assesment

213

JOURNAL OF APPLIED BEHAVIOR ANALYSIS 2002, 35, 213-231 NUMBER 3 (FALL 2002)

USING THE PICTURE EXCHANGE COMMUNICATIONSYSTEM (PECS) WITH CHILDREN WITH AUTISM:

ASSESSMENT OF PECS ACQUISITION, SPEECH,SOCIAL-COMMUNICATIVE BEHAVIOR, AND PROBLEM BEHAVIOR

MARJORIE H. CHARLOP-CHRISTYCLAREMONT MCKENNA COLLEGE

MICHAEL CARPENTER AND LOC LECLAREMONT GRADUATE UNIVERSITY

AND

LINDA A. LEBLANC AND KRISTEN KELLETCLAREMONT MCKENNA COLLEGE

The picture exchange communication system (PECS) is an augmentative communicationsystem frequently used with children with autism (Bondy & Frost, 1994; Siegel, 2000;Yamall, 2000). Despite its common clinical use, no well-controlled empirical investiga-tions have been conducted to test the effectiveness of PECS. Using a multiple baselinedesign, the present study examined the acquisition of PECS with 3 children with autism.In addition, the study examined the effects of PECS training on the emergence of speechin play and academic settings. Ancillary measures of social-communicative behaviors andproblem behaviors were recorded. Results indicated that all 3 children met the learningcriterion for PECS and showed concomitant increases in verbal speech. Ancillary gainswere associated with increases in social-communicative behaviors and decreases in prob-lem behaviors. The results are discussed in terms of the provision of empirical supportfor PECS as well as the concomitant positive side effects of its use.

DESCRIPTORS: autism, communication, PECS

One hallmark feature of children with au-tism is deviant or delayed speech and lan-guage skills (Charlop & Haymes, 1994). Be-havioral interventions such as discrete-trialprocedures (Lovaas, 1987), incidental teach-ing (Hart & Risley, 1980), delay procedures(Charlop, Schreibman, & Thibodeau, 1985;Halle, Marshall, & Spradlin, 1979), and piv-otal response training (Koegel, Koegel, &Schreibman, 1991) have been used to in-crease speech, but more than 50% of chil-

We thank the staff of the Claremont Autism Centerfor assistance with data collection and Andy Bondyfor helpful comments on the study.

Address correspondence to Linda A. LeBlanc, whois now at the Department of Psychology, WesternMichigan University, 1903 W. Michigan Ave., Kala-mazoo, Michigan 49008-5052 (e-mail: [email protected]).

dren with autism still remain mute (Charlop& Haymes, 1994). Other interventions havebeen developed to focus on alternative com-munication strategies for children who donot develop speech. These programs involvenonvocal methods of communication (Mus-tonen, Locke, Reichle, Solbrack, & Lind-gren, 1991) and include sign language, pic-ture-point systems, electronic devices, andother picture-communication systems (Carr& Kologinsky, 1983; Mirenda & Schuler,1988; Reichle & Sigafoos, 1991).

The picture exchange communication sys-tem (PECS) is a pictorial system that wasdeveloped for children with social-commu-nication deficits (Frost & Bondy, 1994). Thesystem uses basic behavioral principles andtechniques such as shaping, differential re-

214 MARJORIE H. CHARLOP-CHRISTY et al.

inforcement, and transfer of stimulus controlvia delay to teach children functional com-munication using pictures (black-and-whiteor color drawings) as the communicative ref-erent. The pictures are kept by the child ona notebook (PECS board) with Velcrot. Thechild is taught to use his or her PECS boardand create a sentence by selecting picturecards (e.g., I want card plus juice card)and delivering the cards to a communicativepartner as a request for a desired item. PECSemphasizes teaching a child to initiate re-quests (for seen and unseen items), respondto questions (e.g., What do you want?),and make social comments (e.g., I see [ob-ject]).

The PECS system has gained widespreaduse nationally and internationally with chil-dren with autism and is appealing for severalreasons (Siegel, 2000; Yamall, 2000). First,the system requires few complex motormovements on the part of the speaker anddoes not require the listener to be familiarwith an additional language such as sign lan-guage (Bondy & Frost, 1994). Second, thePECS system has a relatively low cost and isportable and suitable for use in many set-tings. Third, case reports indicate that thesystem can be taught relatively rapidly. Bon-dy and Frost (1993) described the proce-dures used to train school-based staff in Peruto use the system over a 5-day period. Al-though no formal data were collected, theschool reported that over a 3-month period,approximately 74 children began the PECStraining procedures and many children hadprogressed to the second training phase. Fi-nally, the PECS system incorporates func-tional communicative responses that pro-mote meaningful interactions between thechild and the environment (Frost & Bondy,1994). The PECS system is unique amongalternative communication systems in that itrequires the child to approach a listener andinitiate interaction prior to emitting a ref-

erential communicative act (Bondy, 2001;Frost & Bondy, 1998).

Several informational reports have sug-gested that a large number of children wholearn PECS also develop spoken language.Bondy and Frost (1994) indicated positiveoutcomes for 85 children who were taughtto use PECS. Schwartz, Garfinkle, andBauer (1998) reported that children whoinitially had a limited spontaneous vocal rep-ertoire continued to have increased sponta-neous language following PECS training,whereas children with no initial spontaneousvocalizations did not make gains (Bondy &Frost, 1994). Other positive effects havebeen suggested with the use of PECS. An-ecdotal reports have indicated that the useof PECS may result in a decrease in problembehavior and improved social behavior(Bondy & Frost, 1994; Peterson, Bondy,Vincent, & Finnegan, 1995). However, it isimportant to note that none of these reportsincluded an experimental research design toeliminate potential confounding factors suchas maturation effects.

Perhaps because of these potential advan-tages and the pragmatic features, PECS hasbeen adopted in the autism treatment com-munity. However, the widespread use ofPECS has preceded the empirically con-trolled investigations needed to support it(Charlop-Christy, 2000; Yamall, 2000).Since the publication of the PECS trainingmanual in 1994, no controlled studies dem-onstrating the efficacy of the PECS proce-dure have been published. Instead, supportfor PECS has come in the form of anecdotalreports (Bondy & Frost, 1993), programevaluation data (Bondy & Frost, 1993,1995; Schwartz et al., 1998), and A-B de-sign case studies (Peterson et al., 1995).

Thus, the purpose of the present studywas to empirically assess the utility of PECSwith children with autism using a single-subject design. First, the efficacy of thePECS program was assessed in terms of the

215EFFECTS OF PECS

amount of training needed for mastery ofPECS skills by children with autism. Sec-ond, the collateral effects of PECS trainingon several behaviors were assessed to provideempirical evaluation of ancillary gains thathave been anecdotally reported followingPECS training. The primary dependentmeasures were spoken language in the formof spontaneous and imitative speech (Char-lop et al., 1985; Charlop & Trasowech,1991; Charlop & Walsh, 1986; Hart & Ris-ley, 1968; Ingenmay & Van Houten, 1991;Matson, Sevin, Box, & Francis, 1993; Mat-son, Sevin, Fridley, & Love, 1990). Collat-eral effects on social-communicative behav-ior and problem behavior were also assessed.

METHOD

ParticipantsThree boys with autism participated in

this study during biweekly sessions at an af-terschool behavioral treatment program.Each participant had been diagnosed withautism by two independent agencies. Allchildren had an extensive history of verbalspeech training that had been ineffective inteaching the children to communicate.These children were chosen for the study be-cause they were the first 3 children in theprogram after the initiation of the study thatdid not speak or rarely spoke and neededlanguage programming. Alex was a 12-year-old Ethiopian-American boy with an expres-sive language age-equivalent score of 1 year2 months on the Minnesota Child Devel-opmental Inventory (deAyora & White,1987). His receptive vocabulary age-equiva-lent was 1 year 9 months on the PeabodyPicture Vocabulary Test (PPVT; Dunn &Dunn, 1981). He had very little spontane-ous speech. The term spontaneous speech wasused in the present study to refer to speechthat occurred without a vocal prompt or vo-cal stimulus, regardless of the presence of vi-sual prompts (Charlop & Haymes, 1994;

Charlop & Trasowech, 1991; Hart & Risley,1968; Ingenmay & Van Houten, 1991;Matson et al., 1990, 1993). Alex also imi-tated three-word phrases upon request butrelied on gestures (e.g., pointing, leadingpeople, shaking head, etc.) as a primarymeans of communication. He typically didnot make eye contact, initiate interactionswith others, or engage in unprompted play.He did not exhibit problem behavior duringthe observations conducted in this study.

Jake was a 3-year 8-month old Chinese-American boy. The Vineland Adaptive Be-havior Scales reflected an overall functioningability in the 10-month to 18-month range(11 months for socialization domain, 10months for communication domain) (Spar-row, Ball, & Cicchetti, 1984). He displayedno spontaneous speech, but made consistentattempts to imitate sounds and primarilyused gestures (e.g., pointing, pulling a per-son towards an object) to indicate his de-sires. He exhibited very limited appropriateplay skills and typically used toys as self-stimulatory objects. Jake exhibited severaltopographies of problem behavior includingtantrums, grabbing objects from other peo-ple, leaving his seat during work, and dis-ruptive behaviors (e.g., throwing or kickingobjects). Problem behavior typically oc-curred when desired items were unavailableand when nonpreferred tasks were presented.

Kyle was a 5-year 9-month old Korean-American boy. He had a receptive vocabu-lary of less than 1 year 9 months on thePPVT and no spontaneous speech. He typ-ically attempted communication by leadingadults by the hand, pointing at preferred ob-jects, and pushing away nonpreferred ob-jects. No other clear gestural communicationattempts were evident. He attempted to im-itate sounds and only occasionally made un-prompted requests for food items. He hadpoor eye contact and rarely displayed appro-priate independent play. He also displayedseveral topographies of problem behavior in-


cluding tantrums, grabbing objects fromothers, leaving his seat during work, and dis-ruptive behavior (throwing and banging ob-jects). Problem behavior typically occurredwhen he was unable to obtain a desired itemor when nonpreferred tasks were presented.

Settings

PECS training. PECS training trials wereconducted in several settings as the programprogressed. Initial training trials were con-ducted in a room (2.1 m by 2.1 m) with aone-way observation mirror. The room con-tained a table and two chairs positioned fac-ing each other. Individually identified pre-ferred items were displayed in clear plasticcontainers or on a table, but they remainedout of the childs reach until training trialswere conducted. All sessions were videotapedthrough the one-way mirror. Later trainingsessions were conducted in empty classroomsat the university immediately adjacent to theclinic, at the childs classroom at school, andat the childs home. These additional loca-tions were selected because they were moresimilar to the settings in which the childwould eventually use PECS (e.g., home,school) than the initial training setting. Theywere incorporated to promote generalizationof PECS use in everyday life; however, gen-eralized PECS use in these settings was notevaluated in the current investigation. Theadditional settings allowed increased dis-tance between the child, the therapist, andthe location of the PECS materials, as sug-gested in the PECS training manual.

Free-play sessions. Free-play sessions oc-curred approximately once per week for eachweek prior to, during, and following com-pletion of PECS training. All free-play ses-sions were conducted in a room (2.4 m by4.5 m) with a one-way observation mirror.The room contained a variety of age-appro-priate toys such as toy cars and trucks, build-ing blocks, stuffed animals, basketball andhoop, electronic toys, a small table and four

chairs, and pretend kitchen equipment. Thechild moved freely around the room withany available item. The room contained amounted stationary video system that wasused for taping all sessions.

Academic sessions. All academic sessionsoccurred approximately once per week foreach week prior to, during, and followingcompletion of PECS training. Sessions wereconducted in a room (2.1 m by 2.1 m) witha one-way observation mirror. The roomcontained a table, two chairs positioned fac-ing each other, and toys and academic tasksdisplayed in clear plastic containers that re-mained out of the childs reach until workwas initiated. Although the physical sur-roundings for this setting were similar to thePECS training setting, there were several no-table differences. No PECS training materi-als were used during these academic tasks inorder to assess any ancillary gains associatedwith PECS. Instead, other training materialswere present (e.g., flash cards, coloredblocks), and the tasks presented were tradi-tional preacademic and academic tasks (e.g.,prepositions, color identification, receptivelabeling, handwriting). All sessions were vid-eotaped through the one-way mirror.

PECS Materials

A three-ring binder (15 cm by 23 cm) wasused as a communication board to teachPECS. The binder contained several stripsof Velcrot (sentence strips), an I wantcard, an I see card, yes and no cards,and black-and-white pictures (2.5 cm by 2.5cm) of preferred items. These cards were ei-ther taken from The Picture CommunicationSymbols Combination Book (Mayer-JohnsonCompany, 1994) or constructed from pic-tures of desired food items as recommendedby Frost and Bondy (1994). The sentencestrip was a piece of strengthened paper withVelcrot on the bottom and top. The stripwas attached to the PECS book on the lowerright corner, and picture cards could be at-

217EFFECTS OF PECS

tached to the top layer of the strip to createsentences. For initial training trials, the pic-ture cards were 5 cm by 5 cm. Later, thepicture cards were reduced to 2.5 cm by 2.5cm. Although the participants were not se-lected because of two-dimensional discrimi-nation skills, each child demonstrated theseskills in ongoing curricular assessments.

Design

A multiple baseline design across partici-pants was used to evaluate the collateral ef-fects of PECS training on multiple depen-dent measures in the domains of speech, so-cial-communicative behavior, and problembehavior in free-play and academic settings.One session was conducted for each of thetwo settings each week in random order. Ini-tiation of the PECS training phase was basedon the stability and trend in vocalizations inboth the play and the academic settings. Fol-low-up sessions were conducted at 10months after the last regular session on 3consecutive weeks for 1 child (Alex).

Procedure

All procedures during the play and aca-demic sessions remained constant across allphases. During each play or academic ses-sion, the therapist provided five spontaneousspeech opportunities and five verbal imita-tion opportunities. These opportunities oc-curred at the beginning of each minute, al-ternating between a spontaneous speech trialand an imitative speech trial similar to theprocedures used by Charlop et al. (1985).For spontaneous speech opportunities, thetherapist held up a desired object and waited10 s for the child to make a vocalization. Novocal prompts or models were used. An ap-propriate vocalization resulted in access tothe object, and no vocalizations resulted incontinuation of other play or continuationof academic demands with no access to theobject. For the verbal imitation opportuni-ties, the therapist held up a desired object

and modeled a word or phrase related to theobject (e.g., spin, bounce the ball). Im-itation resulted in access to the object, andno vocalization resulted in no response bythe therapist. Therapists used typical clinicprocedures for dealing with problem behav-ior (i.e., planned ignoring, a contingentno, and differential reinforcement of otherbehavior), and these procedures remainedconstant through all phases.

In the free-play setting, 10-min interac-tions between the child and a therapist werevideotaped once per week. The therapist wasinstructed to play and speak with the childthroughout each session (e.g., playing ball,drawing, building with wooden blocks, orverbally encouraging appropriate toy play).The child was able to move freely aroundthe room, sit or lie on the floor, and playwith any available toy. The therapist also in-teracted with items and remained immedi-ately responsive to any child initiations.

Ten-minute academic sessions were alsoconducted once per week. During these ses-sions, the child was asked to perform tasksincluded in his regular curriculum at the af-terschool program. The child was requiredto remain seated directly across from thetherapist, who presented tasks tailored toeach childs skill level (e.g., following simplecommands, receptive labeling, handwriting,and prepositions).

Stimulus preference assessment. In prepara-tion for PECS training, a preference assess-ment was conducted to identify the mostpreferred items for use during PECS, train-ing as indicated in the PECS proceduresmanual (Bondy & Frost, 1994). The firststep of this assessment was carried out byobserving the child in a play area and byasking parents and therapists what the childpreferred. Next, the therapist sat in a chairfacing the participant with a flat board onhis or her lap and conducted a multiple-stimulus-without-replacement assessment(DeLeon & Iwata, 1996; DeLeon, Iwata, &


Roscoe, 1997). The therapist presented anarray of items identified in the first step onthe board and allowed the child to select oneand briefly interact with the item. The itemswere typically food items and toys. Theseitems were not usually available in the playsetting or the academic setting.

This procedure was repeated until threeto five highly preferred items were identified.An item was considered preferred when thechild reliably reached for it within 5 s, andan item was highly preferred if it was select-ed more than three times. Once an item wasidentified as highly preferred, it was removedfrom the array and replaced with anotheritem. Repeated brief assessments were con-ducted each day to determine which pre-ferred items would be included in the childsPECS training trials. During these assess-ments, a three- to five-item array of the pre-ferred items was presented and the child wasinstructed to pick one. This brief procedurewas repeated again in a training session ifthe childs interest in the initially selecteditem appeared to wane.

PECS training. The children were taughtPECS during 15-min training sessions twiceper week. Weekly play and academic probescontinued during PECS training, but alltraining trials were conducted in separatesessions in which the primary dependentmeasures were trials and training time re-quired to reach criterion. PECS was taughtusing the prompting and differential rein-forcement procedures described by Frost andBondy (1994). This protocol involves sixtraining phases: (a) physical exchange, (b)expanding spontaneity, (c) picture discrimi-nation, (d) sentence structure, (e) What doyou want? and (f ) commenting. The firststeps involve mand training (e.g., Skinner,1957) and include strategies that promotegeneralization of skills to new settings (e.g.,Stokes & Baer, 1977). The child learns todeliver a picture to an adult, who subse-quently provides the object and states the

name of the object. Later phases incorporatestrategies such as a delay (Charlop et al.,1985) between picture delivery by the childand vocal models and reinforcement by theadult to promote vocal communication. Thefinal phase incorporates a form of impuretact training in which the child is taught todescribe an object in his or her environment.A description of the six phases of PECS ispresented in Table 1. For a more detaileddescription of the PECS training procedure,see Frost and Bondy (1994). The criterionfor successful completion of each phase was80% unprompted successful trials in a 10-trial block.

Posttraining. Several sessions were con-ducted in the weeks immediately followingcompletion of the PECS training protocol.The PECS book was available during allother nonresearch clinic activities at our clin-ic and at the childs home from this pointforward.

Long-term follow-up. One participant wasavailable for long-term follow-up. Approxi-mately 10 months after the study, the playand academic setting observations were re-peated once per week for 3 consecutiveweeks.

Dependent Measures and Data Collection

Two dependent measures were collectedin the PECS training setting. A frequencycount was made of the number of trials tocriterion for each phase (80% of trials withcorrect unprompted responding). In addi-tion, the total number of minutes until cri-terion was met was recorded for each phase.

Several dependent measures were collect-ed during the play and academic sessions bycoding videotapes using a cassette recorderand tape marking 10-s intervals. Commu-nication in the form of responses during thespontaneous and imitative speech opportu-nities served as the primary dependent mea-sure, but data were also collected on othersocial-communication and problem behav-

219EFFECTS OF PECS

Table 1Description of Each Phase of PECS Training According to Guidelines Set by Frost and Bondy (1994)

Phase Title Content

1 Physical exchange The child is taught to hand a blank picture card to acommunicative partner.

2 Expanding spontaneity The child is taught to go to his PECS board, get a pic-ture card, seek out a communicative partner, andplace the card in his or her hand to receive a rein-forcer (mand training). The distance between thechild, the board, and the listener (adult) is graduallyincreased and the response is trained in new settings.

3 Picture discrimination The child is taught to discriminate among multiple pic-tures on the PECS board.

4 Sentence structure The child seeks out their PECS board, creates a sen-tence on the sentence strip by combining the Iwant card and the card of a desired item, seeks out acommunicative partner, and gives him or her the sen-tence strip. The listener reads the strip back to thechild, inserting a fixed delay between the words Iwant and the item label. Additional social praise isadded if the child independently provides the labelduring the delay.

5 What do you want? The child is taught to respond to the question, Whatdo you want?

6 Commenting The child is taught to respond to the question, Whatdo you see? by selecting a card depicting the sameobject and combining it with an I see card to ob-tain an unrelated reinforcer (impure tact training ormatching to sample).

Note. The criterion was 80% correct (based on 10 trial blocks) for each of the six PECS phases.

iors. See Table 2 for complete operationaldefinitions and examples for each behavior.

In the play and academic demand set-tings, each speech trial was scored as corrector incorrect, and data are presented as per-centage of trials with correct responding.Spontaneous speech was scored only duringspontaneous speech trials (e.g., the therapistheld up a desired object and waited 10 s fora vocalization). A trial was scored as correctif the child responded with a related verbal-ization (e.g., saying ball or throw uponseeing a ball). Verbal imitation was scoredonly during the verbal imitation opportuni-ties (e.g., the therapist held up a desired ob-ject and simultaneously modeled a word orphrase related to the object (e.g., spin,bounce the ball). A trial was scored as cor-rect if the child responded with a related ver-

balization (e.g., bah or ball as imitationfor ball). Responses were coded as incor-rect if the child responded with an unrelatedverbalization (e.g., shoe as imitation forball or when seeing the ball), no vocali-zation, or an unintelligible vocalization. Thepercentage of trials with correct respondingwas computed for each type of speech bydividing the number of trials scored correctby the total number of speech trials (five)and multiplying by 100%.

The mean length of utterance (MLU) wasscored for each instance of spontaneousspeech that occurred at a spontaneousspeech opportunity. Although other sponta-neous speech may have occurred throughoutthe session, these vocalizations are not in-cluded in the data presented. Mean lengthof utterance was defined as the total number


Table 2Dependent Measures and Operational Definitions for Collateral Behaviors Observed in the Academic and

Play Settings

Category Behavior Setting Measure Operational definition

Social-communicative Cooperative play Free play Percentage ofintervals

Child engaged in the same activity(e.g., basketball, puzzles, boardgames) with the therapist for atleast 10 s.

Joint attention Free play Percentage ofintervals

(a) Observing same object for 5 s.(b) Referential look between thera-

pist and an object.(c) Established common attention

focus with therapist.Requesting Free play Frequency Labeling object while pointing or

reaching for it, handing the ther-apist PECS cards, verbal requests.

Initiation Free play Frequency Independent approach to therapistwith vocal or nonvocal attemptto engage in conversation or play(e.g., pulling on therapists shirtto get attention, play, handingtherapist a toy).

Eye contact Free play Percentage ofintervals

Child looked into therapists eyesfor 2 s.

Problem Tantrums Both Percentage ofintervals

Crying, yelling, or whining.

Grabbing Academic Frequency Attempting to take object fromtherapists hands before it is of-fered or to take object from con-tainer.

Out of seat Academic Percentage ofintervals

Leaving the chair during ongoingtask presentation.

Disruptions Both Frequency Throwing or banging objects, des-troying objects, kicking or hittingan object, wall, floor, or person,knocking objects off a table.

of spontaneous intelligible phonemes (Leo-nard, Miller, & Brown, 1980) made duringthe spontaneous speech trials for a sessiondivided by the total number of trials inwhich a child made a spontaneous request.

Several other social-communicative be-haviors were scored in the free-play sessionsonly: cooperative play, joint attention, re-questing, initiation, and eye contact. Someof these behaviors are communication aswell as social behavior (e.g., initiation, re-questing) but are not captured by our spon-taneous and imitative speech data becausethey did not occur in spoken form. Problembehaviors were scored for the 2 participants

who exhibited problem behavior. The fourproblem behaviors scored for Jake and Kylewere tantrums, grabbing, out of seat, anddisruptions. Grabbing and being out of seatwere scored in the academic setting only.Disruptions and tantrums were scored inboth settings.

Interobserver Agreement

One of several trained observers scored asubset of the sessions independently. Duringobserver training, observers were providedwith operational definitions of the target be-haviors to be scored and examples of eachbehavior. The criterion for completion of

221EFFECTS OF PECS

training was 80% agreement with a criteriontape scored by a primary observer. The op-erational definitions remained availablethroughout subsequent coding. Interobserv-er agreement was calculated by dividing thetotal number of agreements between the rat-ers by the total number of agreements plusdisagreements, and then multiplying by100%.

A second observer scored the PECS train-ing sessions, and the average interobserveragreement for Alex was 92% for total sessiontime and 96% for number of trials. The av-erage interobserver agreement for Jake was99% for total session time and 92% fornumber of trials. The average interobserveragreement for Kyle was 99% for total sessiontime and 97% for number of trials.

Observers scored each speech response bynoting the type of trial (spontaneous or im-itation) and whether the trial was correct orincorrect. Observers also coded each re-sponse by counting the number of utteranc-es emitted. A second observer independentlyscored 39% of sessions for speech, and theaverage interobserver agreement across allspeech behaviors was 98% for Alex, 95% forJake, and 94% for Kyle.

Other behaviors were scored as eitherpercentage of 10-s intervals with occurrenceof the target behavior or frequency. The de-pendent measure for each ancillary behavioris included in Table 2. A second observerindependently scored 43%, 39%, and 35%of sessions for social-communicative behav-iors, and the combined interobserver agree-ment was 84%, 90%, and 84% for Alex,Jake, and Kyle, respectively. A second ob-server scored 25% of sessions for problembehaviors, and the average interobserveragreement across all problem behaviors was93% and 95% for Jake and Kyle, respec-tively. A breakdown of interobserver agree-ment for each specific target behavior isavailable from the authors.

RESULTS

Acquisition of PECS

All 3 children met criterion (80% correctfor each phase) for each PECS phase andacquired PECS skills during an average of170 min (range, 165 to 176) and an averageof 246 total trials (range, 224 to 276). Dif-ferent phases were associated with differentnumbers of trials to criterion, but progresswas generally more rapid during Phases 3and 5 (range, 4 to 8 min; range, 8 to 16trials), and Phases 2 and 4 generally tookmore time and trials (range, 31 to 89 min;range, 45 to 108 trials).

Speech

Spontaneous speech and imitation. Thedata for the academic sessions are shown inFigure 1. Alexs spontaneous speech in-creased from an average of 28% of trials dur-ing pretraining to 100% of trials duringposttraining. Imitation occurred during 76%of trials during pretraining and 90% of trialsduring posttraining. Alex also met criterionduring 1-year follow-up probes, displayingspontaneous speech on an average of 93%of the trials and imitation on 100% of thetrials. Jake did not display any imitation orspontaneous speech during pretraining dur-ing academic sessions but he displayed spon-taneous speech on 83% of trials and imita-tion on 80% of trials during posttraining.Kyle rarely displayed spontaneous speech (M5 2%) or imitation (M 5 4%) during pre-training academic sessions. After PECStraining, he displayed spontaneous speechon an average of 68% of the trials and im-itation on 72% of the trials.

Data for the free-play sessions for Alex,Jake, and Kyle are shown in Figure 2. Alexdisplayed some spontaneous speech (M 544%) and imitation (M 5 68%) in pretrain-ing, and demonstrated gains in each area(spontaneous speech, M 5 90% of trials;imitation, M 5 80% of trials) during post-


Figure 1. Percentage of structured opportunities with spontaneous speech and imitation during academicsessions for Alex (top panel), Jake (middle panel), and Kyle (bottom panel).

training. During 1-year follow-up sessions,spontaneous speech and imitation gains weremaintained (100% of trials). Jake did notdisplay any imitation or spontaneous speechduring pretraining and demonstrated gainsin both spontaneous speech (M 5 63% oftrials) and imitation (M 5 73% of trials)during posttraining sessions. Kyle did notdisplay any speech during pretraining butdemonstrated gains in both spontaneousspeech (M 5 80% of trials) and imitation(M 5 72% of trials) during posttraining ses-sions.

Mean length of utterance (MLU). TheMLU data from both academic and play ses-sions are depicted in Figure 3. During pre-training, Alex displayed an MLU of 2 wordsin academic sessions, and an MLU of 1.7words in free-play sessions when makingspontaneous requests. Following PECStraining, Alex displayed an MLU of 2 words

in academic sessions and an MLU of 2.3words in play sessions when making spon-taneous requests. At 1-year follow-up, hedisplayed an MLU of 2.7 words in academicsessions and 2.6 words during free-play ses-sions. Jake did not display any speech duringpretraining academic sessions or play ses-sions. During posttraining sessions, theMLU was 2 words in the academic settingand 1.8 words in the play setting. Kyle alsodisplayed an increase in MLU when makingspontaneous requests. During all pretrainingacademic sessions, he made only one spon-taneous request (a single word) in compari-son to an MLU of 1.5 words during post-training when making spontaneous requests.He displayed an MLU of 2.4 words duringthe last two academic sessions when hereached criterion. Similarly, he did not usespontaneous speech during free-play sessionsduring pretraining. He displayed an MLU

223EFFECTS OF PECS

Figure 2. Percentage of structured opportunities with spontaneous speech and imitation during play sessionsfor Alex (top panel), Jake (middle panel), and Kyle (bottom panel).

of 1.6 for all posttreatment free-play sessionsand an MLU of 2.5 during his last two free-play sessions when he reached criterion.

Social-Communicative BehaviorsThe data for social-communicative behav-

iors in the free-play sessions for Alex, Jake,and Kyle are shown in Figure 4. For Alex,either joint attention, eye contact, or toyplay occurred during an average of 25% ofintervals during baseline and increased to anaverage of 54% of intervals following PECStraining and an average of 61% of intervalsat long-term follow-up. An average of 11 re-quests and initiations per session occurredduring baseline, which increased to 28 persession following PECS training and 52 dur-ing follow-up sessions. For Jake, either jointattention, eye contact, or toy play occurredduring an average of 16% of intervals during

baseline and increased to an average of 41%of intervals following PECS training. An av-erage of 2.9 requests and initiations per ses-sion occurred during baseline, which in-creased to 38 per session following PECStraining. For Kyle, either joint attention, eyecontact, or toy play occurred during an av-erage of 20% of intervals during baselineand increased to an average of 39% of in-tervals following PECS training. An averageof 2.8 requests and initiations per session oc-curred during baseline, which increased to27 per session following PECS training.

Problem BehaviorThe problem behavior data from both ac-

ademic and play sessions are depicted in Fig-ure 5. For Jake, tantrums and out of seatoccurred in the work setting during an av-erage of 14% of intervals in baseline and


Figure 3. Mean length of utterance (MLU) for spontaneous speech opportunities during academic (opensquares) and play (filled triangles) sessions for Alex (top panel), Jake (middle panel), and Kyle (bottom panel).

decreased to an average of 5% of intervalsfollowing PECS training. An average of 24disruptions and grabs per session occurredin baseline, which decreased to an average of9.5 per session following PECS. For Kyle,tantrums and out of seat occurred in thework setting during an average of 7% of in-tervals in baseline and decreased to an av-erage of 0.5% of intervals following PECStraining. An average of 12.3 disruptions andgrabs per session occurred in baseline, whichdecreased to an average of 2.6 per sessionfollowing PECS. For Jake, tantrums oc-curred in the play setting during an averageof 15% of intervals in baseline and decreasedto an average of 2% of intervals followingPECS training. An average of 1.7 disrup-tions per session occurred in baseline, where-as none occurred following PECS. For Kyle,tantrums occurred in the play setting during

an average of 13% of intervals in baseline,and none occurred following PECS training.An average of 2.7 disruptions per session oc-curred in baseline, which decreased to an av-erage of 0.2 per session following PECS.Overall, percentage reduction scores werecomputed for each behavior in each setting(N 5 12). A 70% or greater reduction wasobserved for 10 of 12 behaviors, and fourbehaviors were eliminated. The greatestchange for Jake was the elimination of dis-ruptions in the academic setting. The great-est change for Kyle was the elimination oftantrums in the play setting.

DISCUSSION

In the present study, 3 children with au-tism were taught to use the picture exchangecommunication system (PECS). A multiple

225EFFECTS OF PECS

Figure 4. Percentage of 10-s intervals with cooperative play, joint attention, or eye contact (filled circles)and combined frequency of initiations and requests (open circles) for Alex (top panel), Jake (middle panel),and Kyle (bottom panel).


Figure 5. Percentage of 10-s intervals with tantrums and out of seat (filled circles) and frequency of dis-ruptions and grabbing (open circles) in work settings for Jake (top panel) and Kyle (second panel). Percentageof 10-s intervals with tantrums (filled circles) and frequency of disruptions (open circles) in play settings forJake (third panel) and Kyle (bottom panel).

227EFFECTS OF PECS

baseline design across children illustrated theeffects of the PECS training procedure onseveral behaviors related to pictorial com-munication: vocal communication, social-communicative behaviors, and problem be-haviors. This study provides the first empir-ical evidence to support previous informa-tional reports (i.e., Frost & Bondy, 1994)and program evaluations (Schwartz et al.,1998) and adds experimental data to sup-port the already-widespread use of PECS.

All 3 children mastered PECS use withina relatively short time (see trials to criterionand minutes of training in the results).These children were the first 3 childrenidentified who had extensive language skilldeficits, and no children were eliminated orselected based on the presence of any prelim-inary skills. Thus, there is minimal likeli-hood that quick skill acquisition was due toselection procedures.

Several factors included in the PECStraining procedure may explain the relativelyquick skill acquisition for these children.First, children with autism frequently learntasks presented in a structured concrete for-mat more easily than tasks presented in amore abstract format (Schopler, Mesibov, &Hearsey, 1995). The structured context andconcrete nature of the physical exchange isperhaps better suited for learning for chil-dren with autism than traditional spokenlanguage of an items label. The use of pic-ture cards in PECS provides a visual repre-sentation for communication and incorpo-rates visual discriminations as part of thecommunication exchange, which may en-hance the speed of learning for children withautism (Happe & Frith, 1995). Specifically,a PECS card (two-dimensional visual stim-ulus) is exchanged for an item (three-dimen-sional visual stimulus). This visualvisualdiscrimination may have resulted in moreeasily understood communication for thechild than did mixed auditory-visual dis-criminations, which have typically been

more difficult (Harapiak, Martin, & Yu,1999). Third, the PECS protocol focuses oncreating establishing operations and func-tional relations with the environment. In thePECS protocol, children are taught to usemands to specify their desired reinforcers(e.g., I want juice), allowing the childrento obtain important objects and events intheir environment. The childs own fluctu-ating deprivation states are establishing op-erations that make communication morelikely to occur. This direct establishment ofcontact with a listener prior to emitting areferential communicative act is an impor-tant feature of PECS that may enhance thesuccess of manding for children with autism.Finally, PECS incorporates the promptingprocedure of delay (e.g., Charlop et al.,1985; Charlop & Walsh, 1986; Touchette,1971) that occasions transfer of stimuluscontrol of the communicative behavior tothe presence of the desired item.

Emergence of Speech

Although the demonstration of the effi-cacy of PECS is important in and of itself,the increase in speech is perhaps the mostimportant finding. Several features of thePECS system may contribute to the emer-gence of vocal as well as pictorial commu-nication. First, the PECS program teachesfunctional communicative behaviors that in-corporate strong reinforcers and are likely tobe supported in natural environments. Manycommunication training programs initiallyteach labeling, which involves teaching thechild to identify an object with a symbol, ahand gesture, or a vocal response (Carr,1982; Lovaas, 1987). The focus on mandsin the PECS program may indeed contributeto the initiation of verbal behavior (Skinner,1957).

The development of speech may also arisefrom the pairing of the phrase spoken by theadult (e.g., I want juice) with the pictorialcommunicative act of handing a PECS sen-


tence strip to a communicative partner.Thus, vocal and pictorial mands are pre-sented simultaneously and, if the child be-gins to imitate the vocalizations in laterphases of PECS, the two responses may bereinforced simultaneously.

The use of delay, inherent in the PECSprotocol, may have also contributed to pro-moting speech (Charlop et al., 1985; Char-lop & Trasowech, 1991). Indeed, the dataduring PECS training may support this no-tion. All of the children displayed morespeech gains as delay was incorporated intothe training procedure during Phases 4 and5. Thus, the transfer of stimulus controlfrom the teachers verbalization of Good,youre telling me, I want juice to the pre-sentation of the PECS card (juice card onthe PECS board) and then to the mere pres-ence of the object (juice) occurred (e.g.,Charlop et al., 1985; Touchette, 1971).

It is important to note that the emergentspeech produced by the children in thisstudy occurred with novel persons, in twonontraining settings, and with stimuli notdirectly included in the training settings.The PECS procedure may promote gener-alization by incorporating child-selected re-inforcers, multiple settings, and interactionswith multiple trainers that occur throughoutthe day in their natural environment. Thesetechniques have been described by Stokesand Baer (1977) as ways to promote gener-alization. Also, the use of child-initiated re-quests and child-selected reinforcers throughthe childs daily routine is similar to manynaturalistic teaching strategies that focus spe-cifically on promoting speech across envi-ronments and listeners (cf. Hart & Risley,1968).

The children in this study displayed someability to imitate, which may have facilitatedtheir verbal behavior. The children in thisstudy may be similar to the children inSchwartz et al. (1998) whom she calledtalkers. These children demonstrated some

ability to imitate or produce spontaneousspeech during and after PECS training incomparison to the nontalkers, who wereable to use PECS as a functional commu-nication but did not show the dramatic in-crease in speech production.

Collateral Improvements

Another finding is that childrens social-communicative behaviors increased afterlearning to use PECS. Eight social-commu-nicative behaviors were observed with initi-ations and requests increasing the most, con-comitant with PECS training. Joint atten-tion also increased in all 3 children, althoughnot as much as initiations and requests.Mundy, Sigman, and Kasari (1990) andMundy, Sigman, Ungerer, and Sherman(1986) suggested that there is a direct posi-tive relation between joint attention andcommunication in children with autism. Im-provement in one, as in this study, may havestimulated an increase in the other. As awhole, however, the results from the presentstudy are consistent with prior research onthe relations between communication andsocial behaviors (e.g., Baker & Cantwell,1987; Black & Logan, 1995; Mundy et al.,1986, 1990; Prizant et al., 1990; Shabani etal., 2002; Thiemann & Goldstein, 2001).

These results also indicate that increasedcommunication skills occurred in conjunc-tion with decreases in problem behaviors.The results of this study are consistent withprior research on the inverse relation be-tween communication skills and problembehaviors (Carr & Durand, 1985; Durand& Carr, 1991; Hagopian, Fisher, Sullivan,Acquisto, & LeBlanc, 1998). Each partici-pant experienced a decrease in one or moreproblem behaviors. It is important to notethat these findings are concomitant changesrather than causal, and a functional analysisof the problem behaviors was not conduct-ed.

Limitations of the study include the small

229EFFECTS OF PECS

sample size, and replication with additionalsubjects is needed. Specifically, future re-search should explore a profile analysis ofwhich children would likely become thetalkers (Schwartz et al., 1998), as in thepresent study, and which ones would not.Future studies might assess the generaliza-tion of treatment effects across home,school, and clinic settings. Finally, this studyprimarily examined collateral effects ofPECS training rather than direct use andgeneralization of PECS use across settings.Anecdotally, we can report that all childrenused their PECS books in addition to vocalcommunication during posttraining, but thiswas not the focus of the present study.

The present study demonstrated the effi-cacy of the PECS protocol with 3 childrenwith autism, the emergence of speech, andthe collateral gains in social-communicativebehaviors and concomitant decreases inproblem behavior. These findings togethersupport the use of PECS by providing thefirst empirically controlled data on the PECSprogram. We encourage the evaluation ofPECS and the continued pursuit of visuallypresented speech training programs for chil-dren with autism.

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Received April 3, 2001Final acceptance May 31, 2002Action Editor, Linda Cooper-Brown

STUDY QUESTIONS

1. What is PECS, and what types of behavioral strategies are used during PECS training?

2. What direct and indirect effects of PECS were evaluated in this study?

3. Briefly describe the procedures used to determine whether spontaneous speech and verbalimitation were acquired.

4. Although the specific reinforcers delivered for correct responses during PECS training werenot described, based on the information contained in Table 1, what was the relationshipbetween responses and reinforcers in Phase 2 and in Phase 6?

5. Describe the effect of PECS training on spontaneous speech.

6. Describe the effect of PECS training on social-communicative and problem behavior.

7. What features of PECS were suggested by the authors as potential contributors to theemergence of speech, and which of these, in your opinion, seems the most tenable?

8. What procedures were implemented in an attempt to promote stimulus generalization?

Questions prepared by Claudia Dozier and Pamela Neidert, The University of Florida

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