JOURNAL OF APPLIED BEHAVIOR ANALYSIS
JOURNAL OF APPLIED BEHAVIOR ANALYSIS
WHAT MAKES EXTINCTION WORK: AN ANALYSIS OF PROCEDURAL FORM AND FUNCTION
BRIAN A. IWATA THE UNIVERSITY OF FLORIDA
GARY M. PACE THE KENNEDY INSTITUTE, BALTIMORE, MARYLAND
GLYNNIS EDWARDS COWDERY WE CARE, INC., BERKELEY, CALIFORNIA
AND
RAYMOND G. MILTENBERGER NORTH DAKOTA STATE UNIVERSITY
We examined methods for determining how extinction should be applied to different functions of self-injurious behavior (SIB). Assessment data indicated that the head banging of 3 children with developmental disabilities was maintained by different reinforcement contingencies: One subject’s SIB was positively reinforced by attention from adults, the 2nd subject’s SIB was negatively reinforced by escape from educational tasks, and the 3rd subject’s SIB appeared to be automatically reinforced or “self-stimulatory” in nature. Three functional variations of extinction-EXT (attention), EXT (escape), and EXT (sensory)-were evaluated, and each subject was exposed to at least two of these variations in reversal or multiple baseline designs. Reductions in SIB were observed only when implementation of “extinction” involved the discontinuation of reinforcement previously shown to be responsible for maintaining the behavior. These results highlight important differences among treatment techniques based on the same behavioral principle (extinction) when applied to topo- graphically similar but functionally dissimilar responses, and further illustrate the practical impli- cations of a functional analysis of behavior disorders for designing, selecting, and classifying ther- apeutic interventions. DESCRIPTORS: extinction, functional analysis, self-injurious behavior
Research on the functional analysis of severe behavior disorders has produced a variety of inter- ventions based on the modification of antecedent events that occasion behavior problems as well as the consequences that maintain them (see Iwata, Vollmer, & Zarcone, 1990, and Mace, Lalli, & Lalli, 1991, for recent reviews). Much of the em- phasis in treatment has been on strengthening new stimulus-response-consequence relationships. By contrast, relatively little attention has been paid to eliminating reinforcement that maintained the be-
This research was supported in part by a grant from the Developmental Disabilities Planning Council and the Florida Department of Health and Rehabilitative Services.
Reprints may be obtained from Brian Iwata, Psychology Department, University of Florida, Gainesville, Florida 3261 1.
havior problem in the first place, even though many of the interventions described in the literature im- plicitly contained such a provision. That is, pun- ishment of Response A is almost always combined with the cessation of reinforcement; likewise, treat- ment involving reinforcement of Response B as a replacement for Response A usually coincides with the termination of reinforcement for Response A. Moreover, data from several recent studies suggest that the effects of reinforcement-based interventions may be limited unless extinction (withholding the behavior’s maintaining reinforcers) is included as part of the treatment program. It has been shown, for example, that interventions based on the de- velopment of communicative responses (Carr & Durand, 1985) and on behavioral momentum (Mace & Belfiore, 1990) produced either mixed
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results (Wacker et al., 1990) or no treatment effect (Zarcone, Iwata, Hughes, & Vollmer, 1993) when implemented without extinction, and that the crit- ical feature of procedures such as differential rein- forcement of other behavior (DRO) contingencies appears to be the extinction component rather than the reinforcement component (Mazaleski, Iwata, Vollmer, Zarcone, & Smith, 1993).
The assessment and treatment of self-injurious behavior (SIB) provide an important context for the examination of extinction, because it has been demonstrated that SIB can be maintained through a variety of operant mechanisms. Nevertheless, be- cause the “discontinuation of reinforcement” for behavior problems in general often involves ces- sation of ongoing events, this procedure has become so common that some textbooks define extinction solely through reference to “ignoring,” time-out, and other examples of stimulus termination (e.g., LaVigna & Donnellan, 1986). However, research has shown that procedural time-out can serve dif- ferent functions, not all of which are behavior re- ducing (Plummer, Baer, & LeBlanc, 1977; Solnick, Rincover, & Peterson, 1977), and the same is true of procedural approaches to defining extinction. 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. The procedures that define extinction in a given situation are determined by the specific nature of the reinforcement to be “discontinued.”
In cases in which SIB was maintained by social- positive reinforcement in the form of adult atten- tion, extinction consisted of withholding attention or terminating it contingent on the occurrence of SIB (e.g., Day, Rea, Schussler, Larsen, & Johnson, 1988; Lovaas & Simmons, 1969). By contrast, SIB maintained through social-negative reinforcement in the form of escape from task demands has been extinguished by preventing escape; in other words, continuing and not terminating the ongoing sit- uation (e.g., Iwata, Pace, Kalsher, Cowdery, & Cataldo, 1990; Repp, Felce, & Barton, 1988). Finally, SIB apparently maintained by nonsocial, automatic reinforcement (e.g., sensory stimulation)
has shown extinction-like decreases when the in- dividuals wore equipment that allowed the behav- ior to occur, but attenuated its consequences (e.g., Rincover & Devany, 1982). Thus, at least three functional variations of extinction have been used as treatment for SIB, each designed to terminate a different source of reinforcement, and each ame- nable to a number of procedural modifications and descriptive labels.
Although extinction procedures are clearly unique from the standpoint of both form (specific therapist actions) and function (the maintaining contingen- cies to which they apply), these variations are not well differentiated through existing terminology. Planned ignoring, the label perhaps most often applied to extinction of attention-maintained be- havior (Nelson & Rutherford, 1983), provides an adequate description of the therapist’s response, but it does not describe the underlying behavioral pro- cess (extinction), nor does it identify the source of reinforcement being withheld (attention). Escape extinction, a term used to describe extinction of escape-maintained behavior (Iwata, Pace, Kalsher, Cowdery, & Cataldo, 1990), specifies the relevant process as well as the reinforcer, but not the pro- cedure. Finally, sensory extinction, which refers to a variety of techniques designed to attenuate stim- ulation directly produced by a response (Rincover, 1978; Rincover, Cook, Peoples, & Packard, 1979), has the same descriptive characteristics as escape extinction (it specifies process and reinforcer, but not procedure); in addition, the wording is awk- ward because nothing “sensory” is extinguished. In an attempt to promote brevity as well as con- sistency of terminology, we have adopted through- out this paper the convention of referring to dif- ferentfunctional variations of extinction by using the abbreviation “EXT” followed in parentheses by the source of reinforcement withheld, as in EXT (attention), EXT (escape), and EXT (sensory). We chose “EXT” (attention) over “attention EXT” because the former places emphasis on behavioral process, with the reinforcer incidental, whereas the latter connotes that attention is extinguished.
This terminology is still incomplete because it does not differentiate procedural variations within
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VARIATIONS OF EXTINCTION
a given functional class of extinction techniques. For example, EXT (attention) may take different forms depending on the situational context in which it is applied. If the target behavior occurs in the absence of ongoing social interaction, EXT (atten- tion) requires no response from the therapist and simply consists of withholding attention that pre- viously followed the behavior. A more complicated situation exists if the target behavior occurs while the therapist is interacting with the client. In this case, withholding reinforcement [EXT (attention)] would consist of terminating the interaction.’ Be- cause similar variations are also characteristic of both EXT (escape) and EXT (sensory), we did not attempt to specify any particular procedure by way of descriptive label; this practice is consistent with terms such as DRO, time-out, punishment, and so forth, all of which require further elaboration. A reasonable conclusion based on descriptions
of behavior, procedure, and outcome reported in the above studies is that extinction designed for SIB serving one function may have little or no therapeutic effect on SIB serving a different func- tion. Given the variations of extinction described previously and the maintaining contingencies for which they might be used, it is possible to construct a contingency matrix such as that found in Figure 1, which allows predictions about behavioral out- come. For example, elimination of social reinforce- ment for SIB using EXT (attention) or EXT (es- cape) will not interfere with the delivery of sensory (automatic) reinforcement, and EXT (sensory) would have no effect on social sources of reinforce- ment. Most seriously, EXT (attention) applied to escape-maintained SIB (i.e., stimulus removal con- tingent on escape behavior) and, conversely, EXT (escape) applied to attention-maintained SIB (i.e., stimulus continuation contingent on attention-get- ting behavior) may be countertherapeutic and se- riously exacerbate the behavior problem. At the
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