- Email: [email protected]
Identifying specific sensory modalities maintaining the stereotypy of students with multiple profound disabilities
Research in Developmental Disabilities 24 (2003) 433–451
Identifying specific sensory modalities maintaining the stereotypy of students with multiple profound disabilities$ Jung-Chang Tang1, Tina G. Patterson, Craig H. Kennedy* Department of Special Education, Box 328, Peabody College, Vanderbilt University, Nashville, TN 37203, USA Received 4 January 2002; received in revised form 8 November 2002; accepted 10 February 2003
Abstract In Experiment 1, analogue functional analyses were conducted to identify the functions of stereotypy for six students with multiple profound disabilities. Results indicated that stereotypy (a) occurred across conditions, (b) occurred primarily when alone, or (c) occurred during all sessions except in the Control condition. Experiment 2 analyzed stereotypy while masking visual, auditory, or tactile sensory consequences. Results showed that stereotypy was maintained by visual stimulation, tactile stimulation, or was undifferentiated across conditions. In Experiment 3, we showed that stereotypy could be reduced by providing competing sensory stimulation. In Experiment 4, stereotypy that was undifferentiated in Experiment 1 was analyzed using a concurrent operants procedure. Results showed that stereotypy was not multiply determined, but occurred to produce visual sensory stimulation. Our findings are discussed in terms of the sensory and social reinforcers that maintain stereotypy, assessment procedures used to identify those reinforcers, and the interpretation of assessment results. # 2003 Elsevier Ltd. All rights reserved. Keywords: stereotypy; sensory reinforcement; functional analysis; functional assessment; private events; severe disabilities; developmental disabilities
$ This article is based on a dissertation submitted to Vanderbilt University in partial fulfillment of the Ph.D. degree by the first author. * Corresponding author. Tel.: þ1-615-322-8178; fax: þ1-615-343-1570. E-mail address: [email protected] (C.H. Kennedy). 1 Present address: National Chia Yi University, Taiwan.
0891-4222/$ – see front matter # 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.ridd.2003.02.001
434
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
Stereotypy is defined as behavior that occurs at a high frequency and is topographically invariant. Researchers have shown that stereotypies occur across a range of individuals, but that there is an increased probability of stereotypy inversely related to a person’s intellectual functioning level (Berkson & Tupa, 2002). Initial accounts suggested that stereotypy occurred for ‘‘homeostatic’’ reasons (Baumeister & Forehand, 1973). That is, this type of responding might occur to increase or decrease levels of environmental stimulation. Both types of response functions have been conceptualized as providing sensory consequences to the person engaging in stereotypy (Lovaas, Newson, & Hickman, 1987). Recent research has suggested that this conceptualization of stereotypy is accurate, but incomplete (Guess & Carr, 1991; Kennedy, 2002). For example, Kennedy, Meyer, Knowles, and Shukla (2000) analyzed the stereotypy of students with autism and found several patterns. For some students, stereotypy was a function of sensory and social reinforcement, while for others an undifferentiated pattern of behavior occurred across conditions. These findings suggest that the causes of stereotypy are more complex than researchers originally hypothesized. Current findings suggest that stereotypy can be a function of (a) positive sensory reinforcement, (b) negative sensory reinforcement, (c) positive social reinforcement, and/or (d) negative social reinforcement. Although research has shown that stereotypy can be multiply determined and include reinforcing stimuli that are socially mediated, less attention has been given to the nature of sensory reinforcers. This lack of attention may be due to two reasons. First, functional analyses of stimuli maintaining stereotypy have not occurred because the behavior was assumed to be maintained by sensory stimulation and, thus, it was not necessary to confirm this hypothesis. Second, the analysis of presumed sensory reinforcers is technically challenging and, in some cases, may not be amenable to an experimental analysis. This is because the response itself might produce biologically reinforcing stimulation (Kennedy, Caruso & Thompson, 2001; Symons, 2002; Turner & Lewis, 2002) and involve private events not accessible to others (Kennedy, 1994; Moore, 1992). However, some researchers have sought to overcome the technical difficulties of studying stereotypy (Fisher, Lindauer, Alterson, & Thompson, 1998; Goh et al., 1995; Hanley, Iwata, Thompson, & Lindberg, 2000; Kennedy et al., 2000; Lindberg, Iwata, & Kahng, 1999). In general, these approaches have focused on providing alternative sources of stimulation to compete with hypothesized private events maintaining responding. For example, Goh et al. (1995) analyzed handmouthing by providing competing forms of stimulation (i.e., items that could be mouthed and/or manually manipulated). Goh et al.’s results suggested that handmouthing was maintained primarily by manual stimulation of the hands. Results such as these help reveal the nature of sensory reinforcers involved in maintaining stereotypy, but have the limitation of being indirect tests of response– reinforcer relations. An alternative procedure for testing possible sensory functions of stereotypy would be to mask specific sensory modalities associated with behavioral maintenance. For example, Rincover, Cook, Peoples, and Packard (1979) masked
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
435
auditory, tactile, or visual modalities and found that stereotypy was a function of specific types of sensory stimulation. The responses Rincover et al. analyzed involved the manipulation of specific objects as stereotypical behaviors (e.g., plate spinning). However, many stereotypical behaviors do not involve the manipulation of objects (e.g., handmouthing, body rocking, and hand flapping). In such cases, no direct test of specific sensory modalities associated with stereotypy has been conducted. In the current series of experiments, we sought to extend previous work on sensory stimulation associated with stereotypy using procedures similar to those of Rincover et al. (1979). In Experiment 1, analogue functional analyses were used to identify patterns of stereotypy that might suggest sensory reinforcement. In Experiment 2, specific sensory modalities (i.e., auditory, tactile, or visual) were masked to assess whether stereotypy might be sensitive to a specific form of sensory stimulation. Competing stimuli consistent with the findings of Experiment 2 were tested in Experiment 3 to assess their effect on stereotypy. Finally, a concurrent operants procedure was used to analyze possible sensory and/or social reinforcers associated with stereotypy to clarify findings from an earlier undifferentiated analogue functional analysis outcome in Experiment 1. Our goal was to identify specific sensory modalities that might be involved in the maintenance of stereotypy that were produced directly by the behavior.
1. General method 1.1. Students and settings Six students participated in the study. The students were selected for inclusion in the study if (a) they engaged in only one or two stereotypies, (b) those stereotypic topographies were invariant, (c) stereotypical behavior(s) were emitted during 50% of the time, (d) students had multiple profound disabilities, and (e) they attended a public school. Sessions were conducted in a room at each student’s school that measured 5 m 6 m or 8 m 10 m. The rooms contained several tables/chairs and provided a quiet environment free of distractions. Table 1 provides student demographic information. The students’ primary mode of ambulation was with a wheelchair, except Janey who was ambulatory. James was diagnosed with profound intellectual disabilities and multiple physical impairments. His partial absence seizures were controlled by phenobarbital (60 mg once per day). He communicated using single consonant utterances and followed simple requests with partial physical assistance. Janey had a profound intellectual disability and autism. She communicated using single consonant utterances and required partial physical prompts to follow requests. Linda was diagnosed with profound intellectual disabilities, multiple physical impairments, and visual impairments (right eye retinopathy, left eye corneal opacity). She communicated through single consonant utterances and required full physical guidance to follow requests. Lisa was diagnosed with profound
436
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
Table 1 Student demographics Student
Gender
Age
Stereotypical behavior(s)
Receptive comprehensiona
Expressive communicationa
James Janey Linda Lisa Peter Tom
Male Female Female Female Male Male
11 6 17 8 17 4
Hand mouthing Hand mouthing Finger movement Finger movement Finger movement, head shaking Finger licking, eye-covering
6 6 6 6 7 6
9 months 9 months 4 months 12 months 5 months 9 months
a
months months months months months months
Estimated using the Preschool Language Scales-3.
intellectual disabilities, multiple physical impairments, and autistic-like behavior. She spoke using one or two word repetitive utterances and could follow simple, one-step verbal requests. Peter was diagnosed with profound intellectual disabilities, multiple physical impairments, and autistic-like behavior. Peter had generalized tonic–clonic epilepsy that was controlled by phenobarbital (100 mg once per day). He used facial gestures to communicate and could follow simple requests with partial physical assistance. Tom was diagnosed with profound intellectual disabilities and was legally blind (congenital corneal dystrophy with optic nerve hypoplasia). He communicated with others through vocal sounds or touching and required full physical guidance to follow requests. 1.2. Responses, data collection, and interobserver agreement Stereotypical responses are listed in Table 1. Each session was videotaped for later scoring. A trained graduate student scored each session using a 15-s partial interval pencil-and-paper observation system. In Experiment 4, the same observation system was used to estimate Lisa’s alternative communication responses. Across students, responses, and experiments, 22% of sessions (range 20–33%) were scored for interobserver agreement (IOA) by having a second observer independently record the occurrence of stereotypy and/or alternative communication responses. Occurrence IOA was scored using the formula: Agreements divided by agreements plus disagreements multiplied by 100%. IOA means for stereotypy were 96% (range 80–100%), 95% (range 80–100%), 96% (range 90–100%), and 94% (range 85–100%) for Experiments 1, 2, 3, and 4, respectively. For Lisa’s alternative communication response mean agreement was 96% (range 85–100%).
2. Experiment 1 The first experiment assessed the possible function(s) of stereotypy using analogue functional analysis procedures.
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
437
2.1. Method 2.1.1. Students, design, and procedures All students listed in the Section 1 participated in Experiment 1. A multielement design (Sidman, 1960) was used to assess the occurrence of stereotypy across four conditions: (a) Alone, (b) Attention, (c) Demand, and (d) Control (see Iwata, Dorsey, Slifer, Bauman, & Richman, 1982; Kennedy et al., 2000). Each condition was presented for 5 min, once per day with a random sequence occurring across days. Sessions were conducted at the same time, 3–5 days per week. During the Attention condition, an instructor (the first author) and student sat at a table. When seated, the instructor engaged in paperwork, while the student was provided with several activities (see Control condition). If stereotypy occurred, the instructor provided 5 s of social comments to the student and told him or her not to engage in stereotypy. All occurrences of stereotypy occasioned a similar response from the adult. This condition assessed the degree to which stereotypy was positively reinforced by attention. During the Demand condition, an instructor delivered a verbal demand every 10 s. Correct responding was praised and incorrect or no responding resulted in a full physical prompt after 10 s. Any occurrence of stereotypy resulted in a 30-s cessation in task demands. This condition assessed the degree to which stereotypy was negatively reinforced by escaping/avoiding demands. During the Alone condition, students were seated at a table and received no social interaction or activities. The Alone condition assessed the degree to which stereotypy occurred in the absence of programmed contingencies or environmental stimulation. During the Control condition, students were provided with various activities identified by teachers as being preferred and praised every 30 s in the absence of stereotypy. The Control condition was used to minimize the occurrence of stereotypy. 2.2. Results and discussion Fig. 1 displays the percentage of intervals with stereotypy across the assessment conditions for Linda, Lisa, James, and Janey. Across all conditions and sessions, Linda engaged in high levels of stereotypy. The stereotypical responding of Lisa also showed an undifferentiated pattern, as did James’ stereotypy. Janey displayed a similar pattern of undifferentiated stereotypy across experimental conditions, but her pattern was more variable than that of the other students in Fig. 1. Fig. 2 shows stereotypy data for Peter and Tom. The data are presented separately for each topography of stereotypy within a specific session for each student. Peter’s finger movements occurred at the highest levels in the Alone condition, occurred at moderate-to-low levels in the Attention and Demand conditions, and lowest in the Control condition. Peter’s head shaking was clearly differentiated with this response occurring at the highest levels in the Alone condition. Tom’s finger licking occurred at high levels in the Alone, Attention,
438
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
Fig. 1. Results of the analogue functional analysis of stereotypy in Experiment 1 for Linda, Lisa, James, and Janey.
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
439
Fig. 2. Results of the analogue functional analysis of stereotypy in Experiment 1 for Peter (finger movements: Tier 1; head shaking: Tier 2) and Tom (finger movements: Tier 3; eye-covering: Tier 4).
440
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
and Demand conditions, and at lower levels in the Control condition. Tom’s eyecovering occurred at low levels, but showed a pattern similar to that of finger licking. These data suggest three general patterns. First, the stereotypy of students in Fig. 1 showed an undifferentiated pattern that makes interpretation of specific operant functions difficult. Second, for Peter, both his topographies of stereotypy occurred primarily in the Alone condition, but with slightly different patterns for each behavior. Third, Tom’s finger licking and eye-covering appeared to be multiply determined. These data replicate the findings of Kennedy et al. (2000) demonstrating that stereotypy (a) occurred in an undifferentiated pattern (i.e., no identified reinforcing stimulus), (b) occurred only in the Alone condition (i.e., presumed sensory consequences), or (c) was multiply determined (i.e., social and presumed sensory consequences).
3. Experiment 2 Experiment 2 was conducted to identify possible sources of stereotypy based on sensory consequences in an attempt to further differentiate the patterns of responding from Experiment 1. In Experiment 2, stereotypy during the Alone condition was further analyzed by masking individual sensory consequences. 3.1. Method 3.1.1. Students, design, and procedures Linda, Lisa, Janey, Peter, and Tom participated in Experiment 2 (James was no longer available to participate because he moved to another school). A multielement design with the following conditions was used: (a) Alone, (b) Auditory Masking, (c) Tactile Masking, and (d) Visual Masking. Each condition lasted 5 min and was presented once per day, with a random sequence of conditions across days. Sessions were conducted at the same time, 3–5 days per week. The specific sensory masking technique was individualized based on the topography of each individual’s stereotypy. Because of the potentially intrusive nature of the sensory masking process, we had an advocate/parent review each masking technique, try it herself, and observe sensory masking sessions. All techniques were approved by the advocate/parent and no signs of dissent by students was observed (e.g., removing the stimulus or engaging in problem behavior). The Alone condition was the same as Experiment 1. The Auditory Masking condition was the same as the Alone condition, except that auditory stimuli associated with stereotypy were minimized. All students except Tom wore safety earplugs that reduced or eliminated sounds between 20 Hz and 20 kHz by 35 dB. Tom wore a pair of sound eliminating headphones which reduced auditory stimulation to a similar level. The Tactile Masking condition replicated
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
441
the Alone condition, except that tactile stimuli associated with stereotypy were minimized. All students wore gloves that minimized finger movements or access to the mouth. The Visual Masking condition was the same as the Alone condition, except that visual stimuli associated with stereotypy were minimized. For Peter a pair of opaque plastic safety goggles were sued eliminating all frontal and peripheral vision because his stereotypy tended to occur in both visual fields. For the other students an opaque screen (30 cm by 33 cm) was held approximately 7 cm in front of their faces. This less intrusive screening procedure was used because students’ stereotyped responses occurred only in the frontal visual field (during the analysis no change in stereotypic topographies occurred). 3.2. Results and discussion Fig. 3 shows the sensory masking results for Linda, Lisa, and Janey. Linda engaged in high levels of stereotypy in the Alone (M ¼ 94%), Auditory Masking (M ¼ 94%), and Tactile Masking (M ¼ 79%) conditions, with a slightly lower level of stereotypy occurring in the Visual Masking condition (M ¼ 59%). Lisa engaged in very low levels of stereotypy in the Visual Masking condition (M ¼ 11%), but high levels of stereotypy in the Alone (M ¼ 85%), Auditory Masking (M ¼ 83%), and Tactile Masking (M ¼ 70%) conditions. Janey showed a largely undifferentiated pattern across conditions (M ¼ 78%), with stereotypy being somewhat lower in the Tactile Masking condition (M ¼ 52%). Fig. 4 displays the results for the sensory masking analysis for Peter and Tom. The two topographies of stereotypy for each student are presented separately. Neither finger movements nor head shaking showed any response differentiation across conditions for Peter. For Tom his finger licking was substantially lower in the Tactile Masking condition (M ¼ 38%), when compared to the other three conditions (M ¼ 92–98%). His eye-covering occurred at low levels across conditions. For Lisa, the results of Experiment 2 suggest that the visual sensory consequences were associated with stereotypy. When visual stimulation was minimized, Lisa’s stereotypy occurred at lower levels, whereas in the other masking conditions behaviors occurred at similar levels to the Alone condition. Linda’s stereotypy was also possibly influenced by visual stimulation. Tom’s finger licking appeared to be associated with tactile sensory consequences the response produced (although eye-covering was undifferentiated). Janey’s stereotypy was possibly influenced by tactile stimulation. For Peter, no response differentiation occurred across conditions (see Section 6).
4. Experiment 3 The findings of Experiment 2 were further analyzed for Janey, Linda, and Lisa using competing forms of visual and tactile stimulation.
442
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
Fig. 3. Results of the sensory masking procedures on stereotypy in Experiment 2 for Linda, Lisa, and Janey.
4.1. Method 4.1.1. Students, design, and procedures Linda, Lisa, and Janey participated in Experiment 3 (Tom was unavailable to participate; Peter’s undifferentiated response patterns in Experiment 2 precluded participation in Experiment 3). A multielement design incorporating the same conditions as Experiment 2 was used with the addition of the following arrangements. For Linda and Lisa, a Competing Visual Stimulation condition was used. This condition noncontingently provided the students with a visual stimulus that was
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
443
Fig. 4. Results of the sensory masking procedures on stereotypy in Experiment 2 for Peter (finger movements: Tier 1; head shaking: Tier 2) and Tom (finger movements: Tier 3; eye-covering: Tier 4).
444
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
reported by teachers to be a preferred item (a videogame for Linda and magazine for Lisa). For Janey, the Competing Tactile Stimulation condition noncontingently provided her with a piece of string (which she used to mouth). Apart from these exceptions, all conditions and procedures were the same as in Experiment 2. 4.2. Results and discussion Fig. 5 presents the competing stimulation results for Linda, Lisa, and Janey. Stereotypy was relatively high across conditions for Linda. For Lisa, stereotypy
Fig. 5. Results of the competing stimulation analysis from Experiment 3 for Linda, Lisa, and Janey.
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
445
was clearly reduced in the Visual Stimulation and Competing Visual Stimulation conditions, relative to the other conditions. Finally, Janey’s stereotypy was lowest in the Competing Tactile Stimulation condition, with responding being lower, but more variable in the Tactile masking condition. For Lisa, these results suggest that an alternative form of stimulation, in the same sensory modality that was previously shown to be associated with responding, could effectively reduce the occurrence of stereotypy. For Janey, the outcomes were less clear and should be interpreted with caution because the competing tactile stimulus may have served as another form of stereotypy.
5. Experiment 4 In Experiment 1, the stereotypy of several students was shown to occur across assessment conditions (Linda, Lisa, James, and Janey). Interpretation of undifferentiated outcomes in terms of specific operant functions is difficult, because response differentiation is necessary to identify reinforcers maintaining responding. The undifferentiated patterns observed in Experiment 1 could be interpreted as indicating that behavior was maintained by sensory consequences or multiple sensory and social reinforcers. In order to further study the possible social functions of stereotypy we used a concurrent operants procedure with one the students (Lisa). Given the successful identification in Experiment 2 of visual stimulation as a source of reinforcement for Lisa’s stereotypy, in Experiment 4 we sought to individually test sensory and social reinforcement hypotheses to better understand the results of Experiment 1 using a different assessment procedure. 5.1. Method 5.1.1. Student, design, and procedures Lisa’s stereotypy was analyzed using a mixed design that combined a multiple baseline across operant functions with an ABAB withdrawal analysis (Kennedy, in press). 5.1.1.1. Baseline. Three possible operant functions of stereotypy identified in Experiment 1 were incorporated into three baselines: (a) visual stimulation (Alone condition), (b) negative reinforcement as escape/avoidance from demands (Demand condition), and (c) positive reinforcement as adult attention (Attention condition). The Alone, Attention, and Demand conditions used in Experiment 1 were used to establish baseline performances (see Kennedy et al., 2000). Therefore, in the Alone condition, no programmed contingencies or stimulation occurred; in the Attention condition, stereotypy occasioned social attention; and, in the Demand condition, stereotypy occasioned the removal of task demands. If a topography of behavior consistent with those in the functional communication training (FCT) condition occurred (see below), it was ignored. Alone, Attention, and Demand condition sessions were conducted in a fixed
446
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
sequence, 2–5 days per week. Each session lasted 5 min and was separated by a 5-min intersession interval. 5.1.1.2. Functional communication training. An alternative behavior was selected to occasion a similar reinforcer for each response–reinforcer relation established in baseline (Carr & Durand, 1985). For Alone, Attention, and Demand conditions, Lisa was taught to raise her right hand, sign ‘‘videogame,’’ and sign ‘‘break,’’ respectively, as an alternative response. Consequences for alternative
Fig. 6. Results of the functional communication training FCT intervention across possible operant functions for Lisa’s stereotypy.
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
447
behaviors were the same as stereotypy in the baseline conditions, except that signing ‘‘videogame’’ occasioned the delivery of a videogame for 15 s. That is, in the Alone condition Lisa signing ‘‘videogame’’ occasioned access to the videogame, in the Attention condition, Lisa signing ‘‘high’’ occasioned attention, and in the Demand condition Lisa signing ‘‘Break’’ occasioned the removal of task demands. During training, the occurrence of stereotypy occasioned (a) response interruption, (b) extinction of programmed responses for the stereotypy, (c) partial physical prompting of the alternative response, and (d) presentation of the associated consequence for the alternative response (i.e., the same contingency as established in baseline for stereotypy). Each time the alternative response was emitted, either prompted or unprompted, the associated consequence was implemented. 5.2. Results and discussion Fig. 6 shows the results of Experiment 4 for Lisa. She engaged in high levels of stereotypy and moderate levels of signing in the Alone condition baseline. A rapid reversal in her pattern of behavior occurred with the introduction of FCT. The ABAB withdrawal design showed that the decreases in stereotypy were a function of FCT. However, the introduction of FCT for the Demand and Attention condition baselines resulted in little or no changes in signing or stereotypy. The findings presented in Fig. 6 suggest that Lisa’s stereotypy was sensitive to sensory reinforcement in the form of visual stimulation, but that social reinforcement was not involved in behavioral maintenance. Given that Lisa’s stereotypy was shown to have an undifferentiated pattern when assessed using an analogue functional analysis in Experiment 1, the findings of Experiment 4 help clarify the causes of her stereotypy. A conclusion that can be drawn from these datasets is that her stereotypy was a function of visual sensory reinforcement that occurred apart from the programmed contingencies in the analogue functional analysis (Experiment 1).
6. General discussion In Experiment 1, we demonstrated that the stereotypy of students with multiple profound disabilities occurred in an undifferentiated pattern (Linda, Lisa, James, and Janey), only in the Alone condition (Peter), or was only suppressed in the Control condition (Tom). These findings left unclear the nature of the reinforcer(s) maintaining stereotypy. In Experiment 2, specific sensory consequences that might be associated with the maintenance of stereotypy were masked. The analysis showed that stereotypy was maintained by visual stimulation (Lisa), tactile stimulation (Tom), or an inconclusive pattern resulted (Peter). Two other students showed a possible relation between stereotypy and visual stimulation (Linda) or tactile stimulation (Janey). In a third experiment, competing sensory stimulation was presented in the same modality as was shown in Experiment 2 to
448
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
maintain stereotypy. One student (Lisa) showed decreased levels of stereotypy when competing sensory stimulation was presented, with another student showing a slight reduction in levels of stereotypy (Janey). In the final experiment, we used an alternative procedure to analyze the possible functions of stereotypy for a student whose behavior was undifferentiated across conditions in Experiment 1. The results of Experiment 4 suggested that the undifferentiated analogue functional analysis results in Experiment 1 were a function of visual sensory reinforcement competing with the programmed social contingencies. Our findings suggest that, as with students with autism (Kennedy et al., 2000), the stereotypy of students with multiple profound disabilities occurs for a variety of reasons. The current findings replicate our previous findings regarding the complex nature of stereotypy and extend it to a different student population. As a whole, these results suggest that stereotypy can be maintained by sensory and social reinforcers and that an assessment of behavioral function(s) is necessary in order to establish why the behavior occurs. Stereotypy might occur for sensory stimulation, but it can also serve other communicative functions. If the data from the current experiments and Kennedy et al. (2000) are combined (for an N ¼ 11) the following patterns of stereotypy have been documented. First, one student’s stereotypy occurred only in the Alone condition which suggests that the behavior was a function of sensory consequences. Second, one student’s stereotypy only occurred in conditions that assessed socially mediated contingencies (i.e., Demand and Attention). For six other students, stereotypy occurred across all assessment conditions. Finally, for three students, stereotypy occurred in all assessment conditions except the Control condition. Two of these patterns, in particular, deserve further discussion because of the interpretative challenges they present to researchers. The basis for experimental control in single-case designs is response differentiation across conditions (Kennedy, in press; Sidman, 1960). However, in 55% of the functional analyses of stereotypy that our research group has conducted, an undifferentiated pattern emerged across conditions. In essence, there is no experimental control demonstrated in these cases. This makes interpretation of the data difficult because any estimate of behavioral function is premature. It is possible to conclude that stereotypy is occurring only for sensory consequences; however, that interpretation requires an inference above what the dataset offers. Such concerns were the primary reason for conducting the experiments reported in this paper. By attempting to isolate specific sensory modalities, our goal was to induce response differentiation and identify possible sensory consequences causing responding. We were successful in identifying a sensory modality associated with stereotypy in two cases, suggesting that the behavior was maintained by a specific sensory consequence. To further explore the implications of these findings, we used a concurrent operants procedure to test specific sensory and social reinforcement hypotheses for one student. For Lisa, we were only able to replace stereotypy with an alternative response using FCT in the visual stimulation condition. This suggests that the results of her undifferentiated analogue functional analysis in Experiment 1 was due to sensory reinforcers
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
449
successfully competing with programmed social contingencies. Whether such patterns of responding occur for other cases of stereotypy that produce undifferentiated analogue functional analysis outcomes awaits further study. A second pattern of stereotypic responding that requires discussion is that observed for Tom in the current analysis and two other students in the Kennedy et al. (2000) study (i.e., Brad and James). For these students stereotypy occurred at elevated levels in the Alone, Attention, and Demand conditions, but not in the Control condition. Two equally plausible, but incompatible interpretations of these data are possible. One interpretation is that the behavior is multiply determined and is maintained by sensory reinforcement, positive social reinforcement, and negative social reinforcement. A second interpretation is that the behavior only occurred for sensory consequences that effectively competed with social reinforcement in the Attention and Demand conditions, but not in the Control condition (Conners, Iwata, & Shores, 2001). Given the results of the functional analysis, either interpretation could be accurate, although they have substantially different implications for treatment selection. Because this assessment outcome has occurred in 27% of the cases that have been studied, additional research is necessary to further clarify the operant nature of these stereotypical behaviors. Another finding worth noting is that the separate topographies of stereotypy emitted by Peter (finger movements and head shaking) and Tom (finger movement and eye-covering) showed similar analogue functional analysis outcomes. This might suggest that multiple topographies of stereotypy can belong to the same response class. However, this interpretation of the data should be met with caution because it is possible that although the stereotypical responses were both reinforced by sensory consequences, the specific nature of those consequences differed. This distinction may be important because developing an intervention plan based on a general assessment outcome of ‘‘sensory reinforcement’’ may not take into account that different stereotypical responses may serve different sensory functions (e.g., visual versus auditory). This preceding observation also points out a limitation of this study and, perhaps, the analysis of sensory consequences in general. That is, some topographies of stereotypy may not lend themselves to a functional analysis. For example, Peter’s head shaking occurred only in the Alone condition in Experiment 1, but we were unsuccessful in Experiment 2 in isolating a specific sensory function. This result may have been due to our inability to identify and control the sensory stimulation produced by head shaking. These topography-specific limitations to analyzing stereotypy will be a challenge for future researchers studying this topic. In summary, the results of the current experiments suggest that stereotypy can occur for a range of sensory and social reinforcement functions. For sensory reinforcers, it appears possible to identify, at least in some cases, the specific sensory modality that is maintaining the stereotypical behavior. These findings have practical implications in terms of intervention development and theoretical implications in regard to the experimental analysis of private events. The study of
450
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
stereotypy is emerging as an area of keen interest in applied behavior analysis. We look forward to future research that further clarifies issues relating to this very complex and challenging topic, and hope that the findings presented in this paper offer researcher possible avenues for future analysis.
Acknowledgments The first author thanks his committee members Stephen Camarata, Mark Harvey, Craig Kennedy (Chair), Daniel Reschly, Mark Wolery, and Joseph Wehby.
References Baumeister, A. A., & Forehand, R. (1973). Stereotyped acts. In N. R. Ellis (Ed.), International review of research in mental retardation (Vol. 6, pp. 55–96). New York: Academic Press. Berkson, G., & Tupa, M. (2002). Studies of the development of stereotyped and self-injurious behaviors in young children. In S. Schroeder, M. L. Oster-Granite, (Ed.), Self-injurious behavior: Gene-brain-behavior relationships (pp. 145–150). Washington, DC: American Psychological Association. Carr, E. G., & Durand, V. M. (1985). Reducing behavior problems through functional communication training. Journal of Applied Behavior Analysis, 18, 111–126. Conners, J., Iwata, B. A., & Shores, B. (2001, May). Structural and functional analysis of stereotypic behavior. Paper Presented at the Annual Conference of the Association for Behavior Analysis, New Orleans, LA. Fisher, W. W., Lindauer, S. E., Alterson, C. J., & Thompson, R. H. (1998). Assessment and treatment of destructive behavior maintained by stereotypic object manipulation. Journal of Applied Behavior Analysis, 31, 513–527. Goh, H., Iwata, B. A., Shore, B. A., DeLeon, I. G., Lerman, D. C., Ulrich, S. M., & Smith, R. G. (1995). An analysis of the reinforcing properties of hand mouthing. Journal of Applied Behavior Analysis, 28, 269–283. Guess, D., & Carr, E. G. (1991). Emergence and maintenance of stereotypy and self-injury. American Journal on Mental Retardation, 96, 299–319. Hanley, G. P., Iwata, B. A., Thompson, R. H., & Lindberg, J. S. (2000). A component analysis of ‘‘stereotypy as reinforcement’’ for alternative behavior. Journal of Applied Behavior Analysis, 33, 285–297. Iwata, B. A., Dorsey, M. F., Slifer, K. J., Bauman, K. E., Richman, G. S. (1982). Toward a functional analysis of self-injury. Analysis and Intervention in Developmental Disabilities, 2, 3–20. Journal of Applied Behavior Analysis, 27, 197–209. (reprint) Kennedy, C. H. (1994). Automatic reinforcement: Oxymoron or hypothetical construct? Journal of Behavioral Education, 4, 387–396. Kennedy, C. H. (2002). The evolution of stereotypy into self-injury. In S. Schroeder, M. L. OsterGranite, T.Thompson (Eds.), Self-injurious behavior: Gene-brain-behavior relationships (pp. 133–144). Washington, DC: American Psychological Association. Kennedy, C. H., Caruso, M., & Thompson, T. (2001). Experimental analyses of gene-brain-behavior relations, with some notes on their application. Journal of Applied Behavior Analysis, 34, 539–549. Kennedy, C. H., Meyer, K. A., Knowles, T., & Shukla, S. (2000). Analyzing the multiple functions of stereotypical behavior for students with autism: Implications for assessment and treatment. Journal of Applied Behavior Analysis, 33, 559–571. Kennedy, C. H., (in press). Single-case designs for educational research. Boston: Allyn & Bacon.
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
451
Lindberg, J. S., Iwata, B. A., & Kahng, S. (1999). On the relation between object manipulation and stereotypic self-injurious behavior. Journal of Applied Behavior Analysis, 32, 51–62. Lovaas, I., Newsom, C., & Hickman, C. (1987). Self-stimulatory behavior and perceptual reinforcement. Journal of Applied Behavior Analysis, 20, 45–68. Moore, J. (1992). On private events and theoretical terms. Journal of Mind and Behavior, 13, 329–345. Rincover, A., Cook, R., Peoples, A., & Packard, D. (1979). Sensory extinction and sensory reinforcement principles for programming multiple adaptive behavior change. Journal of Applied Behavior Analysis, 12, 221–233. Sidman, M. (1960). Tactics of scientific research: Evaluating experimental data in psychology. New York: Basic Books. Symons, F. S. (2002). Self-injury and pain: Models and mechanisms. In S. Schroeder, M. L. OsterGranite, (Ed.), Self-injurious behavior: Gene-brain-behavior relationships (pp. 223–234). Washington, DC: American Psychological Association. Turner, C. A., & Lewis, M. H. (2002). Dopaminergic mechanisms in self-injurious behavior and related disorders. In S. Schroeder, M. L. Oster-Granite, (Ed.), Self-injurious behavior: Gene-brain-behavior relationships (pp. 165–180). Washington, DC: American Psychological Association.
Identifying specific sensory modalities maintaining the stereotypy of students with multiple profound disabilities$ Jung-Chang Tang1, Tina G. Patterson, Craig H. Kennedy* Department of Special Education, Box 328, Peabody College, Vanderbilt University, Nashville, TN 37203, USA Received 4 January 2002; received in revised form 8 November 2002; accepted 10 February 2003
Abstract In Experiment 1, analogue functional analyses were conducted to identify the functions of stereotypy for six students with multiple profound disabilities. Results indicated that stereotypy (a) occurred across conditions, (b) occurred primarily when alone, or (c) occurred during all sessions except in the Control condition. Experiment 2 analyzed stereotypy while masking visual, auditory, or tactile sensory consequences. Results showed that stereotypy was maintained by visual stimulation, tactile stimulation, or was undifferentiated across conditions. In Experiment 3, we showed that stereotypy could be reduced by providing competing sensory stimulation. In Experiment 4, stereotypy that was undifferentiated in Experiment 1 was analyzed using a concurrent operants procedure. Results showed that stereotypy was not multiply determined, but occurred to produce visual sensory stimulation. Our findings are discussed in terms of the sensory and social reinforcers that maintain stereotypy, assessment procedures used to identify those reinforcers, and the interpretation of assessment results. # 2003 Elsevier Ltd. All rights reserved. Keywords: stereotypy; sensory reinforcement; functional analysis; functional assessment; private events; severe disabilities; developmental disabilities
$ This article is based on a dissertation submitted to Vanderbilt University in partial fulfillment of the Ph.D. degree by the first author. * Corresponding author. Tel.: þ1-615-322-8178; fax: þ1-615-343-1570. E-mail address: [email protected] (C.H. Kennedy). 1 Present address: National Chia Yi University, Taiwan.
0891-4222/$ – see front matter # 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.ridd.2003.02.001
434
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
Stereotypy is defined as behavior that occurs at a high frequency and is topographically invariant. Researchers have shown that stereotypies occur across a range of individuals, but that there is an increased probability of stereotypy inversely related to a person’s intellectual functioning level (Berkson & Tupa, 2002). Initial accounts suggested that stereotypy occurred for ‘‘homeostatic’’ reasons (Baumeister & Forehand, 1973). That is, this type of responding might occur to increase or decrease levels of environmental stimulation. Both types of response functions have been conceptualized as providing sensory consequences to the person engaging in stereotypy (Lovaas, Newson, & Hickman, 1987). Recent research has suggested that this conceptualization of stereotypy is accurate, but incomplete (Guess & Carr, 1991; Kennedy, 2002). For example, Kennedy, Meyer, Knowles, and Shukla (2000) analyzed the stereotypy of students with autism and found several patterns. For some students, stereotypy was a function of sensory and social reinforcement, while for others an undifferentiated pattern of behavior occurred across conditions. These findings suggest that the causes of stereotypy are more complex than researchers originally hypothesized. Current findings suggest that stereotypy can be a function of (a) positive sensory reinforcement, (b) negative sensory reinforcement, (c) positive social reinforcement, and/or (d) negative social reinforcement. Although research has shown that stereotypy can be multiply determined and include reinforcing stimuli that are socially mediated, less attention has been given to the nature of sensory reinforcers. This lack of attention may be due to two reasons. First, functional analyses of stimuli maintaining stereotypy have not occurred because the behavior was assumed to be maintained by sensory stimulation and, thus, it was not necessary to confirm this hypothesis. Second, the analysis of presumed sensory reinforcers is technically challenging and, in some cases, may not be amenable to an experimental analysis. This is because the response itself might produce biologically reinforcing stimulation (Kennedy, Caruso & Thompson, 2001; Symons, 2002; Turner & Lewis, 2002) and involve private events not accessible to others (Kennedy, 1994; Moore, 1992). However, some researchers have sought to overcome the technical difficulties of studying stereotypy (Fisher, Lindauer, Alterson, & Thompson, 1998; Goh et al., 1995; Hanley, Iwata, Thompson, & Lindberg, 2000; Kennedy et al., 2000; Lindberg, Iwata, & Kahng, 1999). In general, these approaches have focused on providing alternative sources of stimulation to compete with hypothesized private events maintaining responding. For example, Goh et al. (1995) analyzed handmouthing by providing competing forms of stimulation (i.e., items that could be mouthed and/or manually manipulated). Goh et al.’s results suggested that handmouthing was maintained primarily by manual stimulation of the hands. Results such as these help reveal the nature of sensory reinforcers involved in maintaining stereotypy, but have the limitation of being indirect tests of response– reinforcer relations. An alternative procedure for testing possible sensory functions of stereotypy would be to mask specific sensory modalities associated with behavioral maintenance. For example, Rincover, Cook, Peoples, and Packard (1979) masked
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
435
auditory, tactile, or visual modalities and found that stereotypy was a function of specific types of sensory stimulation. The responses Rincover et al. analyzed involved the manipulation of specific objects as stereotypical behaviors (e.g., plate spinning). However, many stereotypical behaviors do not involve the manipulation of objects (e.g., handmouthing, body rocking, and hand flapping). In such cases, no direct test of specific sensory modalities associated with stereotypy has been conducted. In the current series of experiments, we sought to extend previous work on sensory stimulation associated with stereotypy using procedures similar to those of Rincover et al. (1979). In Experiment 1, analogue functional analyses were used to identify patterns of stereotypy that might suggest sensory reinforcement. In Experiment 2, specific sensory modalities (i.e., auditory, tactile, or visual) were masked to assess whether stereotypy might be sensitive to a specific form of sensory stimulation. Competing stimuli consistent with the findings of Experiment 2 were tested in Experiment 3 to assess their effect on stereotypy. Finally, a concurrent operants procedure was used to analyze possible sensory and/or social reinforcers associated with stereotypy to clarify findings from an earlier undifferentiated analogue functional analysis outcome in Experiment 1. Our goal was to identify specific sensory modalities that might be involved in the maintenance of stereotypy that were produced directly by the behavior.
1. General method 1.1. Students and settings Six students participated in the study. The students were selected for inclusion in the study if (a) they engaged in only one or two stereotypies, (b) those stereotypic topographies were invariant, (c) stereotypical behavior(s) were emitted during 50% of the time, (d) students had multiple profound disabilities, and (e) they attended a public school. Sessions were conducted in a room at each student’s school that measured 5 m 6 m or 8 m 10 m. The rooms contained several tables/chairs and provided a quiet environment free of distractions. Table 1 provides student demographic information. The students’ primary mode of ambulation was with a wheelchair, except Janey who was ambulatory. James was diagnosed with profound intellectual disabilities and multiple physical impairments. His partial absence seizures were controlled by phenobarbital (60 mg once per day). He communicated using single consonant utterances and followed simple requests with partial physical assistance. Janey had a profound intellectual disability and autism. She communicated using single consonant utterances and required partial physical prompts to follow requests. Linda was diagnosed with profound intellectual disabilities, multiple physical impairments, and visual impairments (right eye retinopathy, left eye corneal opacity). She communicated through single consonant utterances and required full physical guidance to follow requests. Lisa was diagnosed with profound
436
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
Table 1 Student demographics Student
Gender
Age
Stereotypical behavior(s)
Receptive comprehensiona
Expressive communicationa
James Janey Linda Lisa Peter Tom
Male Female Female Female Male Male
11 6 17 8 17 4
Hand mouthing Hand mouthing Finger movement Finger movement Finger movement, head shaking Finger licking, eye-covering
6 6 6 6 7 6
9 months 9 months 4 months 12 months 5 months 9 months
a
months months months months months months
Estimated using the Preschool Language Scales-3.
intellectual disabilities, multiple physical impairments, and autistic-like behavior. She spoke using one or two word repetitive utterances and could follow simple, one-step verbal requests. Peter was diagnosed with profound intellectual disabilities, multiple physical impairments, and autistic-like behavior. Peter had generalized tonic–clonic epilepsy that was controlled by phenobarbital (100 mg once per day). He used facial gestures to communicate and could follow simple requests with partial physical assistance. Tom was diagnosed with profound intellectual disabilities and was legally blind (congenital corneal dystrophy with optic nerve hypoplasia). He communicated with others through vocal sounds or touching and required full physical guidance to follow requests. 1.2. Responses, data collection, and interobserver agreement Stereotypical responses are listed in Table 1. Each session was videotaped for later scoring. A trained graduate student scored each session using a 15-s partial interval pencil-and-paper observation system. In Experiment 4, the same observation system was used to estimate Lisa’s alternative communication responses. Across students, responses, and experiments, 22% of sessions (range 20–33%) were scored for interobserver agreement (IOA) by having a second observer independently record the occurrence of stereotypy and/or alternative communication responses. Occurrence IOA was scored using the formula: Agreements divided by agreements plus disagreements multiplied by 100%. IOA means for stereotypy were 96% (range 80–100%), 95% (range 80–100%), 96% (range 90–100%), and 94% (range 85–100%) for Experiments 1, 2, 3, and 4, respectively. For Lisa’s alternative communication response mean agreement was 96% (range 85–100%).
2. Experiment 1 The first experiment assessed the possible function(s) of stereotypy using analogue functional analysis procedures.
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
437
2.1. Method 2.1.1. Students, design, and procedures All students listed in the Section 1 participated in Experiment 1. A multielement design (Sidman, 1960) was used to assess the occurrence of stereotypy across four conditions: (a) Alone, (b) Attention, (c) Demand, and (d) Control (see Iwata, Dorsey, Slifer, Bauman, & Richman, 1982; Kennedy et al., 2000). Each condition was presented for 5 min, once per day with a random sequence occurring across days. Sessions were conducted at the same time, 3–5 days per week. During the Attention condition, an instructor (the first author) and student sat at a table. When seated, the instructor engaged in paperwork, while the student was provided with several activities (see Control condition). If stereotypy occurred, the instructor provided 5 s of social comments to the student and told him or her not to engage in stereotypy. All occurrences of stereotypy occasioned a similar response from the adult. This condition assessed the degree to which stereotypy was positively reinforced by attention. During the Demand condition, an instructor delivered a verbal demand every 10 s. Correct responding was praised and incorrect or no responding resulted in a full physical prompt after 10 s. Any occurrence of stereotypy resulted in a 30-s cessation in task demands. This condition assessed the degree to which stereotypy was negatively reinforced by escaping/avoiding demands. During the Alone condition, students were seated at a table and received no social interaction or activities. The Alone condition assessed the degree to which stereotypy occurred in the absence of programmed contingencies or environmental stimulation. During the Control condition, students were provided with various activities identified by teachers as being preferred and praised every 30 s in the absence of stereotypy. The Control condition was used to minimize the occurrence of stereotypy. 2.2. Results and discussion Fig. 1 displays the percentage of intervals with stereotypy across the assessment conditions for Linda, Lisa, James, and Janey. Across all conditions and sessions, Linda engaged in high levels of stereotypy. The stereotypical responding of Lisa also showed an undifferentiated pattern, as did James’ stereotypy. Janey displayed a similar pattern of undifferentiated stereotypy across experimental conditions, but her pattern was more variable than that of the other students in Fig. 1. Fig. 2 shows stereotypy data for Peter and Tom. The data are presented separately for each topography of stereotypy within a specific session for each student. Peter’s finger movements occurred at the highest levels in the Alone condition, occurred at moderate-to-low levels in the Attention and Demand conditions, and lowest in the Control condition. Peter’s head shaking was clearly differentiated with this response occurring at the highest levels in the Alone condition. Tom’s finger licking occurred at high levels in the Alone, Attention,
438
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
Fig. 1. Results of the analogue functional analysis of stereotypy in Experiment 1 for Linda, Lisa, James, and Janey.
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
439
Fig. 2. Results of the analogue functional analysis of stereotypy in Experiment 1 for Peter (finger movements: Tier 1; head shaking: Tier 2) and Tom (finger movements: Tier 3; eye-covering: Tier 4).
440
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
and Demand conditions, and at lower levels in the Control condition. Tom’s eyecovering occurred at low levels, but showed a pattern similar to that of finger licking. These data suggest three general patterns. First, the stereotypy of students in Fig. 1 showed an undifferentiated pattern that makes interpretation of specific operant functions difficult. Second, for Peter, both his topographies of stereotypy occurred primarily in the Alone condition, but with slightly different patterns for each behavior. Third, Tom’s finger licking and eye-covering appeared to be multiply determined. These data replicate the findings of Kennedy et al. (2000) demonstrating that stereotypy (a) occurred in an undifferentiated pattern (i.e., no identified reinforcing stimulus), (b) occurred only in the Alone condition (i.e., presumed sensory consequences), or (c) was multiply determined (i.e., social and presumed sensory consequences).
3. Experiment 2 Experiment 2 was conducted to identify possible sources of stereotypy based on sensory consequences in an attempt to further differentiate the patterns of responding from Experiment 1. In Experiment 2, stereotypy during the Alone condition was further analyzed by masking individual sensory consequences. 3.1. Method 3.1.1. Students, design, and procedures Linda, Lisa, Janey, Peter, and Tom participated in Experiment 2 (James was no longer available to participate because he moved to another school). A multielement design with the following conditions was used: (a) Alone, (b) Auditory Masking, (c) Tactile Masking, and (d) Visual Masking. Each condition lasted 5 min and was presented once per day, with a random sequence of conditions across days. Sessions were conducted at the same time, 3–5 days per week. The specific sensory masking technique was individualized based on the topography of each individual’s stereotypy. Because of the potentially intrusive nature of the sensory masking process, we had an advocate/parent review each masking technique, try it herself, and observe sensory masking sessions. All techniques were approved by the advocate/parent and no signs of dissent by students was observed (e.g., removing the stimulus or engaging in problem behavior). The Alone condition was the same as Experiment 1. The Auditory Masking condition was the same as the Alone condition, except that auditory stimuli associated with stereotypy were minimized. All students except Tom wore safety earplugs that reduced or eliminated sounds between 20 Hz and 20 kHz by 35 dB. Tom wore a pair of sound eliminating headphones which reduced auditory stimulation to a similar level. The Tactile Masking condition replicated
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
441
the Alone condition, except that tactile stimuli associated with stereotypy were minimized. All students wore gloves that minimized finger movements or access to the mouth. The Visual Masking condition was the same as the Alone condition, except that visual stimuli associated with stereotypy were minimized. For Peter a pair of opaque plastic safety goggles were sued eliminating all frontal and peripheral vision because his stereotypy tended to occur in both visual fields. For the other students an opaque screen (30 cm by 33 cm) was held approximately 7 cm in front of their faces. This less intrusive screening procedure was used because students’ stereotyped responses occurred only in the frontal visual field (during the analysis no change in stereotypic topographies occurred). 3.2. Results and discussion Fig. 3 shows the sensory masking results for Linda, Lisa, and Janey. Linda engaged in high levels of stereotypy in the Alone (M ¼ 94%), Auditory Masking (M ¼ 94%), and Tactile Masking (M ¼ 79%) conditions, with a slightly lower level of stereotypy occurring in the Visual Masking condition (M ¼ 59%). Lisa engaged in very low levels of stereotypy in the Visual Masking condition (M ¼ 11%), but high levels of stereotypy in the Alone (M ¼ 85%), Auditory Masking (M ¼ 83%), and Tactile Masking (M ¼ 70%) conditions. Janey showed a largely undifferentiated pattern across conditions (M ¼ 78%), with stereotypy being somewhat lower in the Tactile Masking condition (M ¼ 52%). Fig. 4 displays the results for the sensory masking analysis for Peter and Tom. The two topographies of stereotypy for each student are presented separately. Neither finger movements nor head shaking showed any response differentiation across conditions for Peter. For Tom his finger licking was substantially lower in the Tactile Masking condition (M ¼ 38%), when compared to the other three conditions (M ¼ 92–98%). His eye-covering occurred at low levels across conditions. For Lisa, the results of Experiment 2 suggest that the visual sensory consequences were associated with stereotypy. When visual stimulation was minimized, Lisa’s stereotypy occurred at lower levels, whereas in the other masking conditions behaviors occurred at similar levels to the Alone condition. Linda’s stereotypy was also possibly influenced by visual stimulation. Tom’s finger licking appeared to be associated with tactile sensory consequences the response produced (although eye-covering was undifferentiated). Janey’s stereotypy was possibly influenced by tactile stimulation. For Peter, no response differentiation occurred across conditions (see Section 6).
4. Experiment 3 The findings of Experiment 2 were further analyzed for Janey, Linda, and Lisa using competing forms of visual and tactile stimulation.
442
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
Fig. 3. Results of the sensory masking procedures on stereotypy in Experiment 2 for Linda, Lisa, and Janey.
4.1. Method 4.1.1. Students, design, and procedures Linda, Lisa, and Janey participated in Experiment 3 (Tom was unavailable to participate; Peter’s undifferentiated response patterns in Experiment 2 precluded participation in Experiment 3). A multielement design incorporating the same conditions as Experiment 2 was used with the addition of the following arrangements. For Linda and Lisa, a Competing Visual Stimulation condition was used. This condition noncontingently provided the students with a visual stimulus that was
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
443
Fig. 4. Results of the sensory masking procedures on stereotypy in Experiment 2 for Peter (finger movements: Tier 1; head shaking: Tier 2) and Tom (finger movements: Tier 3; eye-covering: Tier 4).
444
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
reported by teachers to be a preferred item (a videogame for Linda and magazine for Lisa). For Janey, the Competing Tactile Stimulation condition noncontingently provided her with a piece of string (which she used to mouth). Apart from these exceptions, all conditions and procedures were the same as in Experiment 2. 4.2. Results and discussion Fig. 5 presents the competing stimulation results for Linda, Lisa, and Janey. Stereotypy was relatively high across conditions for Linda. For Lisa, stereotypy
Fig. 5. Results of the competing stimulation analysis from Experiment 3 for Linda, Lisa, and Janey.
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
445
was clearly reduced in the Visual Stimulation and Competing Visual Stimulation conditions, relative to the other conditions. Finally, Janey’s stereotypy was lowest in the Competing Tactile Stimulation condition, with responding being lower, but more variable in the Tactile masking condition. For Lisa, these results suggest that an alternative form of stimulation, in the same sensory modality that was previously shown to be associated with responding, could effectively reduce the occurrence of stereotypy. For Janey, the outcomes were less clear and should be interpreted with caution because the competing tactile stimulus may have served as another form of stereotypy.
5. Experiment 4 In Experiment 1, the stereotypy of several students was shown to occur across assessment conditions (Linda, Lisa, James, and Janey). Interpretation of undifferentiated outcomes in terms of specific operant functions is difficult, because response differentiation is necessary to identify reinforcers maintaining responding. The undifferentiated patterns observed in Experiment 1 could be interpreted as indicating that behavior was maintained by sensory consequences or multiple sensory and social reinforcers. In order to further study the possible social functions of stereotypy we used a concurrent operants procedure with one the students (Lisa). Given the successful identification in Experiment 2 of visual stimulation as a source of reinforcement for Lisa’s stereotypy, in Experiment 4 we sought to individually test sensory and social reinforcement hypotheses to better understand the results of Experiment 1 using a different assessment procedure. 5.1. Method 5.1.1. Student, design, and procedures Lisa’s stereotypy was analyzed using a mixed design that combined a multiple baseline across operant functions with an ABAB withdrawal analysis (Kennedy, in press). 5.1.1.1. Baseline. Three possible operant functions of stereotypy identified in Experiment 1 were incorporated into three baselines: (a) visual stimulation (Alone condition), (b) negative reinforcement as escape/avoidance from demands (Demand condition), and (c) positive reinforcement as adult attention (Attention condition). The Alone, Attention, and Demand conditions used in Experiment 1 were used to establish baseline performances (see Kennedy et al., 2000). Therefore, in the Alone condition, no programmed contingencies or stimulation occurred; in the Attention condition, stereotypy occasioned social attention; and, in the Demand condition, stereotypy occasioned the removal of task demands. If a topography of behavior consistent with those in the functional communication training (FCT) condition occurred (see below), it was ignored. Alone, Attention, and Demand condition sessions were conducted in a fixed
446
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
sequence, 2–5 days per week. Each session lasted 5 min and was separated by a 5-min intersession interval. 5.1.1.2. Functional communication training. An alternative behavior was selected to occasion a similar reinforcer for each response–reinforcer relation established in baseline (Carr & Durand, 1985). For Alone, Attention, and Demand conditions, Lisa was taught to raise her right hand, sign ‘‘videogame,’’ and sign ‘‘break,’’ respectively, as an alternative response. Consequences for alternative
Fig. 6. Results of the functional communication training FCT intervention across possible operant functions for Lisa’s stereotypy.
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
447
behaviors were the same as stereotypy in the baseline conditions, except that signing ‘‘videogame’’ occasioned the delivery of a videogame for 15 s. That is, in the Alone condition Lisa signing ‘‘videogame’’ occasioned access to the videogame, in the Attention condition, Lisa signing ‘‘high’’ occasioned attention, and in the Demand condition Lisa signing ‘‘Break’’ occasioned the removal of task demands. During training, the occurrence of stereotypy occasioned (a) response interruption, (b) extinction of programmed responses for the stereotypy, (c) partial physical prompting of the alternative response, and (d) presentation of the associated consequence for the alternative response (i.e., the same contingency as established in baseline for stereotypy). Each time the alternative response was emitted, either prompted or unprompted, the associated consequence was implemented. 5.2. Results and discussion Fig. 6 shows the results of Experiment 4 for Lisa. She engaged in high levels of stereotypy and moderate levels of signing in the Alone condition baseline. A rapid reversal in her pattern of behavior occurred with the introduction of FCT. The ABAB withdrawal design showed that the decreases in stereotypy were a function of FCT. However, the introduction of FCT for the Demand and Attention condition baselines resulted in little or no changes in signing or stereotypy. The findings presented in Fig. 6 suggest that Lisa’s stereotypy was sensitive to sensory reinforcement in the form of visual stimulation, but that social reinforcement was not involved in behavioral maintenance. Given that Lisa’s stereotypy was shown to have an undifferentiated pattern when assessed using an analogue functional analysis in Experiment 1, the findings of Experiment 4 help clarify the causes of her stereotypy. A conclusion that can be drawn from these datasets is that her stereotypy was a function of visual sensory reinforcement that occurred apart from the programmed contingencies in the analogue functional analysis (Experiment 1).
6. General discussion In Experiment 1, we demonstrated that the stereotypy of students with multiple profound disabilities occurred in an undifferentiated pattern (Linda, Lisa, James, and Janey), only in the Alone condition (Peter), or was only suppressed in the Control condition (Tom). These findings left unclear the nature of the reinforcer(s) maintaining stereotypy. In Experiment 2, specific sensory consequences that might be associated with the maintenance of stereotypy were masked. The analysis showed that stereotypy was maintained by visual stimulation (Lisa), tactile stimulation (Tom), or an inconclusive pattern resulted (Peter). Two other students showed a possible relation between stereotypy and visual stimulation (Linda) or tactile stimulation (Janey). In a third experiment, competing sensory stimulation was presented in the same modality as was shown in Experiment 2 to
448
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
maintain stereotypy. One student (Lisa) showed decreased levels of stereotypy when competing sensory stimulation was presented, with another student showing a slight reduction in levels of stereotypy (Janey). In the final experiment, we used an alternative procedure to analyze the possible functions of stereotypy for a student whose behavior was undifferentiated across conditions in Experiment 1. The results of Experiment 4 suggested that the undifferentiated analogue functional analysis results in Experiment 1 were a function of visual sensory reinforcement competing with the programmed social contingencies. Our findings suggest that, as with students with autism (Kennedy et al., 2000), the stereotypy of students with multiple profound disabilities occurs for a variety of reasons. The current findings replicate our previous findings regarding the complex nature of stereotypy and extend it to a different student population. As a whole, these results suggest that stereotypy can be maintained by sensory and social reinforcers and that an assessment of behavioral function(s) is necessary in order to establish why the behavior occurs. Stereotypy might occur for sensory stimulation, but it can also serve other communicative functions. If the data from the current experiments and Kennedy et al. (2000) are combined (for an N ¼ 11) the following patterns of stereotypy have been documented. First, one student’s stereotypy occurred only in the Alone condition which suggests that the behavior was a function of sensory consequences. Second, one student’s stereotypy only occurred in conditions that assessed socially mediated contingencies (i.e., Demand and Attention). For six other students, stereotypy occurred across all assessment conditions. Finally, for three students, stereotypy occurred in all assessment conditions except the Control condition. Two of these patterns, in particular, deserve further discussion because of the interpretative challenges they present to researchers. The basis for experimental control in single-case designs is response differentiation across conditions (Kennedy, in press; Sidman, 1960). However, in 55% of the functional analyses of stereotypy that our research group has conducted, an undifferentiated pattern emerged across conditions. In essence, there is no experimental control demonstrated in these cases. This makes interpretation of the data difficult because any estimate of behavioral function is premature. It is possible to conclude that stereotypy is occurring only for sensory consequences; however, that interpretation requires an inference above what the dataset offers. Such concerns were the primary reason for conducting the experiments reported in this paper. By attempting to isolate specific sensory modalities, our goal was to induce response differentiation and identify possible sensory consequences causing responding. We were successful in identifying a sensory modality associated with stereotypy in two cases, suggesting that the behavior was maintained by a specific sensory consequence. To further explore the implications of these findings, we used a concurrent operants procedure to test specific sensory and social reinforcement hypotheses for one student. For Lisa, we were only able to replace stereotypy with an alternative response using FCT in the visual stimulation condition. This suggests that the results of her undifferentiated analogue functional analysis in Experiment 1 was due to sensory reinforcers
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
449
successfully competing with programmed social contingencies. Whether such patterns of responding occur for other cases of stereotypy that produce undifferentiated analogue functional analysis outcomes awaits further study. A second pattern of stereotypic responding that requires discussion is that observed for Tom in the current analysis and two other students in the Kennedy et al. (2000) study (i.e., Brad and James). For these students stereotypy occurred at elevated levels in the Alone, Attention, and Demand conditions, but not in the Control condition. Two equally plausible, but incompatible interpretations of these data are possible. One interpretation is that the behavior is multiply determined and is maintained by sensory reinforcement, positive social reinforcement, and negative social reinforcement. A second interpretation is that the behavior only occurred for sensory consequences that effectively competed with social reinforcement in the Attention and Demand conditions, but not in the Control condition (Conners, Iwata, & Shores, 2001). Given the results of the functional analysis, either interpretation could be accurate, although they have substantially different implications for treatment selection. Because this assessment outcome has occurred in 27% of the cases that have been studied, additional research is necessary to further clarify the operant nature of these stereotypical behaviors. Another finding worth noting is that the separate topographies of stereotypy emitted by Peter (finger movements and head shaking) and Tom (finger movement and eye-covering) showed similar analogue functional analysis outcomes. This might suggest that multiple topographies of stereotypy can belong to the same response class. However, this interpretation of the data should be met with caution because it is possible that although the stereotypical responses were both reinforced by sensory consequences, the specific nature of those consequences differed. This distinction may be important because developing an intervention plan based on a general assessment outcome of ‘‘sensory reinforcement’’ may not take into account that different stereotypical responses may serve different sensory functions (e.g., visual versus auditory). This preceding observation also points out a limitation of this study and, perhaps, the analysis of sensory consequences in general. That is, some topographies of stereotypy may not lend themselves to a functional analysis. For example, Peter’s head shaking occurred only in the Alone condition in Experiment 1, but we were unsuccessful in Experiment 2 in isolating a specific sensory function. This result may have been due to our inability to identify and control the sensory stimulation produced by head shaking. These topography-specific limitations to analyzing stereotypy will be a challenge for future researchers studying this topic. In summary, the results of the current experiments suggest that stereotypy can occur for a range of sensory and social reinforcement functions. For sensory reinforcers, it appears possible to identify, at least in some cases, the specific sensory modality that is maintaining the stereotypical behavior. These findings have practical implications in terms of intervention development and theoretical implications in regard to the experimental analysis of private events. The study of
450
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
stereotypy is emerging as an area of keen interest in applied behavior analysis. We look forward to future research that further clarifies issues relating to this very complex and challenging topic, and hope that the findings presented in this paper offer researcher possible avenues for future analysis.
Acknowledgments The first author thanks his committee members Stephen Camarata, Mark Harvey, Craig Kennedy (Chair), Daniel Reschly, Mark Wolery, and Joseph Wehby.
References Baumeister, A. A., & Forehand, R. (1973). Stereotyped acts. In N. R. Ellis (Ed.), International review of research in mental retardation (Vol. 6, pp. 55–96). New York: Academic Press. Berkson, G., & Tupa, M. (2002). Studies of the development of stereotyped and self-injurious behaviors in young children. In S. Schroeder, M. L. Oster-Granite, (Ed.), Self-injurious behavior: Gene-brain-behavior relationships (pp. 145–150). Washington, DC: American Psychological Association. Carr, E. G., & Durand, V. M. (1985). Reducing behavior problems through functional communication training. Journal of Applied Behavior Analysis, 18, 111–126. Conners, J., Iwata, B. A., & Shores, B. (2001, May). Structural and functional analysis of stereotypic behavior. Paper Presented at the Annual Conference of the Association for Behavior Analysis, New Orleans, LA. Fisher, W. W., Lindauer, S. E., Alterson, C. J., & Thompson, R. H. (1998). Assessment and treatment of destructive behavior maintained by stereotypic object manipulation. Journal of Applied Behavior Analysis, 31, 513–527. Goh, H., Iwata, B. A., Shore, B. A., DeLeon, I. G., Lerman, D. C., Ulrich, S. M., & Smith, R. G. (1995). An analysis of the reinforcing properties of hand mouthing. Journal of Applied Behavior Analysis, 28, 269–283. Guess, D., & Carr, E. G. (1991). Emergence and maintenance of stereotypy and self-injury. American Journal on Mental Retardation, 96, 299–319. Hanley, G. P., Iwata, B. A., Thompson, R. H., & Lindberg, J. S. (2000). A component analysis of ‘‘stereotypy as reinforcement’’ for alternative behavior. Journal of Applied Behavior Analysis, 33, 285–297. Iwata, B. A., Dorsey, M. F., Slifer, K. J., Bauman, K. E., Richman, G. S. (1982). Toward a functional analysis of self-injury. Analysis and Intervention in Developmental Disabilities, 2, 3–20. Journal of Applied Behavior Analysis, 27, 197–209. (reprint) Kennedy, C. H. (1994). Automatic reinforcement: Oxymoron or hypothetical construct? Journal of Behavioral Education, 4, 387–396. Kennedy, C. H. (2002). The evolution of stereotypy into self-injury. In S. Schroeder, M. L. OsterGranite, T.Thompson (Eds.), Self-injurious behavior: Gene-brain-behavior relationships (pp. 133–144). Washington, DC: American Psychological Association. Kennedy, C. H., Caruso, M., & Thompson, T. (2001). Experimental analyses of gene-brain-behavior relations, with some notes on their application. Journal of Applied Behavior Analysis, 34, 539–549. Kennedy, C. H., Meyer, K. A., Knowles, T., & Shukla, S. (2000). Analyzing the multiple functions of stereotypical behavior for students with autism: Implications for assessment and treatment. Journal of Applied Behavior Analysis, 33, 559–571. Kennedy, C. H., (in press). Single-case designs for educational research. Boston: Allyn & Bacon.
J.-C. Tang et al. / Research in Developmental Disabilities 24 (2003) 433–451
451
Lindberg, J. S., Iwata, B. A., & Kahng, S. (1999). On the relation between object manipulation and stereotypic self-injurious behavior. Journal of Applied Behavior Analysis, 32, 51–62. Lovaas, I., Newsom, C., & Hickman, C. (1987). Self-stimulatory behavior and perceptual reinforcement. Journal of Applied Behavior Analysis, 20, 45–68. Moore, J. (1992). On private events and theoretical terms. Journal of Mind and Behavior, 13, 329–345. Rincover, A., Cook, R., Peoples, A., & Packard, D. (1979). Sensory extinction and sensory reinforcement principles for programming multiple adaptive behavior change. Journal of Applied Behavior Analysis, 12, 221–233. Sidman, M. (1960). Tactics of scientific research: Evaluating experimental data in psychology. New York: Basic Books. Symons, F. S. (2002). Self-injury and pain: Models and mechanisms. In S. Schroeder, M. L. OsterGranite, (Ed.), Self-injurious behavior: Gene-brain-behavior relationships (pp. 223–234). Washington, DC: American Psychological Association. Turner, C. A., & Lewis, M. H. (2002). Dopaminergic mechanisms in self-injurious behavior and related disorders. In S. Schroeder, M. L. Oster-Granite, (Ed.), Self-injurious behavior: Gene-brain-behavior relationships (pp. 165–180). Washington, DC: American Psychological Association.