ACQUISITION OF INTRAVERBAL BEHAVIOR: TEACHING … · tion probes in their classrooms. Fourth, in the previous study, teaching was implemented in the context of toy play, two trials

ACQUISITION OF INTRAVERBAL BEHAVIOR: TEACHING CHILDRENWITH AUTISM TO MAND FOR ANSWERS TO QUESTIONS

EINAR T. INGVARSSON

UNIVERSITY OF NORTH TEXAS

CHILD STUDY CENTER, FORT WORTH

AND

TATIA HOLLOBAUGH

YOUNGSTOWN STATE UNIVERSITY

Four boys with autism were taught via echoic prompting and constant prompt delay to mand foranswers to questions by saying ‘‘I don’t know please tell me’’ (IDKPTM). This interventionresulted in acquisition of the IDKPTM response for all 4 participants and in acquisition ofcorrect answers to most of the previously unknown questions for 2 participants. For 1participant, tangible reinforcement resulted in increased frequency of correct answers, and directprompting of correct answers was eventually conducted for the final participant. The IDKPTMresponse generalized to untargeted unknown questions with 3 participants. Results of person andsetting generalization probes varied, but some generalization eventually occurred for allparticipants following additional training or interspersal of probe trials with training trials.

Key words: autism, generalization, intraverbals, manding for information, questionanswering, verbal behavior

_______________________________________________________________________________

Autism is a developmental disability thataffects an increasing number of families world-wide. Recent estimates indicate that 1 of every150 8-year-old children in the United States hasan autism spectrum disorder (Centers forDisease Control and Prevention, n.d.). One ofthe defining characteristics of autism spectrumdisorders is marked delay in or absence offunctional language or other communication(Filipek et al., 1999). Any comprehensiveintervention program for children with autismshould therefore emphasize the goal of increas-ing language and communication skills. Someearly intensive behavioral intervention (EIBI)

approaches (e.g., Sundberg & Partington,1998) emphasize language and communicationinterventions based on B. F. Skinner’s VerbalBehavior (1957). In this approach, verbalbehavior is defined as any behavior whosereinforcement is mediated by other people. Adistinction is made between verbal operantsbased on characteristic features of stimuluscontrol, motivational operations, and reinforce-ment.

Four verbal operants—the tact, the mand,the echoic, and the intraverbal—are relevant tothe current discussion. The tact is under specificstimulus control and is maintained by ageneralized social reinforcer (e.g., a child maysay ‘‘cookie’’ in the presence of a cookie, andthe response is reinforced with praise). Themand is evoked by a specific motivatingoperation and reinforced with a characteristicconsequence related to the motivating operation(e.g., a child may say ‘‘cookie’’ when hungry,and the response is reinforced with access to thecookie). The echoic is a verbal operant that isunder the stimulus control of a preceding verbal

We thank Bernadette Treece, Jacob Gailey, DeniseKurelko, Renee Reagan, and Michael Clayton for theirassistance with the conduct of the study and AnthonyCammilleri for useful comments on an earlier version ofthis manuscript. In addition, we are grateful to theteachers, staff, and students at the Rich Center for Autismin Youngstown, Ohio, for their cooperation and support.

Address correspondence to Einar T. Ingvarsson,Department of Behavior Analysis, 1155 Union Circle,Box 310919, University of North Texas, Denton, Texas76203 (e-mail: [email protected]).

doi: 10.1901/jaba.2010.43-1

JOURNAL OF APPLIED BEHAVIOR ANALYSIS 2010, 43, 1–17 NUMBER 1 (SPRING 2010)

1

stimulus, maintained by generalized reinforce-ment, and has a point-to-point topographicalcorrespondence to the preceding stimulus (e.g.,a child says ‘‘cookie’’ when an adult says‘‘cookie,’’ and the child receives praise as aresult). The intraverbal, which is the main focusof the current experiment, is a verbal operantthat is under the stimulus control of a precedingverbal stimulus, without point-to-point corre-spondence, and is maintained by generalizedreinforcement (e.g., a child says ‘‘cookie’’ whenasked ‘‘What did you have for snack?’’ and thechild receives praise).

Target behaviors in intraverbal traininginclude conversational turns, categorization,and fill-in-the-blank tasks; the current studyfocused on question answering. Questionanswering is commonly included in EIBIcurricula, either targeted directly as a separateprogram (Sundberg & Partington, 1998; Taylor& Jasper, 2001; Taylor & McDonough, 1996)or indirectly through programs that target othergeneral skills (e.g., concepts such as yes–no,emotions, functions of body parts, and generalknowledge; McEachin & Leaf, 1999). Previousresearch has indicated that transfer-of-functionprocedures are effective in establishing intra-verbal behavior (Braam & Poling, 1983;Partington & Bailey, 1993). Transfer-of-function procedures include the delivery ofprompts that reliably evoke the desired re-sponse topography. The prompts are thenfaded (e.g., through delayed prompting), andstimulus control is transferred to the desiredantecedent.

A handful of studies have evaluated the use ofsuch procedures to teach question answeringand other intraverbal behavior to children withautism. Finkel and Williams (2001) found thattextual prompts (i.e., printed text) were moreefficient than echoic prompts in establishingquestion answering in a young boy with autism.The target answers were multiword phrases, andthe prompts were faded by reducing the lengthof the prompts one word at a time until the

child acquired intraverbal responding. Gold-smith, LeBlanc, and Sautter (2007) taught 3young boys with autism to answer questionsrelated to categories (e.g., ‘‘What are somethings you wear?’’) using tact prompts (e.g.,pictures of clothing) and prompt delay.

Although it is clearly desirable to teachcorrect answers directly (as in Finkel &Williams, 2001; Goldsmith et al., 2007), analternative strategy is to teach a general responsethat may lead to acquisition of intraverbals. Inother words, the children may be taught tomand for information (Sundberg & Michael,2001). Some support for this notion comesfrom research by Sundberg, Loeb, Hale, andEigenheer (2002) and Endicott and Higbee(2007). These researchers taught children withautism to ask the questions ‘‘Where is it?’’ and‘‘Who has it?’’ with regard to items initiallypresented noncontingently and then hidden outof view in specified locations or on people in theimmediate environment. These investigatorsfound that the children manded equally withhigh-preference and low-preference items, sug-gesting that the information regarding thelocation of the item may have taken onreinforcing quality that may not have beencompletely dependent on the value of thehidden item. This lends some support to thenotion that questions such as ‘‘Where is it?’’may be maintained by getting access to‘‘information’’ and may thus be conceptualizedas mands for information. In addition, Wil-liams, Perez-Gonzalez, and Vogt (2003) taught2 children with autism to ask ‘‘What’s in thebox?,’’ ‘‘Can I see it?,’’ and finally ‘‘Can I haveit?’’ regarding preferred items placed out ofsight in a box. In the latter two cases thequestions (i.e., mands) were reinforced by thesight of the object and access to the object.However, the question ‘‘What’s in the box?’’may be conceptualized as a mand for informa-tion because the reinforcer consisted of a verbalstatement describing which preferred item washidden in the box.

2 EINAR T. INGVARSSON and TATIA HOLLOBAUGH

Previous research has evaluated similar pro-cedures in order to establish verbal operantsother than intraverbals. For example, Taylorand Harris (1995) presented children withautism with items they were able to tact, alongwith some items they were not able to tact. Aprompt-delay procedure established the phrase‘‘What is that?’’ as a mand for information,which generalized across environments andresulted in the acquisition of novel tacts. Asecond example was provided by Esbenshadeand Rosales-Ruiz (2001), who found evidenceof tact acquisition in a 5-year-old boy withautism after he was taught to ask ‘‘What isthat?’’ in the presence of unknown items acrossa variety of tasks. However, we are aware of onlyone study that has evaluated procedures to teacha mand that led to the acquisition of newintraverbals. Ingvarsson, Tiger, Hanley, andStephenson (2007) first taught the participantsto say ‘‘I don’t know’’ (IDK) in response tounknown questions. Desirable generalizationacross teachers and unknown questions wasfound, but undesirable generalization to previ-ously known questions also occurred (i.e., thechildren started responding to previouslyknown questions by saying IDK). Second, thechildren were taught to say ‘‘I don’t know,please tell me’’ (IDKPTM) in response tounknown questions. Every time the childrenengaged in the IDKPTM response, they wereprovided with the correct answer to thequestion. IDKPTM generalized across teachersand questions, but correct answers increased toacceptable levels only after toy access was madecontingent on their occurrence.

Teaching a mand for information, such asthe IDKPTM response, may be valuable for atleast three reasons. First, research has suggestedthat levels of stereotypic behavior (e.g., echola-lia) in children with autism are greatest whenunfamiliar tasks (e.g., unknown questions) arepresented (Charlop, 1986; Turner, 1999).Other studies have shown that demand-relatedproblem behavior is more likely to occur under

difficult rather than easy demand conditions(Weeks & Gaylord-Ross, 1981). A mand forinformation may morph a difficult and unfa-miliar demand situation into an easier demandsituation, thereby reducing stereotypy and otherundesirable behavior. Second, the IDKPTMresponse may enable children to mand for amore intrusive prompting level while avoidingerrors. This may reduce the overall numbers oferrors that may otherwise occur as less intrusiveprompts are introduced during most-to-leastprompt fading, progressive prompt delay, orother errorless teaching procedures. Third, theIDKPTM response may enable children tobenefit from a broad range of programmed andnaturally occurring learning opportunities ifshown to generalize across settings, people, andstimuli.

To date, the majority of research on verbalbehavior has focused on tacts and mands ratherthan intraverbals (Dymond, O’Hora, Whelan,& O’Donovan, 2006; Sautter & LeBlanc,2006). Although a handful of studies onintraverbal behavior have been published inthe last 2 to 3 years (e.g., Perez-Gonzalez,Garcia-Asenjo, Williams, & Carnerero, 2007;Petursdottir, Carr, Lechago, & Almason, 2008;Petursdottir, Olafsdottir, & Aradottir, 2008),more research is needed. Hence, a broad goal ofthe current study was to strengthen theempirical basis for intraverbal training forchildren with autism. A more specific goal wasto replicate and extend the Ingvarsson et al.(2007) study systematically. The current studydiffered from the previous one in the followingmanner. First, the participants were childrenwith autism spectrum disorders rather thanchildren with language delays. Second, it ispossible that in the previous study, a history ofsaying IDK to unknown questions reduced theacquisition of correct answers after IDKPTMtraining occurred. Therefore, IDK was nottaught prior to teaching IDKPTM in thecurrent study. Third, we added generalizationmeasures that consisted of asking the partici-

INTRAVERBAL BEHAVIOR 3

pants’ regular teachers to carry out generaliza-tion probes in their classrooms. Fourth, in theprevious study, teaching was implementedin the context of toy play, two trials werepresented per minute, and all question setswere interspersed randomly in each session(i.e., known and unknown, targeted anduntargeted questions were interspersed). Thisarrangement mimicked everyday classroominteraction and probably supported the gener-alization of IDK and IDKPTM to untargetedsets. However, it may also have reduced thespeed of acquisition of IDK, IDKPTM, andcorrect answers. Therefore, in the currentstudy, we conducted brief sessions with rapidlypresented trials and did not intersperse questionsets.

METHOD

Participants

The participants were 4 boys with a diagnosisof autism—Chris, Neil, Matt, and Jim—whowere 10, 7, 6, and 4 years old, respectively.Chris, Matt, and Jim were Caucasian, and Neilwas African American. All the boys attended auniversity-based school for children with au-tism, where they received full-day educationalservices 5 days per week. The participants wereselected based on the recommendations of thespeech-language therapist who worked at theschool and who was familiar with the verbalabilities of all the students. Specifically, she wasasked to nominate children who had difficultyanswering common questions. Based on infor-mation from the speech-language pathologist, aswell as informal observations conducted by thefirst author, Chris, Jim, and Neil had fairlywell-established echoic, manding, and tactingskills. Matt also had relatively strong echoicskills, but more limited tacting and mandingrepertoires compared with the others. All theparticipants had relatively undeveloped intra-verbal skills compared with same-age peers,with Matt displaying the greatest deficiency inthat skill area.

Setting

Sessions were conducted in small classrooms(henceforth referred to as training rooms)designed for small group or individualizedteaching, located at the participants’ school.The training rooms contained child-sizedfurniture, art materials, and toys. During eachsession, the experimenter and the participant satin chairs facing each other, and the observers sat2 to 3 m to the side. We conducted classroomgeneralization probes in the participants’ regularclassrooms with other children present. Theseclassrooms varied in size and layout, but werelarge enough to accommodate eight to 10students and two or three teachers. During theclassroom generalization probe sessions, theclassroom teacher asked questions while seatednext to the child at a child-sized desk, and theobservers stood or sat 2 to 3 m to the side.

Measurement

Observers scored the participants’ verbalresponses using event recording. For each trial(i.e., the presentation of a single question), theobservers circled codes on a data sheet indicat-ing whether the participants gave the correctanswer to the question or whether they saidIDKPTM. The observers also scored whetherthese responses were prompted (i.e., precededby an echoic prompt) or independent. Theobservers scored responses as prompted if theywere initiated within 5 s after the promptpresentation and independent if they wereinitiated within 5 s of the question and beforethe prompt.

Interobserver Agreement

A second observer simultaneously but inde-pendently collected data during 55% of sessionsfor Chris, 58% for Neil, 45% for Matt, and51% for Jim. We scored a trial (i.e., thepresentation of a single question) as anagreement if both observers circled the samecode or as a disagreement if any scoring for agiven trial differed. For each session, thenumber of trials scored in agreement was


divided by the total number of trials andconverted into a percentage. Mean agreementwas 99% (range, 87% to 100%) for Chris, 98%(range, 80% to 100%) for Neil, 99% (range,89% to 100%) for Matt, and 99% (range, 90%to 100%) for Jim.

Procedure

Pretest and question selection. The pretestswere similar to those described by Ingvarsson etal. (2007) and included similar questions. Thequestions targeted personal information (e.g.,‘‘Where do you live?’’), general knowledge (e.g.,‘‘Where do you buy groceries?’’), and academicskills (e.g., ‘‘How much is a dime?’’). A total of56 questions were included in the pretest. Wedivided the questions into four sets, three ofwhich contained 15 questions and one con-tained 11 questions. Each set was targeted threetimes. Thus, we conducted a total of 12 pretestsand asked each question three times. Thepretests were conducted over a span of 3 to 7days. We delivered no prompts during thepretest. The experimenter praised correct an-swers and ignored incorrect answers.

Based on the pretest results, we classified eachquestion as unknown if it was always answeredincorrectly (or no answer occurred) and knownif it was always answered correctly. We thencreated four unique sets of unknown questionsand two unique sets of known questions basedon this classification, with five unique questionsin each set (due to experimenter error, Matt’sUnknown Set 3 included four questions). Insubsequent experimental sessions, the firstauthor targeted Known Set 1 and UnknownSets 1 and 2 in experimental sessions in thetraining room. One of the research assistantstargeted Known Set 2 and Unknown Set 3 ingeneralization probes in the training room, andeach participant’s classroom teacher targetedUnknown Set 4 and Known Set 1 in classroomgeneralization probes. Questions that weresometimes answered correctly and sometimesincorrectly during the pretest were not givenany classification and were not used in

subsequent experimental phases. The partici-pants’ teachers agreed to refrain from includingthe selected questions in educational activitiesduring other parts of the school day.

Baseline. In baseline, the experimenter tar-geted questions from Known Set 1, UnknownSet 1, and Unknown Set 2. Thus, a total of 15questions were targeted in each session. Thisnumber remained constant for experimentalsessions (but not generalization probes, seebelow) throughout the experiment. The ques-tions were always asked in the same order;Known Set 1 first, followed by Unknown Set 1,and finally Unknown Set 2. The order ofquestions within each set also remained thesame. The experimenter asked the 15 questionsin rapid succession, allowing 5 s for an answerto occur. The responses ‘‘I don’t know, pleasetell me’’ and ‘‘I don’t know’’ would have beenpraised, but no such responses occurred (‘‘Idon’t know’’ never occurred throughout theexperiment). Correct answers were followed bydescriptive praise (e.g., ‘‘That’s right, a cow saysmoo’’). The experimenter delivered descriptivepraise throughout the experiment whenevercorrect answers occurred to any question. Ifthe participant gave an incorrect or no answer,the experimenter asked the next question butprovided no other consequence.

IDKPTM training. This phase was identicalto baseline, except that the questions fromUnknown Set 1 were targeted for IDKPTMtraining. The experimenter used echoic prompt-ing and constant prompt delay (Wolery et al.,1992) to teach the participants to engage in theIDKPTM response in the following manner:Initially, the experimenter prompted theIDKPTM response by providing an immediateverbal prompt after asking a question fromUnknown Set 1. (e.g., ‘‘How much is a dime?Say ‘I don’t know, please tell me’’’). After theparticipant’s IDKPTM response, the experi-menter modeled the correct answer (e.g., ‘‘Adime is 10 cents’’). If the child did not repeatthe correct answer (‘‘10 cents’’), the experi-


menter provided a prompt (e.g., ‘‘say ‘10cents’’’). When the child stated the correctanswer (with or without a prompt), theexperimenter provided descriptive praise (e.g.,‘‘That’s right, a dime is 10 cents’’).

When the participant echoed the IDKPTMprompt on two consecutive trials, we intro-duced a 5-s delay between the question andthe prompt. We reintroduced an immediateprompt if the participant did not engage ineither the IDKPTM response or the correctanswer for two consecutive trials. When theIDKPTM response occurred unprompted (i.e.,during the 5-s delay), only the latter part of theteaching sequence was implemented (i.e., theexperimenter provided the correct answer andprompted the participant to say it if necessary).We also implemented only the latter part of theteaching sequence if the IDKPTM responseoccurred following questions from UnknownSet 2 and Known Set 1 (i.e., if the IDKPTMresponse generalized to untargeted questions).Otherwise, the contingencies for Known Set 1and Unknown Set 2 were identical to baseline(i.e., no prompting was conducted, and incor-rect answers were ignored). An exceptionoccurred for Matt, with whom we eventuallyconducted IDKPTM training for Unknown Set2, because generalization across questions didnot occur following initial IDKPTM trainingwith Unknown Set 1.

Additional interventions. With Neil and Matt,IDKPTM training did not lead to acceptableacquisition of correct answers. We thereforeimplemented additional interventions, but theprocedures differed for these 2 participants as afunction of their response patterns. With Neil,correct answers occurred at intermediate levelsduring the IDKPTM training phase, but thetarget level of at least 80% correct across twoconsecutive sessions was not reached. Wetherefore added edible items contingent oncorrect answers while other contingencies werekept intact from the previous phase (i.e., correctanswers and IDKPTM were praised, and

incorrect answers were ignored). We chose thisintervention because his classroom teachersindicated that food was used successfully inthe past to increase participation in theclassroom, and the use of these reinforcers wasacceptable to the teachers and his family. Hispreference hierarchy was determined by obtain-ing a list of 10 potentially preferred edible itemsfrom his teachers and then conducting a paired-choice preference assessment based on themethods of Fisher et al. (1992). The experi-menter then delivered the three most preferreditems in alternation according to the prevailingschedule.

In the initial stages of the edible reinforce-ment phase, the experimenter delivered edibleitems contingent on correct answers on a fixed-ratio (FR) 1 schedule (note that correct answerswere reinforced only if they were not precededby IDKPTM). Schedule thinning began afterrandom question order had been implementedaccording to the criteria described below. Theschedule of edible delivery was thinned whenNeil answered at least 60% of the questions ineach unknown set (Unknown Sets 1 and 2)correctly across two consecutive sessions. Theschedule thinning proceeded as follows: FR 1,FR 2, FR 3, FR 4, FR 5, NCR. The NCRschedule involved delivering the mean numberof edible items that had been delivered in thepreceding FR 5 sessions; however, they weremade available as each session started, indepen-dent of any particular behavior other thanattending the session. We chose to deliver edibleitems independent of correct answers followingschedule thinning to strengthen the case thatthe answers functioned as intraverbals and toreduce the likelihood that the answers weremaintained primarily by access to edible itemsrather than praise and approval.

We could not implement additional rein-forcement for correct answers with Matt,because no independent correct answers oc-curred during the IDKPTM training phase.Therefore, the experimenter conducted one


session (Session 38) in which correct answers tothe questions in Unknown Set 1 were directlyprompted (using 5-s constant prompt delay)while IDKPTM training was suspended. Be-cause independent (unprompted) correct an-swers started to occur immediately, we sus-pended direct prompting of correct answersfollowing Session 38, in order to evaluatewhether the correct answers would continue tooccur under simple differential reinforcement.During Sessions 39 to 47, correct answers werepraised, and IDKPTM resulted in provision ofthe correct answer. No prompting was con-ducted during these sessions. We reinstated theIDKPTM training contingencies starting withSession 48 after we noticed a reduction incorrect answers.

Random question order. As described above,the experimenter always asked the questions inthe same order during baseline and initial stagesof IDKPTM training. However, after acquisi-tion of correct answers had become evident, theexperimenter asked the questions in randomorder to ensure that question answering wasunder the stimulus control of the relevantquestions and not other aspects of the experi-mental context. This was accomplished by theexperimenter asking the questions from all threesets (Known Set 1, Unknown Set 1, andUnknown Set 2) in random order from sessionto session, such that all 15 questions wereintermixed randomly.

Generalization probes. The purpose of thegeneralization probes was to evaluate whetherIDKPTM would generalize to questions (Un-known Sets 3 and 4) not included in theIDKPTM training sessions, across persons(research assistant and classroom teacher), andsetting (classroom). The procedures during thegeneralization probes were identical to thoseused during baseline in that the experimenterpraised correct answers, ignored incorrectanswers, provided the correct answer ifIDKTPM occurred, but delivered no prompts.Two types of generalization probes were

conducted. Research assistants conductedprobes in the training room, and each partic-ipant’s classroom teacher conducted probes intheir regular classroom. A unique set ofunknown questions was used for each type ofprobe: Unknown Set 3 in the training roomprobes and Unknown Set 4 in the classroomprobes. These sets were never targeted in anyother condition. A unique set of knownquestions (Known Set 2) also was targeted inthe training room probes, but the classroomprobes included the same set of knownquestions that had been targeted in theexperimental sessions (Known Set 1). We chosethis approach because only a limited number ofknown questions were identified for someparticipants. The questions were always askedin the same order, with known questions first,followed by unknown questions.

One or both of the authors supervised allprobe sessions and instructed the researchassistants and classroom teachers how toproceed. The instructions specified that ques-tions should be asked in sequence, incorrectresponses ignored, correct answers praised, andIDKPTM should result in the participant beinggiven the correct answer and prompted torepeat the correct answer if necessary.

Preintervention probes consisted of twotraining room probes and one classroom probe,conducted in that order. The experimenterconducted the first probe following Session 1for Chris, Session 2 for Neil, Session 3 for Matt,and Session 1 for Jim. The experimenterconducted the remaining two probes followingSession 2 for Chris, Session 5 for Neil, Session 9for Matt, and Session 12 for Jim. The experi-menter conducted postintervention probeswhen acquisition of IDKPTM had been seenwith Unknown Sets 1 and 2 and when relativestability in the levels of both IDKPTM andcorrect answers had been observed. The post-intervention probes were conducted followingSession 24 for Chris, Session 32 for Neil,Session 35 for Matt, and Session 19 for Jim.


If generalization of the IDKPTM response toUnknown Sets 3 and 4 did not occur during theprobe sessions, we implemented additionalinterventions. For Chris and Neil, a researchassistant conducted a single session of directtraining with Unknown Set 3. The proceduresduring this training were identical to theIDKPTM training described above. For Neil,the classroom teacher also conducted directtraining with Unknown Set 1 (previouslytargeted during initial IDKPTM training) aftergeneralization to the classroom failed to occurfor the second time. For Matt, the researchassistant conducted a single interspersal session,in which Unknown Set 3 trials were inter-spersed randomly with trials containing ques-tions from Unknown Sets 1 and 2 (with whichMatt had already shown acquisition ofIDKPTM).

Experimental Design

The direct and indirect effects of theIDKPTM training (and additional interven-tions) were evaluated in a nonconcurrentmultiple baseline design across participants.Generalization of the IDKPTM response acrossquestions was evaluated by including nontar-geted (Unknown Set 2) questions in theexperimental sessions. In addition, generaliza-tion across questions, people, and settings wasevaluated via pre- and postintervention gener-alization probes.

RESULTS

The results for the experimental sessions areshown in Figure 1. Only unprompted responsesare shown. Results for Chris are presented in thetop two panels. Chris answered the known, butnot the unknown, questions correctly inbaseline. There were no instances of IDKPTMin baseline. When we implemented IDKPTMtraining, evidence of acquisition of theIDKPTM response was seen quickly, both withthe target (Unknown Set 1) and the generaliza-tion (Unknown Set 2) sets. Undesirable

generalization of IDKPTM to known questionswas not evident, in that correct answers toKnown Set 1 remained stable throughout.Moreover, the data show that Chris graduallylearned the correct answers to the questions inUnknown Sets 1 and 2 during this phase. Afteran initial increase in IDKPTM, a graduallydecreasing trend of IDKPTM was seen, in thatcorrect answers increased for both question sets.Toward the end of his participation, he wasanswering at least 80% of questions from bothsets correctly across repeated sessions. Hisaccuracy remained high during the last fivesessions, which were implemented with randomquestion order.

Neil’s results are shown in the third andfourth panels of Figure 1. Like Chris, Neilanswered known questions, but not unknownquestions, correctly in baseline. There were noinstances of IDKPTM in baseline. With theinitiation of IDKPTM training, acquisition ofIDKPTM was quickly evident across both thetarget (Unknown Set 1) and the generalization(Unknown Set 2) sets. Undesirable generaliza-tion of IDKPTM to the known questions wasminimal (there were only three instances in theIDKPTM training phase). An increase incorrect answers was seen across both unknownsets after three sessions of IDKPTM training.However, the number of correct answersremained variable throughout this phase anddid not reach the stable high levels that hadbeen seen with Chris. Therefore, starting withSession 38, preferred edible items were deliv-ered contingent on correct answers while otherprocedures remained identical to the IDKPTMphase. With this intervention, Neil consistentlyanswered three to five questions from eachunknown set correctly for the remainder of theexperimental sessions. Undesirable generaliza-tion of IDKPTM to the known questionsoccurred infrequently in this phase, with a totalof five instances. This performance remainedstable while the schedule of edible delivery wasthinned from FR 1 to FR 5 and during


Figure 1. The number of correct answers and IDKPTM responses for Chris, Neil, Matt, and Jim. The dotted phaselines indicate when randomized question order began with each participant.


noncontingent edible delivery. His accuracyremained high after the order of question waschanged to random during the last 15 sessions.

Matt’s results are shown in the fifth and sixthpanels of Figure 1. In baseline, he answered allof the known questions and none of the un-known questions correctly. There were noinstances of IDKPTM in baseline. WhenIDKPTM training was implemented,IDKPTM increased for Unknown Set 1 butdid not generalize to Unknown Set 2 (with theexception of one response in Session 10). Noundesirable generalization of IDKPTM toknown questions occurred. No evidence ofacquisition of correct answers was observed inthis phase. Because of the lack of generalizationof the IDKPTM response across unknownquestions, IDKPTM training was next carriedout with Unknown Set 2, resulting in imme-diate acquisition of IDKPTM with that set ofquestions. However, correct answers did notemerge. Because no correct answers occurred,we could not implement additional reinforce-ment of correct answers as we had with Neil.Therefore, we carried out a single session ofdirect training of correct answers (Session 38)while IDKPTM training was suspended. In thesubsequent sessions, correct answers increasedacross both unknown sets. However, a decreasewas seen later without an accompanyingincrease in IDKPTM. Therefore, IDKPTMtraining was reinstated, resulting in a briefincrease in IDKPTM and an eventual recoveryof high levels of correct answers. The last 10sessions were carried out using random sessionorder. Accuracy was high during the majority ofthese sessions.

Jim’s results are shown in the bottom twopanels of Figure 1. Jim answered all knownquestions correctly in baseline, and there wereno instances of IDKPTM. Initially, Jimanswered all unknown questions incorrectly,but during the last five sessions of baseline, heanswered one question in Unknown Set 1correctly. When we implemented IDKPTM

training, Jim showed quick acquisition of thatresponse, which generalized to Unknown Set 2.There was only one instance of undesirablegeneralization of IDKPTM to the knownquestions. Acquisition of IDKPTM was quicklyfollowed by an increase in correct answers acrossboth unknown sets and a correspondingdecrease in IDKPTM. The last four sessionsincluded random question order; Jim’s accuracyremained high.

To evaluate the extent to which individualunknown questions were acquired by eachparticipant, we counted the number of ques-tions answered correctly from Known Set 1,Unknown Set 1, and Unknown Set 2 duringthe last two sessions of baseline, as well as thelast two sessions of the last intervention phasefor each participant. To be counted as correct,an individual question had to be answeredcorrectly in two consecutive sessions. All 4participants answered all five known questionscorrectly towards the end of both baseline andintervention. None of the participants answeredany unknown questions correctly in the last twosessions of baseline, except for Jim, whoanswered one question from Unknown Set 1correctly. All 4 participants answered either fouror five (out of five) questions from the twounknown sets correctly in their last two sessionsof intervention, indicating that acquisition ofcorrect answers had taken place for most of thepreviously unknown questions.

The results of the generalization probes areshown in Figure 2. Results are shown only forUnknown Set 3 (training room probe) andUnknown Set 4 (classroom probe). Known Sets1 and 2 also were included in these probesessions; however, all 4 participants answeredthe known questions 100% correctly in eachgeneralization probe session. Therefore, tosimplify the data presentation, the results forthe known questions are not presented.

Results for Chris are shown in the top panelof Figure 2. No instances of IDKPTM wereevident in the preintervention probes. Follow-


Figure 2. The percentage of correct IDKPTM responses by Chris, Neil, Matt, and Jim during the generalizationprobe session. A research assistant conducted all the probe sessions with Unknown Set 3 in the training room, and eachparticipant’s classroom teacher conducted all the probes involving Unknown Set 4 in the classroom.


ing intervention, IDKPTM initially did notgeneralize to either the training room or theclassroom probes. After the research assistantconducted direct training with Unknown Set 3in the training room, generalization ofIDKPTM to the classroom occurred (ProbeSession 8). It is important to note that althoughChris answered four of the five training roomprobe questions with IDKPTM during ProbeSession 7, this is not evidence of generalization,because direct training was carried out with thatset of questions in that setting.

Neil’s generalization probe results are shownin the second panel of Figure 2. No IDKPTMresponses occurred in preintervention probes,and generalization was not evident initially inpostintervention probes. Unlike Chris, general-ization to the classroom did not occur for Neilfollowing direct training with Unknown Set 3in the training room. As with Chris, Neil’sperformance in the training room probe (ProbeSession 6) is not evidence of generalizationbecause direct training had been conductedwith that set. Generalization to the classroomwith Unknown Set 4 did occur after theclassroom teacher conducted direct trainingwith the target set previously targeted in thetraining room (Unknown Set 1).

Matt’s generalization probe results are shownin the third panel of Figure 2. No instances ofIDKPTM were seen in the preinterventionprobes. Similar to Chris and Neil, generaliza-tion of the IDKPTM response to the trainingroom probes was not seen with Matt (ProbeSession 4). However, generalization ofIDKPTM was seen in the classroom probe(Probe Session 5). Because of these unexpectedresults, two additional training room probeswere conducted, but no generalization wasfound. Because he had shown generalizationto the classroom already, we attempted toproduce generalization in the training roomprobes without the kind of direct training thatwe had conducted with Chris and Neil. Theresearch assistant therefore conducted training

with Unknown Sets 1 and 2 (previously onlytargeted by the first author in experimentalsessions). However, in the subsequent trainingroom probe, generalization did not occur withUnknown Set 3 (Probe Session 8). The researchassistant then conducted two interspersal probesessions in which Unknown Set 1 and 2questions were interspersed randomly withUnknown Set 3 questions (Unknown Set 3was never trained directly). Generalizationoccurred under these conditions (Probe Sessions9 and 10). In these interspersal sessions, theresearch assistant delivered a total of oneIDKPTM prompt (with the first question inUnknown Set 1).

Jim’s generalization probe results are shownin the fourth panel of Figure 2. No instances ofIDKPTM were seen in the preinterventionprobes. Jim was the only participant whoshowed generalization of the IDKPTM re-sponse in both the training room and classroomgeneralization probes immediately followingIDKPTM training. He answered three of thefive questions in each set with IDKPTM. Inboth the training room and the classroom probesessions, he gave the correct answer to one ofthe unknown questions.

DISCUSSION

Four boys with autism were taught to mandfor answers to questions by saying IDKPTM.For 2 participants (Chris and Jim), thisintervention led to quick acquisition andgeneralization (across questions) of theIDKPTM response, as well as acquisition ofcorrect answers to previously unknown ques-tions. For Neil, acquisition and questiongeneralization of IDKPTM occurred, butcorrect answers did not increase to acceptablelevels until edible items were made contingenton their occurrence. For Matt, IDKPTMacquisition occurred, but the response did notgeneralize to untargeted questions. Matt’scorrect answers did not increase until after briefdirect training of correct answers.


These findings provide a replication andextension of the Ingvarsson et al. (2007) study,in which preschool children with and withoutdisabilities were first taught ‘‘I don’t know’’(IDK) and later IDKPTM in response to asubset of unknown questions. In both studies,IDKPTM was acquired readily as a result ofintraverbal training. In both studies, IDKPTMgeneralized to untargeted unknown questionsfor most or all participants. The current studyextends previous research on manding forinformation (e.g., Sundberg et al., 2002; Taylor& Harris, 1995), in which children with autismwere taught to ask questions when presentedwith unknown stimuli or unknown locations ofpreferred objects. In these studies, the childrenacquired either new tacts (Taylor & Harris) ormands that allowed the children to bettercontrol their access to reinforcers (Sundberg etal.). In the current study, intraverbal trainingwas used to establish mands for informationthat led to the acquisition of new intraverbals(answers to questions). The current study alsodemonstrates that IDKPTM training can beapplied with children with autism.

An important aspect of IDKPTM training isthat stimulus control by each question over itsrelevant answer is likely to develop, whereaswith IDK training (as in Ingvarsson et al.,2007), other aspects of the training context arerelatively more likely to gain stimulus controlover the IDK response. Because in the currentstudy IDKPTM training was implementedimmediately following baseline, the probabilityof the development of this appropriate stimuluscontrol was likely increased. In the earlier study,IDK training followed baseline and may haveled to undesirable stimulus control of thebroader training context over IDK responding,resulting in undesirable generalization of theIDK response to known questions. WhenIDKPTM training replaced IDK training, thisundesirable stimulus control may have partiallytransferred such that it now controlledIDKPTM responding, preventing the acquisi-

tion of correct answers. Thus, the fact that IDKtraining was not conducted in the current studymay in part explain why there was increasedprobability of acquisition of correct answersfollowing IDKPTM training and less undesir-able generalization to known questions, com-pared to the earlier study.

In the current study, acquisition of correctanswers following IDKPTM training may havebeen facilitated by relatively fast-paced blockedtraining trials. By contrast, Ingvarsson et al.(2007) presented only two questions per minuteand interspersed training trials with trials thatcontained either known questions or unknownquestions (i.e., the generalization sets). There issome evidence that interspersal of training trialswith unknown tasks may slow acquisition(Rowan & Pear, 1985). Conversely, interspersalof multiple training items may produce greatergeneralization when compared with serialtraining in which the same item (or set ofitems) is targeted repeatedly (e.g., Panyan &Hall, 1978). Future research should explore theeffects of blocked versus interspersed trials andlonger versus shorter intertrial intervals on theacquisition of intraverbal behavior.

There are several aspects of the IDKPTMprocedure that may have influenced the shift inresponse allocation to correct answers followingIDKPTM acquisition. The training procedureincluded potential sources of negative reinforce-ment, a differential delay to reinforcement,potential increases in reinforcement density,and differences in response effort followingdifferent responses. First, negative reinforce-ment may have been in place because byengaging in the correct answer, the participantscould avoid the IDKPTM teaching procedureand avoid a prolonged session. This negativereinforcement contingency may have beenoperating if exposure to the IDKPTM trainingwas relatively nonpreferred. Second, IDKPTMtraining involved a relatively long delay to praiseif the participants engaged in either an incorrectanswer or the IDKPTM response (due to the


requirement to engage in the correct answer orprompting of the IDKPTM response). Engag-ing in the correct answer, however, led to arelatively shorter delay to praise. This aspect ofthe IDKPTM training arrangement may haveled to response allocation shifting fromIDKPTM to the correct answers after acquisi-tion of correct answers had occurred (Chung &Herrnstein, 1967; Hursh & Fantino, 1973).Third, as a result of the shorter delay, engagingin correct answers may have resulted in a higherdensity of reinforcement (i.e., more reinforce-ment delivered per unit of time) compared withengaging in the IDKPTM response or anincorrect answer. This may have increased thelikelihood of response allocation shifting tocorrect answers. Fourth, it may be argued thatduring IDKPTM training, engagement in theIDKPTM response or an incorrect answer ledto relatively greater response effort (again,because of the prompting of the IDKPTMresponse and the requirement to say the correctanswer). The correct answer resulted in arelatively lower response effort because it didnot lead to additional instruction with the samequestion but rather to the delivery of praise andthe presentation of the next trial (cf. Neef &Lutz, 2001). Future research should evaluate theextent to which each of these variables contrib-utes to the effectiveness of intraverbal trainingprocedures. For instance, it is possible that theimplementation of additional training trialsduring each instance of IDKPTM training(effectively increasing the response effort anddelay to reinforcement associated with engage-ment in IDKPTM and incorrect answers) mightfurther increase the likelihood of responseallocation shifting to correct answers followingtheir acquisition.

The suggestion that the IDKPTM responsemay have functioned as a mand for informationpoints to additional behavioral processes ofpotential interest. One interpretation is thatmanding for information is evoked by atransitive conditioned establishing operation

(CEO; see Michael, 2000). In this case, thepresentation of an unknown question mightserve as a transitive CEO, establishing the valueof the information (i.e., being told the correctanswer) as a reinforcer. In this interpretation,the information (i.e., the correct answer, asspoken by the experimenter) functions as aconditioned reinforcer, retaining its reinforcingeffect through an association with the terminalreinforcer (e.g., praise) that maintains thecorrect answer. Deprivation from the reinforcerthat maintains the correct answer (e.g., atten-tion) should serve to increase the reinforcerestablishing and evocative effects of the transi-tive CEO (Laraway, Snycerski, Michael, &Poling, 2003). However, the answer spoken bythe experimenter should not be an effectivereinforcer if the participant already knew theanswer to the question; thus, the IDKPTMresponse would not be evoked under thoseconditions. The results of the current study arebroadly consistent with this interpretationbecause the IDKPTM response generalized tounknown questions but not to known ques-tions. Future research should attempt to furtherelucidate the function of the IDMPTMresponse (and other similar information-seekingresponses) by systematically evaluating thevariables that establish information as a rein-forcer and the extent to which information(e.g., being told the correct answer) may be saidto derive its reinforcing value by associationwith other reinforcers.

The current study included setting general-ization probes that were conducted in theparticipants’ regular classroom. In addition,person generalization was assessed across twopeople, a research assistant and the participant’sregular classroom teacher. The results of theseprobes varied across participants. The Ingvars-son et al. (2007) study included no settinggeneralization conditions, but person general-ization sessions alternated frequently with theIDKPTM training condition within the samesetting. This arrangement led to reliable


generalization of the IDKPTM response acrossuntargeted question sets and across people. Theless reliable person generalization in the currentstudy was perhaps a function of generalizationprobes not being conducted until severalsessions after the first instances of the IDKPTMresponse for each participant, whereas in theprevious study, opportunities for generalizationoccurred early and often.

Two aspects of Matt’s data merit discussion.First, unlike the other participants, generaliza-tion of the IDKPTM response was not seenacross questions or to the research assistant.However, the IDKPTM response generalized tohis regular classroom teacher. Although thereason for this idiosyncratic pattern is un-known, it is possible that a history of learningmultiple exemplars from that particular teacherplayed a role. Perhaps if Matt were providedwith a history of learning of multiple exemplarsacross many teachers and a variety of environ-ments, skills might generalize more easilybecause such a history might reduce thelikelihood of the development of restricted orirrelevant stimulus control over question an-swering (Baer, Peterson, & Sherman, 1967).Future research should examine the effects ofproviding such a history with children whoshow limited generalization. It also becameapparent that when questions that had receivedIDKPTM training previously were interspersedwith untargeted questions, IDKPTM respond-ing emerged with the untargeted questions. It ispossible that interspersal of previously learnedand novel items might increase the likelihood ofgeneralization with Matt, and question gener-alization might have occurred earlier if suchinterspersal had been conducted during histraining phase. More research is needed onprerequisite skills or histories of reinforcementthat produce reliable generalization.

Second, Matt did not show acquisition ofcorrect answers until correct answers weredirectly prompted during one session. In thatsession, the experimenter directly prompted

only three answers, yet many more emergedimmediately afterwards. It appears that Matt’sbehavior of saying the correct answer withoutthe preceding IDKPTM procedure simply hadto contact praise for previously learned correctanswers to emerge. Anecdotally, it appeared thatMatt often said the correct answers to thequestions after engaging in the IDKPTMresponse, without necessarily waiting for theexperimenter’s prompt to say the correctanswer. However, our measurement systemwas not sensitive enough to capture thisbehavior because we scored only the firstresponse that occurred after each question(i.e., IDKPTM and the correct answer weremutually exclusive and could not both be scoredin the same trial). This suggests that Matt hadlearned some correct answers previous to thedirect prompting condition, but this learninghad not been expressed in measured perfor-mance.

It is noteworthy that Neil’s correct answersdid not increase to acceptable levels until edibleitems were included. Future research shouldinvestigate procedures that lead to the estab-lishment of naturally occurring aspects of theteaching situations (e.g., praise, smiles, nods ofteachers) as effective reinforcers. The establish-ment of such stimuli as reinforcers is crucial forchildren to learn effectively from their socialenvironments and may be essential for theestablishment of important social skills inchildren with autism (Holth, 2005/2007).

Although directly teaching children theanswers to questions (e.g., ‘‘What is yourname?’’) is undoubtedly valuable, the currentintervention has the advantage of targeting ageneral skill that may lead to learning a varietyof new answers to questions across a number ofenvironments. Future research should evaluateprocedures that enable children with autism andother developmental disabilities to seek outlearning opportunities and recruit promptingand instruction from adults and peers in theireveryday environments.


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Received December 5, 2008Final acceptance June 22, 2009Action Editor, Rachel Thompson


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ACQUISITION OF INTRAVERBAL BEHAVIOR: TEACHING … · tion probes in their classrooms. Fourth, in the previous study, teaching was implemented in the context of toy play, two trials