What Makes Extinction Work: An Analysis of Procedural Form and Function

Introduction

This study from the Journal of Applied Behavior Analysis explores how extinction should be applied based on the different functions maintaining self-injurious behavior (SIB).

The authors are Brian A. Iwata, Gary M. Pace, Glynnis Edwards Cowdery, and Raymond G. Miltenberger.

Key aspects explored in the paper are:

• Functional analysis of self-injurious behavior (SIB).
• Variations of extinction (EXT) based on different maintaining reinforcers (attention, escape, sensory).
• The importance of matching the extinction procedure to the function of the behavior.

Methods

The study examined 3 children with developmental disabilities engaging in head banging. Functional analysis indicated that:

• Subject 1: SIB was positively reinforced by attention.
• Subject 2: SIB was negatively reinforced by escape from educational tasks.
• Subject 3: SIB appeared to be automatically reinforced (sensory).

Three functional variations of extinction were evaluated:

• EXT (attention): Withholding attention.
• EXT (escape): Preventing escape from tasks.
• EXT (sensory): Attenuation of sensory consequences.

Subjects were exposed to at least two of these variations in reversal or multiple baseline designs.

Key Findings

Reductions in SIB were observed only when the extinction procedure matched the maintaining reinforcer identified by the initial functional analysis.

The study highlights the critical differences among treatment approaches based on the same behavioral principle (extinction) but applied to topographically similar but functionally dissimilar responses.

The practical implications of a functional analysis of behavior disorders for designing, selecting, and classifying therapeutic interventions are emphasized.

Background and Rationale

Research has focused on antecedent events and consequences that maintain behavior problems (Iwata, Vollmer, & Zarcone, 1990; Mace, Lalli, & Lalli, 1991).

Emphasis in treatment is on strengthening new stimulus-response-consequence relationships.

Little attention has been paid to eliminating reinforcement that maintained the problem behavior.

Many interventions implicitly contain extinction (punishment of Response A is combined with cessation of reinforcement; reinforcement of Response B usually coincides with termination of reinforcement for Response A).

Recent studies suggest that reinforcement-based interventions may be limited unless extinction is included.

Examples are interventions based on:

• Development of communicative responses (Carr & Durand, 1985).
• Behavioral momentum (Mace & Belfiore, 1990).

Mixed results (Wacker et al., 1990) or no treatment effect (Zarcone, Iwata, Hughes, & Vollmer, 1993) when implemented without extinction.

The critical feature of DRO contingencies appears to be the extinction component rather than the reinforcement component (Mazaleski, Iwata, Vollmer, Zarcone, & Smith, 1993).

Extinction and SIB

The assessment and treatment of self-injurious behavior provide an important context for examining extinction, because SIB can be maintained through various operant mechanisms.

"Discontinuation of reinforcement" often involves cessation of ongoing events (e.g., ignoring, time-out).

Some textbooks define extinction solely through reference to stimulus termination (LaVigna & Donnellan, 1986).

Procedural time-out can serve different functions (Plummer, Baer, & LeBlanc, 1977; Solnick, Rincover, & Peterson, 1977).

Ignoring misbehavior may represent extinction in some cases but not in others; conversely, the correct application of extinction may require termination of events in some cases but continuation in others.

Defining Extinction Procedures

The procedures that define extinction are determined by the specific nature of the reinforcement to be "discontinued."

• SIB maintained by social-positive reinforcement (adult attention): extinction consisted of withholding attention (Day, Rea, Schussler, Larsen, & Johnson, 1988; Lovaas & Simmons, 1969).
• SIB maintained through social-negative reinforcement (escape from task demands): extinction involved preventing escape (Iwata, Pace, Kalsher, Cowdery, & Cataldo, 1990; Repp, Felce, & Barton, 1988).
• SIB maintained by nonsocial, automatic reinforcement (sensory stimulation): extinction-like decreases occurred when individuals wore equipment that attenuated consequences (Rincover & Devany, 1982).

Functional Variations of Extinction

Three functional variations of extinction have been used as treatment for SIB, each designed to terminate a different source of reinforcement.

Variations are not well differentiated through existing terminology.

Terminology:

• Planned ignoring: adequate description of therapist's response, but does not describe the underlying behavioral process (extinction) or identify the source of reinforcement being withheld (attention) (Nelson & Rutherford, 1983).
• Escape extinction: specifies the relevant process and the reinforcer, but not the procedure (Iwata, Pace, Kalsher, Cowdery, & Cataldo, 1990).
• Sensory extinction: specifies process and reinforcer, but not procedure; wording is awkward because nothing "sensory" is extinguished (Rincover, 1978; Rincover, Cook, Peoples, & Packard, 1979).

The convention adopted in the paper is:

• "EXT" followed in parentheses by the source of reinforcement withheld: EXT (attention), EXT (escape), and EXT (sensory).

Emphasis is placed on behavioral process, with the reinforcer incidental.

Terminology is incomplete because it does not differentiate procedural variations within a given functional class of extinction techniques.

EXT (attention) may take different forms depending on the situational context.

Withholding reinforcement would consist of terminating the interaction.

Similar variations are characteristic of both EXT (escape) and EXT (sensory).

Contingency Matrix and Predictions

Extinction designed for SIB serving one function may have little or no therapeutic effect on SIB serving a different function.

Figure 1 presents a contingency matrix allowing predictions about behavioral outcome.

Elimination of social reinforcement for SIB using EXT (attention) or EXT (escape) will not interfere with the delivery of sensory (automatic) reinforcement, and EXT (sensory) would have no effect on social sources of reinforcement.

EXT (attention) applied to escape-maintained SIB (stimulus removal contingent on escape behavior) and, conversely, EXT (escape) applied to attention-maintained SIB (stimulus continuation contingent on attention-getting behavior) may be countertherapeutic and seriously exacerbate the behavior problem.

Evidence directly supporting these predictions can be found in only a few studies.

Research on the treatment of self-injurious escape behavior sometimes has included a baseline condition in which time-out from educational tasks was made contingent on SIB (Iwata, Pace, Kalsher, Cowdery, & Cataldo, 1990; Repp et al., 1988; Steege et al., 1990).

This condition procedurally amounted to EXT (attention) but was associated with increases in escape-maintained SIB.

The study provides an empirical evaluation of the key predictions found in Figure 1 by conducting a comparative analysis of extinction techniques.

The relative effects of three functional variations of extinction were examined when applied to the same topography of SIB maintained by three different contingencies of reinforcement.

Subjects and Setting

Subjects were selected based on:

• Similar topographies of SIB.
• Outcomes of functional analysis baselines indicating that their SIB was maintained by different sources of reinforcement.

Three children with developmental disabilities who met these criteria were included as participants.

All exhibited head banging that produced contusions or lacerations on the head and face.

Subject Descriptions:

• Donnie: 7-year-old boy with severe mental retardation. SIB was maintained by automatic consequences.
• Jack: 12-year-old boy with severe mental retardation. SIB was maintained by escape from demands.
• Millie: 8-year-old girl with moderate mental retardation. SIB was maintained by social-positive reinforcement.

Sessions were conducted individually in therapy rooms or in a large group area.

Sessions were 15 min in duration and usually were conducted 5 days per week, with four to eight sessions daily and at least 15-min breaks between sessions.

Response Measurement and Reliability

SIB was defined as any audible contact between the head or face and either a fist or an object.

Data were recorded using:

• Paper during continuous 10-s intervals.
• Hand-held computer (Panasonic Model RL-H1800).

All data were converted into percentage of 10-s intervals during which one or more instances of SIB occurred.

Data were also collected on experimenter behaviors (delivery of instructions or attention, withdrawal of instructions or attention, placement and removal of apparatus).

Experimenter compliance exceeded 90% across all categories.

Interobserver agreement was assessed by having a second observer simultaneously but independently record data during 23% of all sessions.

Mean agreement was 92% across subjects, with all values exceeding 86%.

Experimental Designs and Sequence

During the initial baseline, subjects were exposed to a series of assessment conditions in a multielement design (Sidman, 1960; Ulman & Sulzer-Azaroff, 1975) to identify the maintaining variables for their SIB.

Subsequently, each subject was exposed to two or more functional variations of extinction by way of reversal or multiple baseline designs.

Specific conditions and their order of presentation were determined by subjects' baseline performances.

Functional Analysis Baseline

Subjects were exposed to four conditions based on Iwata, Dorsey, Slifer, Bauman, and Richman (1982).

Conditions:

• Attention: Experimenter ignored the subject while seeming to do paperwork. Contingent on SIB, the experimenter expressed concern and briefly interrupted the response.
• Demand: Experimenter presented academic tasks. The experimenter used modeling and physical guidance as supplementary prompts, delivered praise contingent on correct responses, and implemented a 30-s time-out contingent on SIB.
• Alone: Subject was observed while alone in the room.
• Play: Experimenter provided continuous access to toys, delivered praise approximately every 30 s contingent on the absence of SIB, and ignored occurrences of SIB.

Extinction Conditions

Three variations of extinction were evaluated, each designed to discontinue a different source of reinforcement for SIB.

An attempt was made to implement each type of extinction with each subject.

EXT (attention): This variation of extinction was designed to discontinue positive reinforcement in the form of attention delivered by the experimenter. EXT (attention) already was a component of three of the baseline conditions. This extinction contingency consisted of having the experimenter ignore SIB combined with experimenter attention for the absence of SIB, which was delivered on a 30-s DRO schedule. Occurrences of SIB reset the DRO interval.

EXT (escape): This variation of extinction discontinued negative reinforcement in the form of escape from tasks. During EXT (escape), learning trials continued as during baseline but were not terminated contingent on SIB. Instead, the experimenter physically guided the subject to comply with the instruction and continued the session according to schedule. The physical guidance component of this intervention may represent a punishment contingency.

EXT (sensory): This variation of extinction was designed to attenuate the sensory consequences produced by subjects' head banging. Each subject was fitted with an oversized helmet reinforced with additional padding. The helmet was placed on the subject's head at the beginning of a session and remained in place throughout.

Results for Donnie

Donnie exhibited a considerable amount of SIB across all of the baseline conditions, thus permitting a series of manipulations on each baseline.

Moderate levels of SIB were observed during the demand, attention, and play conditions, whereas SIB occurred almost continuously during the alone condition.

These data suggested that Donnie's SIB was maintained by factors independent of the social and physical environment and were consistent with behavior reinforced by directly produced, automatic consequences.

Interventions for Donnie:

• Alone Baseline: EXT (sensory) was implemented in a reversal (ABAB) design, and results showed decreases in SIB associated with the helmet intervention.
• Demand Baseline: introduction of EXT (sensory) was associated with a rapid and large decrease in Donnie's SIB. Next, EXT (sensory) was removed and EXT (escape) was implemented; this resulted in an increase in SIB to its baseline level. Finally, the contingent helmet procedure was combined with EXT (escape). This condition was associated with a decrease in SIB similar to that seen during the previous EXT (sensory) condition.
• Attention Baseline: introduction of EXT (attention) had no effect on Donnie's SIB. During the next condition, EXT (sensory), SIB decreased even though it produced attention from the experimenter. The final procedure implemented on this baseline consisted of EXT (attention) combined with a 2-min time-out in the helmet contingent on occurrences of SIB, and was associated with a reduction in SIB similar to that seen in the EXT (sensory) condition.
• Play Baseline: which contained an EXT (attention) component, no decrease in SIB was observed until EXT (sensory) was introduced. Subsequently, SIB increased temporarily but decreased again when the procedure was changed to a 2-min time-out in the helmet contingent on SIB.

Results for Jack

Jack exhibited little or no SIB except during the demand condition, which contained two distinctive features: the presentation of task demands and a brief time-out from the task contingent on SIB. The time-out component procedurally resembled EXT (attention) but appeared to function as (negative) reinforcement for escape behavior.

Because little or no SIB was observed during other conditions, all subsequent manipulations were made on the demand baseline.

EXT (sensory) and EXT (escape) were implemented concurrently and resulted in a large decrease in Jack's SIB.

A partial reversal was then conducted in which EXT (escape) was removed while EXT (sensory) remained in effect; this change resulted in an increase in Jack's SIB to its original baseline level.

SIB decreased again when EXT (escape) was reintroduced, and it remained low following the removal of EXT (sensory).

Results for Millie

Millie's SIB occurred almost exclusively during the attention condition, suggesting that the behavior was maintained by social-positive reinforcement.

Very little SIB was observed during the play and demand conditions, both of which contained a brief time-out from attention contingent on SIB, and SIB decreased throughout the alone condition, which contained no attention whatsoever.

Millie's assessment data revealed not only a reinforcement effect during the attention condition but also an apparent extinction effect during others.

In light of these results, subsequent interventions were implemented only on the attention baseline.

EXT (attention) with attention delivered a 30-s DRO schedule was introduced concurrent with EXT (sensory) and resulted in a large decrease in Millie's SIB.

Next, while EXT (sensory) remained in effect, a reversal was conducted in which EXT (attention) + DRO was removed; this partial return to baseline was associated with an immediate and large increase in SIB.

When EXT (attention) + DRO was reinstated, SIB decreased to near-zero levels.

EXT (sensory) was then removed while EXT (attention) + DRO remained in effect, and no increase was observed in SIB.

During this final condition, the length of the DRO interval was gradually increased to 1, 2, and finally 5 min, and SIB remained low across all schedule changes.

Summary of Key Comparisons

Table 1 contains a summary of the results from selected baseline and extinction conditions for Donnie, Jack, and Millie.

The data reflect reductions or increases in SIB expressed as mean percentages of baseline responding (EXT mean/baseline mean) for relevant and irrelevant extinction conditions compared to their appropriate baselines.

All percentages are based on the last five sessions of a condition.

For example, under "Relevant EXT," Donnie's mean percentage of SIB during the last five sessions of EXT (sensory) occurred at 0.5% of the mean SIB during the last five sessions of his alone baseline, whereas under "Irrelevant EXT," his five-session mean percentage of SIB during EXT (escape) occurred at 81.9% of his demand baseline mean.

These comparisons show that SIB for all subjects was reduced to below 15% of its baseline mean during relevant extinction conditions (mean reduction = 6.5% of baseline), but was never reduced to lower than 75% of baseline during irrelevant extinction conditions (mean reduction = 91.4% of baseline).

Follow-Up

At the completion of the study, a treatment program designed for each subject was implemented throughout the day in the appropriate situational contexts.

Subjects' parents and teachers were instructed in the use of the above procedures until they demonstrated proficiency in implementation.

Follow-up contacts were faded over a 6-month period, during which SIB occurred at well below baseline levels for all subjects.

Discussion

Results of this study showed that therapeutic techniques previously defined as extinction in the applied literature are different not only procedurally but also in their behavioral effects when applied to the same response topography.

Each of three variations of extinction-EXT (attention), EXT (escape), and EXT (sensory)-reduced SIB only when it resulted in discontinuation of the specific source of reinforcement maintaining the behavior.

Thus, the process of extinction is not tied to any particular form of intervention (e.g., ignoring undesirable behavior); instead, it is determined by the behavior's maintaining contingency.

Moreover, the data presented here indicate that if the source of reinforcement for a behavior disorder such as SIB can be identified on a pretreatment basis, much of the guesswork is removed from the task of selecting an appropriate extinction technique.

Specific Subject Outcomes:

• Donnie: Neither EXT (attention) nor EXT (escape) was effective in reducing Donnie's SIB. His head banging, which apparently was maintained by sensory consequences, was reduced across all baseline conditions when EXT (sensory) was applied, even though SIB still produced attention and escape during the attention and demand baselines, respectively.
• Jack: The brief time-out contingent on SIB during his initial demand baseline closely resembled EXT (attention), yet it actually amounted to negative reinforcement and resulted in the highest levels of SIB when compared to other assessment conditions. EXT (sensory) also had little suppressive effect on Jack's SIB, which decreased only when it no longer produced termination of learning trials during the EXT (escape) condition.
• Millie: Whose baseline data indicated that her SIB was maintained by positive reinforcement in the form of attention, effective treatment consisted of EXT (attention) combined with DRO (attending to her when she did not exhibit SIB), whereas EXT (sensory) had no apparent effect on her behavior.

It is important to note that the procedures used in this study, although labeled "EXT" for each subject, differed in two respects.

First, because only one variation of extinction was effective in reducing SIB (a different one for each subject), the other two variations did not functionally amount to extinction.

Based on the results obtained during assessment and treatment, a more accurate description of the procedures used with each subject might be as follows.

Second difference: EXT (escape) and EXT (sensory) were applied in a consistent manner during treatment sessions. EXT (attention), however, took two different forms: ignoring SIB that occurred in the absence of interaction, and terminating ongoing interaction contingent on the occurrence of SIB.

The lack of therapeutic effects observed when a given variation of extinction was applied to SIB maintained by a different (irrelevant) source of reinforcement provides new data on some of the limiting conditions of extinction.

On the other hand, the positive treatment effects observed during relevant extinction conditions were not particularly novel.

Previous studies have reported reductions in SIB when the reinforcer withheld during extinction was relevant to behavioral maintenance

Implications for Treatment and Research

Extinction is similar to other behavioral processes, such as reinforcement or punishment, from which a number of therapeutic techniques can be derived.

Administrative and treatment manuals place a great deal of emphasis on the topographical aspects of intervention in order to promote procedural consistency by specifying the acceptable limits of therapist behavior when implementing a given technique.

There is a critical need to develop classification systems and treatment manuals that specify not only procedures, topographies for which they may be used, and preferred hierarchy based on consideration of factors such as "intrusiveness," but also how the same principle of learning may be translated into different procedures based on differences in behavioral function

The present results indicated that identification of a behavior's maintaining reinforcers was a prerequisite to the appropriate use of extinction (unknown reinforcers cannot be withheld).

Extinction is relevant to a consideration of punishment effects because, from the standpoint of methodology, the suppressive properties of a punishing stimulus should be evaluated while behavior is concurrently reinforced, unless it can be shown first that extinction alone does not reduce behavior.

With respect to reinforcement-based interventions, the finding that arbitrary or irrelevant reinforcers-those that do not maintain the target behavior-delivered in a DRO or DRA schedule successfully competed with an intact baseline of reinforcement for the behavior problem argues against the necessity of identifying the maintaining reinforcer.

Extinction alone is rarely recommended and perhaps accounts for the fact that little research has been conducted on extinction effects per se.

Future research on the treatment of severe behavior disorders should include more careful consideration of extinction as an integral component of intervention as well as a significant source of confounding effects when evaluating both reinforcement- and punishment-based approaches to treatment.