Focus on Autism and Other Developmental               Disabilities                                                  http:/...
Behavior Analytic Instruction for             Learners with Autism:            Advances in Stimulus Control               ...
73lished the foundation for much of the              methods involve manipulations of ante-                               ...
74sponses, and        some that are hybrids or           and field research in behavior analysis has                      ...
75forcing particular  responses in the pres-                 mon   categories and illustrations of con-                   ...
76consistently (i.e., to respond correctly on          be followed whenever the objective is to                           ...
77cally, sometimes on every trial. The risk                prove even with repeated presentations.                        ...
78such    the comparison stimulus the in-       as                                                 opment of stimulus cont...
79more    effective for teaching discrimina-         spoken words, the instructor might hold                             a...
80developing  children and adults, and in-                 preschoolers with autism in another ex-                        ...
81MacDuff, & McClannahan, 1993; Mac-                           vice is   activated,                                       ...
82(Buggey, Toombs, Gardener, & Cervetti,                quency of initiations to use the toilet and                       ...
Behavior analytic instruction for learners with autism advances in stimulus control technology-gina green 2001
Behavior analytic instruction for learners with autism advances in stimulus control technology-gina green 2001
Behavior analytic instruction for learners with autism advances in stimulus control technology-gina green 2001
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Behavior analytic instruction for learners with autism advances in stimulus control technology-gina green 2001


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Behavior analytic instruction for learners with autism advances in stimulus control technology-gina green 2001

  1. 1. Focus on Autism and Other Developmental Disabilities Behavior Analytic Instruction for Learners with Autism: Advances in Stimulus Control Technology Gina Green Focus Autism Other Dev Disabl 2001; 16; 72 DOI: 10.1177/108835760101600203 The online version of this article can be found at: Published by: Hammill Institute on Disabilities and Additional services and information for Focus on Autism and Other Developmental Disabilities can be found at: Email Alerts: Subscriptions: Reprints: Permissions: Downloaded from at WESTERN MICHIGAN UNIVERSITY on September 20, 2008
  2. 2. Behavior Analytic Instruction for Learners with Autism: Advances in Stimulus Control Technology Gina GreenNumerous behavior analytic methods developed since the early 1960s have proved treatment, Dicky was wearing his glasseseffective for developing a wide range of skills in learners with autism. Recent advances most of the time, and his problem behav-in stimulus control technology, in particular, offer effective methods for teaching many iors had diminished enough that he couldimportant skills and for promoting independent, generalized performances. This article be returned to his home (Wolf, Risley, &reviews selected stimulus control techniques, including new methods for teaching con-ditional discrimination (matching) skills, stimulus equivalence procedures, prompt and Mees, 1964). At the age of 5, Dicky was enrolled in the Institute’s nursery school.prompt-fading techniques, and incidental teaching procedures. He still had few skills; some of the old problem behavior had recurred, and ag- gressive behavior had developed. Wolfn 1948 an event occurred that was Baer published their classic text Child De- and Risley trained the nursery school to have far-reaching effects: Sidney velopment: A Systematic and Empirical staff to implement behavioral teaching Bijou became director of the Insti- Theory) in which they examined devel- procedures with Dicky. The goal was totute of Child Development at the Uni- opment from a behavioral perspective develop sufficient language and otherversity of Washington. Bijou was a Co- (Bijou, 1996). skills that Dicky could enroll in publiclumbia University-trained psychologist How is this history relevant to the school. By the beginning of the nextwith a strong interest in child develop- topic at hand? Some researchers might be school year that goal had been achievedment, learning theory, and the relatively surprised to learn that much of the sem- (Wolf, Risley, Johnston, Harris, & Allen,new radical behaviorism of B. F. Skinner, inal research on behavior analytic meth- 1967). Dicky ultimately graduated fromwith whom he had worked for 2 years at ods for teaching children with autism was high school. He had been deemed &dquo;un-Indiana University. Shortly after Bijou conducted at the University of Wash- testable&dquo; as a youngster; at age 26 hewent to the University of Washington, a ington Institute for Child Development achieved a score of 98 on an IQ test.research program was established within under Bijou’s direction. In the early When he was in his 30s, Dicky was livingthe Institute of Child Development to 1960s a local physician asked Bijou if and working independently and had rela-study normal and abnormal behavior in the staff at the institute might be able to tively good reading, writing, and socialyoung children in a laboratory and in an teach a visually impaired boy with autism skills (Bijou, 1996; Wolf, 1999).experimental school. There Bijou and his to wear glasses. Dicky, then 3V2 years old, Wolf went on to start the Journal ofcolleagues and students blended Skinner’s exhibited severe tantrums; self-injurious Applied Behavior Analysis and, with Baernatural science approach to behavior- behavior; problems with sleeping and and Risley, set out the very first defini-including methods of functionally ana- eating; and very limited communication, tion of applied behavior analysis, or ABAlyzing individual behavior-with re- social, and self-care skills. Bijou had seen (Baer, Wolf, & Risley, 1968). They andsearch on child development. Over the Charles Ferster and Marion DeMyer use others who worked or studied with Bijounext two decades they conducted land- Skinnerian methods to build the reper- at the University of Washington (includ-mark studies of operant behavior in toires of children with autism at Indiana ing Jay Birnbrauer, Betty Hart, Ivaryoung children and pioneered numerous University Hospital (Ferster & DeMyer, Lovaas, Howard Sloane, and Robertmethods for managing problem behav- 1961), so he asked his colleague, behav- Wahler, among others) made invaluableior, teaching academic skills to students ioral psychologist Montrose Wolf, a contributions in many areas, particularlywith mental retardation, training parents graduate student, Todd Risley, and clini- applications of Skinner’s science of be-to work as therapists with their own chil- cal psychologist, Hayden Mees to take havior to human development, language,dren, and conducting research in natural on Dicky’s case. Fortunately, they did. education, mental retardation, autism, andsettings. In 1961 Bijou and Donald M. After 7 months of intensive behavioral behavior disorders. Their work estab- Downloaded from at WESTERN MICHIGAN UNIVERSITY on September 20, 2008
  3. 3. 73lished the foundation for much of the methods involve manipulations of ante- Behavior analytic instruction beginsfield of applied behavior analysis, and for cedent stimuli, the focus here is on se- with a comprehensive assessment of eachthe hundreds of studies of behavior ana- lected recent advances in using stimulus learner’s current skills and needs, accom-lytic interventions for autism that have control principles and procedures to build plished by observing the learner directlybeen published since the 1960s (see Mat- skills in learners with autism and related in a variety of situations and recordingson, Benavidez, Compton, Paclawskyj, & disorders. Space limitations prohibit ex- what she or he does and does not do.Baglio, 1996). That research, in turn, has haustive coverage of all stimulus control Every skill that is selected for instructionmade it possible for people with autism procedures. Excluded, for example, are (often called a &dquo;target&dquo;) is defined into achieve unprecedented outcomes today. instructional techniques that make use of clear, observable terms and broken down The interventions designed by Bijou, establishing operations, which are ma- into its components. Each componentWolf, Risley, and colleagues in the 1960s nipulations of antecedent stimuli that in- response is taught by presenting or ar-had several key features: (a) integration fluence the momentary effectiveness of ranging one or more specific antecedentsof developmental and behavioral ap- reinforcers. (For discussions of establish- stimuli, such as cues or instructions fromproaches ; (b) an emphasis on positive re- ing operations teaching language to in another person, and/or items of interestinforcement procedures to build useful learners with autism, see Sundberg & to the learner. Often, the kinds of cuesrepertoires; (c) functional analysis of in- Partington, 1998, 1999.) Because the that are effective with typically develop-dividual behavior (i.e., experimental topic is skill development, antecedent ma- ing children (such as spoken instruc-demonstrations of functional relations nipulations designed primarily to man- tions) are not effective when a skill is firstbetween environmental events and be- age or reduce problem behavior are also introduced to a learner with autism; thathavior) ; (d) use of scientific methods to excluded. is, those cues are not reliably followed byevaluate the effects of interventions; (discriminative for) the desired response.(e) individualization of goals and in- In such cases, another antecedent, calledstructional procedures; (f) gradual, sys- ABA for Autism: a prompt, is often added to get the re-tematic progression from simple to more An Overview sponse going. Effective prompts arecomplex skills; (g) training of parents and stimuli that are reliably followed by theothers to implement interventions in To provide context for readers, the be- desired responses. For example, givenmultiple environments; and (h) transfer havior analytic framework and basic ABA the language deficits that are often ob-of intervention from structured to nat- methods are first reviewed briefly in this served in children with autism, spokenural settings. Contrary to assertions that section. They have been detailed in nu- instructions like &dquo;Come here&dquo; or &dquo;Touchthese features characterize only certain merous books, chapters, and articles, in- your nose&dquo; may not be followed by the&dquo;contemporary&dquo; versions of ABA (e.g., cluding the principal sources used here actions they specify initially-that is, theyPrizant & Rubin, 1999; Prizant & (Anderson & Romanczyk, 1999; Ander- are not discriminative stimuli for thoseWetherby, 1998; Wetherby, Schuler, & son, Taras, & Cannon, 1996; Green, responses. But gentle physical guidancePrizant, 1997), the facts are that they 1996; Hall, 1997; Keenan, Kerr, & Dil- is effective for getting many children tohave characterized genuine, comprehen- lenburger, 2000; Koegel & Koegel, carry out actions, so it might be added tosive ABA programming for learners with 1995; Lovaas et al., 1981; Matson et al., the spoken instructions as a prompt dur-autism since the 1960s, and the work of 1996; Romanczyk, 1996; Sundberg & ing initial teaching, and gradually re-Bijou and his colleagues has long been Partington, 1998). duced (faded) over successive learningincluded in many graduate training cur- In the behavior analytic view, autism is opportunities.ricula in behavior analysis. a syndrome of behavioral deficits and ex- When target responses occur, they are Of course, many additional techniques cesses that have a biological basis but are followed immediately by consequenceshave been developed and integrated into nonetheless amenable to change through that have been found to function as re-ABA programming for learners with carefully orchestrated, constructive inter- inforcers ; that is, repeated observationsautism since those early days. Indeed, a actions with the physical and social envi- have verified that when those conse-very large array of behavior analytic pro- ronment. Behavior analytic intervention quences consistently followed a particu-cedures have been proved effective for seeks to redress those deficits and ex- lar response, the response occurred againdeveloping a wide range of skills in indi- cesses by providing multiple planned op- and again. Incorrect or interfering re-viduals with autism of all ages. This arti- portunities for the learner to develop and sponses are explicitly not reinforced. Eachcle does not provide an exhaustive or de- practice skills that are useful in a variety antecedent-response-consequence cycletailed review of all of them; that would of situations, and are effective alterna- constitutes a learning opportunity, or trial.take many pages, and, besides, some tives to less socially acceptable behaviors, There are many behavior analytic proce-good comprehensive reviews of the rele- such as tantrums, stereotypy, and de- dures for arranging learning opportuni-vant research have been published re- structive behaviors (Green, 1996; Koegel ties, some adult-initiated, some learner-cently (e.g., Hall, 1997; Matson et al., & Koegel, 1995; Lovaas & Smith, 1989; initiated, some embedded in typically1996). Instead, because all instructional Schreibman, 1988). occurring activities or sequences of re- Downloaded from at WESTERN MICHIGAN UNIVERSITY on September 20, 2008
  4. 4. 74sponses, and some that are hybrids or and field research in behavior analysis has effective and efficient techniques for es-permutations of these. Each type of pro- derived from the principle of stimulus tablishing discriminations and stimuluscedure has its uses and advantages. Gen- control. Because the aim of virtually all classes (sets of mutually substitutable stim-uine ABA programming uses any and all instruction is to get specific responses to uli) in learners with developmental dis-procedures required to accomplish the occur reliably under particular antece- abilities, including autism. To date, how-job of skill development and skill gener- dent stimulus conditions and not under ever, those techniques have not enjoyedalization with each individual learner; it other conditions, all instructional tech- widespread adoption, even among ap-is by no means just &dquo;discrete trial train- niques involve manipulations of antece- plied behavior analysts, perhaps becauseing&dquo; (e.g., see Anderson & Romanczyk, dent stimuli, along with manipulations of they have not yet been &dquo;packaged&dquo; in1999; Sundberg & Partington, 1999). consequent stimuli. That is certainly true comprehensive, user-friendly programs Learning opportunities are typically of ABA techniques for building skills in that are readily available to practitionersrepeated many times until the learner learners with autism. Basic procedures (although some steps in that directionperforms the target response readily and for establishing stimuli as discriminative have been taken, e.g., Johnson, White,fluently, without prompts from adults. for reinforcement for learners with au- Green, Langer, & MacDonald, 2000;Again, there are many ways to arrange tism are described in some of the sources Serna, Dube, & McIlvane, 1997). Amultiple, repeated learning opportuni- listed at the beginning of the Overview complete presentation of the aforemen-ties ; they need not (and should not) be section, among others, they so are not re- tioned stimulus control research is be-limited to blocks of massed trials pre- iterated here. Instead, some specific ap- yond the scope of this article, so whatsented as drills. The learner’s responses plications of stimulus control technology follows is a summary of principles andare recorded frequently according to with learners with autism are discussed. methods drawn from some of that lit-specific, objective criteria. Those data are erature.summarized and graphed to provide pic-tures of the learner’s progress and to en- Teaching Discriminations and Types of Discriminations. As notedable frequent adjustments in instruc- Stimulus Equivalence Classes earlier, virtually all skills involve discrim-.tional procedures when the data show From the first incarnations in the 1960s inating among, or responding differen-that the learner is not making the de- to the present versions, many behavior tially to, environmental events-sounds,sired gains. analytic curricula have included tech- colors, shapes, letters, numbers, words, The timing and pacing of teaching ses- niques for teaching learners with autism foods, clothing items, people, responses,sions, practice opportunities, and conse- to discriminate among various types of locations, and the like. At the same time,quence delivery are determined precisely stimuli, and to match certain stimuli to many functional skills require learners tofor each learner and each skill. To maxi- one another. Discrimination and match- treat some environmental events as ifmize the learner’s success, skills are prac- ing skills are components of many (argu- they are the same, including some thatticed and reinforced in many settings. ably, czll ) cognitive, communication, so- bear little or no physical resemblance toThe long-range goal is to build simple re- cial, academic, work, and self-care skills, one another (such as spoken words andsponses systematically into complex and so this emphasis is understandable and ap- various types of visual stimuli). As it turnsfluid combinations of age-appropriate re- propriate. Lovaas, Schreibman, and their out, these latter types of performances alsosponses. In quality ABA programming, colleagues conducted some seminal re- require complex discriminations amongthe overarching goal is to teach learners search on teaching discrimination and stimuli-discriminations that are madewith autism how to learn from typical en- matching skills to learners with autism in up of other, simpler discriminations andvironments, and how to act in ways that the 1970s. Procedures developed in those that have particular and unique charac-will consistently produce positive out- early studies seem to have been adopted teristics. In short, discriminations vary incomes for the learner and those around by many practitioners, perhaps because their complexity and in the types of envi-him or her. they have been widely disseminated in ronmental events they comprise. There- such media as The ME Book (Lovaas et al., fore, a useful strategy for analyzing and 1981). Meanwhile, during the ensuing teaching discrimination skills is to break Tapping the Power of three decades, a great deal of stimulus each discrimination into its components Stimulus Control control research has been conducted by (R. Saunders & Green, 1999; Sidman, behavior analysts in laboratories and 1986).Behavior analysts have long recognized classrooms affiliated with the Eunice Ken- Many important skills require simplethat stimuli that accompany or precede nedy Shriver Center, the University of discriminations. A simple discriminationresponses that are reinforced can come to Kansas, and the New England Center for contingency has three elements: the an-influence those responses in important Children, to name a few. Much of that tecedent stimulus (S), the response (R),and often complex ways (e.g., Skinner, research has focused on analyzing various and the consequence (C). That is, simple1938, 1953). A great deal of laboratory types of discriminations and developing discriminations are established by rein- Downloaded from at WESTERN MICHIGAN UNIVERSITY on September 20, 2008
  5. 5. 75forcing particular responses in the pres- mon categories and illustrations of con- other stimuli is then presented, called theence of particular antecedents, and not in ditional discriminations are: comparison, or choice) stimuli. The learnerthe presence of other antecedents. When is required to respond to one compari-the defined responses occur reliably in ~ Conditional identity ~catchin8: For son, usually by touching or pointing tothe presence of the defined stimuli and example, in the presence of a red it. One comparison is designated correctnot in the presence of other stimuli, the patch (S3), pointing to an identical (discriminative for reinforcement; S+)stimuli are said to be discriminative for red patch (S1) is reinforced, whereas with each sample; that is, responses toreinforcement. Some examples relevant pointing to a blue patch (S2) is not, it are followed by reinforcer delivery,to teaching learners with autism include: AND, in the presence of a blue patch whereas responses to the other compar- ( S4 ), pointing to an identical blue isons in the presence of that sample are~ Oral naming: For example, in the patch (S2) is reinforced, whereas not reinforced (S-). After a brief inter- presence of a spoon (S1), the vocal pointing to a red patch (Sl) is not. trial interval, the next trial is presented in response &dquo;spoon&dquo; (Rl) is reinforced ~ Object-picture correspondence: For ex- similar fashion. The sample stimulus typ- and &dquo;fork&dquo; ( R2 ) is not; in the pres- ample, in the presence of a ball (S3), ically varies unsystematically from trial to ence of a fork (S2), the response pointing to a picture of a ball (S1) is trial, as does the position of the S+ com- &dquo;fork&dquo; (R2) is reinforced and reinforced, whereas pointing to a pic- parison stimulus on each trial. &dquo;spoon&dquo; (Rl) is not. ture of a toy car (S2) is not, AND, in Match-to-sample procedures are com-~ Instruction following: For example, in the presence of a toy car (S4), point- monly used to teach learners with autism the presence of the spoken instruc- ing to a picture of a car (S2) is rein- to match identical visual stimuli (e.g., ob- tion &dquo;Stand up&dquo; (S1), standing up forced, whereas pointing to a picture jects, colors, shapes, letters, numerals) and ( Rl ) is reinforced and sitting down of a ball (S1) is not. nonidentical visual stimuli (e.g., pictures (R2) is not; in the presence of the ~ Receptive vocctbulary, or &dquo;receptive to objects, pictures to printed words). It spoken instruction &dquo;Sit down&dquo; (S2), identificstion:&dquo; For example, after is important to note, however, that vir- sitting (R2) is reinforced and stand- one hears &dquo;nose&dquo; (S3) spoken by an tually any kind of stimuli that can be ing up (Rl) is not. adult, touching one’s own nose (S1) seen, heard, touched, tasted, or smelled is reinforced, whereas touching one’s can be used in MTS procedures (with a Many other very important skills re- mouth ( S2 ) is not, AND, after hear- few commonsense qualifications; e.g., itquire learners to match stimuli to one an- ing &dquo;mouth&dquo; (S4) spoken by the is not practical to present two or moreother, that is, to treat them as if they are adult, touching one’s mouth (S2) is auditory stimuli simultaneously as com-the same, in some sense. For instance, reinforced, whereas touching one’s parisons). More importantly, as the fore-language comprehension entails matching nose (Sl) is not. going examples illustrate, many func-spoken words with corresponding ob- ~ Picture-bczsed communication: For tional skills call for learners to makejects, symbols (such as pictures and example, when cookies (S3) are avail- conditional discriminations, whether orprinted words), actions, people, and so able, bringing Mom a picture of a not explicit MTS procedures are in-forth; basic math skills involve matching cookie (S1 ) is reinforced, whereas volved. Skills that are often termed &dquo;re-corresponding printed numerals, quanti- bringing Mom a picture of juice (S2) ceptive vocabulary,&dquo; &dquo;receptive identifi-ties, and spoken number names; and so is not reinforced, AND, when juice cation,&dquo; or &dquo;language comprehension,&dquo;on. True matching requires conditional (S4) is available, bringing Mom a for instance, require learners to responddiscriminations. Conditional discrimina- picture of juice (S2) is reinforced, to each of a number of visual stimuli (e.g.,tions are established by reinforcing re- whereas bringing Mom a picture body parts, objects, pictures, printedsponses to particular antecedent stimuli of a cookie (S1) is not. words) if and only if that stimulus wasif and only if they are preceded or ac- preceded by a particular spoken word.companied by particular additional stim- Conditional Discrimination Teach- The spoken words can be thought of asuli. In contrast with simple discrimina- ing Methods. A handy and reliable set samples, the visual stimuli as compari-tions, here each antecedent stimulus is of procedures for potentially teaching sons. When samples and their corre-discriminative for reinforcement or not, conditional discriminations is match-to- sponding correct comparisons are notdepending on (conditional on) the pres- sample (MTS). Typically, each of a series physically identical to one another, theence of another particular antecedent of MTS trials begins with the presenta- procedure is often referred to as arbi-(Sidman, 1986; Sidman et al., 1982; Sid- tion of a designated sample (or condi- trary & Tailby, 1982). Conditional dis- tional) stimulus to the learner, who is re- Analyzing the components of condi-crimination contingencies, thus, involve quired to respond to it (e.g., by touching tional discriminations reveals precisely whatfour (rather than three) elements: con- it if it is visual, or touching a blank card makes them more complex than simpleditional stimuli, antecedent stimuli, re- or a key computer on a screen if the sam- discriminations. To fulfill conditional dis-sponses, and consequences. Some com- ple is auditory). An array of two or more crimination reinforcement contingencies Downloaded from at WESTERN MICHIGAN UNIVERSITY on September 20, 2008
  6. 6. 76consistently (i.e., to respond correctly on be followed whenever the objective is to should never appear in the same positionmost opportunities), the learner must establish conditional discriminations, in the comparison array for more than(a) discriminate each sample from every whether or not the teaching procedures two trials consecutively.other sample presented across a series of are explicitly MTS (e.g., for receptive vo- Some examples of MTS trials that ful-trials (these are successive simple discrim- cabulary instruction, picture-based com- fill these parameters are illustrated in Ta-inations), (b) discriminate each compari- munication training, etc.). ble 1. Each trial has three comparisonsson from all other comparisons presented 1. Within a session or block of MTS presented in horizontal arrays with posi-within each trial (simultaneous simple dis- trials, a different sample should be pre- tions designated from the learner’s (rathercriminations), and (c) relate (match) each sented on each trial, but the same com- than the instructor’s) perspective. Ofcomparison stimulus with one and only parisons should appear on every trial. course, multiple trials (in multiples ofone sample stimulus. Put another way, in Each comparison should be the S+ with three, in this case) should be presented inconditional discriminations the sample one and only one sample, and should be each teaching session or block of trials,stimuli exert stimulus control over the S- equally often with each of the other arranged in accordance with the proce-functions served by the comparison stim- samples. dures described above.uli (as S+ or S-) from trial to trial. This 2. For most purposes, it is preferable Any deviation from the arrangementskind of stimulus control develops only to have at least three comparisons on of balanced trial types and teaching se-when contingencies consistently require every trial. Because each comparison is quences just described creates the poten-the learner to observe the sample stimu- designated correct with one sample, the tial for one or more types of extraneouslus on each trial, discriminate it from the number of different sample stimuli pre- stimulus control to interfere with devel-other samples and from the comparisons, sented in a session or block of trials opment of the desired control by sampleand discriminate each comparison from should equal the number of comparison stimuli over the selection of comparisonevery other comparison and from the stimuli presented on each trial. stimuli. For example, if the S+ appears 3. Each sample should be presented more often in one position in the com-samples (K. Saunders & Spradlin, 1989,1993; R. Saunders & Green, 1999; Sid- equally often within a session or block of parison array than in the others acrossman, 1986, 1994). Teaching procedures trials, in unsystematic order. A good rule trials, the learner’s comparison selectionsthat arrange other kinds of contingen- of thumb is that the same sample should may come to be controlled by positioncies, explicitly or inadvertently, are likely not be presented on more than two con- rather than by sample stimuli. Anotherto establish something other than the de- secutive trials. type of extraneous stimulus control cansired stimulus control. 4. The position of the S+ comparison arise from the common practice of pre- During the past 20 years or so, many should vary unsystematically from trial to senting novel incorrect comparisons (of-researchers have investigated conditional trial. A good rule of thumb is that the S+ ten referred to as &dquo;distractors&dquo;) periodi-discrimination learning in developmen-tally young learners and those with de-velopmental disabilities. Some analyzedthe kinds of faulty stimulus control that TABLE 1can easily arise from certain arrange- Examples of Balanced Three-Choice Match-to-Sample Trialsments of trials and trial sequences (e.g.,Harrison & Green, 1990; Johnson &Sidman, 1993; McIlvane & Stoddard,1985; Stromer & Osborne, 1982). Oth-ers tested procedures for minimizing er-rors and for establishing conditional dis-criminations with learners who did notreadily acquire them via standard trainingprocedures (e.g., Dube & Serna, 1998;McIlvane & Stoddard, 1981; K. Saun-ders & Spradlin, 1989, 1993; Zygmont,Lazar, Dube, & Mcllvane, 1992). Thefollowing recommended general proce-dures for teaching conditional discrimi-nation skills have been extracted fromthat research (cf. Green & Saunders,1998). They are discussed in MTS terms,but it is important to reiterate that thesame basic guidelines can and should Note. MTS = match-to-sample. Downloaded from at WESTERN MICHIGAN UNIVERSITY on September 20, 2008
  7. 7. 77cally, sometimes on every trial. The risk prove even with repeated presentations. 6. When the sample stimuli are audi-with such a procedure is that learners will That is probably because the contingen- tory (e.g., spoken words, as in receptiverespond either to the novel stimuli or away cies on the mixed trials require condi- language tasks), the sample should befrom them simply because they are novel tional discriminations rather than simple presented clearly to start the trial, thento the context. In either case, learners ones, but the immediate history of re- repeated when the comparison stimulimay not observe the sample stimuli and inforcement for simple discriminations are presented, and again every 2 secondstherefore may not learn the intended may predispose learners to simply track or so until the learner responds to a com-conditional discriminations. If the incor- the stimuli to which re- comparison parison or to some maximum number ofrect (S-) comparisons presented with any sponses reinforced most recently were repetitions. The rationale is as follows: Ifgiven sample change from trial to trial or most often in the training that just an auditory sample is presented onlywhile the S+ remains constant, learners preceded. once to start a trial, learners have just thatmay simply learn to respond away from Training in isolation may even inad- one fleeting opportunity to &dquo;observe&dquo; it.the comparisons that are new from trial vertently teach learners not to attend to There is considerable risk that (a) theyto trial. If so, performance will seem to be sample stimuli at all, because attending will not hear it, (b) they will hear it buthighly accurate-the learner will touch to the sample is not required on those not discriminate it from samples pre-the S+ consistently-but, again, she or he trials; it is most efficient for the learner to sented on other trials, or (c) they willneed not observe or discriminate the simply touch the one available compari- hear it but not remember it throughoutsample stimuli in order to satisfy the re- son stimulus quickly in order to maxi- the interval that elapses while they exam-inforcement contingencies (Harrison & mize reinforcement. This same type of ine the comparison array and respondGreen, 1990; Johnson & Sidman, 1993). faulty stimulus control may develop to one comparison. Repeating auditory Another common practice that may when children with autism are taught to samples reduces those risks.create unwanted stimulus control is re- use pictures presented repeatedly in iso- Another desirable practice is to limitpeated presentation of each sample with lation to request preferred items, as in the auditory stimulus presented to startits designated correct comparison and no the initial phases of Picture Exchange each trial to the word to which one ofother comparisons, often referred to as Communication System training (Frost the comparisons is to be matched (e.g.,teaching &dquo;in isolation&dquo; (cf. Lovaas et al., & Bondy, 1994). These are simple dis- &dquo;spoon,&dquo; &dquo;fork,&dquo; or &dquo;knife&dquo;), rather than1981). For example, in an attempt to crimination contingencies that do not re- starting each trial with a nominal in-teach picture-object matching, the in- quire the learner to observe the item that struction like &dquo;Touch ,&dquo; orstructor may start by presenting a picture corresponds to each picture, or even to &dquo;Point to &dquo; If every sample con- -of a spoon (the nominal sample) and an observe the features of each of the pic- sists of a series of sounds, the first ofactual spoon (the nominal comparison) tures, in order to obtain reinforcers con- which are exactly the same from trial tofor many repeated trials, reinforcing sistently and quickly. All he or she has to trial while only the last differs, it is likelytouches to the spoon. Trials to teach do is pick up the only picture that is avail- to be very difficult for many learners to&dquo;fork&dquo; are presented in similar fashion, able and hand it to an adult, to immedi- discriminate among those sounds and re-then &dquo;knife.&dquo; In this procedure, the rein- ately receive a preferred item. Following spond to the critical one on each trial. In-forcement contingencies do not require such training, it would not be surprising stead of using spoken instructions likethe learner to discriminate among differ- to see many learners perform at chance &dquo;touch&dquo; or &dquo;point to,&dquo; it is preferable toent sample stimuli, or among different levels when two or more pictures (com- teach learners to point to comparisonscomparison stimuli, because all he or she parison stimuli) are presented simultane- through nonverbal methods, such ashas to do is touch the one comparison ously, only one of which matches the physical guidance or modeling, and tothat is available on each trial to earn rein- item available on any given requesting help them discriminate among auditoryforcers consistently-a simple, not a con- opportunity. samples by presenting each one distinctlyditional, discrimination. After two or three 5. Learners should be required to make and repeatedly, unaccompanied by re-samples and their corresponding correct an &dquo;observing response&dquo; to the sample dundant and extraneous words.comparisons are each presented in isola- stimulus on each trial (e.g., by pointing 7. Instead of rearranging the compar-tion for a number of trials, the stimuli are to the stimulus or to a blank card or ison stimuli in front of the learner be-typically mixed so that all comparisons key when the actual sample cannot be tween trials, prepare the comparison ar-(the spoon, fork, and knife) appear on touched, such as a spoken word). Of ray for each trial on a mat or board outevery trial but the sample (picture of course, requiring learners to touch sam- of the learner’s sight (e.g., behind a screen,spoon, fork, or knife) differs from trial to ple stimuli does not guarantee that they on a chair next to you) during the in-trial, as in the MTS trials described ear- are actually looking at or listening to the tertrial interval. Then present the wholelier. Many learners with autism perform samples, but it does make those re- comparison array after the sample hasat chance levels when mixed trials are sponses more likely than simply present- been presented and responded to. Thisintroduced following isolation training, ing samples without requiring an observ- helps reduce the likelihood that theand their performance often does not im- ing response. learner will respond to extraneous cues, Downloaded from at WESTERN MICHIGAN UNIVERSITY on September 20, 2008
  8. 8. 78such the comparison stimulus the in- as opment of stimulus control by the rele- kinds of new skills to learners with au-structor touched first or last when she or vant features of stimuli and put the tism, because virtually all skills entail dis-he rearranged the comparisons. learner at a distinct disadvantage when he criminations. Strategies for minimizing 8. Teach learners how to perform MTS or she is confronted with stimuli that errors and prompt dependency whiletasks before trying to teach them new cannot be readily matched by aligning teaching such things as communicationconditional discrimination using those identical features. and play skills are discussed further in theprocedures. Several skills are required to 9. Use errorless teaching methods section on prompting and prompt fad-perform these tasks: sitting quietly be- rather than trial-and-error procedures to ing. Here, some specific methods for teach-tween trials, orienting to the stimuli, teach conditional discriminations. There ing discriminations with few errors aremaking observing responses to sample is a large body of research on errorless highlighted briefly. One category of er-stimuli, scanning arrays of multiple com- discrimination learning that goes back rorless discrimination training methods isparisons, and responding to just one many years (e.g., Sidman & Stoddard, within-stimulus prompts. These methodscomparison on each trial. If the learner 1967; Terrace, 1963) and provides rich involve altering the physical characteris-lacks one or more of these skills, she or information about the benefits of, and tics of the stimuli to be discriminated to in-he is likely to make errors on MTS tasks methods for, minimizing errors early in crease the likelihood that correct responsesthat might be erroneously interpreted to training. (Few, if any, truly &dquo;errorless&dquo; will occur early in training. For example,reflect deficient conditional discrimination training procedures exist, but there are simple or conditional discriminations canskills (Johnson et al., 2000). Similarly, many that can maximize the probability be taught by making the stimuli differ inauditory-visual matching and visual- that correct responses will occur.) Some intensity on initial teaching trials. Withvisual matching procedures differ some- of that research has shown that errors visual stimuli, such as printed letters orwhat. If the learner does not know how lead to further errors and emotional re- line drawings, the S- might be made toto do tasks that employ both types of sponses that can interfere with acquisi- appear very faint and the S+ dark. If theprocedures, his or her performance on tion, can be difficult to correct, and can intensity difference is an effective prompt,one or the other may lead to erroneous inhibit skill generalization (see Hecka- the learner will respond to the more in-conclusions about discrimination skill mon, Alber, Hooper, & Heward, 1998; tense stimulus. Over successive trials, thedeficiencies (Kelly, Green, & Sidman, MacDuff, Krantz, & McClannahan, in intensity difference is gradually decreased1998). press ) . in a series of graded steps-that is, the S- One very important skill involved in Errorless teaching methods generally gradually becomes darker (or louder)-performing MTS is pointing to the sam- entail the addition of stimuli that reli- until both the S+ and the S- are pre-ple stimulus (or to a designated sample ably control the target response-that is, sented at the same intensity. If the learner&dquo;key&dquo; or card) that starts each trial, and prompts-to the target antecedents at continues to respond reliably to the S+pointing to one comparison stimulus on the beginning of instruction. Prompts and not to the S-, it is evidence that stim-each trial. It is strongly recommended are reduced (faded) systematically across ulus control has transferred from thethat learners be taught to point- to sam- successive trials in an effort to transfer prompt to the target stimulus. This pro-ples and comparisons rather than to place stimulus control to the target antece- cedure is usually termed intensity fading.samples on top of or alongside compar- dents, resulting in final performances Size difference can also serve as a within-isons (&dquo;put with same;&dquo; Lovaas et al., that are unprompted. Put another way, stimulus prompt. For example, the S-1981 ), for a couple of reasons: (a) Point- errorless teaching methods are most-to- might be made very small and the S+ing is a much more generally useful skill least prompt- and prompt-fading meth- large on initial teaching trials. Over suc-than &dquo;putting with.&dquo; Many stimuli that ods : The learner is given the most assis- cessive trials the size difference is gradu-learners are required to match in every- stance necessary on initial trials to ensure ally decreased, analogous to intensity fad-day situations (such as spoken words and that the target response occurs so that ing, until the S+ and S- are the same sizecorresponding objects, people, or actions) it can be reinforced frequently, and to (sometimes called size fadin8).cannot be physically &dquo;put with&dquo; one an- minimize errors; the amount of assistance is Another within-stimulus promptingother, but learners can readily indicate then systematically decreased as long as procedure involves altering the physicalthat such stimuli go together by point- the learner continues to respond cor- appearance of only those features of theing to them; (b) teaching matching skills rectly. If an error occurs, there is typically stimuli that differentiate them from oneby requiring learners to put identical or a provision for &dquo;backing up&dquo; to the pre- another. An example is exaggerating thephysically similar stimuli on top of or ceding prompt level on the very next trial vertical parts of the lowercase letters balongside one another may establish to reduce the likelihood that another and p on early training trials and gradu-stimulus control by identical outlines or error will occur. Following a correct ally making them appear more and moreother identical features of the stimuli, be- response, the systematic fading process alike over succeeding trials. Such proce-cause that is all the learner needs to at- resumes. dures are often referred to as criterion-tend to in order to obtain reinforcement Errorless discrimination training meth- related prompting. In general, criterion-consistently. That could block the devel- ods can and should be used to teach all related prompting has been found to be Downloaded from at WESTERN MICHIGAN UNIVERSITY on September 20, 2008
  9. 9. 79more effective for teaching discrimina- spoken words, the instructor might hold and prompt-fading procedures, thesetions to learners with disabilities than up pictures one at a time and simultane- should be used judiciously (Etzel & Le-noncriterion-related prompting, but the ously model the name of each picture. Blanc, 1979; MacDuff et al., in press;efficacy of the various within-stimulus Extra-stimulus prompts can be faded Oppenheimer, Saunders, & Spradlin,prompting methods can vary with the along any of several dimensions, such as 1993).characteristics of the stimuli involved, the intensity, distance relative to the targetlearner’s skills, and the complexity of the stimulus, or time relative to presentation Developing Stimulus Equivalencediscriminations being trained (for reviews of the target stimulus. When prompts are Classes. One of the most exciting areassee Demchak, 1990; Etzel & LeBlanc, faded along the time dimension, the pro- of research in contemporary behavior1979; MacDuff et al., in press). cedure is often referred to as time delay analysis is stimulus equivalence. Most of A unique within-stimulus prompting (although delayed cue or delczyed prompt the work on this topic has been con-procedure for teaching arbitrary MTS is more accurate, as it is the prompt rather ducted within a conceptual and analyticalhas been termed sample stivnulus control than time that is delayed). For instance, framework developed by Murray Sidmanshaping. In this procedure, the initial when an instructor’s point to the S+ and his colleagues (Sidman, 1971, 1994;teaching trials are identity MTS trials pre- comparison is used as an extra-stimulus Sidman et al., 1982; Sidman & Tailby,senting samples that are physically iden- prompt within MTS procedures, on 1982). In a nutshell, the Sidman modeltical to their corresponding S+ compar- initial trials the prompt is provided im- provides methods for analyzing howisons (e.g., identical line drawings). Over mediately upon presentation of the com- physically dissimilar stimuli come to besuccessive trials, the sample stimuli are parison array. If the learner follows the treated as equivalent to, or substitut-gradually transformed into entirely dif- prompt and responds correctly for a spe- able for, one another in certain contexts.ferent stimuli (e.g., line drawings change cified number of trials, on subsequent Scores of experiments using these meth-into printed letters). Sample stimulus trials the instructor begins to delay the ods have shown that after certain arrange-control shaping has proven efficacious prompt for a short period of time (say, ments of conditional discriminations arefor teaching arbitrary conditional discrim- 1 sec) after presentation of the compari- trained (usually, though not always, withinations to learners who can do condi- son array. After a specified number of MTS procedures), other conditional dis-tional identity MTS but have failed to ac- correct responses at that delay interval, criminations emerge without any furtherquire arbitrary conditional discriminations the delay is gradually increased (e.g., in training or direct reinforcement. In histhrough other training methods (Carr, 1-sec increments) over successive trials. first experiment on stimulus equivalence,Wilkinson, Blackman, & McIlvane, 2000; Such a procedure is referred to as pro- Sidman (1971) set out to investigate sight-Zygmont et al., 1992). gressive delczy. Alternatively, after a speci- word reading in a young man with severe One of the major drawbacks of within- fied number of trials on which the prompt mental retardation. When he entered thestimulus prompting procedures is that a is provided immediately ( 0-delay) or experiment, the young man could matchgreat deal of advance stimulus prepara- after a brief delay (e.g., 1 sec), the delay 20 common pictures (e.g., a bed, a hat)tion is required, which can make them interval might be increased to a certain to their corresponding dictated Englishdifficult to use in typical instructional set- value (say, 5 sec) that is maintained for all names, but he did not match corre-tings. (Many recent studies on this topic subsequent trials. This is termed a con- sponding printed words to those sametook advantage of computer technology stant or fixed delczy procedure. If delayed pictures, or to the dictated words; that is,and rather sophisticated software to ac- prompting is effective, the learner begins he did not have a sight-word readingcomplish very precise stimulus transfor- at some point to respond correctly before repertoire with those words. After he wasmations, timing, backing up and advanc- the prompt is provided (sometimes re- trained with standard MTS proceduresing through prompt hierarchies, etc.). An ferred to as &dquo;anticipations&dquo;), probably be- to match the printed words to the dic-alternative errorless teaching method is cause preempting the prompt reduces the tated words, the young man provede.~^a-stimulus prov~cptin8, in which prompts delay to reinforcement. Delayed prompt- immediately capable of matching theare separate from and external to the stim- ing has been shown to be an effective pictures to their corresponding printeduli to be discriminated (Etzel & LeBlanc, method of transferring stimulus control words and vice versa, without further in-1979; MacDuff et al., in press). One ex- from extra-stimulus prompts to target struction or reinforcement. Those out-ample of an extra-stimulus prompt in the stimuli in some studies, but it is not uni- comes documented the development ofcontext of teaching conditional discrimi- versally effective. The main risk in using 20 classes of equivalent stimuli, each con-nations is an instructor’s gesture (such as this method is that learners will not an- sisting of a corresponding picture, dic-a point) toward the correct comparison ticipate the prompt but will simply wait tated word, and printed word. This basicstimulus on initial teaching trials. In for it on trial after trial, probably because finding has been replicated hundreds ofother contexts, extra-stimulus prompts waiting for the prompt maximizes the times by many investigators using acould be models provided by the in- probability of reinforcement. Progressive wide array of visual, auditory, tactile, andstructor ; for example, to teach picture delay procedures in particular can shape olfactory stimuli with a wide array ofnaming to a learner who reliably imitates waiting behavior. Therefore, like all prompt learners, including nonhumans, typically Downloaded from at WESTERN MICHIGAN UNIVERSITY on September 20, 2008
  10. 10. 80developing children and adults, and in- preschoolers with autism in another ex- stimulus control research has focused ondividuals with various disabilities (e.g., periment (Eikeseth & Smith, 1992). techniques that either fade adult-deliveredsee Green & Saunders, 1998; Sidman, Numerous other experiments with par- prompts very rapidly after they are intro-1994). ticipants with learning difficulties have duced, or never introduce them in the Much of the interest in the stimulus demonstrated the efficacy and efficiency first place. Again, an exhaustive review isequivalence model stems from the fact of stimulus equivalence procedures for beyond the scope of this article, so just athat it enables experimental analyses of developing classes of stimuli relevant to few recent advances and novel applica-phenomena that were long considered such skills as reading, spelling, math, and tions are presented here as examples.outside the realm of behavior analysis, augmentative or alternative communi- Activity schedules. A very powerfulsuch as concept formation, transitive in- cation (for overviews see Remington, and flexible technology for promotingferences, symbolic learning, and genera- 1994; Sidman, 1994; Stromer, Mackay, independent performances in learners withtive behavior (Mcllvane, Dube, Green, & Stoddard, 1992). Like the aforemen- autism has been developed primarily by& Serna, 1993). For practitioners, stim- tioned discrimination training methods, scientist-practitioners at the Princetonulus equivalence methods can provide a the rich technology for developing stim- Child Development Institute. Learnerslot of &dquo;bang for the buck,&dquo; because after ulus equivalence classes does not seem to are taught to use activity schedules con-just a few conditional discriminations are have made its way from laboratory re- sisting of photos or printed wordsestablished through direct training, many search into widespread application with arranged in notebooks to guide extendedothers typically emerge &dquo;for free,&dquo; with- learners with autism, so this is an area sequences of behavior in the absence ofout any additional instruction whatso- that is ripe with possibilities for field re- adult instruction or supervision. Initially,ever. Additionally, generative (untrained) search and practice. adults deliver nonverbal prompts (usuallyperformances, which have been notori- manual guidance) and reinforcers fromously difficult to produce in learners with behind the learner. In this fashion, theautism and related disorders, occur quite Promoting Independence learner is taught to touch a photo or text and Initiationsreliably when stimulus equivalence pro- that represents a particular task or actioncedures are used. Prompting and Prompt Fading. (such as assembling a puzzle), obtain the For example, in one experiment an ado- Prompting procedures were discussed relevant materials, complete the task orlescent with severe autism who could match earlier in the context of teaching dis- action, turn to the next page in the note-the printed numerals 1 through 6 to cor- criminations, but they have broad utility book, and repeat the process with theresponding dictated number names was for teaching all sorts of new skills to photo or text shown there. The manualtrained with MTS procedures to match learners with autism. Prompts, or auxil- prompts are faded rapidly as long as cor-quantitites of one to six dots (each ar- iary antecedent stimuli, can take many rect responding occurs; when they haveranged in three different configurations forms: physical guidance, gestures, mod- been completely removed, adult proxim-on cards) to those same dictated number els, verbal cues, other types of auditory ity is also faded. Adult-delivered rein-names. He then matched the quantities stimuli, colors, pictures of various kinds, forcers are also thinned, and shifted fromto corresponding printed numerals and written text, and tactile stimuli. Prompts prompted to unprompted responses.vice versa on unreinforced probe trials, like manual guidance are often necessary This training is designed to establish eachmaking very few errors. Similarly accu- to new responses to occur in learn- get of a series of photos or textual stimulirate performances were demonstrated on ers with autism who are just entering in- (rather than adult-delivered instructions)unreinforced probes with quantities of struction, and it is often necessary to use as discriminative for lengthy chains of be-pennies and of pictures of apples and prompting procedures to make the most havior. Once a basic schedule-followinghouses-stimuli that had never been pre- efficient use of instructional time. But repertoire has been established, the ordersented in training-appearing as compar- whenever prompts are used, there is the of stimuli in the activity schedule is var-ison stimuli with dictated number names risk that learners will become dependent ied. Activity schedules can incorporateas samples, as comparisons with printed on them so that their responding does not stimuli that discriminative for inde- arenumerals as samples, and as samples with come under the control of the relevant pendent performance of a host of self-the numerals as comparisons. Collectively, environmental stimuli (Demchak, 1990; care, domestic, vocational, leisure, aca-these performances documented the de- MacDuff et al., in press). Therefore, con- demic, and social activities in a varietyvelopment of six equivalence classes, each siderable research in applied behavior of settings. Research and practice havecontaining a dictated number name, the analysis has focused on instructional shown that individuals with autism cancorresponding printed numeral, and cor- techniques that preclude or minimize readily learn to choose and sequence theirresponding quantities of dots, pennies, prompt dependence and promote spon- own activities, and that activity schedulespictures of apples, and pictures of houses taneous, independent performances in can be transformed into the types of(Green, 1992). Equivalence classes of learners with autism. Because adult- schedules that many of us use routinely,Greek letters and their dictated names delivered prompts (especially verbal cues) such as calendars, appointment books,were demonstrated by high-functioning can be particularly difficult to fade, some class schedules, and &dquo;to do&dquo; lists (Krantz, Downloaded from at WESTERN MICHIGAN UNIVERSITY on September 20, 2008
  11. 11. 81MacDuff, & McClannahan, 1993; Mac- vice is activated, an adult models a verbal or comments to peers (e.g., &dquo;Susie, let’sDuff, Krantz, & McClannahan, 1993; statement for the learner to imitate as an teeter-totter&dquo; ) and to engage in con-McClannahan & Krantz, 1999). It is im- initiation to another person. The verbal versations. Another automated auditoryportant to note that this technology dif- model is faded until the learner reliably prompting technique involves recordingfers considerably from other uses of vis- initiates responses when he or she feels spoken instructions on audiotape andual schedules with learners with autism, the device vibrate, without an adult- teaching the learner with autism to de-such as depictions of daily activities for an delivered prompt. The device is then liver them to himself via a self-operatedentire class of students, and pictures or placed in the learner’s pocket and used to personal tape player and headphonesprinted words on cards that the learner prompt initiations to peers. This type of (e.g., Taber, Seltzer, Heflin, & Alberto,moves from a centrally located envelope prompt has the multiple advantages of 1999). Like the vibrating beeper, thisto the physical locations in which each of being portable and unobtrusive so that it type of prompting system is portable anda series of activities takes place (as in the can be used in various settings, such as can be used in various settings withoutTEACCH model; e.g., Schopler, Mesi- classrooms, and functional in the absence disturbing others or drawing undue at-bov, & Hearsey, 1995). of adult cues or reinforcer delivery (Hol- tention to the learner with autism. The Other nonverbal prompts. As noted berton, Taylor, & Levin, 1998; Taylor & utility and generality of automated audi-previously, just about any type of stimu- Levin, 1998). tory prompting systems remain to be in-lus that reliably sets the occasion for tar- Automated auditory prompts. Ver- vestigated fully.get behaviors can be used in prompt and bal prompts from adults or other chil-prompt-fading procedures. For instance, dren can impede spontaneity on the part Video Modeling. A few studies haveonce learners with autism have reliable of the learner with autism and can be dif- demonstrated that learners with autismreading repertoires, prompts in the form ficult to fade, but verbal prompts pre- can imitate various skills after viewingof written or typed words can be used sented via automated devices can be very videotaped segments of themselves oreffectively to get them to engage in de- effective because they do not require the others performing those skills. For ex-sirable behaviors without verbal or other constant presence of another person; learn- ample, three young adults with autisminstructions from adults. Such textual ers with autism can be taught to activate were taught purchasing skills in class-prompts can be as simple as single words the devices themselves. Such prompts rooms and in either their school cafeteriaor short phrases embedded in an activity can also be faded very systematically and or a nearby convenience store (Haring,schedule (such as &dquo;Take a shower&dquo; or &dquo;Tell precisely and (unlike textual prompts) Kennedy, Adams, & Pitts-Conway, 1987).Dad a joke&dquo;), or as complex as lengthy can be used with nonreaders. Probes conducted in three communityscripts that specify a series of interactions One useful automated system for es- settings indicated that very little skillamong two or more people. In one ex- tablishing and fading verbal prompts is generalization occurred. After the youthsample of the latter, adolescents with au- the Language Master (Stevenson, Krantz, viewed videotapes of same-age nonhan-tism were taught to initiate and respond & McClannahan, 2000; Taylor, in press). dicapped peers making purchases in threeto verbal statements (i.e., to engage in Spoken statements or questions that are community settings and responded to anconversational exchanges) in the context to serve as models for the learner are re- instructor’s questions about what theyof everyday activities, such as completing corded on cards with electromagnetic were viewing, generalization increasedclassroom art projects (Krantz & Mc- strips. The cards are run through the substantially. Another set of investiga-Clannahan, 1993). In another, young Language Master machine, which plays tors reported acquisition and generaliza-children with autism and minimal read- the recorded message. These auditory tion of conversational speech (three briefing skills learned to initiate comments to prompts can be faded gradually by re- question-and-answer exchanges withothers by responding to such textual cording several versions of the message, therapists) in three young children withprompts as &dquo;Look&dquo; and &dquo;Watch me&dquo; in each of which eliminates one word from autism after the children observed video-their activity schedules (Krantz & Mc- the end of the previous version, thus tapes of familiar adults engaging in suchClannahan, 1998). Textual prompts are fading the prompt across successive ver- conversations, and then practiced theoften faded by gradually removing com- sions. Alternatively, the prompt can be conversations with a therapist (Charlopponents (words or letters) from the last removed all at once by activating a block- & Milstein, 1989). More recently, the ef-component to the first. ing option on the Language Master ma- ficacy of video self-modeling was evalu- One innovative procedure makes use chine that renders the recorded message ated with three children with autism. Theof a tactile prompt in the form of a vi- inaudible when the card is run through children viewed specially prepared video-brating beeper. Learners with autism have it. Studies have shown that after learn- tapes of themselves answering a series ofbeen taught to initiate verbal play bids ers with autism learn to imitate verbal questions presented by adults. The in-and conversations with adults, then with models provided via Language Masters, vestigators reported that after viewingpeers, in response to activation of the prompt and prompt-fading techniques the videotapes several times, all threebeeper. Initially, the learner’s hand is using those devices are effective for children showed increased accuracy ofplaced on the device, and when the de- teaching the learners to initiate requests responding to the same questions in vivo Downloaded from at WESTERN MICHIGAN UNIVERSITY on September 20, 2008
  12. 12. 82(Buggey, Toombs, Gardener, & Cervetti, quency of initiations to use the toilet and havior in learners with autism would be1999). of dry diapers with a preschooler with complete without a discussion of inci- Video modeling is another potentially autism (Bainbridge & Myles, 1999). In dental teaching and related techniquespromising technique that is ripe for field another study, previewing specially pre- for promoting spontaneous communica-and laboratory research. Some questions pared videos of settings in which three tion. Some popular misconceptions arethat need tobe addressed in careful ex- young children with autism had exhib- that traditional applied behavior analysisperimental analyses include (a) whether ited disruptive behavior was reported to eschews everything but highly structured,the initial studies on this topic can be substantially decrease the problem be- adult-directed instructional procedures,replicated by independent investigators, havior exhibited by all three children in and that only the more &dquo;contemporary&dquo;(b) the entry skills required for learners the actual settings (Schreibman, Whalen, behavioral approach has incorporatedwith autism tobenefit from video in- & Stahmer, 2000). naturalistic methods drawn from the de-struction, (c) the efficacy of video mod- Many important questions about prim- velopmental social-pragmatic approacheling for establishing an initial imitative ing remain to be addressed in well- to communication enhancement (e.g.,repertoire (including generalized imita- controlled studies, some of them parallel Prizant & Wetherby, 1998; Wetherby,tion), (d) factors that may account for to the questions about video modeling Schuler, & Prizant, 1997). An even morethe rapid skill acquisition and broad gen- raised earlier. First, the handful of pub- egregious misrepresentation is that &dquo;ap-eralization reported in the few studies lished studies on this topic need to be proaches to enhance spontaneous lan-published to date (if indeed those find- replicated. Replications and extensions guage use, including incidental teachingings can be replicated), (e) whether should specify the entry skills of the and pivotal response training, were de-simply viewing video models (without learners and address questions about the veloped primarily because of concernspracticing the target skills) suffices to es- &dquo;active ingredients&dquo; in this intervention. about children’s inability to generalize com-tablish new skills, and (f) the compara- For example, is it necessary for learners municative use of language ‘learned’ intive efficacy of in vivo and video model- with autism to practice target skills or discrete trial training&dquo; (Prizant & Rubin,ing for producing skill acquisition and otherwise respond actively during prim- 1999, p. 204).generalization. ing sessions (as in Zanolli et al., 1996), The fact is that incidental teaching or is mere exposure to the priming stim- methods were developed in the 1960s by Priming. Another antecedent manip- uli (as in Schreibman et al., 2000) suffi- Betty Hart and Todd Risley, who beganulation that bears further careful investi- cient to change behavior? What is the re- their long collaboration at the Institutegation with learners with autism has been lation between the rate or probability of of Child Development at the Universitytermed &dquo;priming.&dquo; This term generally reinforcer delivery in priming sessions of Washington under the leadership ofrefers to providing learners with a pre- and behavior change in the subsequent Sidney Bijou, as recounted in the intro-view of upcoming events by presenting activity? It has been hypothesized that duction to this article. Working withthe stimuli and/or activities involved in priming works by making future events disadvantaged preschoolers, Hart andthose events under low-demand, high- predictable for learners with autism Risley found that the children’s sponta-reinforcement conditions (Wilde, Koe- (Schreibman et al., 2000). That raises neous use of color-noun combinationsgel, & Koegel, 1992). In one study, for questions as to the comparative efficacy increased when access to snacks and playexample (Zanolli, Daggett, & Adams, of priming and other, perhaps briefer and materials (naturalistic consequences) were1996), each of two preschool boys with simpler methods of previewing what is made contingent on language produc-autism was prompted by a teacher to ini- about to happen, such as providing a tion. They went on to specify incidentaltiate verbal and nonverbal interactions simple spoken description or showing teaching procedures for elaborating lan-with a typically developing peer. The peer the learner a picture. The predictability guage, as follows: (a) Make available sev-provided reinforcers to the child with hypothesis also suggests that the degree eral items of interest to the child; (b) waitautism contingent on correct responses. of correspondence between the priming for the child to show interest in anThese priming sessions were followed im- activity and the actual activity might be item and initiate an interaction about it;mediately by sessions in which the child related to the occurrence of the target (c) ask the child for approximations towith autism was given opportunities to behavior in the actual situation: Do prim- speech, or for more elaborate language ifengage in preferred activities with a ing activities that are very similar to he or she offers some speech (providingtrained peer, without adult-delivered the actual situations produce behavior a model for the child to imitate, if neces-prompts or reinforcers for the child with change more reliably than priming activ- sary) ; (d) when the child makes the re-autism. Unprompted initiations by both ities that bear less resemblance to the ac- quested response, provide her or himboys with autism, which were at near- tual situations? with the item for which she or he initi-zero rates during a baseline phase, were ated (Hart & Risley, 1968, 1982, 1995).reported to increase after the priming in- IncidentalTeaching and Other As mentioned at the beginning of this ar-tervention. Recently, priming in the form Techniques. No article &dquo;Naturalistic&dquo; ticle, Hart and Risley were among the pi-of viewing a commercial toilet-training on behavior analytic methods for pro- oneers who integrated the principles andvideo was reported to increase the fre- moting independent, unprompted be- methods of the experimental analysis of Downloaded from at WESTERN MICHIGAN UNIVERSITY on September 20, 2008