Should we Stop Doing Mand Intraverbal Training What

Should we Stop Doing Mand Intraverbal Training? What do the Data Tell us? Mark L. Sundberg, Ph. D. , BCBA marksundberg@astound. net

Introduction n n n These are some exciting times in the field of behavior analysis Conferences Research Certification (4600+ people) Training programs (85+) Positive press ABA: International is growing at a rapid rate

Membership in ABA: International

Introduction • • • Successful interventions for children with autism are probably the main cause for the increase in ABA’s numbers This success with behavioral interventions comes as no surprise to many in the field of behavior analysis Over 55 years of empirical and clinical research and applications with the developmentally disabled Most of the basic teaching procedures for children with autism were in place during the 1970 s, including mand intraverbal training. None of this is “new. ” Let me hear your voice (1993) by Catherine Maurice brought widespread attention to behavior analysis

Introduction • • However, with this success there is some bad news Everybody is now an expert in behavior analysis Widespread dissemination of behavioral techniques, often by unqualified people Simplifying the concepts and procedures beyond recognition Parallels to B-mod and education in the 60 s “What happened to the promise of behavior modification? ” Similar concerns for the current popularity of the use of behavior analysis for the treatment of children with autism

Introduction • • • • What constitutes a “behavioral approach” to treatment of children with autism? Consumers must be confused because there are so many models out there, often quite different from each other, but all claiming to be a “behavioral approach” DTT Lovaas model CARD model ABA Pivotal response training VB approach CABAS Competent learner model Natural language paradigm Milieu language training Incidental teaching

Introduction • • In addition, there are many other approaches and treatments such as. . . Floor time RDI Son-Rise Holding therapy TEACCH Secretion Auditory training • • • Sensory integration Weighted jackets Deep pressure Special diets Vitamins Medications Swimming with dolphins Decompression chambers Chelation Faciliated communication

Introduction • • Thanks to the efforts of Dr. Gina Green and others, many of these “pseudoscientific” approaches have been identified and consumers have been warned about their ineffectiveness and even potential danger to children. However, recently Dr. Green has added the “Verbal Behavior Approach” to her list of pseudoscientific approaches and suggested that it has similarities to facilitated communication (ABA, 2005). In her recent presentation at the NY-ABA titled “Verbal Behavior; ” An evidence-based technology for autism intervention? ” Dr. Green (2005) concluded “the ‘VB’ approach to autism intervention does not appear to meet accepted criteria for evidence-based practice or transferable behavioral technology” Others have expresses concern about the dissemination of verbal behavior procedures. Carr and Firth (2005) stated “little research exists to support such widespread dissemination (of the VB approach). ”

Introduction • • The purpose of the current presentation is to address the concerns raised by Dr. Green, Carr and Firth, and others about the “unwarranted dissemination of the verbal behavior approach” to language training for children with autism. The goal of clarify what constitutes a “verbal behavior approach, ” while demonstrating its empirical foundation, on-going research agenda, its value to children with autism, and hopefully, to get Dr. Green to remove verbal behavior from her list of pseudosciences.

What Constitutes a Verbal Behavior Approach to Autism Treatment? • • First, I share Dr. Green’s concern for the need for additional verbal behavior research. I believe this point is uncontroversial. (Sundberg, 1991: “ 301 Research topics from Skinner’s book Verbal Behavior”). As of 2003, over 80 of these topics have been addressed (Sundberg, 2003) Research was the primary purpose for starting the journal The Analysis of Verbal Behavior, now in its 22 nd Volume, and published by ABA: International Second, I share Dr. Green’s concern about the improper dissemination of behavioral concepts and procedures

What Constitutes a Verbal Behavior Approach to Autism Treatment? • • • The basic teaching procedures consist of the standard methodology found in applied behavior analysis (e. g. , Cooper, Heron, & Heward, 1987). Prompting Fading Pairing Modeling Shaping Chaining Differential reinforcement procedures (e. g. , DRO, DRI, DRL) Intermittent reinforcement procedures (e. g. , FR, VR, FI, VI)

What Constitutes a Verbal Behavior Approach to Autism Treatment? • • • Extinction procedures (e. g. , planned ignoring) Punishment procedures (e. g. , reprimands, time out, overcorrection) Generalization Discrimination training Errorless learning Transfer of stimulus control Task analysis Contingency contracting Token economies

What Constitutes a Verbal Behavior Approach to Autism Treatment? • • • Additional procedural elements include. . Individualized assessment and intervention program Frequent opportunities to respond Use of discrete trial teaching Incidental & natural environment teaching Data collection Interspersel techniques Behavioral momentum techniques Peer and social interaction Functional analyses On-going analyses of performance by formally trained behavior analysts

What Constitutes a Verbal Behavior Approach to Autism Treatment? • • These procedures are (to varying degrees) common to most behavioral intervention programs for children with autism (e. g. , Howard, Sparkman, Cohen, Green, & Stainlaw, 2005; Koegel & Koegel, 1996; Lovaas, 2003; Maurice, Green, & Luce, 1996), and thus benefit from the same empirical foundation claimed by those programs. But, what theory of language underlies the assessment and curricula for these discrete trial programs/ABA program?

What Constitutes a Verbal Behavior Approach to Autism Treatment? • • • The major difference between the “verbal behavior approach” and the majority of discrete trial and ABA programs available in the literature is the conceptual analysis of language that underlies the assessment and curriculum used in each program Most DTT/ABA programs use the traditional linguistic classification system of expressive and receptive language, and the associated vernacular concerning language which has its roots in cognitive psychology The verbal behavior approach employs Skinner’s (1957) functional analysis of language which has its roots in radical behaviorism

Skinner’s Analysis of Verbal Behavior • • • Language is learned behavior under the functional control of environmental contingencies “What happens when a man speaks or responds to speech is clearly a question about human behavior and hence a question to be answered with the concepts and techniques of psychology as an experimental science of behavior” (Skinner, 1957, p. 5) The analysis of verbal behavior involves the same behavioral principles and concepts that make up the analysis of nonverbal behavior. No new principles of behavior are required. Chapter 1 of Verbal Behavior is titled “A Functional Analysis of Verbal Behavior” In Chapter 2 he identifies the dependent and independent variables for a functional analysis of verbal behavior

Behavior Analysis (Basic Principles of Operant Behavior) Stimulus Control (SD) Motivating Operation (MO/EO) Response Reinforcement Punishment Extinction Conditioned reinforcement Conditioned punishment Intermittent reinforcement

Skinner’s Analysis of Verbal Behavior • • • The traditional linguistic classification of words, sentences, and phrases as expressive and receptive language blends important functional distinctions between types of operant behavior, and appeals to cognitive explanations for the causes of language behavior (Skinner, 1957, Chapter 1) The distinction between the mand, tact, and intraverbal (traditionally all classified as expressive language) identifies three separate sources of antecedent control EO control------->Mand Nonverbal SD---->Tact Verbal SD----->Intraverbal

Skinner’s Analysis of Verbal Behavior • • The empirical question is are these three antecedents variables functionally separate, or is there no value in making this distinction? From a clinical standpoint, the two most common language problems demonstrated by children with autism that I have encountered over the past 32 years is a defective mand repertoire and/or a defective intraverbal repertoire, despite often having strong tact and receptive discrimination repertoires.

The Distinction Between the Mand the Tact • • Based on the distinction between the establishing operation (EO) and stimulus control (SD) as separate sources of control Skinnerian psychology (“radical behaviorism, ” see Skinner, 1974) has always maintained that motivational control is different from stimulus control In Behavior of Organisms (Skinner, 1938) Skinner devoted two chapters to the treatment of motivation; Chapter 9 titled “Drive” and Chapter 10 titled “Drive and Conditioning: The Interaction of Two Variables. ” Skinner also made it clear in the section titled “Drive (is) Not a Stimulus” (pp. 374 -376) that motivation is not the same as discriminative, unconditioned, or conditioned stimuli.

The Distinction Between the Mand the Tact • • • Keller and Schoenfeld (1950) titled Chapter 9 “Motivation” and further developed Skinner’s point, “A drive is not a stimulus” (p. 276), and suggested “a new descriptive term. . . ‘establishing operation’” (p. 271) In Science and Human Behavior (1953) Skinner devoted three chapters to motivation: Chapter 9: “Deprivation and Satiation, ” Chapter 10: “Emotion, ” and Chapter 11: “Aversion, Avoidance, Anxiety. ” In Verbal Behavior (1957) Skinner had a full chapter on motivation and language (The Mand), and throughout the book provided many elaborations on motivational control -- as an antededent variable.

The Distinction Between the Mand the Tact • • • Holland Skinner’s (1961) book contained four chapters on motivation; Chapters 7: “Deprivation, ” 8: “Emotion I, ” 9: “Avoidance and Escape Behavior, ” and 10: “Emotion II. ” Millenson (1968) contained four chapters on motivation and presented an excellent summary of the relevant empirical research (p. 364 -384); Chapters 15: “Motivation I, ” 16: “Motivation II, ” 17: “Aversive Contingencies, ” and 18: “Emotional Behavior. ” However, the topic of motivation was for the most part dropped from the first generation of Applied Behavior Analysis/Behavior Modification textbooks that followed Millenson’s book (e. g. , Fantino & Logan, 1979; Kazden, 1975; Martin & Pear, 1978; Powers & Osborne, 1976; Whaley & Malott, 1971).

The Distinction Between the Mand the Tact • • In explaining what happen to the analysis of motivation in behavior analysis, Michael (1993) pointed out, “In applied behavior analysis or behavior modification, the concept of reinforcement seems to have taken over much of the subject matter that was once considered a part of the topic of motivation” (p. 191). There was a shift from the analysis of motivation as an antecedent variable to motivation as a consequence In addition, motivation as a topic of research was absent from the behavioral journals. For example, The Journal of Applied Behavior Analysis contained no entries for “establishing operations” or “motivation” in the cumulative index (1978) covering the first 10 years of publication. During the next 10 years (1979 -1988) there were still no entries for “establishing operation. ” However, there were 5 entries for “motivation, ” but they all involved the use of motivation as a consequence, rather than as an antecedent variable.

The Distinction Between the Mand the Tact • • Motivation has returned to behavior analysis textbooks and now is a common topic in JABA thanks to Jack Michael, Brian Iwata, Wayne Fisher, and others. The JABA index for the years 1999 -2005 contains 29 entries for the EO, and 2 for the MO (motivating operations) Malott, Whaley, & Malott (1997) contains a full chapter on the EO. Catania (1994), Martin & Paer (2002), and Pierce & Epling (1995) all contain analyses of motivation throughout their books The new Edition of the Cooper, Heron, & Heward book Applied Behavior Analysis (In press) contains a full chapter on motivation as well as a full chapter on Skinner’s analysis of verbal behavior.

Research on the Mand Tact • • • If a verbal response is established under nonverbal SD (a tact) will it automatically transfer to EO control (a mand), and vice versa? Two teenagers with autism who had strong tact repertoires, but weak mand repertoires (Hall & Sundberg, 1987) Making instant soup: Could tact all items necessary and could complete the chain of behavior. If one of the items needed to complete the chain was missing, neither subject could mand for the missing item, despite strong tact and receptive repertoires for the items. By using an interrupted chain procedure and tact prompting and fading, antecedent control was transferred from a nonverbal SD to an EO, the subjects were taught to mand.

A Sample of Research on the EO, and the Mand Tact • • • Hung (1980) Simic & Bucher (1980) Lamarre & Holland (1985) Pierce, Epling, & Boer (1986) Hall & Sundberg (1987) Carroll & Hesse, (1987) Stafford, Sundberg, & Braam (1988) Yamamoto & Mochizuki (1988) Mc. Pherson & Osborne (1988) De Freitas Ribeiro (1989)

A Sample of Research on the EO, and the Mand Tact • • • Sigafoos, Doss, & Reichle (1989). Sundberg, San Juan, Dawdy, & Arguelles (1990) Sigafoos, Reichle, Doss, Hall, & Pettitt (1990) Baer & Detrich (1990) Braam & Sundberg (1991) Sprague & Horner (1992) Williams, & Greer (1993) Twyman (1996) Drasgow, Halle, & Ostrosky (1998) Drash, High, & Tudor (1999) Brown, Wacker, Derby, Peck, Richman, & Sasso (2000)

A Sample of Research on the EO, and the Mand Tact • • • Knutson & Harding (2000) Barnes-Holmes & Barnes-Holmes (2000) Goh, Iwata, & De. Leon (2000) Sundberg, Loeb, Hale, & Eigenheer (2002) Arntzen & Almas (2002) Ewing, Magee, & Ellis (2002) Winborn, Wacker, Richman, Asmus, & Geier (2002) Chambers & Rehfeldt (2003) Ross & Greer (2003) Nuzzolo-Gomez & Greer (2004) Taylor, Hoch, Potter, Rodriguez, Spinnato, & Kalaigian (2005) Petursdottir, Carr, & Michael (2005)

A Sample of Research on the EO, and the Mand Tact • • Taylor, Hoch, Potter, Rodriguez, Spinnato, & Kalaigian (2005) EO must be present to evoke mands (initiations to peers) Petursdottir, Carr, & Michael (2005). Mand training resulted in tacts, but tact training did not result in mands. There doesn’t appear to be a body of research that contradicts the separation of the mand tact. Research reviews Oah, S. , & Dickinson, A. M. (1989). A review of empirical studies on verbal behavior. The Analysis of Verbal Behavior, 7, 53 -68. Sautter & Le. Blanc (In press). The Empirical Applications of Skinner’s Analysis of Verbal Behavior with Humans. The Analysis of Verbal Behavior.

Clinical Value of EO and Mand to Children with autism • • Many children with autism have absent or defective mand repertoires A functional analysis of the child’s verbal behavior often reveals that the response called a mand or a request is not under EO control, but rather SD control, thus not, by definition a mand

Defective Mand - Ally EO Does not evoke a mand ___________________________ EO Does not evoke a mand Object ___________________________ Intraverbal prompt (e. g. “Sign cookie”) Evokes a response Imitative prompt (not a mand) (ASL sign) __________________________________

EO Antecedent Control and Mand Assessment and Intervention in DTT and ABA Programs • • Lovaas, 1977, 1981, 2003 (clearly the most influential, outcome data) Expressive-receptive framework for language No mention of EO/motivation antecedent control Closest mand training activity is the “I Want___” program found late in the program (between the adjective and preposition chapters). All language skills presented as SD control No focus on the fact that a single word, phrase, or sentence can be strong in one repertoire and not another No functional analysis of words as behavior

EO Antecedent Control and Mand Assessment and Intervention in DTT and ABA Programs • • Taylor & Mc. Donough (1996) Expressive-receptive framework for language Indirect mentioning of EO/motivation antecedent control (desired) Request training provided, but developmentally late (after verbs, body parts, functions of objects. Multiple control (object present) More advanced requesting “asking WH questions” but described as SD rather than EO control Clearly an improvement over Lovaas, but still no focus on a single response form having multiple functions (a functional analysis) Most likely these authors would include EOs and manding should there be a new version of the program, given several recent conference presentations and publications

The Problem of the Terminology of Traditional Linguistics • • What’s wrong with the term “request” and the other terms from linguistics called “communication functions” (e. g. , command, interactional, personal, protesting, label, responsive, greeting, recurrence, existence, nonexistence, rejection, denial, & location) Why would an applied behavior analyst be content with a classification system of language based on response topography alone? That would certain not happen with a functional analysis of problem behavior. Verbal behavior is behavior. A functional analysis is still the hallmark of our field and should not stop at the verbal level Technical vernacular and etymological sanctions Most requests are mands, but many mands are not requests Why we don’t use “reward” either Many “requests” are often multiply controlled, but scored as correct.

The Distinction Between the Tact and the Intraverbal • • • A substantial number of children with autism have extensive tact and RD repertoires, but a weak, absent, or defective intraverbal repertoire The existing body of research support the conceptual analysis that a response acquired under nonverbal stimulus control may not automatically transfer to verbal stimulus control For example, a child may be able to say “French fry” when he sees a French fry but not say “French fry” when asked “What do you call potatoes cut up in strips and fried? (despite the echoic prompt)

Charlie: Quick Assessment

Nathan: Quick Assessment

Matt: Quick Assessment

Empirical Research on the Distinction Between the Tact and Intraverbal • • • Braam & Poling (1983) Chase, Johnson, & Sulzer-Azaroff (1985) Luciano (1986) Daly (1987) Lodhi & Greer (1989) Tenenbaum & Wolking (1989) Watkins, Pack-Teixeira, & Howard (1989) Sundberg, San Juan, Dawdy, & Arguelles (1990) Partington, & Bailey (1993) Sundberg, Endicott, & Eigenheer (2000) Finkel & Williams (2001) Miguel, Petursdottir, & Carr (2005)

Empirical Research on the Distinction Between the Tact and Intraverbal • • Two examples of research Braam & Poling (1983) found that children with autism who could emit specific responses under tact control could not emit the same response forms under intraverbal control. Transfer of stimulus control between nonverbal SDs and verbal stimuli were successful. Miguel, Petursdottir, & Carr (2005) replicated the basic procedures from Braam and Poling (1983) and concluded “ while participants were able to tact…and point to the pictures…. they were not necessarily able to reliably produce thematically related intraverbal responses…(until) intraverbal training was used” No body of research has emerged to show the tact and intraverbal are the same

Clinical Value of Verbal Stimulus Control and the Intraverbal to Children with Autism • • • Many children with autism have absent or defective intraverbal repertoires Verbal behavior evoked by verbal discriminative stimuli constitute a significant element of human verbal interaction A functional analysis of the child with autism’s verbal behavior often reveals that the response called intraverbal or conversational is not under verbal stimulus control, but rather under nonverbal stimulus control, or EO control, thus not, by definition an intraverbal Verbal stimulus control is extremely complicated, usually involving verbal conditional discriminations (one verbal stimulus alters the evocative effect of another verbal stimulus). Many common verbal errors by children with autism are related to defective verbal stimulus control Many aspects of more complex VB involve multiple stimulus control consisting of tact and intraverbal relations (e. g. , “What color is that? ” “What shape is that? ”)

Verbal Stimulus Control and Intraverbal Assessment and Intervention in DTT and ABA Programs • • Lovaas (1977, 1981, 2003) No sections answering questions, fill-in’s, verbal categories, etc. or what could be identified as intraverbal training. No mention of verbal antecedent control of verbal behavior (all under receptive langauge) Taylor & Mc. Donough (1996) Several aspects of the program contain intraverbal activities (answering questions, fill-ins, etc. ) Clearly an improvement over Lovaas, but still no focus on a single response form having multiple functions; a structural listing vs. a functional analysis No focus on verbal stimulus control and verbal conditional discriminations. Sequence of tasks are out of order, both developmentally and based on a functional analysis of the increasing complexity of verbal stimulus control

Is There Empirical Support for Skinner’s Analysis of Verbal Behavior? • • What type of support is necessary and sufficient to claim that there exists an empirical foundation for the analysis of verbal behavior? Conceptual • • Experimental • • (e. g. , Behavioral vs. cognitive explanations) (e. g. , mand vs. tact; intraverbal vs. tact) Applied • (e. g. , A VB approach vs. a Discrete Trial approach)

Conceptual Support • • • The analysis of verbal behavior involves the same behavioral principles and concepts that make up the analysis of nonverbal behavior No new principles of behavior are required “The emphasis is upon an orderly arrangement of well-known facts, in accordance with a formulation of behavior derived from an experimental analysis of a more rigorous sort” (Skinner, 1957, p. 11) Is there empirical support for principles and concepts that form the basis of behavior analysis in general? YES! (e. g. , JEAB)

Conceptual Support n n Is there the necessary and sufficient empirical support for the basic principles that provide the foundation of Skinner’s conceptual analysis of language? Yes, it’s the same as behavior analysis in general

Conceptual Support • • • What are the alternatives? Cognitive theories of language (e. g. , Piaget, Brown, Pinker) Biological/Genetic theories of language (e. g. , Chomsky, Lenneberg, Pinker) Is the necessary and sufficient empirical support available for those theories? NO!

Experimental Support • • • However, was Skinner’s interpretation of the basic facts correct? For example… Is the distinction between the mand, tact, and intraverbal a valid distinction? Do multiple sources of control have an additive effects? Are autoclitics tacts of the controlling variables of primary responses emitted because of their special effects on listeners? There clearly are a number of research projects that would be necessary to conclusively say whether the analysis has empirical support or not (Sundberg, 1991).

Experimental Support • • • What is the current status? There is a growing body of empirical evidence that supports elements of Skinner’s analysis, such as distinction between the elementary verbal operants (e. g. , Sautter & Le. Blanc, 2005). For example… Is MO control different from SD control? Is nonverbal stimulus control different from verbal stimulus control? Does tact training produce mands and intraverbals?

Experimental Support • • • Does this constitute the necessary and sufficient empirical support? No, but it is a good start on the necessary support Substantially better than the empirical support for not recognizing the distinction between the mand tact Substantially better than the empirical support for the distinctions related to traditional treatments of language Is there a comparable line of research available from, for example, the elements of Piaget’s, or Pinker’s analysis of language and autism? The existing data on VB are not yet sufficient

Applied Support • • Is there enough empirical support for the separation of the elementary verbal operants to use them as a basis for language assessment and intervention for language delayed children? For example: The distinction between the mand, tact and intraverbal. Yes Is there stronger evidence that there is no distinction between the mand, tact, and intraverbal? No Does the conceptual and empirical evidence obtained thus far suggest that it is okay to ignore the mand intraverbal? No

Applied Support • • • Is an approach to language assessment and training that is based on Skinner’s analysis of verbal behavior more effective than an approach based on cognitive theories of language? It is an empirical question However, given the evidence obtained thus far on the separation of the verbal operants, transfer of antecedent control between operants, and the use of multiple sources of control to generate new operants, the distinction seems quite valuable

Applied Support • • • Is there empirical support for the various VB teaching procedures and strategies to generate verbal repertoires for children with autism or other language delays? No There are many different ways to use behavior modification procedures to teach a mand

Applied Support • • • Is there enough evidence to support a behavioral approach to language versus traditional approaches to language? Yes Clearly more basic and applied research is necessary, but thus far the data support the analysis, and the interventions have been successful

Conclusion • • Language is behavior and rightfully, the subject matter of behavior analysts. The “verbal behavior approach” is behavior analysis. It makes use of the same basic components of applied behavior analysis as the other behavioral approaches, but employs a behavioral analysis of language as its conceptual foundation. The term “VB approach” has only been used to distinguish it from approaches that use behavioral procedures, but do not make use of a behavioral analysis of language

Conclusion • “The ‘VB approach’ is simply normative applied behavior analysis with a few refinements. That is, it incorporates all of the standard methodology of applied behavior analysis, but it explicitly adopts Skinner's interpretive framework for analyzing verbal contingencies. In other words, it is a small variation on a methodology that has an enormous empirical foundation. The worst-case scenario is that the added framework doesn't help. But even in that case the child is still getting a full-fledged program of applied behavior analysis procedures” (Palmer, 2005).

Conclusion • “It is simply hard to believe that a set of procedures guided only by a distinction between receptive and expressive language can be as sharp as one that respects all of the various types of contingencies analyzed by Skinner” (Palmer, 2005).

Conclusion n n The necessary and sufficient empirical support exists for the basic principles that provide the foundation of Skinner’s analysis of language The necessary and sufficient empirical support for the specific distinctions that Skinner makes is emerging and very positive. However, much needs to be accomplished The necessary and sufficient empirical support for specific applications of the analysis do not exist, and may never exist in the same form as those above (e. g. , outcome data). It is a mistake to reject verbal behavior approaches based solely on applied support A substantial amount of research is still needed.

Conclusion • • • Western Michigan University undergraduate curriculum in the 1970 s WMU had/has the largest behavior analyst faculty in the world (20+) (Keller, Michael, Malott, Iwata, Ulrich, Hawkins, Lyon, Snapper, etc. ) Psych 150 Introduction to Behavior Modification (Malott) & rat lab Psych 160 Child Development (Bijou & Baer) Psych 250 Abnormal Psychology (Ulmann & Krasner) Psych 260 Verbal Behavior (Skinner) Psych 350 Applied Behavior Analysis (Science and Human Behavior. Skinner, JABA, ), Applied Lab (e. g. , KVMC w/ Jerry Shook) Psych 360 Experimental Analysis of Behavior (Operant Conditioning, Honig, JEAB), & Pigeon Lab Psych 450 Research Methods (Stat book) Psych 460 Systems and theories (General Psych book)

Conclusion • • • B. F. Skinner wrote in 1978… “Verbal Behavior…will, I believe, prove to be my most important work” (p. 122) Let’s get on with the proving!

Thank You! For an electronic version of this presentation email: marksundberg@astound. net

An Assessment of Typical Children’s Intraverbal Behavior • • • 28 typical children served as participants Most were from the Seattle area Ages ranged from 17 months old to 5 1/2 years old. Parents administered the assessment Instructions were given to the parents, including to write down exactly what the child said following the presentation of the verbal stimulus

Typical Children Age and Scores on the Intraverbal Assessment

Children with Autism Age and Scores on the Intraverbal Assessment