AN EVALUATION OF PERSISTENCE OF TREATMENT ...AN EVALUATION OF PERSISTENCE OF TREATMENT EFFECTS DURING LONG-TERM TREATMENT OF DESTRUCTIVE BEHAVIOR DAVID P. WACKER 1,JAY W. HARDING 1,WENDY

AN EVALUATION OF PERSISTENCE OF TREATMENT EFFECTS DURING LONG-TERMTREATMENT OF DESTRUCTIVE BEHAVIOR

DAVID P. WACKER1, JAY W. HARDING

1, WENDY K. BERG1, JOHN F. LEE

1, KELLY M. SCHIELTZ1,

YANIZ C. PADILLA1, JOHN A. NEVIN

2, AND TIMOTHY A. SHAHAN3

1THE UNIVERSITY OF IOWA2THE UNIVERSITY OF NEW HAMPSHIRE

3UTAH STATE UNIVERSITY

Eight young children who displayed destructive behavior maintained, at least in part, by negativereinforcement received long-term functional communication training (FCT). During FCT, the childrencompleted a portion of a task and then touched a communication card attached to a microswitch toobtain brief breaks. Prior to and intermittently throughout FCT, extinction probes were conductedwithin a withdrawal design in which task completion, manding, and destructive behavior were placed onextinction to evaluate the relative persistence of appropriate and destructive behavior over the course oftreatment. FCT continued until appropriate behavior persisted and destructive behavior failed to recurat baseline levels during extinction probes. The completion of FCT was followed by four challenges tothe persistence of treatment effects conducted within mixed- or multiple-schedule designs: (a)extended extinction sessions (from 5 to 15 min), (b) introduction of a novel task, (c) removal of themicroswitch and communication card, and (d) a mixed schedule of reinforcement in which bothappropriate and destructive behavior produced reinforcement. The results showed that although FCToften resulted in quick reductions in destructive behavior and increases in appropriate behavior,destructive behavior often recurred during the extinction probes conducted during the initialtreatment. When the effects of treatment persisted during the extinction probes, the remainingchallenges to treatment effects resulted in only mild to moderate disruptions in behavior. These resultsare consistent with the quantitative predictions of behavioral momentum theory and may provide analternative definition of maintenance as constituting behavioral persistence.

Key words: functional communication training, behavioral persistence, behavioral momentum,destructive behavior, young children

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Functional communication training (FCT)is currently among the most common rein-forcement-based treatments for destructive

behavior, with over 60 citations listed inPsychInfo (Tiger, Hanley, & Bruzek, 2008).Epidemiological studies reported by Kurtzet al. (2003), Wacker et al. (1998), and Wackeret al. (2005) have shown that FCT can beconducted by parents in outpatient and homesettings and that the results can be maintainedand generalized across stimulus conditions.Most previous studies have defined and eval-uated maintenance as steady-state respondingunder treatment conditions (e.g., Stokes &Baer, 1977). Thus, relative to FCT, mainte-nance is shown to occur when appropriatebehavior remains high and stable and destruc-tive behavior remains low and stable over thelong-term course of FCT treatment.

For example, Berg, Wacker, Harding, Gan-zer, and Barretto (2007), Derby et al. (1997),Durand and Carr (1991), Durand and Carr(1992), Wacker et al. (1998), and Wacker et al.(2005) all reported that long-term mainte-nance of FCT occurred frequently and reduc-tions in destructive behavior were correlatedwith manding (Durand & Carr, 1991; Wackeret al., 2005) or other prosocial behaviors

David P. Wacker is at Department of Pediatrics, TheUniversity of Iowa Children’s Hospital, Iowa City; Jay W.Harding, Wendy K. Berg, John F. Lee, Kelly M. Schieltz,and Yaniz C. Padilla are at Center for Disabilities andDevelopment, The University of Iowa Children’s Hospital,Iowa City; John A. Nevin is at Department of Psychology,The University of New Hampshire, Durham, NH; andTimothy A. Shahan is at Department of Psychology, UtahState University, Logan, UT 84322.

This investigation was supported by Grant R01HD029402 from the National Institute of Child Healthand Human Development of the National Institutes ofHealth. The content is solely the responsibility of theauthors and does not necessarily represent the officialviews of the National Institute of Child Health and HumanDevelopment or the National Institutes of Health. Theauthors express their appreciation to the families whoparticipated in this investigation and to Agnes DeRaad forher assistance with manuscript preparation.

Address correspondence to David P. Wacker, Ph.D.,Center for Disabilities and Development, 100 Hawkins DrRoom 251, Iowa City, IA 52242 (e-mail: [email protected]).

doi: 10.1901/jeab.2011.96-261

JOURNAL OF THE EXPERIMENTAL ANALYSIS OF BEHAVIOR 2011, 96, 261–282 NUMBER 2 (SEPTEMBER)

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(Derby et al., 1997). However, most long-termevaluations of maintenance have providedonly correlational analyses and not experimen-tal analyses of the long-term effects of treat-ment. For example, Derby et al. (1997) andWacker et al. (1998) showed that maintenanceoccurred and was correlated with increases inmanding and other adaptive behavior undertreatment conditions. Experimental analysesof maintenance (i.e., the conditions underwhich destructive and adaptive behavior oc-curred following long-term treatment) werenot conducted.

An alternative approach to evaluating thelong-term effects of treatment based onthe theory of behavioral momentum (Nevin,1992) is to evaluate behavioral persistence(Dube, Ahearn, Lionello-DeNolf, & McIlvane,2009) during challenges to treatment (e.g.,extinction). An analysis of challenges totreatment would evaluate the effects of treat-ment over time to determine if appropriatebehavior persisted (Dube, McIlvane, Mazzitilli,& McNamara, 2003) or if destructive behaviorrecurred (Lattal & St. Peter Pipkin, 2009;Lieving & Lattal, 2003; Volkert, Lerman, Call,& Trosclair-Lasserre, 2009). Behavioral persis-tence might be established if treatment effectspersisted during the treatment challenges(Nevin & Wacker, in press).

In this study, we conducted two analyses ofbehavioral persistence that constituted chal-lenges to treatment. First, throughout treat-ment, we conducted intermittent extinctionprobes during which appropriate communica-tion, destructive behavior, and compliance totask requests all resulted in extinction. Theseprobes were used to evaluate the persistence ofdestructive and appropriate behavior when theeffects of treatment were challenged at differ-ent points in treatment via brief periods ofextinction. Our goal was to determine if long-term FCT treatment decreased the persistenceof destructive behavior and increased thepersistence of appropriate behavior later butnot earlier in treatment. We defined treatmentas having been successful when appropriatebehavior persisted and destructive behaviordid not recur during the extinction probes.

Second, at the completion of successfultreatment, we further challenged the effectsof treatment by extending the length of theextinction period from 5 to 15 min, alteringthe antecedent stimulus conditions (by chang-

ing the tasks and removing the microswitch),and implementing a concurrent schedule (FR1 FR 1) of reinforcement for destructive andappropriate behavior. These challenges wereconducted posttreatment specifically to iden-tify potential conditions (e.g., increased timein the relevant motivating operation, stimuluscontrol, changes in reinforcement schedules)that may be related to the persistence oftreatment effects.

Each of these challenges was selectedbecause they represent conditions in appliedsettings that often vary from the originaltreatment plan. Duration of demands increas-es (extinction challenge), different tasks areintroduced, augmentative communication de-vices are not deployed, and care providersreinforce destructive behavior, at least inter-mittently. Thus, this study evaluated the long-term effects of FCT in the treatment of escape-maintained destructive behavior. We presentsingle-case analyses for 2 participants (Tinaand Jose) as exemplars of the analyses com-pleted for all children. We then providesummary data for all 8 children and quantita-tive analyses for 7 of the children.

METHOD

Participants and Settings

Eight young children participated in thisinvestigation as part of a federally fundedresearch project1. Criteria for enrollment inthe current study were (a) 6 years of age orless, (b) diagnosed developmental disability,(c) occurrence of destructive behavior duringthe negative reinforcement condition of afunctional analysis, and (d) informed consent.All participants were asked to enroll for aperiod of 2 years.

Tina and Jose were the 2 participants forwhom single-case analyses are presentedin the results. (The functional analyses forboth participants were previously publishedin Schieltz, Wacker, Harding, Berg, Lee, &Padilla Dalmau, 2010; Tina’s functional anal-ysis and FCT results were also previouslypublished in Wacker, Berg, Harding, & Coo-per-Brown, 2009). Tina was 3 years 11 months

1 Wacker, D. P., Berg, W. K., & Harding, J. W. (2004).Maintenance effects of functional communication training.Washington, DC: Department of Health and HumanServices, National Institute of Child Health and HumanDevelopment.

262 DAVID P. WACKER et al.

old and was diagnosed with autism anddevelopmental delay. Destructive behaviorincluded aggression (hitting, kicking) andproperty destruction (throwing objects). Com-munication consisted of a limited vocabularyof single words. Jose was 4 years 4 months oldand was diagnosed with fragile X syndromeand moderate intellectual disability. Destruc-tive behavior included aggression (biting,hitting), self-injury (finger biting), and prop-erty destruction (throwing toys). Communica-tion consisted of a few single words andmanual signs (e.g., ‘‘Done’’). Subject descrip-tions for all 8 participants are presented inTable 1.

All assessment and treatment procedureswere conducted in the living room or partic-ipant’s bedroom (Andy only) of the children’shomes. The children’s mothers served astherapists with coaching from the investigatorsduring all procedures. All sessions were video-taped for subsequent data collection andanalysis.

Materials

Given the children’s limited vocal commu-nication and manual signing skills, the inves-tigators provided the parents with a BIGMackHmicroswitch and a 10.2 cm 3 10.2 cm com-munication card created with BoardmakerH asan augmentative communication device dur-ing FCT. The card displayed the word ‘‘play’’and a drawing of a child surrounded by toys.

The card was taped to the touch plate of themicroswitch. The parents programmed themicroswitch to say, ‘‘Play, please,’’ when thecard on the microswitch was touched. Thecard attached to the microswitch was used as avisual discriminative stimulus that reinforce-ment was available for appropriate manding.

Response Definitions and Interobserver Agreement

A 6-s partial-interval recording system wasused to measure child behavior. Self-injury wasdefined as any behavior that produced orcould produce tissue damage on the child.Aggression was defined as any behavior thatproduced or could produce tissue damage onanother person. Property destruction was definedas any behavior that damaged or coulddamage items in the home. For the purposeof this investigation, intervals in which aggres-sion, self-injury, and property destructionoccurred were combined and labeled asdestructive behavior. Independent target mandingwas defined as saying the word ‘‘Play,’’emitting the manual sign for ‘‘Play,’’ ortouching a ‘‘Play’’ communication card thatwas attached to the touch plate of a micro-switch that played the recorded message,‘‘Play, please,’’ without a specific promptinstructing the child what to say or do.Prompted target manding was defined as thechild emitting the mand within two 6-sintervals of a specific prompt (e.g., ‘‘Say,play’’; ‘‘Touch the switch’’). Other independent

Table 1

Participant Description.

Participant Age Diagnoses Destructive Behavior Language Skills Target Work Task

Tina 3.11 Autism,Developmental Delay

Aggression,Property destruction

Single words Stacking blocks

Jose 4.4 Fragile X,Moderate Intellectual

Disability

Aggression,Property destruction,Self-injury

Single words,manual signs

Pointing to pictures

Cam 2.11 Developmental Delay Aggression,Self-injury


Picking up toys

Kevin 2.3 Developmental Delay Aggression,Self-injury


Stacking blocks

Juan 3.11 Autism,Developmental Delay

Aggression,Self-injury

Short spokensentences

Putting puzzletogether

Andy 2.6 Developmental Delay Aggression,Property destruction


Stacking blocks

Bud 3.6 Autism,Mild Intellectual Disability

Self-injury,Aggression

Single words Pointing to pictures

Rose 3.4 Mild Intellectual Disability Self-injury,Aggression,Property destruction

Single words Picking up blocks

EVALUATION OF PERSISTENCE 263

manding was defined as a word or manual signthat indicated the child wanted a break fromthe assigned task (e.g., saying, ‘‘All done.’’).Other prompted manding was defined as thechild’s emitting an alternative request for abreak within two 6-s intervals of a specificprompt from the parent (e.g., ‘‘Tell me, ‘Alldone’’’). An event-recording system was usedto measure child task completion. Independenttask completion was defined as the child’scompletion of required work activities (e.g.,stacking blocks) without physical guidance.

Trained data collectors independentlyscored the occurrence of child behavior usinga 6-s partial-interval recording system. Interob-server agreement on the occurrence of behav-ior was calculated based on exact interval-by-interval comparisons in which the number ofagreements was divided by the number ofagreements plus disagreements and multipliedby 100%. Interobserver agreement for childbehaviors was assessed for 30% of each sessionand averaged 96% (range 5 93% to 98%)across children. Data collectors scored theoccurrence of task completion using a trial-recording procedure in which the child’sresponse to an adult task request was recordedduring each trial as (a) independent taskcompletion, (b) task not completed, or (c)task completed with physical assistance. Inter-observer agreement was calculated based ontrial-by-trial comparisons in which the numberof agreements was divided by the number ofagreements plus disagreements and multipliedby 100%. Interobserver agreement for taskcompletion was assessed for 30% of eachsession and was 100%.

Experimental Design

The investigation was conducted in fourphases. During Phase 1, a functional analysis(Iwata, Dorsey, Slifer, Bauman, & Richman,1982/1994) was conducted within a multipleschedule design to identify the maintainingconditions for destructive behavior. DuringPhase 2, extinction probes of a target task andthree additional age-appropriate tasks wereconducted within a multiple schedule designto evaluate the occurrence of destructive andappropriate behavior under extinction condi-tions. During Phase 3, FCT and extinctionprobes of the target behaviors were conductedwithin a withdrawal design. Phase 3 continueduntil the child (a) independently completed

the amount of work presented during theinitial extinction condition and (b) displayedsubstantially reduced levels of destructivebehavior during two to three consecutiveextinction sessions. During Phase 4, treatmentchallenge conditions were conducted to eval-uate each child’s behavior during increasedperiods of extinction, changes in tasks, remov-al of the microswitch, and changes in rein-forcement contingencies. The extent to whichparents were satisfied with the FCT program atthe conclusion of the study was assessed via atreatment acceptability questionnaire (Treat-ment Acceptability Rating Form—Revised [TARF-R]; Reimers & Wacker, 1988).

Procedures

Phase 1: Functional analysis. Functional anal-yses were conducted by parents and werecompleted over an average period of 4 weeks(range 5 3 to 8 weeks). An average of 13sessions (range 5 10 to 15 sessions) wereconducted for each child’s analysis with anaverage of three sessions conducted duringeach visit. During the functional analysis, fourassessment conditions were conducted toidentify the maintaining variables for destruc-tive behavior. During the negative reinforce-ment condition, the parent used a least-to-most restrictive prompt hierarchy to guide thechild in completing a task (e.g., stackingblocks). The target task involved a nonpre-ferred toy identified during a free-operantpreference assessment (Roane, Vollmer, Ring-dahl, & Marcus, 1998). For example, if thechild’s least favorite toy was blocks, then age-appropriate block activities (e.g., stacking,picking up) were used as the target work task.The target work task for Kevin, Tina, and Andywas stacking blocks. Cam’s task was picking uptoys, Juan’s task was putting a puzzle together,Bud’s and Jose’s task was pointing to picturesin a book, and Rose’s task was picking upblocks. If the child engaged in destructivebehavior following task instructions, then thetask was removed for 20 s. During the firstpositive reinforcement condition, the parentdiverted her attention from the child (e.g.,read a magazine). If the child engaged indestructive behavior, the parent providedattention in the form of reprimands (e.g.,‘‘Stop doing that’’) and redirection for 20 s.During the second positive reinforcementcondition, the child was initially allowed to


play with a preferred toy that was identifiedduring the previously conducted preferenceassessment. After a brief period of play, thepreferred toy was removed and the child wasgiven a less preferred toy. If the child engagedin destructive behavior, the preferred toy wasreturned for 20 s. During the free-playcondition, the child had continuous access totoys and parent attention. Sessions werecounterbalanced and lasted 5 min.

Coaching, as described by Harding, Wacker,Berg, Lee, and Dolezal (2009), was provided byan investigator who videotaped the sessions.Prior to conducting each session, the investi-gator explained the purpose of the conditionand how the parent should respond to thechild’s behavior. During sessions, the investi-gator cued the parent when it was time todeliver reinforcement and when the reinforce-ment period had elapsed. In the case of thenegative reinforcement condition, the investi-gator demonstrated how to deliver task re-quests in a three-step prompt sequence.

Phase 2: Initial extinction. The first extinctioncondition was conducted to evaluate theoccurrence of destructive behavior duringdemands in the absence of reinforcement(i.e., programmed breaks from demands).The communication card/microswitch wasnot present during this condition, and mand-ing and destructive behavior were ignored orblocked in a neutral fashion. During the firstextinction condition, the parent presented thesame task that was used during the child’sfunctional analysis negative reinforcementcondition. Task demands were presented in aseries of 30-s trials during 5-min sessions. Theparent presented the task to the child (e.g.,‘‘Put the red block on the blue block’’) andmodeled the appropriate response but did notprovide additional physical assistance. If thechild completed the task, the parent providedverbal praise. If 30 s elapsed, the parentpresented a new task. If the child refused toengage in the task, the parent repeated theinstructions and kept the task in front of thechild. During extinction, the children wereasked to complete an average of eight tasks(e.g., stack eight blocks) per session (range 55 to 11 tasks per session).

In addition to the target task that was usedduring the functional analysis and the initialextinction condition, a 5-min extinction de-mand condition was conducted with three

additional tasks for each child. The purpose ofthis assessment was to identify at least oneother task that occasioned destructive behaviorand resulted in low levels of independent taskcompletion. The three additional tasks wereselected from the children’s toys and includeditems such as books, blocks, and puzzles.Children were asked to complete age-appro-priate tasks such as pointing to pictures,picking up blocks, and completing puzzlesusing the same procedures that were conduct-ed with the initial extinction condition task.The task that resulted in the highest level ofdestructive behavior and lowest level of taskcompletion was selected as the novel task thatwas used during the treatment challenges.Novel tasks selected for the treatment chal-lenges included picking up toys and blocks(Kevin, Tina, Juan, Andy), stacking blocks(Cam, Bud), putting together a puzzle (Rose),and placing balls in an electronic toy (Jose).

Phase 3: Functional communication training(FCT). Initially, from one to three FCT sessionswere conducted during weekly visits for all 8children. Following an average of 9 months(range 5 5 to 15 months) of weekly visits,FCT sessions were conducted on a monthlybasis for 5 children (Cam, Kevin, Juan, Andy,Bud). Overall, FCT sessions were conductedfor an average of 14 months (range 59 to 17 months) across children. The averagenumber of FCT sessions conducted acrosschildren was 41 (range 5 19 to 69).

During FCT, the child was first taught tocomply with the task request and then torequest a break to play. Thus, FCT wascomposed of a two-step chain in whichcompliance produced the word card attachedto the microswitch and touching the card/switch produced a brief (1- to 2-min) break.Each FCT training session began with theparent’s providing attention to the child whilethe child played with preferred toys for 20 to30 s. After this brief period of play, the parentshowed the child a word card that said,‘‘Work,’’ and told the child, ‘‘Time to work.When we’re done, you can play.’’ Andy, Tina,Jose, and Bud were directed to sit at a deskduring their work tasks, whereas Cam, Juan,Kevin, and Rose completed their work tasks onthe floor. The parent provided specific verbaldirections and modeled how to complete eachtask. If the child completed the task, he or shereceived praise. If the child refused to attempt


the task, the parent provided hand-over-handphysical guidance. The parent then presentedanother task for the child to complete withoutassistance. The child was required to completeeach task independently prior to receivingboth praise and the word card attached to themicroswitch to obtain negative reinforcement.As training continued, the work requirementfor each training session was increased pro-gressively within a demand fading program(Lalli, Casey, & Kates, 1995) to the initialextinction condition levels (eight tasks). Dur-ing initial FCT sessions, each child wasrequired to complete two work tasks (FCT[2]) during the course of two trials (i.e., onetask per trial). Over time, work requirementswere increased to completing four work tasks(FCT [4]) per session (i.e., two tasks per trial),and then eight work tasks (FCT [8]) persession (i.e., four work tasks per trial). For onechild (Juan), task demands were increased to12 tasks (FCT [12]) per session (i.e., six worktasks per trial) after 4 months.

After the child completed the required worktask independently, the parent presented themicroswitch and a piece of the work task to thechild and said, ‘‘More work or play?’’ or ‘‘Tellme if you want to play.’’ Over time, a moregeneral prompt was typically delivered such as,‘‘What do you want to do?’’ If the childemitted the target mand or other functionallyequivalent mand in an appropriate fashion, heor she received praise (e.g., ‘‘Thank you fortelling me!’’) and a 1- to 2-min break to playwith toys with the parent. After 1 to 2 min, thechild was again directed to the work task. If thechild did not emit an appropriate mand butwas not engaging in destructive behavior, theparent provided a more specific prompt, suchas ‘‘Say, ‘play,’’’ or ‘‘Touch the switch if youwant to play,’’ or gave hand-over-hand assis-tance in touching the switch.

During FCT sessions, destructive behaviorduring work activities was blocked in a neutralfashion (i.e., did not result in escape). If thechild engaged in destructive behavior duringbreak activities, the break was ended and thechild was required to return to work. Milddisruptive behavior such as crying or whiningwas ignored. Parents were asked to practiceFCT for 10 to 15 min per day at a time that wasconvenient and free of interruptions. Theinvestigators provided parents with writteninstructions on conducting the program,

procedural demonstrations, and prescriptivefeedback during FCT sessions. No observationsof the parents conducting the treatment athome were obtained and thus their treatmentintegrity is not known.

Repeated extinction. Extinction in the absenceof FCT was repeated two to four times duringthe course of intervention at mean intervalsof approximately two months (8 children), sixmonths (8 children), ten months (5 children),and sixteen months (2 children) from thebeginning of FCT. Extinction conditionslasted two to four sessions (mean number ofsessions 5 3). Extinction conditions wererepeated (a) to demonstrate the experimentalcontrol of the treatment procedures and (b) toevaluate the persistence of destructive behav-ior and appropriate behavior when compli-ance and manding no longer produced breaksfrom the task. We conducted multiple replica-tions of extinction over the long-term courseof FCT to determine if destructive behaviorcontinued to occur or if the effects oftreatment persisted despite being challengedvia brief periods of extinction. Reductions indestructive behavior and increases in appro-priate behavior (task completion) relative tothe initial extinction baseline were the criteriaestablished for initiating the remaining behav-ioral challenges.

Phase 4: Treatment challenges. The treatmentchallenge conditions were conducted follow-ing a substantial decrease in destructivebehavior and an improvement in task comple-tion during two to three sequential extinctioncondition sessions. For some children, thisimprovement occurred after a relatively shorttime (e.g., 4 months), whereas others tookconsiderably longer to meet these criteria(e.g., up to 16 months). For children whomet the criteria early in treatment, we contin-ued to conduct FCT probes, extinction condi-tions, and additional treatment challengeconditions until their participation in thestudy was concluded.

The purpose of the treatment challengeswas to evaluate the occurrence of destructivebehavior and appropriate behavior whendistinct components of the FCT programwere manipulated. Treatment challenges wereconducted over the course of two to threeweekly visits. For 6 of the 8 children, anextended extinction (EE) test was conductedfirst and the order of the other challenge


conditions was counterbalanced across chil-dren. For the remaining 2 children, the orderof all challenge conditions was counterbal-anced.

The EE challenge was presented to evaluatewhether increasing the amount of work timeunder extinction conditions resulted in in-creased levels of destructive behavior anddecreased levels of appropriate behavior.During a preceding extinction condition inPhase 3, the investigators determined thateach child had emitted steady-state respondingrelative to both destructive behavior and taskcompletion. In this challenge, the extinctioncondition was conducted for 15 min instead offor 5 min with a correlated increase in theamount of work to be completed (e.g., 24 taskrequests instead of 8 task requests). All otherprocedures were the same as during the initialextinction condition.

The novel task challenge required the childto complete a second task that had beenassessed during the initial extinction conditionand was shown to be associated with destruc-tive behavior but was not included as a trainingtask during FCT. The purpose of this chal-lenge was to evaluate whether changes in childbehavior occurred with the introduction of atask that had not acquired a treatment historywith the FCT program. The children werepresented with initial extinction conditiontask levels (e.g., eight tasks) rather than thereduced task requirements that were imple-mented at the beginning of FCT. All otherprocedures of the FCT program (e.g., se-quence of task prompts, manding, reinforce-ment schedule) remained the same as duringPhase 3.

During the no-switch challenge, the micro-switch with attached word card was not presentduring FCT sessions. The purpose of thischallenge was to evaluate if other mands(e.g., vocal or manual sign) and compliancepersisted and if destructive behavior recurredin the absence of the microswitch with theattached word card. Parents continued todeliver a general mand prompt (e.g., ‘‘Whatdo you want to do?’’) following independenttask completion. Reinforcement was deliveredif the child emitted the vocal mand ‘‘play’’ orother functionally equivalent mand such asvocally requesting a specific item (‘‘wantbook’’) or pointing to a specific toy. All otherFCT procedures remained the same.

In the competing reinforcement schedule chal-lenge, the same reinforcement contingencieswere made available for either manding orengaging in destructive behavior (FR 1 FR 1schedule) following the presentation of thework task. Thus, in this condition, bothmanding and destructive behavior resulted inthe same 1- to 2-min break with parentattention and preferred toys. All other FCTprocedures remained the same.

RESULTS

Case Examples

Tina. The results of Tina’s functionalanalysis are shown in the top panel of Figure 1.Destructive behavior averaged 25.33% (range5 12% to 32%) during the demand condi-tion, 25% (range 5 14% to 36%) during thetangible condition, 4% (range 5 0% to 8%)during the attention condition, and 2.66%(0% to 4%) during the free-play condition.Thus, destructive behavior appeared to bemaintained by both negative and tangiblereinforcement.

The results of Tina’s extinction and FCTanalyses are shown in Figure 2. The top panelshows the percentage of intervals of destruc-tive behavior. During the three target taskinitial extinction sessions, destructive behavioraveraged 28.66% (range 5 12% to 42%) andshowed an increasing trend. These resultsshowed that destructive behavior continuedto occur under brief periods of extinction. Aprobe of a novel task (picking up blocks)showed destructive behavior at 32%. Duringthe initial FCT (2) condition, destructivebehavior decreased to 0%. A return toextinction was conducted during Sessions 20and 21, and destructive behavior averaged16% (range 5 12% to 20%). A return to FCT(2) showed a decrease in destructive behavior,and Tina’s task demands were increased tofour task requests per session during Session26. During FCT (4), destructive behaviordecreased to 0%. A third extinction probewas conducted during Sessions 37 and 38, anddestructive behavior averaged 21% (range 510% to 32%), again showing that destructivebehavior recurred during brief periods ofextinction. A return to FCT (4) showed adecrease in destructive behavior. Task de-mands were increased to eight task requestsper session (FCT [8]) during Session 42, in


which destructive behavior remained at 0%. Afourth extinction probe was conducted duringSessions 48 through 51 and showed a decreasein destructive behavior to 0%. The final FCT(8) sessions were conducted during threemonthly probes, and destructive behavior wasat 0% across all three sessions.

The middle panel of Figure 2 shows thepercentage of intervals of Tina’s independenttarget manding and other manding. Tinadisplayed 0% of target manding during thetarget work task and novel task extinctionsessions. Other manding was also at 0% duringthe initial extinction condition and remainedat 0% across all subsequent baseline and FCT

sessions. During the initial FCT (2), targetmanding increased and remained stable. Areturn to extinction was conducted duringSessions 20 and 21. Target manding was at 6%during the first extinction session. However,this manding occurred because of an error incondition implementation; the microswitchwas not removed from the room and Tinatouched the microswitch several times. Themicroswitch was not present during the secondsession, and target manding decreased to 0%.A return to FCT (2) and a subsequent increaseto FCT (4) showed relatively stable targetmanding with the exception of Session 31. Athird extinction probe was conducted during

Fig. 1. Percentage of intervals of destructive behavior during functional analysis for Tina (top panel) and Jose(bottom panel). Tina’s and Jose’s functional analysis results were published in Schieltz, K. M.et al.(2010). Tina’sfunctional analysis results were also published as a bar graph in Wacker et al. (2009).


Sessions 37 and 38, and target mandingdecreased to 0%. A return to FCT (4) and anincrease in task demands to FCT (8) showedstable levels of target manding. A fourthextinction probe was conducted during Ses-sions 48 through 51, and target manding againdecreased to 0%. Target manding was stableduring the final three FCT (8) monthlyprobes. Overall, manding failed to persistduring the extinction probes.

The bottom panel of Figure 2 shows thepercentage of Tina’s independent task com-pletion. During the initial extinction condi-tion, task completion averaged 45.66% (range5 20% to 67%) and showed a decreasingtrend during the target work task. Thus, taskcompletion failed to persist during brief

periods of extinction. Task completion duringthe novel work task was 75%. During the initialFCT (2), task completion increased to 100%with the exception of Sessions 9, 11, and 13,which were correlated with increases in de-structive behavior. During the first return toextinction, task completion decreased to 50%.The return to FCT (2) and subsequentincrease to FCT (4) showed that task comple-tion remained stable at 100%. Task comple-tion decreased to 0% (M 5 39%, range 5 0%to 78%) during the third extinction probe,again showing a lack of persistence duringbrief periods of extinction. A return to FCT(4) and subsequent increase to FCT (8) againshowed task completion at 100%. During thefourth extinction probe, task completion

Fig. 2. Percentage of intervals of destructive behavior (top panel), percentage of intervals of independent targetmanding and other manding (middle panel), and percentage of independent task completion (bottom panel) duringFCT for Tina. FCT 5 functional communication training. Ext 5 extinction. Tina’s FCT results were also published as abar graph in Wacker et al. (2009).


showed a relatively modest decrease (M 585.75%, range 5 75% to 100%). Thus, taskcompletion persisted during extinction. Taskcompletion then increased to 100% during thefinal three FCT (8) monthly probes.

When the persistence of treatment effects(decreased destructive behavior and increasedtask completion) was obtained, the treatmentchallenges were conducted. The results ofTina’s treatment challenges conducted after11 months of treatment are displayed inFigure 3. The top panel shows the percentageof intervals of destructive behavior during theEE, no-switch, competing reinforcement, andnovel task challenge conditions. Destructivebehavior averaged 1.99% (range 5 0.66 to3.33%) during the EE challenge, 0.8% duringthe no-switch challenge, 2% during the com-peting reinforcement challenge probe, and2% during the novel task challenge probe (ascompared to 32% during the initial extinctioncondition). Therefore, the persistence oftreatment effects was evident for destructivebehavior.

The middle panel shows the percentage ofintervals of Tina’s independent target mand-ing and other manding. During the EEchallenge, target manding averaged 0% andother manding was at 2.33%. Target mandingaveraged 1.2% (range 5 0% to 4%) and othermanding averaged 6% (4% to 12%) duringthe no-switch condition. During both thecompeting reinforcement and novel taskchallenges, target manding was at 4% andother manding was at 0%. These levels ofmanding showed that persistence occurred asthe percent occurrence across conditions wassimilar to what was observed during FCT.

The bottom panel shows the percentage ofTina’s independent task completion. Duringthe EE challenge, task completion averaged92% (range 5 90% to 94%). Task completionwas at 100% during the no-switch challenge.During the competing reinforcement andnovel task challenges, task completion was at66% and 100%, respectively. These resultsshow modest (competing reinforcement chal-lenge) to high levels of persistence. Overall,the persistence of appropriate behavior andreduced levels of destructive behavior duringthe treatment challenges indicate that long-term FCT produced durable effects.

Jose. The results of Jose’s functional analysisare shown in the bottom panel of Figure 1.

Destructive behavior averaged 16.66% (range5 14% to 20%) during the demand condition,8.66% (range 5 2% to 22%) during thetangible condition, 5.33% (range 5 4% to6%) during the attention condition, and 2%(range 5 0% to 4%) during the free-playcondition. Although Jose displayed relativelyhigh mean levels of destructive behaviorduring the tangible condition, most of hisdestructive behavior occurred during the firsttangible condition session (22%), and destruc-tive behavior decreased to 2% during each ofthe subsequent sessions. Thus, Jose’s destruc-tive behavior appeared to be maintained bynegative reinforcement.

The results of Jose’s extinction and FCTconditions are shown in Figure 4. The toppanel shows the percentage of intervals ofdestructive behavior. During the three targettask extinction sessions, destructive behavioraveraged 32% (range 5 26% to 42%). Duringthe novel task extinction probe, destructivebehavior was 46%. During the initial FCT (2)condition, destructive behavior decreased to0%. A return to extinction was conductedduring Sessions 21 through 23 and showed 0%destructive behavior. A return to FCT (2)showed continued zero to near-zero percent-ages of destructive behavior. Jose’s task de-mands were increased to eight task requestsper session (FCT [8]) during Session 28.Destructive behavior remained at 0% duringFCT (8) with the exception of Session 29. Athird extinction probe was conducted duringSessions 36 through 38, and destructivebehavior remained at 0%. During the finalreturn to FCT (8), destructive behavior re-mained at low levels. Sessions 42 through 46were conducted at approximately one-monthto three-month intervals.

The middle panel of Figure 4 shows thepercentage of intervals of independent targetmanding and other manding. Jose displayed0% other manding across all FCT and extinc-tion sessions. Jose displayed 0% target mand-ing during the target work task and novel worktask during the initial extinction sessions.During the initial FCT (2) condition, targetmanding increased immediately and remainedstable at 4% to 6% across sessions. A return toextinction was conducted during Sessions 21through 23, and target manding decreased to0% during these three sessions. During thereturn to FCT (2) and subsequent increase to


Fig. 3. Percentage of intervals of destructive behavior (top panel), percentage of intervals of independent targetmanding and other manding (middle panel), and percentage of independent task completion (bottom panel) duringtreatment challenge conditions for Tina. EE 5 extended extinction; Comp. Sr+ 5 Competing reinforcement; NT 5novel task.


FCT (8), target manding again increased andwas relatively stable at 2% to 6% acrosssessions. During the third extinction probe,target manding again decreased to 0%. Duringthe final return to FCT (8), target mandingremained relatively stable at 2% to 6% acrosssessions.

The bottom panel of Figure 4 shows thepercentage of Jose’s independent task com-pletion. During the initial extinction probe,task completion averaged 53.33% (range 550% to 60%). During the initial FCT (2)condition, task completion increased and wasat 100% with the exception of Sessions 5, 10,13, and 14. During the first return to extinc-tion, task completion showed a decreasingtrend and averaged 69.33% (range 5 50% to80%). Thus, task completion did not persist

during brief periods of extinction. During thereturn to FCT (2) and subsequent increase toFCT (8), task completion remained at 100%with the exception of Session 30 (50%).During the third extinction probe, task com-pletion was 90% or higher across all threesessions, showing that it now persisted duringextinction. During the final return to FCT (8),Jose displayed some variability in task comple-tion, but all sessions were higher than duringthe initial extinction condition with theexception of Session 41 (33%).

The results of Jose’s treatment challengesare displayed in Figure 5. The top panel showsthe percentage of intervals of destructivebehavior during the EE, novel task, competingreinforcement, and no-switch conditions. Dur-ing the first treatment challenge (left panel),

Fig. 4. Percentage of intervals of destructive behavior (top panel), percentage of intervals of independent targetmanding and other manding (middle panel), and percentage of independent task completion (bottom panel) duringFCT for Jose. FCT 5 functional communication training. Ext 5 extinction.


Fig. 5. Percentage of intervals of destructive behavior (top panel), percentage of intervals of independent targetmanding and other manding (middle panel), and percentage of independent task completion (bottom panel) duringtreatment challenge conditions for Jose. EE 5 extended extinction; Comp. Sr+ 5 Competing reinforcement; NS 5

no switch.


destructive behavior was at 0% during the EEchallenge. Destructive behavior averaged1.33% (range 5 0% to 4%) during thecompeting reinforcement challenge, and 0%during the novel task challenge and the no-switch challenge.

The middle (left) panel of Figure 5 showsthe percentage of intervals of Jose’s indepen-dent target manding and other manding.During the EE challenge, Jose displayed 0%target manding. During the competing rein-forcement challenge, target manding averaged3% (range 5 0% to 6%). During the novel taskchallenge, target manding averaged 4.66%(range 5 4% to 6%). During the no-switchchallenge, target manding averaged 4%. Josedisplayed 0% other manding during the firstchallenge conditions.

The bottom (left) panel of Figure 5 showsJose’s percentage of independent task com-pletion. During the EE challenge, task com-pletion averaged 93.66% (range 5 90.66 to96.66%). Task completion during the compet-ing reinforcement challenge averaged 94.33%(range 5 67% to 100%). Task completionaveraged 100% during both the novel task andno-switch challenges.

The top (right) panel of Figure 5 showsJose’s percentage of destructive behavior dur-ing the second treatment challenges conducted5 months after the first treatment challenges.Destructive behavior was at 3.33% duringthe EE challenge and 0% during the noveltask challenge. Destructive behavior averaged3.33% (range 5 2% to 6%) during thecompeting reinforcement challenge and wasat 2% during the no-switch challenge. Themiddle (right) panel shows the percentage ofindependent manding. Jose displayed 0%target or other manding during the EEchallenge. During the novel task challenge,target manding was at 4% and other mandingwas 0%. During the competing reinforcementchallenge, target manding averaged 2% andother manding was 0%. During the no-switchchallenge, target manding was 0% and othermanding was 4%. The bottom (right) panelshows the percentage of independent taskcompletion. Task completion was at 88%during the EE challenge and 100% during thenovel task challenge. Task completion averaged76.66% (range 5 60% to 100%) during thecompeting reinforcement challenge and was at92% during the no-switch challenge.

Overall, Tina and Jose showed substantialdecreases in destructive behavior and increasesin task completion in comparison to initialextinction condition levels across all challengeconditions. More modest increases occurredfor manding. One explanation for thesefindings is that treatment abolished thereinforcing effects of escaping the tasks. Theseresults suggest that FCT resulted in long-termeffects across the target behaviors. For Tina,persistence of treatment effects occurred onlyafter long-term treatment for both destructivebehavior and task completion. For Jose, morerapid effects occurred for destructive behaviorthan for task completion. These two patternsof effects were representative of those ob-tained for all 8 participants. It is unclear whythese two patterns of responding occurred. Asmentioned previously, integrity data were notcollected when the investigators were notpresent, and so it is possible that thesedifferent patterns were related to the degreeof treatment integrity during interventionconducted by the parents. The patterns alsomay be correlated with the reinforcementhistory of each participant.

Summary of Results

The results of the functional analyses forall children are summarized in Table 2. Allchildren showed a higher mean percentage ofdestructive behavior during the negative rein-forcement (demand) test condition thanduring the free-play (control) condition. For7 of the 8 children, the highest meanpercentage of destructive behavior occurredduring the negative reinforcement condition.Thus, all children appeared to display destruc-tive behavior that was maintained at least inpart by negative reinforcement. These results

Table 2

Mean Percentage of Intervals of Destructive Behaviorduring Functional Analysis Conditions.

Child Demand Attention Tangible Free Play

Tina 25.33 4 25 2.66Jose 16.66 5.33 8.66 2Cam 10.66 .66 4.66 3Kevin 23.33 1.33 11.33 0Juan 4.66 0 2.66 0Andy 26.66 5.50 5 3Bud 2.5 2 18 0Rose 14 7.33 10.66 1.5


were substantiated using the criteria proposedby Hagopian et al. (1997).

The percentages of destructive behaviorduring extinction and FCT sessions are sum-marized for all 8 participants in Figure 6. Eachpanel presents the average percentage foreach successive block of extinction or FCTsessions expressed as a proportion of thepercentage of destructive behavior during thefunctional analysis demand sessions. Duringthe initial extinction condition, proportions of

baseline ranged from 2.60 (Bud) to 0.31(Cam). Averaged over all 8 children, the valuewas 1.09; thus, on average, destructive behaviorpersisted unchanged during the initial extinc-tion condition.

Figure 6 also shows that proportions ofbaseline were lower during the final extinctiontest for all participants, reaching zero for Tinaand Rose; however, the trend was irregularacross successive tests for some children.Finally, Figure 6 shows that the proportions

Fig. 6. Individual data for destructive behavior of all children, expressed as proportions of the functional analysisbaseline, during successive blocks of FCT sessions (black bars) and extinction sessions (white bars). Note that y-axis scalesvary across children.


of baseline (functional analysis) destructivebehavior were usually higher during extinctionsessions than during the preceding or follow-ing FCT sessions, exemplifying resurgence.Exceptions were Kevin, Block 2; Bud, Block 5;and Jose, whose destructive behavior did notrecur during extinction after the initial expo-sure to FCT. By inspection, the data for Buddiffer substantially from those for the other 7children in both their levels and their variabil-ity (note the y-axis scale). Averaged over thecourse of treatment, Bud’s proportions ofbaseline during FCT and extinction were18.2 and 8.4 standard deviation units, respec-tively, from the means of the other 7 children.Although Bud did not emit destructive behav-ior during his fifth extinction session, we haveomitted his data from further quantitativetreatment and modeling.

Persistence During Treatment Challenges

The percentage of intervals of destructivebehavior during all treatment challenge con-ditions for each child is displayed in Table 3.The first series of challenges was conductedfor all children in the investigation. Treatmentchallenges were repeated twice for 4 children(Cam, Juan, Andy, Jose), three times for 2children (Cam, Juan), and a fourth time for 1child (Juan). The first treatment challenge wasconducted between 5 months and 18 months(M 5 10.25 months) after FCT was imple-mented. During the first series of challenges,destructive behavior averaged 0.83% (range 50% to 2.66%) of intervals during the EEchallenge, 0.5% (range 5 0% to 2%) duringthe novel task challenge, 0.91% (range 5 0%to 4%) during the competing reinforcement

challenge, and 0.85% (range 5 0% to 4%)during the no-switch challenge. The secondtreatment challenge was conducted between2 months and 7 months (M 5 3.25 months)after the first challenge. During the secondseries of challenges (n 5 4), destructivebehavior averaged 1.33% (range 5 0% to3.33%) of intervals during the EE challenge,0% during the novel task challenge, .83% (0%to 3.33%) during the competing reinforce-ment challenge, and 1.00% (0% to 2%) duringthe no-switch challenge. The third challengewas conducted between 2 months and3 months (M 5 2.50 months) after the secondchallenge. The fourth challenge was conduct-ed 4 months after the third challenge for 1child. During the third (n 5 2) and fourth (n5 1) series of challenges, destructive behaviorwas 0% across all challenge conditions.

In summary, the overall results of thechallenges demonstrated that all childrendisplayed reduced levels of destructive behav-ior during each of the challenge conditions incomparison to the mean levels of destructivebehavior (M 5 15.45%) displayed during theinitial extinction condition. This reduction wasevident across individual children and collec-tively as a group. Furthermore, this reductionin destructive behavior from the initial extinc-tion levels continued to be displayed duringrepetitions of the challenge conditions over anextended period of time.

A summary of the results of all of thechildren’s initial extinction probes, final threeFCT probes, final extinction probes, and finalchallenge condition outcomes are displayed inFigure 7. The top panel shows the meanpercentage of intervals of destructive behavior

Table 3

Percentage of Intervals of Destructive Behavior during Treatment Challenge Conditions.

Child

Treatment #1 Treatment #2 Treatment #3 Treatment #4

EE NT CR NS EE NT CR NS EE NT CR NS EE NT CR NS

Tina 1.99 2 2 .80Jose 0 0 1.33 0 3.33 0 3.33 2Cam .66 0 0 0 0 0 0 2 0 0 0 0Kevin 0 0 0 0Juan 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0Andy 1.33 2 0 2 2 0 0 0Bud 0 0 4 4Rose 2.66 0 0 0

EE 5 Extended extinction condition, NT 5 Novel task condition, CR 5 Competing reinforcement condition, NS 5 Noswitch condition


across conditions. Destructive behavior aver-aged 15.45% (range 5 2.4% to 32%) acrossparticipants during the initial (target task)extinction condition. Destructive behavioraveraged 16.25% (range 5 0% to 46%) during

the initial novel task extinction condition. Theaverage percentage of destructive behaviorduring the final three FCT sessions for eachparticipant was 0.58% (range 5 0% to 2.66%).During the final extinction condition for each

Fig. 7. Percentage of intervals of destructive behavior (top panel), percentage of intervals of independent targetmanding and other manding (middle panel), and percentage of independent task completion (bottom panel) duringinitial extinction, final three treatment probes, and treatment challenge conditions for all participants. FCT 5 functionalcommunication training; EE 5 extended extinction; Ext 5 extinction.


participant, destructive behavior averaged1.25% (range 5 0% to 6%).

During the EE challenge, destructive behav-ior averaged 1.24% (range 5 0% to 3.33%).Destructive behavior averaged 0.25% (range 50% to 2%) during the novel task challenge(compared to an average of 16.25% during theinitial novel task extinction condition), 1.16%(range 5 0% to 4%) during the competingreinforcement challenge, and 0.85% (range 50% to 4%) during the no-switch challenge.These combined results showed that destruc-tive behavior rarely recurred when treatmentwas challenged.

The middle panel of Figure 7 shows themean percentage of intervals of target mand-ing (‘‘play’’) and other manding (‘‘No,’’ ‘‘alldone’’) across conditions. Target manding was0% and other manding averaged 2.85% (range5 0% to 22%) during the initial target taskextinction sessions across participants. Targetmanding occurred in 0% of the intervals andother manding occurred in 1.75% of theintervals for the novel task. The averagepercentage of target manding during the finalthree FCT sessions was 4.57% (range 5 2.66%to 6%) and other manding averaged 1.24%(range 5 0% to 6%). During the finalextinction condition, target manding averaged0.08% (range 5 0% to .66%) and othermanding averaged 0.37% (range 5 0% to 2%).

During the EE challenge, target mandingaveraged 0.16% (range 5 0% to .66%) andother manding averaged 1.04% (range 5 0%to 4%). During the novel task challenge, targetmanding averaged 5% (range 5 4% to 8%)and other manding averaged 1.75% (range 50% to 8%) compared to an average of 0% fortarget manding and 1.75% for other mandingduring the initial novel extinction condition.During the competing reinforcement chal-lenge, target manding averaged 4.58% (range5 2% to 8%) and other manding averaged0.75% (range 5 0% to 6%). During the no-switch challenge, target manding averaged3.15% (range 5 0% to 8%) and othermanding averaged 2.12% (range 5 0% to6%). These results show that modest levels ofpersistence occurred for manding for mostchildren.

The bottom panel of Figure 7 shows themean percentage of independent task com-pletion across conditions. Independent targettask completion averaged 48.67% (range 5

4.66% to 100%) during the initial extinctionsessions across participants. During the finalthree FCT sessions, task completion averaged98.29% (range 5 90.33% to 100%). Duringthe final extinction condition, task completionaveraged 91.67% (range 5 75% to 100%).

During the EE challenge, task completionaveraged 94.12% (range 5 71% to 100%).Task completion averaged 96.37% (range 571% to 100%) during the novel task challenge(compared to an average of 59.87% during theinitial novel task condition), 92.83% (range 566% to 100%) during the competing rein-forcement challenge, and 97.62% (range 589% to 100%) during the no-switch challenge.These results showed that persistence oc-curred for task completion.

Overall, the persistence of treatment effectsacross target behaviors suggested that FCTproduced good long-term effects for thisgroup of children. The persistence of appro-priate behavior and decrease in destructivebehavior remained relatively stable across thechallenges, suggesting that durable treatmenteffects might occur in the future.

Quantitative Analysis of Extinction and Resurgenceof Destructive Behavior

According to behavioral momentum theory,the basic equation for the persistence ofreinforced behavior during challenge or dis-ruption is

logBx

Bo

� �~

{x

r 0:5ð1Þ

where Bo represents baseline responding, Bx

represents responding during disruption, xrepresents the value of a current disruptor,and r represents the rate of reinforcementobtained within the discriminative-stimuluscontext. The sign of x is negative to indicatethat disruptors decrease response rate. Equa-tion 1 states that decreases in behavior relativeto baseline are larger with higher values of x,but such decreases are counteracted by highervalues of r. The rate of reinforcement (i.e., r) israised to the power 0.5 on the basis ofestimates from basic research summarized byNevin (2002). In other words, the greater therate of reinforcement in the stimulus contextduring baseline, the smaller the impact of agiven disruptor. This prediction has beenconfirmed repeatedly (for review and quanti-


tative development see Nevin, 1992; Nevin &Grace, 2000). To bring Equation 2 to bear onsimple proportions rather than log propor-tions of baseline, Equation 1 must be expo-nentiated:

Bx

Bo~e

{x=r 0:5ð Þ ð2Þ

where e is the base of natural logarithms.During extinction, the disruptor x has three

components. First, when extinction begins, theoperant response–reinforcer contingency issuspended. Second, reinforcers—construedas stimuli that accompany responding duringbaseline—are omitted, thus altering the stim-ulus context. Third, time passes, and theeffects of these disruptors are assumed toincrease with the passage of time (see Nevin,McLean, & Grace, 2001, for rationale). Thus,we replace x in Equation 2 with the term2t(c +dr), where t represents time in extinc-tion, c represents the disruptive effect ofsuspending the contingency, and d representsthe discriminability or salience of omitting rreinforcers per unit time.

Shahan and Sweeney (2011) extendedbehavioral momentum theory to account forresurgence of extinguished behavior afterdiscontinuing reinforcement for alternativebehavior. They assumed that reinforcers foralternative behavior serve simultaneously todisrupt target behavior and to increase thefuture strength of target behavior becausesuch reinforcers occur within the same stimu-lus context; both assumptions are supportedby a number of studies reviewed in theirarticle. With the addition of these factors,Equation 2 becomes:

Bt

Bo~e

{t(czdrzpralt )

(rzralt )0:5

� �ð3Þ

where Bt is responding at time t and ralt

represents the rate of reinforcement foralternative behavior. In the denominator, theinclusion of ralt reflects the contribution ofalternative reinforcement to the overall levelof reinforcement in the context in whichtarget behavior occurs. In the numerator, pralt

reflects the added disruptive effect of alterna-tive reinforcement on the target behavior,scaled by the parameter p. Equation 3 predicts

resurgence when alternative reinforcement isremoved from the situation because of thereduction in disruption associated with theremoval of pralt from the numerator (seeShahan & Sweeney, 2011, for discussion).

We fitted Equation 3 to the data of allchildren except Bud, for reasons noted above.For each child, the value of t for eachsuccessive block of FCT sessions was thenumber of sessions per block divided by 2(because responding was averaged over theblock) summed over successive blocks, plusthe number of extinction sessions precedingeach block of FCT sessions. The value of t foreach successive extinction condition was thesum of all preceding FCT and extinctionsessions plus 3 for the current test; the valueof p was set at 0 during extinction because noalternative reinforcers were presented. Thevalues of r and ralt were taken from tabulationsof raw data for each child. The values ofparameters c, d, and p (during FCT) wereestimated from the individual data of the 7children for each block of FCT and extinctionsessions—a total of 52 separate observations—by nonlinear estimation using Microsoft ExcelSolver. The estimated values were c 5 0.3, d 50.01, and p 5 0.016, accounting for 43% of thedata variance. The quality of the fit to dataaveraged across the 7 children is shown inFigure 8. We conclude that Equation 3 gives asatisfactory account of the effects of extendedFCT training on the decrease in resurgence ofdestructive behavior over successive extinctionsessions and on the progressive elimination ofdestructive behavior during FCT sessions.

Treatment Acceptability

At the end of the study, all 8 parents whoparticipated in the investigation completedthe TARF-R (Reimers & Wacker, 1988). Thissurvey asked respondents to answer questionsregarding treatment acceptability, effective-ness, and negative side effects (completeresults are available from the first author byrequest). With respect to the question, ‘‘Howacceptable do you find the treatment to beregarding your concerns about your child?’’parents could rate the treatment on a Likertscale of (1) Not at all acceptable to (7) Veryacceptable. The average rating on treatmentacceptability was 6.62 (range 5 5 to 7). Withregard to ‘‘How effective is this treatmentlikely to be for your child?’’ parents could rate


the treatment from (1) Not at all effective to (7)Very effective. The average rating on treatmenteffectiveness was 6.62 (range 5 5 to 7).Overall, parents viewed the intervention asbeing an acceptable treatment approach andeffective for their child.

DISCUSSION

As discussed by Nevin and Wacker (in press),maintenance in applied studies is most oftendefined as steady-state responding under stabletreatment conditions (e.g., Stokes & Baer,1977). Relative to FCT, several researchers(e.g., Derby et al., 1997) showed that long-termreductions in destructive behavior and im-provements in adaptive behavior were possiblewith continued application of the FCT treat-ment package. These studies thus documentedthe direct effects of treatment and specificallyshowed that these direct effects can be contin-ued over time. These were important findingsfor the development of FCT treatments becausethey showed that FCT could be effectivelyapplied across a variety of settings, behaviors,and subgroups (e.g. Tiger et al., 2008).

Studies showing the long-term direct effectsof FCT provide a necessary but not sufficientanalysis of maintenance. In applied situations,the antecedent and consequent stimuli pres-ent during treatment change over time. Inorder to achieve durable treatment effects, we

need to analyze how treatment conditionsfacilitate or inhibit persistence during chal-lenges to treatment.

One way to document persistence is toconduct analyses of generalized treatmenteffects (e.g., Berg et al., 2007; Durand & Carr,1991). For example, Berg et al. showed thatlong-term FCT treatment could promotegeneralized treatment effects across settings,care providers, and tasks. These studies havesubstantial applied value and can also be usedto identify limitations in treatment.

A second method, based on behavioralmomentum (Nevin, 1992; Nevin & Grace,2000), is to analyze resistance to change withinfunctional contexts. Of the challenges to treat-ment reported in the basic literature, the mostcommon has been extinction (Mace et al.,2009), and thus we first conducted briefextinction probes to test behavioral persistencein Phase 3. The results of this analysis showedthat treatment effects often persisted only afteran extended period of time in treatment.Treatment was considered to be successful onlyafter persistence had been achieved, meaningthat treatment had to be continued for muchlonger than in most previous demonstrations ofthe effectiveness of FCT. Thus, one appliedimplication of analyses of persistence is thatthe continuation of treatment can be basedon empirical demonstrations of resistance tochange rather than only on steady-state respond-

Fig. 8. Proportions of baseline destructive behavior averaged over 7 children during successive blocks of FCT sessions(black bars) and during successive extinction sessions (white bars). Error bars represent standard errors. The predictionsof Equation 3 appear as grey bars; see text for explanation of equation fitting and parameter values.


ing under the prevailing conditions of treat-ment. This may lead to variations in howtreatment is conducted (Mace et al., 2010) orin how we define treatment as being successful.In the current study, success was defined onlyafter appropriate behavior persisted and de-structive behavior failed to recur during briefperiods of extinction.

Decreases in destructive behavior over thecourse of extended treatment were welldescribed by Equation 3, which was derivedfrom behavioral momentum theory and aug-mented by a term for the effects of reinforce-ment for alternative behavior on destructivebehavior. The same equation, with the sameparameters, also described the resurgence ofdestructive behavior when alternative rein-forcement was removed and the progressivedecrease of resurgence over the course oftreatment. Thus, behavioral momentum theo-ry may provide a unifying quantitative modelfor the persistence of treatment effects.

The current results, and those of Mace et al.(2010), suggest that differential reinforcementof alternative behavior (DRA) treatments mayneed to be implemented for long periodsbefore they promote desirable resistance tochange (Nevin & Wacker, in press). Perhapsalterations to those treatments would producegreater resistance more quickly. Mace et al.(2010) proposed that alternative responses,such as mands, might best be trained incontexts in which there is no reinforcementfor destructive behavior to avoid addingreinforcement to the context correlated withreinforcement of problem behavior, therebyavoiding an increase in behavioral mass due tothe introduction of DRA.

Following treatment, treatment challengeswere conducted not only to determine theoverall effectiveness of the treatment but alsoto analyze variables that may be functionallyrelated to the persistence of the effectsachieved during treatment. Changes in dura-tions of extinction, tasks, and reinforcementschedules are all common challenges thatoccur in applied settings. Changes in respond-ing during some challenges but not duringothers might lead to extensions and refine-ments of the treatments.

For example, the no-switch challenge didnot disrupt appropriate behavior or result inthe return of baseline levels of destructivebehavior for Tina. These results suggested that

the use of the switch with attached communi-cation card could be faded for Tina. For bothTina and Jose, the competing reinforcementchallenge appeared to disrupt task comple-tion, suggesting that a fading program mightbe needed. On an individual basis, thechallenge analyses provided an empiricaldetermination of how the treatments mightbe altered to better produce maintenance. Onboth an individual and a group basis, theseanalyses permit inspection of the operantmechanisms that underlie persistence, and assuggested by Nevin and Wacker (in press), mayprovide an explicit technology of maintenancebased on the theory of behavioral momentum.

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Received: September 27, 2010Final Acceptance: May 20, 2011


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AN EVALUATION OF PERSISTENCE OF TREATMENT ...AN EVALUATION OF PERSISTENCE OF TREATMENT EFFECTS DURING LONG-TERM TREATMENT OF DESTRUCTIVE BEHAVIOR DAVID P. WACKER 1,JAY W. HARDING 1,WENDY