Iwata et al. (1994) initially described the FA methodology as tentative in their paper entitled “Toward a functional analysis of self-injury.” Despite 30 years of research, the majority of studies continue to employ a multielement design, evaluate multiple test conditions, analyze results through visual inspection of graphed data, and include the same conditions (e.g., attention, demand, play) described by Iwata et al. For this reason, the original FA is now commonly referred to as the standard or traditional FA. Nonetheless, the literature also suggests an increasing focus on ways to clarify FA outcomes, particularly during the early stages of assessment, via modification to the standard procedures and design. The goal of methodological refinement is a more efficient assessment, with a potential reduction in the risks posed by problem behavior. A number of papers in this issue reflect this trend in the literature.
Several studies evaluated alternative ways to present test conditions. Hammond, Iwata, Rooker, Fritz, and Bloom (2013) examined the utility of a design modification that has been described in the literature but not widely adopted. In their study, presentation of the test and control conditions in a particular sequence rather than randomly yielded more efficient or clearer results for a noteworthy portion of cases. In two papers, a brief FA screening procedure that consisted of a series of alone or no-interaction sessions conducted prior to a full FA successfully differentiated cases of behavior maintained by automatic versus social reinforcement. Querim et al. (2013) evaluated the predictive validity of this screening approach by comparing the results of the brief screen to those of full FAs across a range of problem behaviors and functions. The FA screen predicted the maintaining source of reinforcement (social vs. automatic) in much less time than did full FAs, suggesting that it would increase the efficiency of the FA for behaviors that are likely to be maintained by automatic reinforcement (e.g., stereotypy). Roscoe, Iwata, and Zhou (2013) demonstrated the utility of a similar approach in a study with a large number of subjects on the environmental determinants and treatment of hand mouthing, a behavior that is commonly maintained by automatic reinforcement. Successful treatment did not require a full pretreatment FA for all 14 subjects who participated in both assessment and treatment evaluations.
In two studies, Fahmie and colleagues evaluated modifications to the standard FA conditions described by Iwata et al. (1994). Fahmie, Iwata, Harper, and Querim (2013) found that a variation of the attention condition in which the experimenter's attention was diverted to someone else was just as effective as or more effective than the standard attention condition for identifying attention as a maintaining reinforcer. In light of these findings, the authors suggested that this variation, which has been described previously in the literature, could replace the attention condition in the standard (i.e., initial) FA. Fahmie, Iwata, Querim, and Harper (2013) examined potential replacements for the standard control condition (i.e., play) of the FA. As designed originally, the play condition was a convenient control for multiple EOs and consequences manipulated in the test conditions. Nonetheless, some research findings suggest that the play condition may not be ideal for behaviors with particular functions (e.g., escape). Results of Fahmie et al. indicated that two conditions routinely included in the standard FA (play and ignore or alone) provide adequate control for the test conditions typically alternated in a multielement design.
Some forms of problem behavior warrant special consideration for design of the FA. For example, severe behavior disorders that increase the risk of physical injury require measures to ensure client safety during assessment. As noted previously, one potential strategy to minimize client risk is to identify and assess precursor behavior. In the most extensive evaluation of this approach to date, Fritz, Iwata, Hammond, and Bloom (2013) illustrated an objective yet efficient method for identifying behaviors (e.g., mild forms of problem behavior) that reliably predicted the occurrence of more severe problem behavior for 16 individuals with intellectual disabilities. Of particular relevance was the fact that caregiver interviews failed to identify the precursor behavior in nearly every case. FAs then confirmed that the precursor and target behaviors were members of the same response class. Most notably, the subjects engaged in little severe problem behavior during the FA of precursors, replicating prior work in this area. Subsequent treatment of the precursor behavior with a package that included noncontingent and differential reinforcement not only reduced the precursor behavior but suppressed severe problem behavior as well.
Elopement is another form of problem behavior that presents some unique challenges for the design of the FA, in that it necessarily involves client movement outside of confined (and highly controlled) areas and the introduction of potential confounding variables (e.g., attention in the form of physical retrieval). In this issue, two studies explored modifications to the standard FA with the aim to reduce these potential confounding effects. Neidert, Iwata, Dempsey, and Thomason-Sassi (2013) extended previous research on a trial-based FA format that uses latency to the first instance of elopement as the primary dependent variable. Lehardy, Lerman, Evans, O'Connor, and LeSage (2013) delivered test contingencies for movement across a room in lieu of elopement from the room in modified FAs. Both approaches eliminated the need to retrieve the client following elopement and appear promising for the assessment of this common problem behavior.
A literature review by Schlichenmeyer, Roscoe, Rooker, Wheeler, and Dube (2013) reflects an increasing interest in manipulations that identify idiosyncratic influences on behavior after a standard FA produces undifferentiated outcomes. A retrospective analysis of 176 cases conducted by Hagopian, Rooker, Jessel, and DeLeon (2013) demonstrated the success of this approach when adopted as part of routine clinical practice. A clear function was identified in just 47% of initial FAs; this percentage increased to 87% when clinicians implemented up to two modified FAs after inconclusive outcomes. These modifications primarily consisted of changes to the design (e.g., use of a pairwise design) and to antecedents in the test conditions (e.g., demands).
As discussed earlier in this paper, a review of research conducted between 2001 and 2012 revealed greater use of the FA in naturalistic settings, such as homes and schools, an inevitable and welcome extension indicative of the fact that practitioners who work in more diverse settings are adopting FA methodology. A number of studies in this issue examined refinements to the traditional FA that could affect the likely success of this technology transfer. The lack of qualified individuals to conduct the assessment is one barrier to extending the FA more broadly. Wacker et al. (2013) evaluated the use of a telehealth system to provide remote consultation services to 20 parents of children with autism who engaged in problem behavior. Parents implemented standard FAs with their children at regional medical clinics while they were coached by consultants via video conferencing. The highly promising results suggest that telehealth systems could increase access to FA services in areas that lack qualified professionals. In three other studies, experimenters evaluated a methodology for conducting FAs more readily in classrooms and other community settings, which involved teachers or caregivers periodically presenting FA trials within the context of naturally occurring activities. Bloom, Lambert, Dayton, and Samaha (2013) and Kodak, Fisher, Paden, and Dickes (2013) demonstrated that classroom staff could successfully conduct trial-based FAs in their classrooms. Moreover, Bloom et al. showed that results of these FAs led to effective interventions for students' problem behavior. Extending the trial-based FA to another setting, Lambert, Bloom, Kunnavatana, Collins, and Clay (2013) taught supervisors of a residential facility to train house managers to conduct FAs of clients' problem behavior. Results of all three studies provide further evidence of the utility of this format for conducting FAs in natural settings.
Regardless of the FA methodology, conducting assessments in naturalistic settings has potential advantages and disadvantages that have not been thoroughly explored. Thomason-Sassi, Iwata, and Fritz (2013) addressed this issue by comparing the results of FAs conducted by experimenters in a clinic setting to those conducted by caregivers or in the home setting. Although FA outcomes were similar in the majority of cases, results for two subjects indicated that the use of familiar versus unfamiliar people could alter the likelihood of identifying behavioral function. Implications of these findings for conducting FAs are complicated by the fact that a familiar person was critical for identifying the function in one case, whereas an unfamiliar person was critical for identifying function in the other case.
The use of formal criteria for interpreting FA data is another refinement that could lead to more efficient FAs and promote transfer of the methodology more broadly. As noted previously, the criteria for visual data inspection described by Hagopian et al. (1997) have not been widely adopted, perhaps because they were established for FAs comprised of lengthy data sets (10 sessions per condition). To address this limitation, Roane, Fisher, Kelley, Mevers, and Bouxsein (2013) modified these criteria so that they could be applied to FAs of any length and found that the use of these criteria by reviewers with varying levels of expertise substantially improved the reliability of data interpretation. They then demonstrated the utility of the visual inspection criteria by having experts apply them to 141 data sets.
In the final paper consistent with the theme of methodological refinement, Iwata, DeLeon, and Roscoe (2013) examined the reliability and validity of a caregiver questionnaire about conditions under which problem behavior might occur. Such indirect assessments are now a common supplement to (and, in practice, a common replacement for) the FA, despite decades of research that has demonstrated the inadequate reliability of these instruments. Iwata et al. developed the Functional Analysis Screening Tool (FAST) with items derived from conditions used in current FA research in an attempt to improve the consistency of verbal report. The resulting moderate reliability of the FAST, however, was similar to that of previously studied instruments. Not surprisingly, the validity of the FAST was found to be inadequate for determining function when caregiver report was compared to the results of standard FAs. Further research is needed on the potential contribution of indirect assessment to the design or modification of FAs.
The application of the FA methodology to treat atypical behavior problems and the problems of individuals without intellectual disabilities has continued to receive some attention in the FA literature, as indicated by the selection of articles in this issue. This research indicates that scientists and clinicians recognize the benefits of taking a function-based approach to understanding and treating behaviors of social importance, regardless of response typography or client population. The FA was extended to such problems as sleep disorders (Jin, Hanley, & Beaulieu, 2013), bruxism (Lang et al., 2013), perseverative speech (Fisher, Rodriguez, & Owen, 2013), crying (Bowman, Hardesty, & Smith, 2013), and rumination (K. E. Woods, Luiselli, & Tomassone, 2013). In addition, Plavnick and Normand (2013) provided an overview and critique of recent research on the use of FA to assess verbal behavior. In a particular novel application of the methodology, Larson, Normand, Morley, and Miller (2013) evaluated conditions under which typically developing children were more or less physically engaged during recess. Such an approach holds promise for the development of function-based interventions to promote physical activity in children. Greer et al. (2013) also extended the FA to assess behavior problems in typically developing children. Therapists conducted standard FAs of aggression and property destruction of four children in a preschool classroom and developed effective, function-based interventions on the basis of the outcomes.
Several studies in this issue illustrate the contribution of the FA methodology to our understanding of variables that affect treatment success. Knowledge of function is essential when attempting (a) to identify mechanisms that underlie commonly used interventions (e.g., extinction), (b) to develop strategies for improving treatment outcomes (e.g., schedule thinning), and (c) to evaluate treatment components most likely to be effective for particular behavioral functions (e.g., automatic reinforcement; social avoidance). Two studies focused on variables that alter resistance to extinction, a particularly important concern given that extinction is a ubiquitous component of function-based treatments. Treatments for behavior maintained by automatic reinforcement are an exception, however, because the functional reinforcer typically is difficult to identify and withhold. Dozier, Iwata, Wilson, Thomason-Sassi, and Roscoe (2013) examined the possibility that response-contingent arbitrary (social) reinforcers might displace automatic reinforcers that maintain stereotypy, leading to successful extinction of responding when the social reinforcer is withheld. Despite making a number of methodological improvements over prior work in this area, Dozier et al. found no evidence for the success of this approach with nine subjects. Knowledge of behavioral function also was essential for studying the relation between reinforcement schedule and resistance to extinction. Consistent with behavioral momentum theory, MacDonald, Ahearn, Parry-Cruwys, Bancroft, and Dube (2013) found that problem behavior was more resistant after continuous reinforcement than after intermittent reinforcement. Such an outcome suggests that behavior may be easier to treat in the natural environment, where reinforcement is typically delivered on an intermittent basis. Nonetheless, the authors also noted that possible challenges may arise when treatment follows exposure to FAs in which behavior contacts continuous reinforcement.
Extinction effects may be implicated in other aspects of treatment delivery. For example, when an FA identifies the reinforcer maintaining problem behavior, the same reinforcer may be provided for appropriate behavior within the context of such treatments as functional communication training. The effectiveness of this intervention, however, often depends on the continued availability of the reinforcer for the alternative behavior (i.e., communication response). Such an arrangement is not practical and may result in excessively high levels of the alternative behavior. With this in mind, Betz, Fisher, Roane, Mintz, and Owen (2013) further evaluated the use of multiple schedules (alternating periods of reinforcement and extinction) to thin the schedule of reinforcement for appropriate behavior during treatment with functional communication training. After successful discrimination training, treatment remained effective even when the reinforcer was unavailable for lengthy periods of time. Furthermore, a component analysis revealed that the success of this approach did not depend on a gradual lengthening of the extinction period.
Thirty years of research on FA has firmly established the relevance of assessment outcome to the selection and design of treatments for problem behavior. As two studies illustrate, this recognition drives research on treatments for behavior disorders with particular functions (e.g., escape) rather than on treatments for particular behavior problems (e.g., aggression). Harper, Iwata, and Camp (2013) evaluated multiple treatments for problem behavior maintained by escape from social interaction, a function that has rarely been addressed in the literature. After modifying the standard FA to confirm maintenance by escape from social interaction per se, the experimenters examined the effects of vicarious reinforcement, conditioning of social interaction, stimulus fading, and differential reinforcement plus extinction during separate treatment conditions. The aim was to reduce the aversiveness of social interaction as demonstrated through a corresponding reduction in problem behavior during baseline. Only differential reinforcement plus extinction reliably reduced problem behavior under both treatment and baseline conditions, suggesting the superiority of consequence-based interventions for reducing social avoidance. Results of modified FAs conducted by Roscoe et al. (2013) revealed that hand mouthing was maintained by automatic reinforcement for nearly all of the 64 subjects. In a subsequent treatment analysis with 14 individuals, the experimenters demonstrated a model for introducing treatments in a least-to-most intrusive hierarchy based on patterns of responding under each intervention component. The outcome of this large-scale analysis provides the field with valuable information regarding the likely success of commonly used reinforcement-based treatments for behavior maintained by automatic reinforcement.
In the 30 years since the original publication of the experimental model proposed by Iwata et al. (1994), FA methodology has become an integral part of behavioral assessment. This is true not only in the field of applied behavior analysis but also in related fields, as evidenced by the increased number of traditional journals that represent a range of human services research in which FA studies are published. Improving the efficiency of assessment while maintaining its accuracy is still an important goal for future research, especially if FA methodology is to be extended to problems experienced by the typical population (only two studies in this special issue focused on typically developing subjects). One area in which FA methodology may be particularly useful in future years is behavioral gerontology. Although problem behavior exhibited by geriatric individuals was examined in only three studies in the present review, its importance as a clinical challenge will surely increase as the largest segment of our population (those born immediately after World War II) continues to age.
Extension to problem behavior associated with aging represents only one of the many areas in which additional research is needed. For example, traditional approaches to the assessment of most clinical disorders are based on structural aspects of behavior (observed symptoms) rather than on cause–effect demonstrations. This fact has not escaped the attention of many psychiatrists for several years. Most recently, McHugh and Slavney (2012), in commenting on revisions to the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 2000), suggested a benefit for organizing clinical disorders based on causation:
Psychiatrists would start moving toward the day when they address psychiatric disorders in the same way that internists address physical disorders, explaining the clinical manifestations as products of nature to be comprehended not simply by their outward show but by the causal processes and generative mechanisms known to provoke them. Only then will psychiatry come of age as a medical discipline. (p. 1854)
The challenges posed in developing function-based approaches to assessment of problems such as obsessive compulsive disorder, chronic depression, and so on, are many, but resolution of complexities related to definition, measurement, and control has always been the strength of our field. Baer, Wolf, and Risley (1968) noted that “applied research is constrained to examining behaviors which are socially important, rather than convenient for study” (p. 92). If the goal of applied behavior analysis is to solve problems of social significance, regardless of the ease with which this can be done, there is no end to the possible extensions of FA methodology that have yet to be accomplished.