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Current limits to reinforcer identification for some persons with profound multiple disabilities
Pergamon
Research in Developmental Disabilities, Vol. 17, No. I, pp. 77-92, 1996 Copyright © 1995 Elsevier Science Ltd Printed in the USA. All rights reserved 0891-4222/96 $15.00 + .00
0891-4222(95)00038-0
Current Limits to Reinforcer Identification for Some Persons With Profound Multiple Disabilities Martin T. Ivancic Western Carolina Center
Jon S. Bailey Florida State University
Fifteen persons with profound mental retardation were divided into two groups. One group was identified with chronic training needs by habilitative staff and the other group served as a control. In an attempt to identify a reinforcer, each participant received a preference assessment and a simple, lofv-effort treatment procedure. In Experiment I, only individuals who approached at least one stimulus on 80% or more of the preference assessment trials ("high preference") showed reinforcement effects in treatment. However, three individuals showing high preference failed to show treatment effects. All persons identified with chronic training needs failed to show reinforcement effects. Experiment 2 analyzed characteristics of the two groups and found significant differences in overall movement and response latency. Limitations of the current reinforcement technology were apparent for identifying reinforcers in the group with chronic training problems. Research is suggested for evaluating training alternatives for people with profound multiple disabilities who move very little or who respond with very long latencies.
Comments from numerous reviewers of earlier versions of this manuscript are gratefully acknowledged including extensive comments from Wayne Fisher, Gary Pace, Dennis Reid, and David Wacker. The cooperation and administrative support of Carol McDuff and Wayne Daniels was also greatly appreciated. Thanks to Dawn Parker who provided reliability observations for the movement analysis. Requests for reprints should be sent to Martin T. Ivancic, Western Carolina Center, 300 Enola Road, Morganton, NC 28655-4608.
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M. T. Ivancic and J. S. Bailey
Training individuals who are profoundly physically disabled (Reid, Phillips, & Green, 1991) is perhaps the most challenging activity in the field of behavior analysis. These individuals, who are characterized as profoundly retarded, present a major obstacle to those using operant procedures when the availability of an effective reinforcer is questioned. An initial training requirement with the operant paradigm is an effective reinforcer. Neverthe-less, even this first training step is difficult for some multiply disabled persons because they are nonverbal and show virtually no operant movement of any kind. Pace, Ivancic, Edwards, Iwata, and Page (1985) reported one of the first studies aimed at developing procedures for identifying reinforcers for persons with profound mental retardation. The first step in Pace et al.'s (1985) twostep procedure identified preferences via approach responding to singlechoice presentations from a large array of assessment stimuli. The second step validated these preferences as reinforcers by increasing compliant behavior when preferred stimuli were applied as consequences and by failing to increase compliant behavior when less preferred stimuli were applied as consequences. In subsequent research (see below), similar preference assessments have overestimated reinforcer identification (false positives) and failed to identify reinforcers (true negatives). When preference assessments have overestimated reinforcers, a forcedchoice assessment has been suggested as a more efficient alternative reinforcement identification procedure (Fisher et al., 1992). When stimulus preference procedures identify no preferences, the lack of an alternative reinforcement identification procedure (Green et al., 1988) is discussed as a major impediment to reinforcement-based training (Green, Reid, Canipe, & Gardner, 199 I; Reid et al., 1991). The beneficial limits of preference assessments for identifying reinforcers for people with profound mental retardation remain unclear. Experiment 1 was conducted to determine whether noneffects observed in Green et al. (1991) would replicate with another sample of persons with profound mental retardation. Several modifications were made in the original Pace et al. (1985) procedure in an attempt to enhance the probability that a reinforcer would be identified. Experiment 2 attempted further to identify characteristics of these people with profound mental retardation to allow more expeditious selection of participants for future research. Participants were analyzed by examining differences between the two groups observed in Experiment 1. EXPERIMENT 1: METHOD Participant Selection
Fifteen persons participated. They were selected from all 61 persons diagnosed with profound mental retardation from two residential facilities. Two groups were formed to highlight the potential differences within the general group diagnosed with profound mental retardation. The fn'st group contained the most severely dis-
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abled individuals from both facilities. This group was selected by asking each treatment team responsible for providing habilitation to these individuals to identify the people in their facilities who had the longest chronic history of training failure. These teams consisted of administrators, program directors, and direct care supervisors with at least one year's experience of providing and evaluating skill acquisition programs for the participants. This fast group consisted of 10 persons randomly selected from the 19 persons identified with long-term "chronic training needs." The other group served as a control and consisted of five individuals randomly selected from the remaining 42 persons diagnosed with profound mental retardation. Ivancic (1989) contains more specific information on the participants. General Procedures
Preference assessment and reinforcer validation procedures similar to those of Pace et al. (1985) were used to evaluate treatment effects for each individual. The preference assessment consisted of 20 trials for each stimulus. (This was more than the number of trials used in some previous preference assessments [Pace et al., 1985, used 10 trials] and less than the number of trials used in other assessments [Green et al., 1988, 1991, used 30 trials]). To maximize response to a presentation, this procedure provided the stimulation noncontingenfly and a second opportunity to approach if no response occurred to the fast opportunity (cf. Pace et al., 1985). Green et al. (1988, 1991) used presession trials in the preference assessment to maximize responding). An array of 16 stimuli (cf. Pace et al., 1985) was used in each preference assessment with an additional item identified by familiar care staff as the stimulus judged by them to be most preferred (cf. Green et al., 1991). Following the stimulus preference assessment, each treatment condition utilized three presession primer trials. (Pace et al., [1985] utilized no presession trials; Green et al. [1988, 1991] utilized one.) The potential negative reinforcement explanation for responding in the treatment condition (i.e., responding to avoid a prompt) was eliminated in the current study by providing preference stimuli in treatment only following behavior that occurred naturally (without prompt). In addition, activation of electromechanical switches was used in treatment to minimize response effort and allow response force to be measured. Also, an attempt was made to maximize learning between the response and consequence in treatment by providing automatic auditory and visual feedback following each switch activation, thus bridging the time between the response of the participant and the manually provided consequence (Reynolds, 1968, p. 21). Responses
In the preference assessment, observers scored an approach, avoid, or nonoccurrence response on each presentation trial. Obvious approach responses such as requesting, reaching to touch, smiling, or turning toward stimulus presentations were individually defined and used for most participants. Eye movement
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M. T. lvancic and J. S. Bailey
was used in the preference assessment for three persons with chronic training need who failed to display a more obvious approach response. Avoid responses included vocally declining, crying, or trying to get away from the stimulus presentation. In the treatment sessions, switch activations were electromechanically scored (Simpson Counter, Model 1041). Independent Observer Reliability Independent observer agreement measures for approach and avoid behavior in the preference assessment were made during 25% of the sessions, evenly distributed across each participant and calculated by dividing agreements over agreements plus disagreements and multiplying by 100. Avoid behavior occurred with only two participants. Overall agreement for approach or avoid behavior was 97% (range: 92%-98%). Average occurrence agreement for approach or avoidance was 90% (range: 14%-100%) and nonoccurrence was 94% (range: 44%,100%). Only two scores averaged below 80%. An individual with chronic training need had a 14% occurrence score because of a low number of responses, and a control group participant had a 44% nonoccurrence score because of a low number of nonoccurrence responses. Both cases involved only five disagreements. Specific Procedures Preference assessment. Of the 17 stimuli presented, gustatory stimuli (cracker and juice) were eliminated for five individuals because they were fed via gastrostomy tubes, and vestibular stimuli (rocking and spinning) were eliminated for two because these movements elicited apparently uncomfortable contractions. Medical approval was obtained for each individual to rule out potential for sensory-evoked seizures from any particular stimulus presentation (Feldman, 1975). Thirteen of the 15 participants received seizure medication and seven received more than one type of medication for seizure control. Presession treatment trials. Immediately before each treatment session three presession trials were used to introduce the preselected stimulus for that session. A presession trial consisted of requesting the target response, gently guiding a switch activation response if a response did not occur, and then providing the preselected stimulus following the automatic feedback. Treatment procedures. Preferences were validated as reinforcers in 10-min, unprompted treatment sessions. These sessions targeted responses previously identified to activate switches through naturally occurring movements using each participant's most comfortable position. Switch movements and comfortISimpson Counter, Model 104, Catalog#12642, Simpson Electronics,853 Dundee Ave, Elgin, IL 60120 (Ph: 312-697-2260).
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able positions were identified by the experimenter in consultation with an occupational and physical therapist familiar with each participant. The group with chronic training needs used an average 168 g of force (range: 57-341) to activate their head or chin switches, and the control group used an average 283 g of force (range: 164-341) to activate their hand switches. In addition, manual delivery of the stimulus consequences following switch activations for each participant was "bridged," as noted earlier, by automatic feedback from a 12-volt red light, a 3600 hz sound (measuring 85 decibels), and the automatic counter click. Treatment conditions. During baseline, switch activation resulted in the automatic feedback. During the more preferred and less preferred conditions, the procedures were identical to baseline except that a stimulus identified during the preference assessment as more or less preferred was presented to the participant for 5 s each time the switch was activated. More preferred stimuli were chosen by randomly drawing a slip from a hat, with all stimuli approached 80% or more. Less preferred stimuli were chosen by drawing from all stimuli approached 30% or less. For individuals failing to approach any stimulus 80% of the opportunities, the stimulus approached the most often was chosen as the most preferred stimulus. When light was identified as the most preferred stimulus in the preference assessment, the light from the automatic feedback device was used as the most preferred stimulus in the treatment session. Experimental Design
Treatment effects were analyzed using an ABAB reversal design (Bailey & Bostow, 1979) to indicate experimental control of the stimuli. In general, the training evaluation for each participant started with a baseline condition followed either by a more preferred or less preferred, but not avoided, treatment condition. Presentation order of these conditions was determined randomly. Preference conditions were altered until the most optimal situation of replicated, repeated conditions (e.g., ABAB) was achieved. Conditions lasted until data were stable. Twenty-two persons identified as experienced in the review of research for persons with developmental disabilities 2 were contacted, and nine of them agreed to judge treatment effects in this study. These judges received individual treatment graphs in random order with generic lettering used to identify conditions.
2These were authors identified as having two or more research articles published in the Behavior Analysis in Developmental Disabilities 1969-1985from the Journal of Applied Behavior Analysis (Bailey, Shook, Iwata, Reid, and Repp, 1985). The editors of that volume were also invited to participate. These judges were likely to have experience observing and making decisions regarding the analytical effects of applied data. Forty-one percent of the judges agreed to participate. Three invitations did not reach their addressees, and three invitations returned. All nine judges who indicated a willingness to review the training data returned their judgements.
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M. T. lvancic and J. S. Bailey
They were asked to consider which repeated conditions showed replicated effects. An individual's graph was considered to show treatment effect when "more preferred" conditions were higher than "less preferred" conditions and was determined to be replicated by at least six of the nine judges (69%). RESULTS Table 1 shows one or more stimuli were approached 80% or more of the preference assessment presentations for 7 of 15 (47%) participants. Such stimuli are often referred to as high preference. For 4 of these 7 (57%) participants, the high-preference stimulus functioned as a reinforcer. That is, the stimulus identified as highly preferred in the assessment increased the rate of switch activations when presented as a consequence to switch activation. In contrast, for the remaining eight participants, the stimulus most preferred, but not approached 80% or more of the preference assessment trials, never functioned as a reinforcer for switch activation. The probability of obtaining these observed cell sizes by chance was p = .025 (Siegle, 1956). Overall approach responding in the preference assessment for the group with chronic training need was 34% compared to 64% for the control group. One or more high preference stimuli were identified for two (20%) individuals in the group with chronic training need and for all five (100%) individuals in the control group. Similarly, reinforcement effects for the more preferred stimulus for each participant were judged to occur for no (0%) individuals in the group with chronic training need and for 4 (80%) individuals in the control group. To show individual results, treatment effects are presented for two representative individuals from each group. Results for Clara and Gwen represent the individual data from the control group. Their overall approach responses in the preference assessment was 32% and 48%, respectively. Their more preferred
TABLE 1
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stimuli were approached 80% (corn puffs) and 100% (chocolate candy) and their less preferred stimuli were 0% (rocking) and 15% (light), respectively. Neither Clara nor Gwen showed any no avoid responses. Figure 1 shows the reinforcement effects for Clara and Gwen, who both showed high preference in the preference assessment. The top panel shows Clara averaged 8.7 switch activations per session in baseline. Clara's first more preferred condition using her more preferred stimulus as a consequence increased her average responding to 17.8 responses per session. Her first less preferred condition reduced responding to 6.5 responses per session. Clara's subsequent repeated more and less preferred conditions followed predicted directions at 27 and 2 responses per session, respectively. Both the more and
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less preferred conditions were judged to replicate. In the bottom panel of Figure 1, Gwen showed a pattern similar to Clara's except that her first more preferred condition was quite a bit lower than her two subsequent more preferred conditions. In the first more preferred condition, chocolate candy was given after each response (CRF). In Gwen's second more preferred condition, responding became so frequent that chocolate candy was reduced first to every third response (FR3) and then to every fifth response (FR5) to avoid within-session satiation. In the final more preferred condition, chocolate candy was provided on every fifth response throughout the condition. For Gwen, repeated more preferred conditions averaged 70 responses per condition. Her repeated less preferred and baseline conditions averaged four and three responses per session, respectively. Both more and less preferred conditions were judged to replicate. Results for Patty and Jerry represent the individual data for the group with chronic training need. Their overall approach responses in the preference assessment were 54% and 13%, respectively. Their more preferred stimuli were approached 73% (music) and 27% (music tones), and their less preferred stimuli were approached 47% (cool) and 5% (vibration), respectively. Figure 2 shows the reinforcement effects for Patty and Jerry who both failed to show high preference in the preference assessment. The top panel shows that Patty averaged 11.4 responses in baseline. Patty's first condition using her less preferred stimulation as the stimulus consequence reduced her average responding to 2.2 responses per session. Her first more preferred condition increased responding to 4.3 responses per session. Patty's subsequent sessions repeating less and more preferred conditions followed predicted directions averaging 4 and 6.5 responses per session, respectively. However, no condition for Patty was judged to replicate. The bottom panel of Figure 2 shows that Jerry averaged one response per condition in baseline, failed to respond in any more preferred stimulus condition, and averaged .75 responses in each less preferred condition. No condition for Jerry was judged to replicate.
DISCUSSION Clara and Gwen were part of a control group of individuals with profound mental retardation who showed high preference in the preference assessment, and these stimuli were judged to be reinforcers later in their treatment sessions. Patty and Jerry's results represent the group identified by their caregivers as showing chronic training needs. Patty and Jerry showed no high preference in the assessment and no reinforcer effect was judged in the treatment sessions when the most preferred stimulus for each individual was used as a consequence. Similar to previous findings (e.g., Green et al., 1991), data from both groups indicated that stimuli approached on at least 80% of trials during the stimulus preference assessment (i.e., "high preference stimuli") tended to func-
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tion as reinforcers, and stimuli approached on fewer trials tended not to function as reinforcers. This current result occurred in this investigation despite multiple assessment trials, use of the stimulus identified as most preferred by care staff, minimized response effort in treatment sessions, and attempts to enhance conditioning between the response and the consequence. The only control group participant who failed to demonstrate treatment effects was also the only person showing any significant avoid responses. In fact, he avoided 42% of his preference assessment presentations by shaking his
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head "No." He frequently smiled and laughed when he refused stimulus presentations. This preference for opposition was evident in the staff-selected stimulus - - a tape with staff playfully complaining about his failure to comply. This vocal tape, shown to be highly preferred in the assessment, may have failed to produce reinforcement effects in the treatment sessions because the treatment situation removed a prompting component that was present in the stimulus preference assessment. Prompts for compliance to presentations in the preference assessment (e.g., social attention) may have occasioned refusal behavior in this individual in an attempt to generate more prompts. When these prompts did not occur in treatment sessions, the strength of the response occasion may have been altered too much to evoke responding. This study used relatively brief conditions to evaluate treatment. Longer conditions have been used with persons of extremely limited responsiveness (e.g., Boyle & Greer, 1983). Nevertheless, conditions in this study were comparable to those used in similar studies. For example, the current study averaged five sessions per condition (range: 3-13) and Pace et al. (1985) averaged seven sessions per condition (range: 3-19). Where substantially longer conditions are anticipated, baseline lengths similar to treatment conditions should be useful in evaluating changes that are small or highly variable. Finally, demonstrating a failure to show high preferences or treatment effects for an individual in no way indicates that reinforcement effects are not possible or that there is no treatment of benefit for him or her. It does suggest that a continued reliance on simple reinforcement-based procedures (i.e., increasing behavior followed by known reinforcers) for people who show no high stimulation preferences may be difficult programming to justify. EXPERIMENT 2
Research to help those showing the most difficulty in responding to current teaching technology is hampered by confusion as to who belongs in this population (see Reid et al., 1991 for a discussion). There have been only a few studies attempting to identify these individuals (Kobe, Mulick, Rash, & Martin, 1994; Landesman-Dwyer & Sackett, 1978). Reid et al. suggested categorizing people who show difficulty learning useful skills as persons with "profound multiple handicaps" or "profound multiple disabilities" (D. H. Reid, personal communication, June 6, 1995). Reid defines a person with profound multiple disabilities as a person who functions with extreme debilitation, that is, besides being diagnosed as profoundly mentally retarded, this individual has physical disabilities that prohibit ambulation and at least one other type of handicap (e.g., some other sensory or motor impairment). All individuals in the group with chronic training need and 3 of the 5 control group participants in Experiment 1 fit this profound multiple disability definition. Failing to show high preference in a comprehensive reinforcer assessment provides a direct way of identifying individuals who are unlikely to
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benefit from current teaching technology, given the close relationship between people who fail to show both high preference and effects from reinforcement-based training (Green et al., 1991; Experiment 1). It is this specific subgroup of individuals with profound multiple disabilities (i.e., those who fail to show any high preference) who would benefit most from research to extend current limitations of behavioral technology. As such, it may be helpful further to analyze characteristics of individuals for whom current teaching technology is not successful to target these individuals and their treatment needs more specifically in future research. Experiment 2 attempted to show further differences within the heterogeneous population of people with profound multiple disabilities by comparing selected characteristics of the two groups in Experiment 1. Specifically, Experiment 2 analyzed movement and response-time differences between the control group, who had identified reinforcers, and the group with chronic training need, who failed to demonstrate reinforcer effects. METHOD
Participants The same individuals who took part in Experiment 1 participated in Experiment 2. The movement analysis was made 1.5 years after Experiment 1 was completed. At that time, 4 of the original 15 participants were unavailable. One person from each group had moved out of state. Two individuals from the group with chronic training need had died of natural causes. This left 7 individuals with chronic training need and 4 control group individuals for the movement analysis.
Procedures Response time analysis. Each treatment session in Experiment 1 was timed with a stopwatch. The experimenter scored the time-to-the-first-response (latency) as it occurred for each individual during each treatment session. Movement analysis. A 5-min video tape was made of each participant and scored for the occurrence of movement across 10-s intervals. The general definition of movement included any body activity excluding minute body movement, simple eyelid movement, or apparent involuntary response. Minute body movement included noticeable breathing or any body response that moved less than 20 cm, excluding movement of the face and eye pupil. Simple eyelid movement included opening and shutting of the eyelids, but did not include expressions such as eye widening, squinting, or grimacing. Involuntary responses included any movement too quick to be functional such as hiccups, coughs, jerks, and nystagmus (eye pupil jerking). Facial expressions and
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M. T. lvancic and J. S. Bailey
stereotypy were included as activity. Observations were cued via an audio tape with an 8-s observe and 2-s record scoring procedure. Independent observations were taken on all 450 participant movement observations. Overall reliability was calculated by dividing agreements on scored occurrence and nonoccurrence of movement intervals by those agreements plus disagreements. Reliability was above 90% for every individual, averaging 1.8 disagreements per person. RESULTS Figure 3 provides the average latency to the first response in treatment conditions (top panel) and average percent intervals with movement in a separate evaluation (bottom panel) for both groups. The top panel of Figure 3 shows that the group with chronic training need averaged 5.0 min to their first response in treatment sessions (4.6 rain in more preferred conditions and 5.3 min in less preferred conditions). All control participants responded more quickly in training sessions, averaging .9 min to their first response (.33 min in more preferred conditions and 1.4 min in less preferred conditions). A small-sample t-test showed that differences between the latencies of response in the two groups for each condition was significant at the .05 level of error (df= 13). The bottom panel of Figure 3 shows that movement was measured in 51% of the intervals for the groups with chronic training need and in 99% of the intervals for the control group. Only one person in the group with chronic training need showed an activity level similar to that observed in the control group. A small-sample t-test showed the differences in general movement between the two groups was significant at a 0.01 level of error (df= 9) DISCUSSION There were significant differences between the control group and the group with chronic training need in overall movement based on brief video samples and in time-to-initiate target responding in treatment sessions. Specifically, the group less likely to demonstrate reinforcers, the group identified with chronic training need, moved 20 cm or more during slightly more than half of the observations. In addition, it took an average of several minutes (M = 4.5 min) to initiate a response in the most preferred condition of the treatment session for the group identified with chronic training need. In contrast, the group more likely to demonstrate reinforcers, the control group, was scored for movement in almost 100% of the intervals, with response latencies averaging 20 s in the more preferred conditions of their treatment sessions. It seems quite reasonable to find people who do not move a great deal or very quickly also show difficulty with training success, given that the criterion for treatment success is based on responding (i.e., movement).
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Although the group with chronic training need had obvious habilitation limitations, their habilitative potential was certainly greater than that of other groups with extreme limits to functioning. For example, there was no concern for individuals in the group with chronic training need over the maintenance of their life-support. Life-support is a frequently discussed concern for lower functioning individuals often labelled as in a "persistive vegetative state" (Bontke, Dolan, & Ivanhoe, 1994). Individuals in a persistive vegetative state do not react to threatening situations (Howard & Miller, 1995), and all the individuals with chronic training need showed response to threat such as crying out to obvious pain or frowns from positioning discomfort.
GENERAL DISCUSSION Individuals with profound multiple disability who show no high preferences in stimulus assessment procedures are unlikely to show reinforcement effects and so are unlikely to benefit from current reinforcement-based teaching procedures. In addition, it is likely that a person at the lowest functioning end of
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M. T. lvancic and Z S. Bailey
the group with profound multiple disabilities (i.e., a person who moves very little and initiates very slowly) can be identified without formal assessment procedures by anyone who has been responsible for that individual's habilitation development or evaluation for at least a year. When simple reinforcement-based procedures are difficult for an individual to demonstrate, alternative procedures for providing habilitation should be sought and empirically validated (Bailey, 1981; Green et al., 1991). Alternative programming for individuals who fail to demonstrate high preferences may include programming to teach approach responding. An individual may fail to show high preference because reinforcement for less conventional approach responses (e.g., eye gaze, switch activity) used during assessment sessions has been limited to contact only during those assessment sessions. When less conventional approach responses are used in preference assessments, further acquisition may be required to condition a response to the strength of more obvious approach responses (e.g., reach-to-touch) which likely contacts a variety of reinforcers throughout a normal day. Another important line of research for a person with profound multiple disability who shows no high preference may be to increase the value of any concurrently available preferences through establishing operations (Michael, 1993, chap. 7) including removal of discomfort. That is, approach responding might occur differently when stimulation is provided in positions of increased comfort (e.g., side lying, standing table), on different medications (e.g., medications for seizures, bowels, or spasticity), or in different contingent or noncontingent rates and/or sequences. Finally, contact with any stimulation, no matter how strongly preference is documented, that elicits (the response occurs following the stimulation) "happy" responding, e.g., smiles, (Green & Reid, in press), that interrupts interfering responding, or that evokes behavior to maintain contact after provision may be considered important to the daily living situation for an individual who receives it (Reid et al., 1991). Stimuli not strong enough to evoke responding any more effortful than a preference (approach) response, but documented as preferred, might be validated as stimuli important for the enrichment for an individual by measures such as those associated with "happiness," inappropriate response interruption, or tracking. An associated measure in the current investigation with some potential to validate the "low" preferences found in the chronic training need group could be that latency to the first response. Six of the 10 individuals in the groups with chronic training need responded more quickly in their more preferred conditions than in their less preferred conditions, even though the latencies for both conditions were quite long. Enrichment value for an individual who shows stimuli assessed to be preferred more than other stimuli but never shows high preference may be validated through such associated measures. Finding such validation for the preference value of the "low" preferred stimulus or the high preferred stimulus that is not demonstrated as a reinforcer may be the empirical justification
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n e e d e d for professionals to r e c o m m e n d these stimuli as e n v i r o n m e n t a l enrichm e n t p r o c e d u r e s for p e o p l e w h o do not exhibit b e h a v i o r any m o r e effortful than an a p p r o a c h response. Reid et al. (1991) expressed concern o v e r the diligence shown for developing an effective teaching technology for people w h o fail to show progress with the current training technology. Hopefully, procedures identifying individuals who are not being serviced by our current technology will direct and increase research necessary to develop a technology that will offer these individuals better lives.
REFERENCES Bailey, J. S. (1981). Wanted: A rational search for the limiting conditions of habilitation. Analysis and Intervention in Developmental Disabilities, 1, 45-52. Bailey, J. S. & Bostow, D. E. (1979). Research methods in applied behavior analysis. Tallahassee, FL: Copy Grafix. Bailey, J. S., Shook, G. L., Iwata, B. A., Reid, D. H., & Repp, A. C. (Eds.). (1985). Behavior analysis in developmental disabilities from the Journal of Applied Behavior Analysis, Reprint Series (Vol. 1). Lawerence, KS: Journal of Applied Behavior Analysis. Bontke, C. E, Dolan, J. M., Ivanhoe, C. B. (1994). Journal of Head Trauma Rehabilitation, 9 (4), 62-69. Boyle, M. A., & Greer, R. D. (1983). Operant procedures and the comatose patient. Journal of Applied Behavior Analysis, 16, 3-12. Feldman, R. G. (1975). Patients with epilepsy. American Family Physician, 12(4), 135-140. Fisher, W., Piazza, C. C. Bowman, L. G., Hagopian, L. P., Owens, J. C., Slevin, 1. (1992). A comparison of two approaches for identifying reinforcers for persons with severe and profound disabilities. Journal of Applied Behavior Analysis, 25, 491-498. Green, C. W., & Reid, D. H. (in press). Defining, validating, and increasing indices of happiness among people with profound multiple disabilities. Journal of Applied Behavior Analysis. Green, C. W., Reid, D. H., White, L. K., Halford, R. C., Brittain, D. P., & Gardner. S. M. (1988). Identifying reinforcers for persons with profound handicaps: Staff opinion versus systematic assessment of preferences. Journal of Applied Behavior Analysis, 21, 31-43. Green, C. W., Reid, D. H., Canipe, V. S., & Gardner, S. M. (1991). A comprehensive evaluation of reinforcer identification processes for persons with profound multiple handicaps. Journal of Applied Behavior Analysis, 24, 537-552. Howard, R. S., & Miller, D.H. (1995). The persistent vegetative state. British Medical Journal, 310, 341-342. Ivancic, M. T. (1989). Assessing operant training potential. Dissertation Abstracts International, 50, 115A- 1826A (Order No. DA8916201 ). Kobe, E H., Mulick, J. A., Rash, T. A., & Martin, J. (1994). Nonambulatory persons with profound mental retardation: Physical, developmental, and behavioral characteristics. Research in Developmental Disabilities, 15, 413-423. Landesman-Dwyer, S., & Sackett, G. P. (1978). Behavioral changes in nonambulatory, profoundly mentally retarded individuals. In C. E. Meyers (Ed.), Quality of life in severely and profoundly mentally retarded people: Research foundations for improvement (pp. 55-144). Washington, DC: American Association for Mental Deficiency. Michael, J. (1993). Concepts and principles of behavior analysis. Kalamazoo, MI: Society for the Advancement of Behavior Analysis. Pace, G. M., Ivancic, M. T., Edwards, G. L., Iwata, B. A., & Page, T. J. (1985). Assessment of stimulus preference and reinforcer value in profoundly retarded individuals. Journal of Applied Behavior Analysis, 18, 249-255.
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Reid, D. H., Phillips,J. E, & Green, C. W. (1991). Teaching persons with profound multiple handicaps: A review of the effectsof behavioral research.Journal of Applied Behavior Analysis,24, 319-336. Reynolds, J. S. (1968), A primer of operant conditioning. Glenview, IL: Scott, Foresman, & Company. Siegle,M. (1956). Nonparametric statistics.NY: McGraw-Hill Book Company.
Research in Developmental Disabilities, Vol. 17, No. I, pp. 77-92, 1996 Copyright © 1995 Elsevier Science Ltd Printed in the USA. All rights reserved 0891-4222/96 $15.00 + .00
0891-4222(95)00038-0
Current Limits to Reinforcer Identification for Some Persons With Profound Multiple Disabilities Martin T. Ivancic Western Carolina Center
Jon S. Bailey Florida State University
Fifteen persons with profound mental retardation were divided into two groups. One group was identified with chronic training needs by habilitative staff and the other group served as a control. In an attempt to identify a reinforcer, each participant received a preference assessment and a simple, lofv-effort treatment procedure. In Experiment I, only individuals who approached at least one stimulus on 80% or more of the preference assessment trials ("high preference") showed reinforcement effects in treatment. However, three individuals showing high preference failed to show treatment effects. All persons identified with chronic training needs failed to show reinforcement effects. Experiment 2 analyzed characteristics of the two groups and found significant differences in overall movement and response latency. Limitations of the current reinforcement technology were apparent for identifying reinforcers in the group with chronic training problems. Research is suggested for evaluating training alternatives for people with profound multiple disabilities who move very little or who respond with very long latencies.
Comments from numerous reviewers of earlier versions of this manuscript are gratefully acknowledged including extensive comments from Wayne Fisher, Gary Pace, Dennis Reid, and David Wacker. The cooperation and administrative support of Carol McDuff and Wayne Daniels was also greatly appreciated. Thanks to Dawn Parker who provided reliability observations for the movement analysis. Requests for reprints should be sent to Martin T. Ivancic, Western Carolina Center, 300 Enola Road, Morganton, NC 28655-4608.
77
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M. T. Ivancic and J. S. Bailey
Training individuals who are profoundly physically disabled (Reid, Phillips, & Green, 1991) is perhaps the most challenging activity in the field of behavior analysis. These individuals, who are characterized as profoundly retarded, present a major obstacle to those using operant procedures when the availability of an effective reinforcer is questioned. An initial training requirement with the operant paradigm is an effective reinforcer. Neverthe-less, even this first training step is difficult for some multiply disabled persons because they are nonverbal and show virtually no operant movement of any kind. Pace, Ivancic, Edwards, Iwata, and Page (1985) reported one of the first studies aimed at developing procedures for identifying reinforcers for persons with profound mental retardation. The first step in Pace et al.'s (1985) twostep procedure identified preferences via approach responding to singlechoice presentations from a large array of assessment stimuli. The second step validated these preferences as reinforcers by increasing compliant behavior when preferred stimuli were applied as consequences and by failing to increase compliant behavior when less preferred stimuli were applied as consequences. In subsequent research (see below), similar preference assessments have overestimated reinforcer identification (false positives) and failed to identify reinforcers (true negatives). When preference assessments have overestimated reinforcers, a forcedchoice assessment has been suggested as a more efficient alternative reinforcement identification procedure (Fisher et al., 1992). When stimulus preference procedures identify no preferences, the lack of an alternative reinforcement identification procedure (Green et al., 1988) is discussed as a major impediment to reinforcement-based training (Green, Reid, Canipe, & Gardner, 199 I; Reid et al., 1991). The beneficial limits of preference assessments for identifying reinforcers for people with profound mental retardation remain unclear. Experiment 1 was conducted to determine whether noneffects observed in Green et al. (1991) would replicate with another sample of persons with profound mental retardation. Several modifications were made in the original Pace et al. (1985) procedure in an attempt to enhance the probability that a reinforcer would be identified. Experiment 2 attempted further to identify characteristics of these people with profound mental retardation to allow more expeditious selection of participants for future research. Participants were analyzed by examining differences between the two groups observed in Experiment 1. EXPERIMENT 1: METHOD Participant Selection
Fifteen persons participated. They were selected from all 61 persons diagnosed with profound mental retardation from two residential facilities. Two groups were formed to highlight the potential differences within the general group diagnosed with profound mental retardation. The fn'st group contained the most severely dis-
Limits to Reinforcer Identification
79
abled individuals from both facilities. This group was selected by asking each treatment team responsible for providing habilitation to these individuals to identify the people in their facilities who had the longest chronic history of training failure. These teams consisted of administrators, program directors, and direct care supervisors with at least one year's experience of providing and evaluating skill acquisition programs for the participants. This fast group consisted of 10 persons randomly selected from the 19 persons identified with long-term "chronic training needs." The other group served as a control and consisted of five individuals randomly selected from the remaining 42 persons diagnosed with profound mental retardation. Ivancic (1989) contains more specific information on the participants. General Procedures
Preference assessment and reinforcer validation procedures similar to those of Pace et al. (1985) were used to evaluate treatment effects for each individual. The preference assessment consisted of 20 trials for each stimulus. (This was more than the number of trials used in some previous preference assessments [Pace et al., 1985, used 10 trials] and less than the number of trials used in other assessments [Green et al., 1988, 1991, used 30 trials]). To maximize response to a presentation, this procedure provided the stimulation noncontingenfly and a second opportunity to approach if no response occurred to the fast opportunity (cf. Pace et al., 1985). Green et al. (1988, 1991) used presession trials in the preference assessment to maximize responding). An array of 16 stimuli (cf. Pace et al., 1985) was used in each preference assessment with an additional item identified by familiar care staff as the stimulus judged by them to be most preferred (cf. Green et al., 1991). Following the stimulus preference assessment, each treatment condition utilized three presession primer trials. (Pace et al., [1985] utilized no presession trials; Green et al. [1988, 1991] utilized one.) The potential negative reinforcement explanation for responding in the treatment condition (i.e., responding to avoid a prompt) was eliminated in the current study by providing preference stimuli in treatment only following behavior that occurred naturally (without prompt). In addition, activation of electromechanical switches was used in treatment to minimize response effort and allow response force to be measured. Also, an attempt was made to maximize learning between the response and consequence in treatment by providing automatic auditory and visual feedback following each switch activation, thus bridging the time between the response of the participant and the manually provided consequence (Reynolds, 1968, p. 21). Responses
In the preference assessment, observers scored an approach, avoid, or nonoccurrence response on each presentation trial. Obvious approach responses such as requesting, reaching to touch, smiling, or turning toward stimulus presentations were individually defined and used for most participants. Eye movement
80
M. T. lvancic and J. S. Bailey
was used in the preference assessment for three persons with chronic training need who failed to display a more obvious approach response. Avoid responses included vocally declining, crying, or trying to get away from the stimulus presentation. In the treatment sessions, switch activations were electromechanically scored (Simpson Counter, Model 1041). Independent Observer Reliability Independent observer agreement measures for approach and avoid behavior in the preference assessment were made during 25% of the sessions, evenly distributed across each participant and calculated by dividing agreements over agreements plus disagreements and multiplying by 100. Avoid behavior occurred with only two participants. Overall agreement for approach or avoid behavior was 97% (range: 92%-98%). Average occurrence agreement for approach or avoidance was 90% (range: 14%-100%) and nonoccurrence was 94% (range: 44%,100%). Only two scores averaged below 80%. An individual with chronic training need had a 14% occurrence score because of a low number of responses, and a control group participant had a 44% nonoccurrence score because of a low number of nonoccurrence responses. Both cases involved only five disagreements. Specific Procedures Preference assessment. Of the 17 stimuli presented, gustatory stimuli (cracker and juice) were eliminated for five individuals because they were fed via gastrostomy tubes, and vestibular stimuli (rocking and spinning) were eliminated for two because these movements elicited apparently uncomfortable contractions. Medical approval was obtained for each individual to rule out potential for sensory-evoked seizures from any particular stimulus presentation (Feldman, 1975). Thirteen of the 15 participants received seizure medication and seven received more than one type of medication for seizure control. Presession treatment trials. Immediately before each treatment session three presession trials were used to introduce the preselected stimulus for that session. A presession trial consisted of requesting the target response, gently guiding a switch activation response if a response did not occur, and then providing the preselected stimulus following the automatic feedback. Treatment procedures. Preferences were validated as reinforcers in 10-min, unprompted treatment sessions. These sessions targeted responses previously identified to activate switches through naturally occurring movements using each participant's most comfortable position. Switch movements and comfortISimpson Counter, Model 104, Catalog#12642, Simpson Electronics,853 Dundee Ave, Elgin, IL 60120 (Ph: 312-697-2260).
Limits to Reinforcer Identification
81
able positions were identified by the experimenter in consultation with an occupational and physical therapist familiar with each participant. The group with chronic training needs used an average 168 g of force (range: 57-341) to activate their head or chin switches, and the control group used an average 283 g of force (range: 164-341) to activate their hand switches. In addition, manual delivery of the stimulus consequences following switch activations for each participant was "bridged," as noted earlier, by automatic feedback from a 12-volt red light, a 3600 hz sound (measuring 85 decibels), and the automatic counter click. Treatment conditions. During baseline, switch activation resulted in the automatic feedback. During the more preferred and less preferred conditions, the procedures were identical to baseline except that a stimulus identified during the preference assessment as more or less preferred was presented to the participant for 5 s each time the switch was activated. More preferred stimuli were chosen by randomly drawing a slip from a hat, with all stimuli approached 80% or more. Less preferred stimuli were chosen by drawing from all stimuli approached 30% or less. For individuals failing to approach any stimulus 80% of the opportunities, the stimulus approached the most often was chosen as the most preferred stimulus. When light was identified as the most preferred stimulus in the preference assessment, the light from the automatic feedback device was used as the most preferred stimulus in the treatment session. Experimental Design
Treatment effects were analyzed using an ABAB reversal design (Bailey & Bostow, 1979) to indicate experimental control of the stimuli. In general, the training evaluation for each participant started with a baseline condition followed either by a more preferred or less preferred, but not avoided, treatment condition. Presentation order of these conditions was determined randomly. Preference conditions were altered until the most optimal situation of replicated, repeated conditions (e.g., ABAB) was achieved. Conditions lasted until data were stable. Twenty-two persons identified as experienced in the review of research for persons with developmental disabilities 2 were contacted, and nine of them agreed to judge treatment effects in this study. These judges received individual treatment graphs in random order with generic lettering used to identify conditions.
2These were authors identified as having two or more research articles published in the Behavior Analysis in Developmental Disabilities 1969-1985from the Journal of Applied Behavior Analysis (Bailey, Shook, Iwata, Reid, and Repp, 1985). The editors of that volume were also invited to participate. These judges were likely to have experience observing and making decisions regarding the analytical effects of applied data. Forty-one percent of the judges agreed to participate. Three invitations did not reach their addressees, and three invitations returned. All nine judges who indicated a willingness to review the training data returned their judgements.
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M. T. lvancic and J. S. Bailey
They were asked to consider which repeated conditions showed replicated effects. An individual's graph was considered to show treatment effect when "more preferred" conditions were higher than "less preferred" conditions and was determined to be replicated by at least six of the nine judges (69%). RESULTS Table 1 shows one or more stimuli were approached 80% or more of the preference assessment presentations for 7 of 15 (47%) participants. Such stimuli are often referred to as high preference. For 4 of these 7 (57%) participants, the high-preference stimulus functioned as a reinforcer. That is, the stimulus identified as highly preferred in the assessment increased the rate of switch activations when presented as a consequence to switch activation. In contrast, for the remaining eight participants, the stimulus most preferred, but not approached 80% or more of the preference assessment trials, never functioned as a reinforcer for switch activation. The probability of obtaining these observed cell sizes by chance was p = .025 (Siegle, 1956). Overall approach responding in the preference assessment for the group with chronic training need was 34% compared to 64% for the control group. One or more high preference stimuli were identified for two (20%) individuals in the group with chronic training need and for all five (100%) individuals in the control group. Similarly, reinforcement effects for the more preferred stimulus for each participant were judged to occur for no (0%) individuals in the group with chronic training need and for 4 (80%) individuals in the control group. To show individual results, treatment effects are presented for two representative individuals from each group. Results for Clara and Gwen represent the individual data from the control group. Their overall approach responses in the preference assessment was 32% and 48%, respectively. Their more preferred
TABLE 1
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Limits to Reinforcer Identification
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stimuli were approached 80% (corn puffs) and 100% (chocolate candy) and their less preferred stimuli were 0% (rocking) and 15% (light), respectively. Neither Clara nor Gwen showed any no avoid responses. Figure 1 shows the reinforcement effects for Clara and Gwen, who both showed high preference in the preference assessment. The top panel shows Clara averaged 8.7 switch activations per session in baseline. Clara's first more preferred condition using her more preferred stimulus as a consequence increased her average responding to 17.8 responses per session. Her first less preferred condition reduced responding to 6.5 responses per session. Clara's subsequent repeated more and less preferred conditions followed predicted directions at 27 and 2 responses per session, respectively. Both the more and
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less preferred conditions were judged to replicate. In the bottom panel of Figure 1, Gwen showed a pattern similar to Clara's except that her first more preferred condition was quite a bit lower than her two subsequent more preferred conditions. In the first more preferred condition, chocolate candy was given after each response (CRF). In Gwen's second more preferred condition, responding became so frequent that chocolate candy was reduced first to every third response (FR3) and then to every fifth response (FR5) to avoid within-session satiation. In the final more preferred condition, chocolate candy was provided on every fifth response throughout the condition. For Gwen, repeated more preferred conditions averaged 70 responses per condition. Her repeated less preferred and baseline conditions averaged four and three responses per session, respectively. Both more and less preferred conditions were judged to replicate. Results for Patty and Jerry represent the individual data for the group with chronic training need. Their overall approach responses in the preference assessment were 54% and 13%, respectively. Their more preferred stimuli were approached 73% (music) and 27% (music tones), and their less preferred stimuli were approached 47% (cool) and 5% (vibration), respectively. Figure 2 shows the reinforcement effects for Patty and Jerry who both failed to show high preference in the preference assessment. The top panel shows that Patty averaged 11.4 responses in baseline. Patty's first condition using her less preferred stimulation as the stimulus consequence reduced her average responding to 2.2 responses per session. Her first more preferred condition increased responding to 4.3 responses per session. Patty's subsequent sessions repeating less and more preferred conditions followed predicted directions averaging 4 and 6.5 responses per session, respectively. However, no condition for Patty was judged to replicate. The bottom panel of Figure 2 shows that Jerry averaged one response per condition in baseline, failed to respond in any more preferred stimulus condition, and averaged .75 responses in each less preferred condition. No condition for Jerry was judged to replicate.
DISCUSSION Clara and Gwen were part of a control group of individuals with profound mental retardation who showed high preference in the preference assessment, and these stimuli were judged to be reinforcers later in their treatment sessions. Patty and Jerry's results represent the group identified by their caregivers as showing chronic training needs. Patty and Jerry showed no high preference in the assessment and no reinforcer effect was judged in the treatment sessions when the most preferred stimulus for each individual was used as a consequence. Similar to previous findings (e.g., Green et al., 1991), data from both groups indicated that stimuli approached on at least 80% of trials during the stimulus preference assessment (i.e., "high preference stimuli") tended to func-
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tion as reinforcers, and stimuli approached on fewer trials tended not to function as reinforcers. This current result occurred in this investigation despite multiple assessment trials, use of the stimulus identified as most preferred by care staff, minimized response effort in treatment sessions, and attempts to enhance conditioning between the response and the consequence. The only control group participant who failed to demonstrate treatment effects was also the only person showing any significant avoid responses. In fact, he avoided 42% of his preference assessment presentations by shaking his
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M. T. Ivancic and J. S. Bailey
head "No." He frequently smiled and laughed when he refused stimulus presentations. This preference for opposition was evident in the staff-selected stimulus - - a tape with staff playfully complaining about his failure to comply. This vocal tape, shown to be highly preferred in the assessment, may have failed to produce reinforcement effects in the treatment sessions because the treatment situation removed a prompting component that was present in the stimulus preference assessment. Prompts for compliance to presentations in the preference assessment (e.g., social attention) may have occasioned refusal behavior in this individual in an attempt to generate more prompts. When these prompts did not occur in treatment sessions, the strength of the response occasion may have been altered too much to evoke responding. This study used relatively brief conditions to evaluate treatment. Longer conditions have been used with persons of extremely limited responsiveness (e.g., Boyle & Greer, 1983). Nevertheless, conditions in this study were comparable to those used in similar studies. For example, the current study averaged five sessions per condition (range: 3-13) and Pace et al. (1985) averaged seven sessions per condition (range: 3-19). Where substantially longer conditions are anticipated, baseline lengths similar to treatment conditions should be useful in evaluating changes that are small or highly variable. Finally, demonstrating a failure to show high preferences or treatment effects for an individual in no way indicates that reinforcement effects are not possible or that there is no treatment of benefit for him or her. It does suggest that a continued reliance on simple reinforcement-based procedures (i.e., increasing behavior followed by known reinforcers) for people who show no high stimulation preferences may be difficult programming to justify. EXPERIMENT 2
Research to help those showing the most difficulty in responding to current teaching technology is hampered by confusion as to who belongs in this population (see Reid et al., 1991 for a discussion). There have been only a few studies attempting to identify these individuals (Kobe, Mulick, Rash, & Martin, 1994; Landesman-Dwyer & Sackett, 1978). Reid et al. suggested categorizing people who show difficulty learning useful skills as persons with "profound multiple handicaps" or "profound multiple disabilities" (D. H. Reid, personal communication, June 6, 1995). Reid defines a person with profound multiple disabilities as a person who functions with extreme debilitation, that is, besides being diagnosed as profoundly mentally retarded, this individual has physical disabilities that prohibit ambulation and at least one other type of handicap (e.g., some other sensory or motor impairment). All individuals in the group with chronic training need and 3 of the 5 control group participants in Experiment 1 fit this profound multiple disability definition. Failing to show high preference in a comprehensive reinforcer assessment provides a direct way of identifying individuals who are unlikely to
Limits to Reinforcer Identification
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benefit from current teaching technology, given the close relationship between people who fail to show both high preference and effects from reinforcement-based training (Green et al., 1991; Experiment 1). It is this specific subgroup of individuals with profound multiple disabilities (i.e., those who fail to show any high preference) who would benefit most from research to extend current limitations of behavioral technology. As such, it may be helpful further to analyze characteristics of individuals for whom current teaching technology is not successful to target these individuals and their treatment needs more specifically in future research. Experiment 2 attempted to show further differences within the heterogeneous population of people with profound multiple disabilities by comparing selected characteristics of the two groups in Experiment 1. Specifically, Experiment 2 analyzed movement and response-time differences between the control group, who had identified reinforcers, and the group with chronic training need, who failed to demonstrate reinforcer effects. METHOD
Participants The same individuals who took part in Experiment 1 participated in Experiment 2. The movement analysis was made 1.5 years after Experiment 1 was completed. At that time, 4 of the original 15 participants were unavailable. One person from each group had moved out of state. Two individuals from the group with chronic training need had died of natural causes. This left 7 individuals with chronic training need and 4 control group individuals for the movement analysis.
Procedures Response time analysis. Each treatment session in Experiment 1 was timed with a stopwatch. The experimenter scored the time-to-the-first-response (latency) as it occurred for each individual during each treatment session. Movement analysis. A 5-min video tape was made of each participant and scored for the occurrence of movement across 10-s intervals. The general definition of movement included any body activity excluding minute body movement, simple eyelid movement, or apparent involuntary response. Minute body movement included noticeable breathing or any body response that moved less than 20 cm, excluding movement of the face and eye pupil. Simple eyelid movement included opening and shutting of the eyelids, but did not include expressions such as eye widening, squinting, or grimacing. Involuntary responses included any movement too quick to be functional such as hiccups, coughs, jerks, and nystagmus (eye pupil jerking). Facial expressions and
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M. T. lvancic and J. S. Bailey
stereotypy were included as activity. Observations were cued via an audio tape with an 8-s observe and 2-s record scoring procedure. Independent observations were taken on all 450 participant movement observations. Overall reliability was calculated by dividing agreements on scored occurrence and nonoccurrence of movement intervals by those agreements plus disagreements. Reliability was above 90% for every individual, averaging 1.8 disagreements per person. RESULTS Figure 3 provides the average latency to the first response in treatment conditions (top panel) and average percent intervals with movement in a separate evaluation (bottom panel) for both groups. The top panel of Figure 3 shows that the group with chronic training need averaged 5.0 min to their first response in treatment sessions (4.6 rain in more preferred conditions and 5.3 min in less preferred conditions). All control participants responded more quickly in training sessions, averaging .9 min to their first response (.33 min in more preferred conditions and 1.4 min in less preferred conditions). A small-sample t-test showed that differences between the latencies of response in the two groups for each condition was significant at the .05 level of error (df= 13). The bottom panel of Figure 3 shows that movement was measured in 51% of the intervals for the groups with chronic training need and in 99% of the intervals for the control group. Only one person in the group with chronic training need showed an activity level similar to that observed in the control group. A small-sample t-test showed the differences in general movement between the two groups was significant at a 0.01 level of error (df= 9) DISCUSSION There were significant differences between the control group and the group with chronic training need in overall movement based on brief video samples and in time-to-initiate target responding in treatment sessions. Specifically, the group less likely to demonstrate reinforcers, the group identified with chronic training need, moved 20 cm or more during slightly more than half of the observations. In addition, it took an average of several minutes (M = 4.5 min) to initiate a response in the most preferred condition of the treatment session for the group identified with chronic training need. In contrast, the group more likely to demonstrate reinforcers, the control group, was scored for movement in almost 100% of the intervals, with response latencies averaging 20 s in the more preferred conditions of their treatment sessions. It seems quite reasonable to find people who do not move a great deal or very quickly also show difficulty with training success, given that the criterion for treatment success is based on responding (i.e., movement).
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Although the group with chronic training need had obvious habilitation limitations, their habilitative potential was certainly greater than that of other groups with extreme limits to functioning. For example, there was no concern for individuals in the group with chronic training need over the maintenance of their life-support. Life-support is a frequently discussed concern for lower functioning individuals often labelled as in a "persistive vegetative state" (Bontke, Dolan, & Ivanhoe, 1994). Individuals in a persistive vegetative state do not react to threatening situations (Howard & Miller, 1995), and all the individuals with chronic training need showed response to threat such as crying out to obvious pain or frowns from positioning discomfort.
GENERAL DISCUSSION Individuals with profound multiple disability who show no high preferences in stimulus assessment procedures are unlikely to show reinforcement effects and so are unlikely to benefit from current reinforcement-based teaching procedures. In addition, it is likely that a person at the lowest functioning end of
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the group with profound multiple disabilities (i.e., a person who moves very little and initiates very slowly) can be identified without formal assessment procedures by anyone who has been responsible for that individual's habilitation development or evaluation for at least a year. When simple reinforcement-based procedures are difficult for an individual to demonstrate, alternative procedures for providing habilitation should be sought and empirically validated (Bailey, 1981; Green et al., 1991). Alternative programming for individuals who fail to demonstrate high preferences may include programming to teach approach responding. An individual may fail to show high preference because reinforcement for less conventional approach responses (e.g., eye gaze, switch activity) used during assessment sessions has been limited to contact only during those assessment sessions. When less conventional approach responses are used in preference assessments, further acquisition may be required to condition a response to the strength of more obvious approach responses (e.g., reach-to-touch) which likely contacts a variety of reinforcers throughout a normal day. Another important line of research for a person with profound multiple disability who shows no high preference may be to increase the value of any concurrently available preferences through establishing operations (Michael, 1993, chap. 7) including removal of discomfort. That is, approach responding might occur differently when stimulation is provided in positions of increased comfort (e.g., side lying, standing table), on different medications (e.g., medications for seizures, bowels, or spasticity), or in different contingent or noncontingent rates and/or sequences. Finally, contact with any stimulation, no matter how strongly preference is documented, that elicits (the response occurs following the stimulation) "happy" responding, e.g., smiles, (Green & Reid, in press), that interrupts interfering responding, or that evokes behavior to maintain contact after provision may be considered important to the daily living situation for an individual who receives it (Reid et al., 1991). Stimuli not strong enough to evoke responding any more effortful than a preference (approach) response, but documented as preferred, might be validated as stimuli important for the enrichment for an individual by measures such as those associated with "happiness," inappropriate response interruption, or tracking. An associated measure in the current investigation with some potential to validate the "low" preferences found in the chronic training need group could be that latency to the first response. Six of the 10 individuals in the groups with chronic training need responded more quickly in their more preferred conditions than in their less preferred conditions, even though the latencies for both conditions were quite long. Enrichment value for an individual who shows stimuli assessed to be preferred more than other stimuli but never shows high preference may be validated through such associated measures. Finding such validation for the preference value of the "low" preferred stimulus or the high preferred stimulus that is not demonstrated as a reinforcer may be the empirical justification
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n e e d e d for professionals to r e c o m m e n d these stimuli as e n v i r o n m e n t a l enrichm e n t p r o c e d u r e s for p e o p l e w h o do not exhibit b e h a v i o r any m o r e effortful than an a p p r o a c h response. Reid et al. (1991) expressed concern o v e r the diligence shown for developing an effective teaching technology for people w h o fail to show progress with the current training technology. Hopefully, procedures identifying individuals who are not being serviced by our current technology will direct and increase research necessary to develop a technology that will offer these individuals better lives.
REFERENCES Bailey, J. S. (1981). Wanted: A rational search for the limiting conditions of habilitation. Analysis and Intervention in Developmental Disabilities, 1, 45-52. Bailey, J. S. & Bostow, D. E. (1979). Research methods in applied behavior analysis. Tallahassee, FL: Copy Grafix. Bailey, J. S., Shook, G. L., Iwata, B. A., Reid, D. H., & Repp, A. C. (Eds.). (1985). Behavior analysis in developmental disabilities from the Journal of Applied Behavior Analysis, Reprint Series (Vol. 1). Lawerence, KS: Journal of Applied Behavior Analysis. Bontke, C. E, Dolan, J. M., Ivanhoe, C. B. (1994). Journal of Head Trauma Rehabilitation, 9 (4), 62-69. Boyle, M. A., & Greer, R. D. (1983). Operant procedures and the comatose patient. Journal of Applied Behavior Analysis, 16, 3-12. Feldman, R. G. (1975). Patients with epilepsy. American Family Physician, 12(4), 135-140. Fisher, W., Piazza, C. C. Bowman, L. G., Hagopian, L. P., Owens, J. C., Slevin, 1. (1992). A comparison of two approaches for identifying reinforcers for persons with severe and profound disabilities. Journal of Applied Behavior Analysis, 25, 491-498. Green, C. W., & Reid, D. H. (in press). Defining, validating, and increasing indices of happiness among people with profound multiple disabilities. Journal of Applied Behavior Analysis. Green, C. W., Reid, D. H., White, L. K., Halford, R. C., Brittain, D. P., & Gardner. S. M. (1988). Identifying reinforcers for persons with profound handicaps: Staff opinion versus systematic assessment of preferences. Journal of Applied Behavior Analysis, 21, 31-43. Green, C. W., Reid, D. H., Canipe, V. S., & Gardner, S. M. (1991). A comprehensive evaluation of reinforcer identification processes for persons with profound multiple handicaps. Journal of Applied Behavior Analysis, 24, 537-552. Howard, R. S., & Miller, D.H. (1995). The persistent vegetative state. British Medical Journal, 310, 341-342. Ivancic, M. T. (1989). Assessing operant training potential. Dissertation Abstracts International, 50, 115A- 1826A (Order No. DA8916201 ). Kobe, E H., Mulick, J. A., Rash, T. A., & Martin, J. (1994). Nonambulatory persons with profound mental retardation: Physical, developmental, and behavioral characteristics. Research in Developmental Disabilities, 15, 413-423. Landesman-Dwyer, S., & Sackett, G. P. (1978). Behavioral changes in nonambulatory, profoundly mentally retarded individuals. In C. E. Meyers (Ed.), Quality of life in severely and profoundly mentally retarded people: Research foundations for improvement (pp. 55-144). Washington, DC: American Association for Mental Deficiency. Michael, J. (1993). Concepts and principles of behavior analysis. Kalamazoo, MI: Society for the Advancement of Behavior Analysis. Pace, G. M., Ivancic, M. T., Edwards, G. L., Iwata, B. A., & Page, T. J. (1985). Assessment of stimulus preference and reinforcer value in profoundly retarded individuals. Journal of Applied Behavior Analysis, 18, 249-255.
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Reid, D. H., Phillips,J. E, & Green, C. W. (1991). Teaching persons with profound multiple handicaps: A review of the effectsof behavioral research.Journal of Applied Behavior Analysis,24, 319-336. Reynolds, J. S. (1968), A primer of operant conditioning. Glenview, IL: Scott, Foresman, & Company. Siegle,M. (1956). Nonparametric statistics.NY: McGraw-Hill Book Company.