Conditional discrimination in the intraverbal relation: a review and recommendations for future research

Differential effect of training impure tacts versus pure tacts plus intraverbal on the emergence of new verbal operants: A conceptual and methodological study

The aim of this research was to test the effect of training impure tact versus pure tact and intraverbals on the emergence of new verbal operants (impure tacts), thus establishing a conceptual and methodological differentiation on these operants. This was done by varying the training order of intraverbal or impure tact to analyze and confirm whether or not impure tact is the mere sum of pure tact plus intraverbal and therefore has different functions and consequences in learning. An experiment was conducted with 30 participants randomly assigned to three groups. In Group 1, pure tact plus intraverbal and then impure tact were trained. In Group 3 the training order of these operants was counterbalanced. Group 2 was the control group, training only pure tact plus intraverbal. After the training phases, the emergence of impure tacts was tested. The results of this research indicate that the training of impure tacts favors the emergence of new impure tacts to a greater extent than the training of pure tact plus intraverbal and that they therefore have different functions. It is also shown that variation in the order of presentation of the type of training influences the subsequent emergence of new operants (impure tacts), so that creating a previous history of learning in impure tacts favors emergence even when the intraverbal alone is subsequently trained. This has important implications at both conceptual and methodological levels as it would contribute to the development of more effective language training technologies.

Comparing the Effect of Echoic and Listener Responding in the Development of Complex Intraverbals

This study aimed to compare the effects of echoic and listener responding in the emergence of complex intraverbal behavior in four children with autism spectrum disorder (ASD). Each participant was taught to provide an echoic response or a listener response for different discriminative stimuli for each condition. We used a nonconcurrent multiple probe design across participants and adapted an alternating treatment design to compare the effects between the two conditions. Pre- and posttests were used to evaluate the effects of the two different prompt types in the emergence of complex intraverbals. The results indicate that the echoic response was more effective than the listener response at increasing the emergence of complex intraverbal responses in three out of four participants.

Combinatorial Language parent-report Scores Differ Significantly Between Typically Developing Children and Those with Autism Spectrum Disorders

Prefrontal synthesis (PFS) is a component of constructive imagination. It is defined as the process of mentally juxtaposing objects into novel combinations. For example, to comprehend the instruction "put the cat under the dog and above the monkey," it is necessary to use PFS in order to correctly determine the spatial arrangement of the cat, dog, and monkey with relation to one another. The acquisition of PFS hinges on the use of combinatorial language during early childhood development. Accordingly, children with developmental delays exhibit a deficit in PFS, and frequent assessments are recommended for such individuals. In 2018, we developed the Mental Synthesis Evaluation Checklist (MSEC), a parent-reported evaluation designed to assess PFS and combinatorial language comprehension. In this manuscript we use MSEC to identify differences in combinatorial language acquisition between ASD (N = 29,138) and neurotypical (N = 111) children. Results emphasize the utility of the MSEC in distinguishing language deficits in ASD from typical development as early as 2 years of age (p < 0.0001).

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.

Simultaneous Prompting to Teach Intraverbal Synonyms to Struggling Readers

In simultaneous prompting procedures, an immediate (i.e., 0-s) prompt is presented during all training trials, and transfer to the target discriminative condition is assessed during daily probes. Previous research suggests that simultaneous prompting procedures are efficacious and may produce acquisition in fewer errors to mastery when compared to prompt delay procedures. To date, only a single study on simultaneous prompting has included intraverbal targets. The current study evaluated the efficacy of a simultaneous prompting procedure on the acquisition of intraverbal synonyms for six children at risk for reading failure. Simultaneous prompting alone produced responding at mastery levels in seven of the 12 evaluations. Antecedent-based procedural modifications were effective in four of the five remaining evaluations. Errors were generally low for all but one participant. The current findings support the use of simultaneous prompting procedures when targeting intraverbals for young children exhibiting reading deficits.

A translational evaluation of component skills for the establishment of multiply controlled intraverbals

Intraverbal behavior is a type of verbal behavior in which the response form has no point-to-point correspondence with its verbal stimulus. However, the form and occurrence of most intraverbals is under the control of multiple variables. Establishing this form of multiple control may depend on a variety of preestablished skills. The purpose of Experiment 1 was to evaluate these potential prerequisites with adult participants using a multiple probe design. The results suggest that training was not required for each putative prerequisite. In Experiment 2, probes for all skills were conducted following convergent intraverbal probes. The results showed that convergent intraverbals only emerged when proficiency of each skill was demonstrated. Finally, Experiment 3 evaluated alternating training of multiple tact and intraverbal categorization. The results showed that this procedure was effective for half of the participants.

The Use of Instructive Feedback to Promote Emergent Tact and Intraverbal Control: A Replication

Instructive feedback (IF) involves incorporating additional acquisition targets into skill-acquisition programs. A recent study by Frampton and Shillingsburg (2020) found that IF led to emergent verbal operants with two elementary-aged children diagnosed with autism spectrum disorder (ASD). The current study replicated Frampton and Shillingsburg with two children with ASD. Therapists conducted sessions of mastered listener-by-name trials (e.g., "Show me otter," with pictures of otter, dog, and elephant) with IF statements for features of the target stimuli (e.g., "It lives in rivers.") embedded during the consequence portion of the trial. We evaluated the acquisition of secondary targets and emergent responses using a concurrent multiple baseline across sets design. We observed increased correct responding for secondary targets and emergent responses for all three sets of stimuli with one participant. The other participant emitted correct responses for secondary targets and emergent operants with the first set but not with the other two sets of stimuli. Results suggested that IF can lead to emergent verbal operants, but the extent of emergence may be idiosyncratic.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40616-022-00171-y.

Emergent Intraverbal and Reverse Intraverbal Behavior Following Listener Training in Children with Autism Spectrum Disorder

We evaluated whether intraverbal and reverse intraverbal behavior emerged following listener training in children with autism spectrum disorder (ASD). Six participants were each taught three sets of three "when?" questions in listener training. A multiple baseline design across behaviors (stimulus sets) was used to assess the effects of listener training. Results showed that intraverbal behavior emerged following listener training for five out of six participants. One participant received additional listener training and intraverbal training before intraverbal behavior emerged. Furthermore, reverse intraverbal responding occurred across all three sets of questions for three of the six participants. Establishing listener behavior may be a pathway for emergent intraverbal and reverse intraverbal responding in children with ASD. Future research could examine what skill repertoire may facilitate such transfer.

Jack Michael's Contributions to the Treatment of Autism

Jack Michael dedicated his life to teaching behavior analysis. He was passionate about Skinner's works and his enthusiasm was contagious. Jack's primary goal for his students was that they be able to analyze behavior like Skinner analyzed behavior, but with a little bit of Jack Michael sprinkled in here and there. Jack is probably best known to behavior analysts for his conceptual contributions to our field (e.g., his work on motivation), but his contributions to the treatment of autism are perhaps his most socially significant achievement. In our tribute to Jack, we will describe how he advanced the treatment of autism not only through his conceptual work and his teaching, but through his role in the development of applied behavior analysis, and in the application of Skinner's (1957) analysis of verbal behavior to language assessment and intervention for children and adults with language delays.

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.

Imagination in Autism: A Chance to Improve Early Language Therapy

Children with autism often have difficulties in imaginative play, Theory of Mind, and playing out different scenarios in their minds. Research shows that the root of these problems may be the voluntary imagination network that involves the lateral prefrontal cortex and its long frontoposterior connections to the temporal-parietal-occipital area. Previously disconnected visuospatial issues (stimulus overselectivity and tunnel vision) and language issues (lack of comprehension of spatial prepositions and complex recursive sentences) may be explained by the same voluntary imagination deficit. This review highlights the new insights into the mechanism of voluntary imagination, its difference from involuntary imagination, and its unusually strong critical period. Clearer developmental terminology and a better understanding of voluntary imagination have the potential to facilitate communication between therapists and parents, and improve therapy outcomes in children.

Novel Prefrontal Synthesis Intervention Improves Language in Children with Autism

Prefrontal synthesis (PFS) is defined as the ability to juxtapose mental visuospatial objects at will. Paralysis of PFS may be responsible for the lack of comprehension of spatial prepositions, semantically-reversible sentences, and recursive sentences observed in 30 to 40% of individuals with autism spectrum disorder (ASD). In this report we present data from a three-year-long clinical trial of 6454 ASD children age 2 to 12 years, which were administered a PFS-targeting intervention. Tablet-based verbal and nonverbal exercises emphasizing mental-juxtaposition-of-objects were organized into an application called Mental Imagery Therapy for Autism (MITA). The test group included participants who completed more than one thousand exercises and made no more than one error per exercise. The control group was selected from the rest of participants by a matching procedure. Each test group participant was matched to the control group participant by age, gender, expressive language, receptive language, sociability, cognitive awareness, and health score at first evaluation using propensity score analysis. The test group showed a 2.2-fold improvement in receptive language score vs. control group (p < 0.0001) and a 1.4-fold improvement in expressive language (p = 0.0144). No statistically significant change was detected in other subscales not targeted by the exercises. These findings show that language acquisition improves after training PFS and that a further investigation of the PFS-targeting intervention in a randomized controlled study is warranted.

Citation Analysis of The Analysis of Verbal Behavior (2008-2018)

Recent articles by the editorial board of The Analysis of Verbal Behavior (TAVB) include calls for greater integration, collaboration, and inclusion. In so doing, it may be helpful to consider TAVB's current reach. Previously, Petursdottir, Peterson, and Peters (The Analysis of Verbal Behavior, 25, 109-121, 2009) described the number of citations of articles published in TAVB from 1983 to 2007. The authors found that the greatest number of references to TAVB were self-citations, followed predominantly by other behavior-analytic outlets, such as the Journal of Applied Behavior Analysis. Here, we replicate and extend the work of Petursdottir et al. (The Analysis of Verbal Behavior, 25, 109-121, 2009) by conducting a citation analysis of references included in TAVB publications from 2008 to 2018 and also report citations by these venues to TAVB. This citation analysis allows for a more recent review of those outlets that articles published in TAVB commonly reference and those that cite TAVB. Generally, self-citations predominated, with articles published in TAVB commonly referencing books and chapters. The implications of these practices on the impact of TAVB and suggestions for moving forward are considered.

Novel linguistic evaluation of prefrontal synthesis (LEPS) test measures prefrontal synthesis acquisition in neurotypical children and predicts high-functioning versus low-functioning class assignment in individuals with autism

In order to grasp the difference between "the cat on the mat" and "the mat on the cat," understanding the words and the grammar is not enough. Rather it is essential to visualize the cat and the mat together to appreciate their relations. This type of imagination, which involves juxtaposition of mental objects is conducted by the prefrontal cortex and is therefore called Prefrontal Synthesis (PFS). PFS acquisition has a strong experience-dependent critical period putting children with language delay in danger of never acquiring PFS and, consequently, not mastering complex language comprehension. In typical children, the timeline of PFS acquisition correlates with vocabulary expansion. Conversely, atypically developing children may learn many words but never acquire PFS. In these individuals, intelligence tests based on vocabulary assessment may miss the profound deficit in PFS. Accordingly, we developed a test specific for PFS - Linguistic Evaluation of Prefrontal Synthesis or LEPS - and administered it to 50 neurotypical children, age 4.1 ± 1.3 years and to 23 individuals with impairments, age 16.4 ± 3.0 years. All neurotypical children older than 4 years received the LEPS score 7/10 or greater indicating good PFS ability. Among individuals with impairments only 39% received the LEPS score 7/10 or greater. LEPS was 90% correct in predicting high-functioning vs. low-functioning class assignment in individuals with impairments.

Review of Methods to Equate Target Sets in the Adapted Alternating Treatments Design

The adapted alternating treatments design is a commonly used experimental design in skill acquisition research. This design allows for the evaluation of two or more independent variables on responding to unique target sets. Equating target sets is necessary to ensure a valid comparison of the independent variables. To date, there is little guidance on best practice when equating target sets and it is unclear how researchers have done so previously. We reviewed the reported methods used to equate target sets in articles published using the adapted alternating treatments design in five behavior-analytic journals. Just over half of the studies published using the adapted alternating treatments design reported any method to equate target sets and the methods varied considerably. Alternative methods, such as random assignment, were prevalent. Considerations for best practice and avenues for future research are discussed.

The Effects of the Interspersal of Related Responses on the Emergence of Intraverbals for Children With Autism Spectrum Disorder

The present study evaluated the emergence of intraverbals for 2 children diagnosed with autism spectrum disorder. Prior to baseline, both children demonstrated tact, tact function, listener, and listener by function responses with 12 pictorial stimuli, yet they failed to demonstrate intraverbals related to the function of the items (e.g., "What do you do with [item]?" and "What do you use to [function]?"). Following baseline, previously mastered related tact, tact function, listener, and listener by function tasks were presented prior to probe trials for the target item-function and function-item intraverbals. Results showed that interspersal of the related tasks for a subset of the intraverbals led to the emergence of untrained item-function and function-item intraverbals for both participants. In Experiment 2, the long-term effects of this remedial training on the emergence of untrained intraverbals was evaluated as new tact and listener responses were trained. Results of Experiment 2 showed that tact function and listener by function training was sufficient to establish the emergence of item-function and function-item intraverbals in the absence of related-task interspersal. These results are discussed in relation to current explanations for emergent responding.

Language evolution to revolution: the leap from rich-vocabulary non-recursive communication system to recursive language 70,000 years ago was associated with acquisition of a novel component of imagination, called Prefrontal Synthesis, enabled by a mutation that slowed down the prefrontal cortex maturation simultaneously in two or more children – the Romulus and Remus hypothesis

There is an overwhelming archeological and genetic evidence that modern speech apparatus was acquired by hominins by 600,000 years ago. On the other hand, artifacts signifying modern imagination, such as (1) composite figurative arts, (2) bone needles with an eye, (3) construction of dwellings, and (4) elaborate burials arose not earlier than 70,000 years ago. It remains unclear (1) why there was a long gap between acquisition of modern speech apparatus and modern imagination, (2) what triggered the acquisition of modern imagination 70,000 years ago, and (3) what role language might have played in this process. Our research into evolutionary origin of modern imagination has been driven by the observation of a temporal limit for the development of a particular component of imagination. Modern children not exposed to recursive language in early childhood never acquire the type of active constructive imagination called Prefrontal Synthesis (PFS). Unlike vocabulary and grammar acquisition, which can be learned throughout one’s lifetime, there is a strong critical period for the development of PFS and individuals not exposed to recursive language in early childhood can never acquire PFS as adults. Their language will always lack understanding of spatial prepositions and recursion that depend on the PFS ability. In a similar manner, early hominins would not have been able to learn recursive language as adults and, therefore, would not be able to teach recursive language to their children. Thus, the existence of a strong critical period for PFS acquisition creates an evolutionary barrier for behavioral modernity. An evolutionary mathematical model suggests that a synergistic confluence of three events (1) a genetic mutation that extended the critical period by slowing down the prefrontal cortex development simultaneously in two or more children, (2) invention of recursive elements of language, such as spatial prepositions, by these children and (3) their dialogic communications using these recursive elements, resulted in concurrent conversion of a non-recursive communication system of their parents to recursive language and acquisition of PFS around 70,000 years ago.

The Verbal Behavior Stimulus Control Ratio Equation: a Quantification of Language

Language is a much sought-after yet elusive subject matter for scientific investigation. Entire fields of study have evolved to address the complexities of language, with most using a structural analysis as the framework for examination. Skinner (Verbal Behavior, 1957) proposed that language fell within the scope of a science of behavior and was therefore open to functional analysis and interpretation. Over the past 60 years, much has been done to further the scientific explanation, prediction, and control of verbal behavior as a function of environmental variables. However, we still need to more accurately describe the subject matter of investigation. The stimulus control ratio equation (SCoRE) is a metric to summarize a behavioral repertoire by comparing the relative frequency of its component parts. The verbal behavior SCoRE compares the observed proportions of responding against the null hypothesis to yield a statistic to describe the present level of functional performance. Such information may be useful for measuring change over time and comparing treatment effects within individuals and across groups. This article provides a conceptualization of the interdependence of the verbal operants identified by Skinner (1957), a model for analyzing the entirety of the verbal repertoire, and implications for research and practice.

Evaluating the Effects of Similar and Distinct Discriminative Stimuli During Auditory Conditional Discrimination Training With Children With Autism

Children with autism are often taught auditory conditional discriminations in the form of personal information questions that might prove useful in conversation (e.g., "What is your favorite food?" "Pizza" and "What is your favorite color?" "Purple"). In these questions, the auditory stimuli presented as part of the compound discriminative stimulus (i.e., what, favorite, color/food) do not always simultaneously control responding. If all components of the auditory stimulus do not control responding, a child may master 1 target but have trouble acquiring subsequent targets that have a component of a previously learned auditory stimulus because the previously learned response is emitted. One way to avoid this problem is to teach many targets that have no overlapping component stimuli before introducing targets that include a previously learned component. Another way to avoid the problem is to systematically introduce overlapping stimulus components simultaneously to facilitate control by all relevant components. Three children with autism were taught auditory conditional discriminations. An adapted alternating-treatments design was used to compare the use of training sets with programmed overlap of component auditory stimuli to training sets with no overlap of stimulus components. The effects of these 2 arrangements were evaluated on trials to criterion and percentage accuracy during acquisition. All participants reached mastery faster with at least 1 target set in the nonoverlap condition compared to the overlapping condition; 2 out of the 3 participants met the mastery criteria for both overlapping and nonoverlapping targets at a similar rate by the 3rd training set.

Development of the Mental Synthesis Evaluation Checklist (MSEC): A Parent-Report Tool for Mental Synthesis Ability Assessment in Children with Language Delay

Mental synthesis is the conscious purposeful process of synthesizing novel mental images from objects stored in memory. Mental synthesis ability is essential for understanding complex syntax, spatial prepositions, and verb tenses. In typical children, the timeline of mental synthesis acquisition is highly correlated with an increasing vocabulary. Children with Autism Spectrum Disorder (ASD), on the other hand, may learn hundreds of words but never acquire mental synthesis. In these individuals, tests assessing vocabulary comprehension may fail to demonstrate the profound deficit in mental synthesis. We developed a parent-reported Mental Synthesis Evaluation Checklist (MSEC) designed to assess mental synthesis acquisition in ASD children. The psychometric quality of MSEC was tested with 3715 parents of ASD children. Internal reliability of the 20-item MSEC was good (Cronbach's alpha >0.9). MSEC exhibited adequate test⁻retest reliability; good construct validity, supported by a positive correlation with the Autism Treatment Evaluation Checklist (ATEC) Communication subscale; and good known group validity reflected by the difference in MSEC scores for children of different ASD severity levels. The MSEC questionnaire is copyright-free and can be used by researchers as a complimentary subscale for the ATEC evaluation. We hope that the addition of MSEC will make the combined assessment more sensitive to small steps in a child's development. As MSEC does not rely on productive language, it may be an especially useful tool for assessing the development of nonverbal and minimally verbal children.

Promoting Conditional Use of Communication Skills for Learners With Complex Communication Needs: A Tutorial

PURPOSE

Conditional use of communication skills refers to the ability of a learner to appropriately generalize and discriminate when, where, and how to communicate based on constant variation and shifts in environmental cues.

METHOD

We describe discrimination and generalization challenges encountered by learners with complex communication needs and ways in which these challenges are fostered through traditional communication intervention programming. We address arrangements in instruction that maximize the probability of learners acquiring the conditional use of new vocabulary and the modest instructional technology implemented when planning for generalization.

RESULTS

We propose establishing well-discriminated and generalized use of new vocabulary items through the application of a general case instruction framework to communication intervention programming.

CONCLUSION

We provide intervention methodology, including intervention steps for general case instruction, a plethora of functional examples, and graphic displays to assess and intervene to promote conditional use of communication skills for learners with complex communication needs.

Teaching children with autism to explain how: A case for problem solving?

Few studies have applied Skinner's (1953) conceptualization of problem solving to teach socially significant behaviors to individuals with developmental disabilities. The current study used a multiple probe design across behavior (sets) to evaluate the effects of problem-solving strategy training (PSST) on the target behavior of explaining how to complete familiar activities. During baseline, none of the three participants with autism spectrum disorder (ASD) could respond to the problems presented to them (i.e., explain how to do the activities). Tact training of the actions in each activity alone was ineffective; however, all participants demonstrated independent explaining-how following PSST. Further, following PSST with Set 1, tact training alone was sufficient for at least one scenario in sets 2 and 3 for all 3 participants. Results have implications for generative responding for individuals with ASD and further the discussion regarding the role of problem solving in complex verbal behavior.

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.

Empirical Investigations of the Intraverbal: 2005-2015

Several papers have reviewed the literature based on Skinner's conceptual framework presented in his 1957 book, Verbal Behavior. These reviews have called for more research on the topic of verbal behavior generally and often for more research on particular verbal operants. For example, Sautter and LeBlanc (2006) urged the behavior-analytic community to conduct more research on the intraverbal because of the scant existing literature base at that time. In the current review, we replicate the procedures used by Sautter and LeBlanc focusing specifically on the intraverbal relation and on the literature published in the 10 years since their call for research. We summarize the publication themes, provide graphs of the trends and types of published articles, and offer ideas for future research specific to the intraverbal.

Emergence of Intraverbal Responding Following Tact Instruction with Compound Stimuli

Effective intraverbal responding often requires control by multiple elements of a verbal stimulus. The purpose of this study was to examine the emergence of such intraverbal relations following tact instruction with compound stimuli and to analyze any resulting error patterns. Participants were seven typically developing children between 3 and 5 years of age. After being taught to tact four overlapping compound stimuli that differed along color and shape dimensions, participants were tested for emergent intraverbal responding. Three participants performed with high accuracy and four with intermediate accuracy when correct intraverbal responding required control by multiple elements (i.e., color names and shape names) of the verbal stimulus. Five participants performed with high accuracy when intraverbal responding required control by only a single stimulus element, and all participants showed emergence of reverse intraverbal relations when the response required naming only a single stimulus element (i.e., color or shape). There was an insufficient number of errors to perform detailed error analyses at the individual level, but overall, the first element of a verbal stimulus was more likely to exert control over the response than the second element, and color words were more likely to exert control than shape words. Results suggest that individual stimulus elements acquired independent control over the responses that had been established as tacts.

Evaluation of a Blocked-Trials Procedure to Establish Complex Stimulus Control over Intraverbal Responses in Children with Autism

We evaluated the use of a blocked-trials procedure to establish complex stimulus control over intraverbal responses. The participants were four young boys with a diagnosis of autism who had struggled to master intraverbals. The blocked-trials procedures involved presentation of stimuli in separate trial blocks. The trial blocks gradually reduced in size contingent upon correct responding, until the stimuli were presented in quasi-random order. All participants acquired multiple discriminations with the blocked-trials procedure, although additional procedures were needed to teach the first discrimination with two participants. Following acquisition of multiple discriminations, two participants acquired a novel discrimination with quasi-random presentation of stimuli, and a third participant demonstrated discriminated responding in intraverbal probes.

Verbal Stimulus Control and the Intraverbal Relation

The importance of the intraverbal relation is missed in most theories of language. Skinner (1957) attributes this to traditional semantic theories of meaning that focus on the nonverbal referents of words and neglect verbal stimuli as separate sources of control for linguistic behavior. An analysis of verbal stimulus control is presented, along with its distinction from nonverbal stimulus control and motivational control. It is suggested that there are at least four different types of increasingly complex verbal discriminations relevant to speaker and listener behavior: simple, compound, verbal conditional, and verbal function-altering (Eikeseth & Smith, 2013; Schlinger & Blakely, 1994). Separate but interlocking accounts of how these specific types of verbal stimuli produce different evocative and function-altering effects for the speaker and for the listener are provided. Finally, the effects of weakening verbal stimulus control and the loss of intraverbal behavior are considered, especially as they relate to dementia, aphasia, and traumatic brain injury.

A Bibliographic Tribute to Jack Michael

"In the late 1950's, Jack Michael, a bright but irritating young psychology instructor, moved from the Universities of Kansas to Houston to Arizona State. Along the way he befriended two nontraditional students, protected them through their Ph.D. programs, and turned them loose on the world: Teodoro Ayllon…and Montrose Wolf…" (Risley, 2001, p. 267). So begins Risley's chapter on the origins of applied behavior analysis. For almost 50 years, Jack Michael provided a model for us to "talk like Skinner" and to analyze behavior as Skinner would. For this, he has been widely respected and revered. The purpose of this bibliography is to explain to new and familiar readers alike Jack's contributions to the field of behavior analysis in areas of his primary focus: (a) behavioral function taxonomy, (b) motivation, (c) reinforcement, (d) response topographies, (e) multiple control, (f) duplic and codic verbal behavior, and (g) teaching. Throughout, we weave his role in the field's history and his leadership in its expansion, as these have been additional areas of significant contributions. Above all, we wish to highlight Jack's work, in bibliographic and narrative form, in a way that expresses a heartfelt tribute on behalf of his students and others whom he influenced to learn about psychology as a natural science and to think and talk like Skinner.

On Intraverbal Control and the Definition of the Intraverbal

Behavior analysts should distinguish between the intraverbal, as a class of verbal operants, and intraverbal control, the potentiating effect, however slight, of a verbal antecedent on a verbal response. If it is to serve an explanatory function, the term intraverbal, as a class of verbal operants, should be restricted to those cases in which a verbal antecedent, as the result of a history of contiguous or correlated usage, is sufficient to evoke the putative intraverbal response. Intraverbal control is pervasive in verbal behavior, but since it is typically just one of many concurrent variables that determine the form of a verbal response, such multiply controlled responses are not usefully called "intraverbals." Because intraverbals and their controlling variables have invariant formal properties, they are conceptually simple, but they nevertheless play a central role in the interpretation of complex phenomena such as the structural regularities in verbal behavior (i.e., grammar).

Evaluating the Emergence of Reverse Intraverbals in Children with Autism

Verbal behavior plays a fundamental role in the development of complex social and communication skills. Many children diagnosed with autism spectrum disorder exhibit profound deficiencies in intraverbal repertoires and the development of social relationships. Recent studies that investigated the effects of intraverbal training on the emergence of reverse intraverbals produced mixed results (e.g., Perez-Gonzalez et al., Journal of Applied Behavior Analysis 40:697-701, 2007)). In the current study, a multiple-probe design across four participants with autism was used to evaluate the effects of intraverbal training on the emergence of reverse intraverbals. Intraverbal training consisted of multiple exemplars taught concurrently, bidirectional stimulus-response teaching formats, general case analysis, reinforcement, and a constant prompt delay (CPD) procedure. Participants were trained on intraverbal targets and probes were conducted to assess emergence of untaught reverse intraverbals. Three participants demonstrated the emergence of reverse intraverbals as a result of the intraverbal training procedures. Social validity and maintenance of target responses and emergent reverse intraverbals were assessed.

Effects of a differential observing response on intraverbal performance of preschool children: a preliminary investigation

Axe (2008) speculated that some instances of intraverbal responding might be associated with limited or delayed acquisition because they require discrimination of multiple components of verbal stimuli. Past studies suggest that acquisition of responses under control of complex, multicomponent antecedent stimuli (e.g., conditional or compound stimulus control) can be facilitated with the introduction of a differential observing response (DOR; Dube & McIlvane, 1999; Gutowski, Geren, Stromer, & Mackay, 1995). The purpose of the current study was to evaluate the effects of a DOR (i.e., repeating the question) on intraverbal responding with six neurotypical preschool children. Findings included that (a) accuracy of intraverbal performance increased when the experimenter prompted a DOR; (b) 1 of 6 participants overtly emitted the DOR for a second relation in the absence of prompts, which was correlated with increased accuracy; and (c) following mastery, response accuracy was variable for 3 participants. Based on these findings, prompted DORs may offer an effective, if temporary, aid to intraverbal instruction for neurotypical preschool children.

An analysis of verbal stimulus control in intraverbal behavior: implications for practice and applied research

A common characteristic of the language deficits experienced by children with autism (and other developmental disorders) is their failure to acquire a complex intraverbal repertoire. The difficulties with learning intraverbal behaviors may, in part, be related to the fact that the stimulus control for such behaviors usually involves highly complex verbal stimuli. The antecedent verbal control of intraverbal behavior may involve discriminative stimuli (i.e., discriminated operants), conditional stimulus control, and/or control by compound stimuli. Distinctions among these different types of antecedent control are presented, along with recommendations for intervention procedures that may facilitate the acquisition of intraverbal behavior.