply controlled verbal behavior. More specifically, they are verbal responses under control of both a nonverbal (visual) stimulus (e.g., a green ball) and a verbal (auditory) stimulus (e.g., "What color?" vs. "What shape?"). Studies have shown that verbal behavior training can be arranged in a way that would lead to the emergence of other verbal operants, including multiply controlled (convergent) intraverbals. Our study sought to evaluate the relevance of a specific set of component skills on the emergence of intraverbal tacts in children with an autism spectrum disorder. Intraverbal tacts were observed only when all component skills were mastered, suggesting that this set of skills was sufficient to produce emergent verbal performance. Preliminary data were obtained on the necessity of 4 of the 6 component skills and tentatively suggest that they may be necessary to produce emergent intraverbal tacts, at least under some conditions.

A Review of Effective Strategies for Parent-Delivered Instruction

Parent involvement in treatment is an important component of effective behavior-analytic services. Whether parents are expected to act as the primary behavior change agent or support treatment in other ways, behavior analysts must provide them with the resources necessary to encourage lasting behavior change. A critical component of supporting lasting behavior change is the foundational skills related to instruction delivery. Without these skills, parents will not likely benefit from more advanced programs and interventions recommended by behavior analysts. Therefore, the purpose of this article is to describe the foundational skills necessary for parents to successfully establish an instructional environment for further program and intervention delivery. To aid practitioners, a parent-friendly handout is included and discussed.

Comparison of sounds and words as sample stimuli for discrimination training

A portion of children diagnosed with autism spectrum disorder (ASD) have difficulty acquiring conditional discrimination. However, previous researchers suggested that the discrimination of nonverbal auditory stimuli may be acquired more efficiently (Eikeseth & Hayward, 2009; Uwer, et al., 2002). For example, a child may learn to touch a picture of a piano after hearing the musical instrument more quickly than when the auditory stimulus is the spoken word "piano." The purpose of the present study was to extend previous research by assessing the acquisition of conditional discriminations with sample stimuli presented as either automated spoken words or high- and low-disparity nonverbal auditory stimuli (i.e., environmental sounds). Conditional discriminations with high-disparity environmental sounds as sample stimuli were acquired rather than or more efficiently than those trained with low-disparity environmental sounds and words as sample stimuli.

Stimulus Control Research and Practice: Considerations of Stimulus Disparity and Salience for Discrimination Training

Stimulus control plays a prominent role in behavior-analytic service delivery, as many discrimination skills are necessary for daily interactions. Clarification and standardization of terminology are necessary for the advancement of research and practice on stimulus control. The purpose of the present article is to provide an overview of stimulus control and discrimination training as they relate to the disparity and salience of stimuli. An overview and examples of stimulus disparity and stimulus salience are provided, followed by recommendations for efficacious service delivery.

Effect of Words Highlighting in School Tasks upon Typical ADHD Behaviors

Abstract Behavioral interventions in classroom are relevant to the educational process of students with ADHD. It is in this context that typical disorder’s behaviors are especially problematic and contribute to high rates of school failure and dropout. The aim of the present study was to analyze the effect of word highlighting on inattention and hyperactivity/impulsivity of three elementary students with ADHD. A multiple baseline design combined with a reversal design was used. Reduction in the frequency of the behaviors of interest and higher frequency of correct answers in school tasks were observed when words were highlighted. The results replicate and extend data of previous studies. The application of the intervention with different contents and tasks is proposed.

Replicating stimulus-presentation orders in discrimination training

Children with autism spectrum disorder (ASD) are taught conditional discriminations often during early intervention. Auditory-visual conditional discrimination (AVCD) training requires the presentation of multiple antecedent stimuli, and the order of stimulus presentation varies in the literature. This series of studies replicated previous literature on stimulus-presentation order in AVCD training. In Experiment 1, we compared sample-first and comparisons-first arrangements in 8 comparisons with 4 participants with ASD. For 3 participants, both presentations were efficacious. For 1 participant, the sample-first order was more likely to be efficacious. In Experiment 2, we added a sample-first-with-repetition arrangement and conducted 6 comparisons with 5 participants with ASD. Across comparisons, all 3 presentations were efficacious. Considerations for teaching AVCD to children with ASD and suggestions for further evaluation and examination of efficacy and efficiency are discussed.

Translations in Stimulus-Stimulus Pairing: Autoshaping of Learner Vocalizations

Stimulus-stimulus pairing (SSP) is a procedure used by behavior analysis practitioners that capitalizes on respondent conditioning processes to elicit vocalizations. These procedures usually are implemented only after other, more customary methods (e.g., standard echoic training via modeling) have been exhausted. Unfortunately, SSP itself has mixed research support, probably because certain as-yet-unidentified procedural variations are more effective than others. Even when SSP produces (or increases) vocalizations, its effects can be short-lived. Although specific features of SSP differ across published accounts, fundamental characteristics include presentation of a vocal stimulus proximal with presentation of a preferred item. In the present article, we draw parallels between SSP procedures and autoshaping, review factors shown to affect autoshaping, and interpret autoshaping research for suggested SSP tests and applications. We then call for extended use and reporting of SSP in behavior-analytic treatments. Finally, three bridges created by this article are identified: basic-applied, respondent-operant, and behavior analysis with other sciences.

The effect of the long anchor duration on performance in the temporal bisection procedure

The present study investigated how the value of the long anchor duration influences the bisection point (BP) in the temporal bisection procedure. The ratio similarity rule (Gibbon, 1981, On the form and location of the psychometric bisection function for time. Journal of Mathematical Psychology, 24(1), 58-87) hypothesizes that the location of the BP is determined by a ratio comparison between the short and long anchor durations. The Short/no short hypothesis (Machado and Keen, 2003, Temporal discrimination in a long operant chamber. Behavioural Processes, 62(1), 157-182) indicates that the location of the BP is influenced mainly by the short duration. Two experiments with pigeons manipulated the long anchor duration while fixing the short anchor duration in a series of anchor pairs. The results showed that the location of the BP depended on the initial training condition, a primacy effect. When the initial training condition used anchors of 3- vs. 9-s, a relatively strong influence of the long anchor duration was observed as predicted by the ratio similarity rule. On the other hand, when anchors were 3- vs. 27-s in the initial training condition, the effect of the long duration was relatively small, conforming more closely to the Short/no short hypothesis. Keypecking to the sample key during a trial, sample-cue responding, was also observed. The functions relating sample-cue responding to elapsed trial time also indicated the primacy effect.

Evaluation of increasing antecedent specificity in goal statements on adherence to positive behavior-management strategies

We evaluated the impact of antecedent specificity in goal statements on adherence to positive behavior-management strategies. Teaching staff were recruited from 2 different school settings where there were routine expectations to use behavior-specific praise in the classroom, but adherence was poor. In a concurrent multiple baseline design, the use of behavior-specific praise by 4 participants was found to be unaffected by goal statements that increasingly specified the behavior to be used and the conditions under which the behavior should occur. However, adherence by 3 of the 4 participants did change when goal statements included teacher-specified frequencies with which the behavior should occur. Results were systematically replicated in a second study in which, in a concurrent multiple baseline design, 3 participants showed marked increases in adherence when goal statements specified the target behavior, the conditions under which it should occur, and the frequency with which it should occur.

Preventing Disruptive Behavior via Classroom Management

Evidence suggests that installing a classroom management system known as the Color Wheel reduced inappropriate behaviors and increased on-task behavior in second- and fourth-grade classrooms; however, no systematic studies of the Color Wheel had been disseminated targeting pre-school or kindergarten participants. To enhance our understanding of the Color Wheel System (CWS) as a prevention system, a multiple-baseline design was used to evaluate the effects of the Color Wheel on inappropriate vocalizations (IVs) in three general education kindergarten classrooms. Partial-interval time-sampling was used to record classwide IVs, which were operationally defined as any comment or vocal noise that was not solicited by the teacher. Time series graphs and effect size calculations suggest that the CWS caused immediate, large, and sustained decreases in IVs across the three classrooms. Teacher acceptability and interview data also supported the CWS. Implications related to prevention are discussed and directions for future research are provided.

Analyzing stimulus-stimulus pairing effects on preferences for speech sounds

Several studies have demonstrated effects of stimulus-stimulus pairing (SSP) on children's vocalizations, but numerous treatment failures have also been reported. The present study attempted to isolate procedural variables related to failures of SSP to condition speech sounds as reinforcers. Three boys diagnosed with autism-spectrum disorders participated. Phase 1 was designed to assess SSP effects on production of auditory stimuli via button pressing. When SSP failed to produce a preference for the target stimulus, we instituted a series of procedural manipulations intended to address potential reasons for failure. One participant preferred the target stimulus when given the opportunity to select preferred items for pairing prior to each session, but a subsequent reversal attempt produced ambiguous results. Two participants showed no consistent preference in Phase 1 and underwent a within-session reinforcer evaluation in Phase 2, in which alternative controlling variables were demonstrated by delivering preferred stimuli contingent on button pressing.

Evaluation of an enhanced stimulus-stimulus pairing procedure to increase early vocalizations of children with autism

Evidence to support stimulus-stimulus pairing (SSP) in speech acquisition is less than robust, calling into question the ability of SSP to reliably establish automatically reinforcing properties of speech and limiting the procedure's clinical utility for increasing vocalizations. We evaluated the effects of a modified SSP procedure on low-frequency within-session vocalizations that were further strengthened through programmed reinforcement. Procedural modifications (e.g., interspersed paired and unpaired trials) were designed to increase stimulus salience during SSP. All 3 participants, preschoolers with autism, showed differential increases of target over nontarget vocal responses during SSP. Results suggested an automatic reinforcement effect of SSP, although alternative interpretations are discussed, and suggestions are made for future research to determine the utility of SSP as a clinical intervention for speech-delayed children.

The development of stimulus control over tics: a potential explanation for contextually-based variability in the symptoms of Tourette syndrome

Research has demonstrated that providing reinforcement for tic-free intervals can decrease tic frequency in controlled analogue settings. The aim of the current study was to determine whether reinforcement could be used to create stimulus control over tic expression. Ten children with chronic tic disorders (including Tourette syndrome) completed four discrimination training sessions. Each session consisted of three exposures to each of three, 5 min. conditions presented in a random order. In one condition, participants were reinforced for tic absence on a 10-s fixed interval schedule in the presence of a purple light. In a second condition, participants were instructed to suppress their tics, but were not reinforced for doing so in the presence of an orange light. In a third condition, participants were instructed not to suppress their tics in the presence of two non-illuminated lights. Confirming findings from other studies, results showed that reinforcing tic suppression reduced tic frequency to a greater extent than only providing instructions to suppress. To test for stimulus control, a fifth session was conducted following the aforementioned discrimination training sessions. The fifth session consisted of three exposures to each of three 5 min. conditions presented in a random order. In one condition, a purple light was illuminated. In a second condition, an orange light was illuminated. In a third condition, neither light was illuminated. Across all three conditions, instructions to suppress (or not suppress) tics were not provided, and reinforcers for successful suppression were not delivered. Results indicated that in the presence of the purple light, tics were significantly lower than when neither light was illuminated. These findings provide preliminary support for the idea that a history of differential reinforcement in various contexts may play a role explaining variability in tic symptom expression.

The Journal of the Experimental Analysis of Behavior at zero, fifty, and one hundred

The experimental content areas represented in JEAB in its first volume (1958) and 50 years later in Volume 87 are in many ways similar with regard to research on schedules of reinforcement, research with human subjects, and several other topics. Experimental analysis has not been displaced by quantitative analysis. Much less research on aversive control has been published in recent than in earlier years. Wishes for progress in the next 50 years include experiments on verbal behavior, the sources of novel behavior, and observing responses based on stimuli correlated with escape or avoidance.

Stimulus control of cocaine self-administration

Environmental stimuli that set the occasion wherein drugs are acquired can "trigger" drug-related behavior. Investigating the stimulus control of drug self-administration in laboratory animals should help us better understand this aspect of human drug abuse. Stimulus control of cocaine self-administration was generated here for the first time using multiple and chained schedules with short, frequently-alternating components--like those typically used to study food-maintained responding. The procedures and results are presented along with case histories to illustrate the strategies used to produce this stimulus control. All these multicomponent schedules contained variable-interval (VI) components as well as differential-reinforcement-of-other-behavior (DRO) or extinction components. Schedule parameters and unit dose were adjusted for each rat to produce stable, moderate rates in VI components, with minimal postreinforcement (infusion) pausing, and response cessation in extinction and DRO components. Whole-body drug levels on terminal baselines calculated retrospectively revealed that all rats maintained fairly stable drug levels (mean, 2.3 to 3.4 mg/kg) and molar rates of intake (approximately 6.0 mg/kg/hr). Within this range, no relation between local VI response rates and drug level was found. The stimulus control revealed in cumulative records was indistinguishable from that achieved with food under these schedules, suggesting that common mechanisms may underlie the control of cocaine- and food-maintained behavior.

When instructions fail. The effects of stimulus control training on brain injury survivors' attending and reporting during hearing screenings

Bedside hearing screenings are routinely conducted by speech and language pathologists for brain injury survivors during rehabilitation. Cognitive deficits resulting from brain injury, however, may interfere with obtaining estimates of auditory thresholds. Poor comprehension or attention deficits often compromise patient abilities to follow procedural instructions. This article describes the effects of jointly applying behavioral methods and psychophysical methods to improve two severely brain-injured survivors' attending and reporting on auditory test stimuli presentation. Treatment consisted of stimulus control training that involved differentially reinforcing responding in the presence and absence of an auditory test tone. Subsequent hearing screenings were conducted with novel auditory test tones and a common titration procedure. Results showed that prior stimulus control training improved attending and reporting such that hearing screenings were conducted and estimates of auditory thresholds were obtained.

Prism adaptation to dynamic events

In the present study, we explored adaptation to prism-displaced dynamic and static events under conditions of minimal information. Many of our interactions with the world are dynamic and involve reaching for or intercepting moving objects. The consequences (or feedback) of those interactions entail the presence or absence of physical contact with the moving objects. In this study, humans learned, with only heptic feedback, to intercept optically displaced falling balls. To eliminate visual feedback, the falling balls disappeared behind an occluder (which systematically varied in size across groups) prior to either striking or missing a subject's hand. As occluder size decreased, adaptation increased. With minimum occluder sizes, the greatest adaptation occurred around the training position, and adaptation decreased as distance between training and testing positions increased. The results can best be described in terms of a generalization gradient centered around the training position. This generalization gradient was not present when subjects were trained with ecologically similar static arrays. Implications for models of adaptation are discussed.

Effects of variable-interval value and amount of training on stimulus generalization

In Experiment 1 pigeons pecked a key that was illuminated with a 501-nm light and obtained food by doing so according to a variable-interval (VI) schedule of reinforcement, the mean value of which differed across groups: either 30 s, 120 s, or 240 s. The pigeons in all three groups were trained for 10 50-min sessions. Generalization testing was conducted in extinction with different wavelengths of light. Absolute and relative generalization gradients were similar in shape for the three groups. Experiment 2 was a systematic replication of Experiment 1 using line orientation as the stimulus dimension and a mean VI value of either 30 s or 240 s. Again, gradients of generalization were similar for the two groups. In Experiment 3 pigeons pecked a key that was illuminated with a 501-nm light and obtained food reinforcers according to either a VI 30-s or a 240-s schedule. Training continued until response rates stabilized (> 30 sessions). For subjects trained with the 30-s schedule, generalization gradients were virtually identical regardless of whether training was for 10 sessions (Experiment 1) or until response rates stabilized. For subjects trained with the VI 240-s schedule, absolute generalization gradients for subjects trained to stability were displaced upward relative to gradients for subjects trained for only 10 sessions (Experiment 1), and relative generalization gradients were slightly flatter. These results indicate that the shape of a generalization gradient does not necessarily depend on the rate of reinforcement during 10-session single-stimulus training but that the effects of prolonged training on stimulus generalization may be schedule dependent.