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Task Variation Versus Task Repetition for People with Profound Developmental Disabilities: An Assessment of Preferences
Pergamon
Research in Developmental Disabilities, Vol. 19, No. 2, pp. 189 –199, 1998 Copyright © 1998 Elsevier Science Ltd Printed in the USA. All rights reserved 0891-4222/98 $19.00 1 .00
PII S0891-4222(97)00051-6
Task Variation Versus Task Repetition for People with Profound Developmental Disabilities: An Assessment of Preferences Giulio E. Lancioni University of Leiden
Mark F. O’Reilly University College Dublin
Francesca Campodonico and Margherita Mantini Lega F. D’Oro Research Center
An assessment of preferences between task variation and task repetition with four adults with profound developmental disabilities was implemented. After participants were exposed to both task variation and task repetition conditions, they were allowed to choose between them. Results showed that all participants had strong preferences; three preferred task variation and one task repetition. Aspects of the assessment and use of assessment data for planning daily work conditions were discussed. © 1998 Elsevier Science Ltd
Requests for reprints should be sent to Giulio E. Lancioni, Department of Psychology, University of Leiden, Wassenaarseweg 52, 2333 AK Leiden, The Netherlands. E-mail: Lancioni@ RULFSW.LeidenUniv.NL
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During the last 15 to 20 years, growing attention has been devoted to the preferences of people with severe and profound developmental disabilities (cf. Bannerman, Sheldon, Sherman, & Harchik, 1990; Guess, Benson, & SiegelCausey, 1985; Lancioni, O’Reilly, & Emerson, 1996; Parsons & Reid, 1990). It has been clearly recognized that these people, as others, have the right to express and satisfy their preferences within their daily situations. There also has been increasing support for the notion that allowing people to satisfy their preferences may have beneficial effects on their behavior, performance, and quality of life (Bambara, Koger, Katzer, & Davenport, 1995; Dyer, Dunlap, & Winterling, 1990; Favell, Realon, & Sutton, 1996; Felce & Perry, 1995). A number of studies have assessed presenting choices and identifying preferences within daily situations with people with severe and profound developmental disabilities. Choices have been presented between food and drink items within meals or snacks (Parsons, McCarn, & Reid, 1993; Reid & Parsons, 1991; Sigafoos, Roberts, Couzens, & Kerr, 1993), between leisure and food items during free time (Schepis & Reid, 1995), and between different tasks or work strategies (alone or with a peer) during work periods (Bambara, Ager, & Koger, 1994; Lancioni, Oliva, Andreoni, & Pirani, 1995; Lancioni, Oliva, Meazzini, & Marconi, 1993; Mithaug & Mar, 1980; Parsons, Reid, Reynolds, & Bumgarner, 1990). The findings from these studies (a) support the notion that people with severe and profound developmental disabilities can express preferences on a variety of daily events, and (b) encourage the extending of the assessment of preferences to other relevant areas. One of those areas concerns vocational arrangements. People with severe and profound developmental disabilities usually are presented either one or a few tasks to be repeated many times throughout the day (Bates, Renzaglia, & Clees, 1980; Dunlap & Plienis, 1991; Sweeney & LeBlanc, 1995); however, task variation could be more effective in promoting alertness and motivation, and could be preferred over task repetition. Furthermore, data from the instructional literature seem to suggest that the use of task variation can facilitate learning, reduce deviant behavior, and improve mood (Cuvo et al., 1980; Dunlap, 1984; Dunlap & Dunlap, 1987; Dunlap & Koegel, 1980; Winterling, Dunlap, & O’Neill, 1987). The present study assessed preferences between task variation and task repetition with four adults with profound developmental disabilities. All participants were instructed on the tasks to be performed using a computer-aided system familiar to them. For task repetition, the system continued to present instructions on the same task. For task variation, the system presented different instructions representing different tasks. Periods in which participants were exposed to both task conditions were followed by periods in which participants were allowed to choose between task conditions. In addition to assessing participants’ preferences for task conditions, the study also checked whether participants had different work performance (i.e., correct responding and ontask behavior) in the two task conditions.
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METHOD Participants Participants were two men (Participants 1 and 2) and two women (Participants 3 and 4) whose ages ranged between 24 and 31 years. They were involved in special programs concerning basic self-help skills, orientation and mobility, and independent occupation in a center for persons with multiple disabilities. All four participants were congenitally deaf, with functional vision, and profound developmental delays. The Vineland Adaptive Behavior Scales showed age equivalents of about 3 years on daily living skills, and less than 1 year on socialization, for each participant. They could eat independently, were toilet trained, washed themselves with help, and put on clothes without fastening buttons. They could carry out a variety of simple vocational tasks (e.g., assembling two-piece objects, placing objects into containers, and sorting objects), and engage in those tasks when shown objects or pictorial representations related to them. All participants performed some tasks daily and would normally receive tangible reinforcement (e.g., small food items) for their performance. During their nonoccupational periods, they were generally sedentary. Setting, Tasks, and Task Sessions Three rooms and a reception area in front of the rooms, located in a vocational and research unit in which participants had often worked, served as the setting. There were 30 tasks that participants had already demonstrated competence performing. These tasks, which were not available outside experimental sessions, required 7 to 18 responses and could be performed usually in less than 2 minutes (e.g., assembling 7 two-piece objects, sorting 18 objects into three groups, putting 8 combs in bags, placing 9 brushes in boxes). For the task variation condition, a session involved 10 different tasks that could change across days. For the task repetition condition, a session involved 10 presentations of the same task. The task available changed every four or five sessions. Five tasks from the pool of 30 were used for these sessions. During each session, the task instructions (representations of objects needed for the tasks) were interspersed with six representations of food reinforcers. Apparatus Two versions of a computer-aided system were used in two adjacent rooms, one for task variation and one for task repetition. Each version consisted of a screen for the display of pictorial representations, a mat sensor placed on the floor in front of the screen and connected to a computer, and a reinforcer dispenser (see Lancioni, Oliva, Raimondi, & Ciattaglia, 1989). At the start of a session, the participant walked to the screen and, by stepping on the mat sensor, caused the first task representation to appear on the screen. This was the first of two
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representations used for a task, and showed objects (e.g., soap bottles) to be taken from a large table. After taking these objects, the participant returned to the screen, and by stepping on the mat sensor caused the second task representation to appear. This showed, for example, boxes for the soap bottles. The participant was to walk to the boxes on the table and put the bottles in the boxes. The subsequent return to the screen caused the appearance of either the first representation of a task or the representation of a food reinforcer. In the latter case, the participant would obtain a favorite food item (as reinforcer for the performance of the previous task) from a reinforcer dispenser connected to the system.
Experimental Design The study included five phases. The first phase served to establish “objectsignals,” objects to be used as cues for the two task conditions and a control condition (i.e., a combination of food items and visual and vibrotactile stimuli of known reinforcing value). During the second phase, participants were assigned the two task conditions an equal number of times. This gave participants equal exposure to the conditions before choosing between them (third phase) and also allowed a check of participants’ performance in the two conditions. The control condition was also assigned a number of times so participants had regular exposure to it. During the third phase, participants could choose between the two task conditions and, sometimes, between one of the task conditions and the control condition. Choice trials that included the control condition were used to examine whether participants engaged in reliable choice behavior. The control condition was allegedly the more favorable alternative since it allowed access to reinforcing items and did not require any effort (see Lancioni et al., 1995, 1996). Participants were therefore expected to choose the control condition when it was presented. The fourth and fifth phases replicated the second and third phases. Phase I: establishing object-signals. The object-signals were a wooden box, a piece of rope, and a dish or plastic bag. Each object-signal had an identical match that was placed either above one of the screens used for task instructions, or on the tray with items used for the control condition. When given an object-signal, participants were to go to the screen or tray where the match was and put one next to the other. For Participants 1 and 3, a match of the wooden box was above a screen with a black frame used to show instructions for task variation; a match of the rope was above a screen with a light-blue frame used to show instructions for task repetition; and a match of the dish was on the tray with food, a flash light, and a vibrator. This tray with reinforcing items served as a control condition. For Participants 2 and 4, a match of the box was above
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the screen with the light-blue frame; and a match of the rope above the screen with the black frame. A match of the plastic bag was on the tray with reinforcing items. Sessions included 10 to 20 trials and lasted less than 15 minutes. For each block of 10 trials, 8 were for object-signals related to the screens for the two task conditions and 2 for the object-signals related to the tray with reinforcing items. An object-signal was never presented more than twice in succession. A correct response was defined as participants going directly to the screen or tray where the match of the object-signal was and matching the two. Correct responses were followed by praise and edibles. A total of 100 consecutive correct responses was required. Phase II: experimenter’s assignment. The experimenter assigned each task condition 22 times and the control condition 16 times by giving the participants an object-signal. The wooden box for Participants 1 and 3, for example, meant that they had to (a) reach the screen with the black frame used for task variation where the match for the box was, (b) put the box next to its match, and (c) begin a task variation session. Each task condition was assigned once or twice a day. There was a break of at least 1.5 hours between assignments. No experimenter feedback was provided for task performance during sessions. Participants obtained food reinforcers as indicated by the representations of those reinforcers on the screen. The assignment of the control condition allowed participants to walk to the room containing the tray with reinforcing items and have access to them for 4 minutes. Phase III: participants’ choice. This phase included 38 choice trials. A choice trial consisted of the presentation of two object-signals. The object-signals were in a container (in the reception area), and participants were to take one of them. Of the 38 choice trials, 24 concerned the two task conditions; 14 concerned one of the task conditions and the control condition. The left-right position of the object-signals of each choice varied systematically. The choice of task variation or task repetition led to a task variation session or a task repetition session. The choice of the control condition led to a 4-minute access to the tray with reinforcing items. Phase IV: experimenter’s assignment. Participants were assigned task and comparison conditions as in Phase II, but the room previously used for task variation was now used for task repetition and vice versa. Phase V: participants’ choice. The differences from Phase III were the change of rooms between task conditions and the presence of 28 to 30 choice trials concerning task conditions.
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Data Collection and Reliability The experimenter who assigned conditions and presented choices also collected the data. The measures recorded during task sessions were (a) number of task-related responses carried out correctly (e.g., number of combs placed in bags correctly) and (b) on-task behavior. Other measures were the responses with object-signals (Phase I) and the alternatives selected during choice trials. On-task behavior was recorded by momentary time interval sampling (Sattler, 1988). At the end of each 10-second interval, a positive score was recorded if participants were using task material, walking, or looking at the screen. Interrater agreement was collected during about 25% of the sessions (for the first two measures), on about 20% of the responses with object-signals, and 70% of the choices. The percentages of agreement on the responses with objectsignals and correct task responses were computed on single sessions by dividing the smaller number of responses by the larger number of responses and multiplying by 100%. The percentages of agreement for on-task were computed on single sessions by dividing agreements (determined on a point-by-point basis) by agreements plus disagreements and multiplying by 100%. The percentages of agreement on alternatives chosen were computed on groups of 10 choices with the formula agreements divided by agreements plus disagreements and multiplied by 100%. Interrater agreement on correct task-related responses and on-task behavior varied between 86% and 100% with means exceeding 94%. Interrater agreement on the other measures varied between 90% and 100% with means exceeding 98%.
RESULTS During Phase I, participants received 128 to 212 (M 5 168) trials on the object-signals. Figure 1 shows participants’ choice data during Phases III and V of the study. During both phases, Participants 1, 2, and 3 preferred task variation over task repetition. They chose the former on 79 –100% of the choice trials. Participant 4, in contrast, preferred task repetition, choosing this condition on 96% and 93% of the trials of the two phases, respectively. With regard to the control condition, participants chose it in all except one of the trials in which it was presented. Contrary to the clear preferences expressed either for task variation or task repetition, participants did not differ in performance in the two task conditions during Phases II and IV (when they had equal exposure to the two conditions). Figure 2 shows that the percentages of correct task-related responses varied between 93 and 100. Figure 3 shows that the percentages of on-task behavior were nearly or above 90 for Participants 1, 2 and 3, and slightly above 60 for Participant 4. The mean length of sessions was about 20 minutes with differences of about 1 minute between conditions.
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FIGURE 1. The four blocks of bars show the participants’ choice percentages for the two task conditions in Phases III and V of the study. The first two bars of each block (one black and one striped) represent the percentages of Phase III, the last two bars the percentages of Phase V.
DISCUSSION The results showed that the four participants had clear preferences; three preferred task variation and one task repetition. In the trials in which the control condition was presented together with a task option, they consistently selected the control condition (i.e., the allegedly more favorable alternative), suggesting reliable choice behavior. The data of this study can be taken as additional evidence of the possibility of enabling people with severe and profound developmental disabilities to express preferences about important daily events. The absence of performance differences in the two task conditions seems to contrast with the strong preferences expressed by all participants. It may be that participants’ familiarity with the tasks and the presence of regular reinforcement ensured a relatively stable responding and work interest in both task conditions. The preference for task variation expressed by Participants 1, 2, and 3 could have been due to the stimulus changes occurring within the sessions. These changes may have served to promote alertness and activity and prevent or minimize the risks of boredom (cf. Egel, 1980; Koegel & Egel, 1979; Morris, Martin, & Nowak, 1981; Sweeney & LeBlanc, 1995). A possible (although very unlikely) alternative explanation for such a preference could be that the task repetition condition involved less attractive/relevant tasks for participants. This
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FIGURE 2. The four blocks of bars show the participants’ percentages of correct task-related responses within the two task conditions in Phases II and IV of the study. The first two bars of each block represent the percentages of Phase II, the last two bars the percentages of Phase IV.
explanation is in clear contrast with the efforts made (in cooperation with staff) to include in this condition tasks considered fairly characteristic of participants’ repertoire. The knowledge that people with profound developmental disabilities have clear preferences about occupational conditions and that these preferences can be assessed may encourage important practical initiatives. For example, new choice opportunities could be built in the people’s daily occupational contexts and efforts could be made to accommodate their preferences in those contexts (cf. Houghton, Bronicki, & Guess, 1987; Parsons et al., 1993; Reid & Parsons, 1991). These initiatives would be perfectly in line with the increasing consensus on the right of all people (irrespective of their disabilities) to express and satisfy personal preferences (Bannerman et al., 1990; Halle, 1995; Lancioni et al., 1996). Obviously, the assessment of preferences and the arrangement of conditions respecting those preferences would require extra time and attention from work and care centers. The arrangement of those conditions may require new ways of preparing the task material and special instruction systems to help the people move from one task to another (Lancioni et al., 1989; Moore, Agran, & Fodor-Davis, 1989; Sowers, Verdi, Bourbeau, & Sheehan, 1985). All this would
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FIGURE 3. The four blocks of bars show the participants’ percentages of on-task behavior within the two task conditions in Phases II and IV of the study. The first two bars of each block represent the percentages of Phase II, the last two bars the percentages of Phase IV.
have significant practical and economical consequences that need to be analyzed and eventually accepted (cf. O’Shea & Kennelly, 1996).
REFERENCES Bambara, L. M., Ager, C., & Koger, F. (1994). The effects of choice and task preference on the work performance of adults with severe disabilities. Journal of Applied Behavior Analysis, 27, 555–556. Bambara, L. M., Koger, F., Katzer, T., & Davenport, T. A. (1995). Embedding choice in the context of daily routines: An experimental case study. Journal of the Association for Persons with Severe Handicaps, 20, 185–195. Bannerman, D. J., Sheldon, J. B., Sherman, J. A., & Harchik, A. E. (1990). Balancing the right to habilitation with the right to personal liberties: The rights of people with developmental disabilities to eat too many doughnuts and take a nap. Journal of Applied Behavior Analysis, 23, 79 – 89. Bates, P., Renzaglia, A., & Clees, T. (1980). Improving the work performance of severely/ profoundly retarded young adults: The use of a changing criterion procedural design. Education and Training of the Mentally Retarded, 15, 95–104. Cuvo, A. J., Klevans, L., Borakove, S., Borakove, L. S., Van Landuyt, J., & Lutzker, J. R. (1980). A comparison of three strategies for teaching object names. Journal of Applied Behavior Analysis, 13, 249 –257. Dunlap, G. (1984). The influence of task variation and maintenance tasks on the learning and affect of autistic children. Journal of Experimental Child Psychology, 37, 41– 64.
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Dunlap L. K., & Dunlap, G. (1987). Using task variation to motivate handicapped students. Teaching Exceptional Children, 19, 16 –19. Dunlap, G., & Koegel, R. L. (1980). Motivating autistic children through stimulus variation. Journal of Applied Behavior Analysis, 13, 619 – 627. Dunlap, G., & Plienis, A. J. (1991). The influence of task size on the unsupervised task performance of students with developmental disabilities. Education and Treatment of Children, 14, 85–95. Dyer, K., Dunlap, G., & Winterling, V. (1990). Effects of choice making on the serious problem behaviors of students with severe handicaps. Journal of Applied Behavior Analysis, 23, 515–524. Egel, A. L. (1980). The effects of constant vs. varied reinforcer presentation on responding by autistic children. Journal of Experimental Child Psychology, 30, 455– 463. Favell, J. E., Realon, R. E., & Sutton, K. A. (1996). Measuring and increasing the happiness of people with profound mental retardation and physical handicaps. Behavioral Interventions, 11, 47–58. Felce, D., & Perry, J. (1995). Quality of life: Its definition and measurement. Research in Developmental Disabilities, 16, 51–74. Guess, D., Benson, H. A., & Siegel-Causey, E. (1985). Concepts and issues related to choicemaking and autonomy among persons with severe disabilities. Journal of the Association for Persons with Severe Handicaps, 10, 79 – 86. Halle, J. W. (1995). Innovations in choice-making research: An editorial introduction. Journal of the Association for Persons with Severe Handicaps, 20, 173–174. Houghton, J., Bronicki, G. J. B., & Guess, D. (1987). Opportunities to express preferences and make choices among students with severe disabilities in classroom settings. Journal of the Association for Persons with Severe Handicaps, 12, 18 –27. Koegel, R. L., & Egel, A. L. (1979). Motivating autistic children. Journal of Abnormal Psychology, 88, 418 – 426. Lancioni, G. E., Oliva, D., Andreoni, S., & Pirani, P. (1995). Working with a peer versus working alone: A preliminary assessment of preferences with four persons with multiple handicaps. Journal of Developmental and Physical Disabilities, 7, 67– 81. Lancioni, G. E., Oliva, D., Meazzini, P., & Marconi, N. (1993). Building choice opportunities within occupational programmes for persons with profound developmental disabilities. Journal of Intellectual Disability Research, 37, 23–39. Lancioni, G. E., Oliva, D., Raimondi, D., & Ciattaglia, F. (1989). Occupational engagement of low-functioning individuals: Extending the applicability of a computer-aided programme. Journal of Mental Deficiency Research, 33, 313–322. Lancioni, G. E., O’Reilly, M. F., & Emerson, E. (1996). A review of choice research with people with severe and profound developmental disabilities. Research in Developmental Disabilities, 17, 391– 411. Mithaug, D. E., & Mar, D. K. (1980). The relation between choosing and working prevocational tasks in two severely retarded young adults. Journal of Applied Behavior Analysis, 13, 177–182. Moore, S. C., Agran, M., & Fodor-Davis, J. (1989). Using self-management strategies to increase the production rates of workers with severe handicaps. Education and Training in Mental Retardation, 24, 324 –332. Morris, J. L., Martin, A. S., & Nowak, M. B. (1981). Job enrichment and the mentally retarded worker. Mental Retardation, 19, 290 –294. O’Shea, E., & Kennelly, B. (1996). The economics of independent living: Efficiency, equity and ethics. International Journal of Rehabilitation Research, 19, 13–26. Parsons, M. B., McCarn, J. E., & Reid, D. H. (1993). Evaluating and increasing meal-related choices throughout a service setting for people with severe disabilities. Journal of the Association for Persons with Severe Handicaps, 18, 253–260. Parsons, M. B., & Reid, D. H. (1990). Assessing food preferences among persons with profound mental retardation: Providing opportunities to make choice. Journal of Applied Behavior Analysis, 23, 183–195.
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Parsons, M. B., Reid, D. H., Reynolds, J., & Bumgarner, M. (1990). Effects of chosen versus assigned jobs on the work performance of persons with severe handicaps. Journal of Applied Behavior Analysis, 23, 253–258. Reid, D. H., & Parsons, M. B. (1991). Making choice a routine part of mealtimes for persons with profound mental retardation. Behavioral Residential Treatment, 6, 249 –261. Sattler, J. M. (1988). Assessment of children (3rd ed.). San Diego: Sattler. Schepis, M. M., & Reid, D. H. (1995). Effects of a voice output communication aid on interactions between support personnel and an individual with multiple disabilities. Journal of Applied Behavior Analysis, 28, 73–77. Sigafoos, J., Roberts, D., Couzens, D., & Kerr, M. (1993). Providing opportunities for choicemaking and turn-taking to adults with multiple disabilities. Journal of Developmental and Physical Disabilities, 5, 297–310. Sowers, J., Verdi, M., Bourbeau, P., & Sheehan, M. (1985). Teaching job independence and flexibility to mentally retarded students through the use of a self-control package. Journal of Applied Behavior Analysis, 18, 81– 85. Sweeney, H. M., & LeBlanc, J. M. (1995). Effects of task size on work-related and aberrant behaviors of youths with autism and mental retardation. Research in Developmental Disabilities, 16, 97–115. Winterling, V., Dunlap, G., & O’Neill, R. E. (1987). The influence of task variation on the aberrant behaviors of autistic students. Education and Treatment of Children, 10, 105–119.
Research in Developmental Disabilities, Vol. 19, No. 2, pp. 189 –199, 1998 Copyright © 1998 Elsevier Science Ltd Printed in the USA. All rights reserved 0891-4222/98 $19.00 1 .00
PII S0891-4222(97)00051-6
Task Variation Versus Task Repetition for People with Profound Developmental Disabilities: An Assessment of Preferences Giulio E. Lancioni University of Leiden
Mark F. O’Reilly University College Dublin
Francesca Campodonico and Margherita Mantini Lega F. D’Oro Research Center
An assessment of preferences between task variation and task repetition with four adults with profound developmental disabilities was implemented. After participants were exposed to both task variation and task repetition conditions, they were allowed to choose between them. Results showed that all participants had strong preferences; three preferred task variation and one task repetition. Aspects of the assessment and use of assessment data for planning daily work conditions were discussed. © 1998 Elsevier Science Ltd
Requests for reprints should be sent to Giulio E. Lancioni, Department of Psychology, University of Leiden, Wassenaarseweg 52, 2333 AK Leiden, The Netherlands. E-mail: Lancioni@ RULFSW.LeidenUniv.NL
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During the last 15 to 20 years, growing attention has been devoted to the preferences of people with severe and profound developmental disabilities (cf. Bannerman, Sheldon, Sherman, & Harchik, 1990; Guess, Benson, & SiegelCausey, 1985; Lancioni, O’Reilly, & Emerson, 1996; Parsons & Reid, 1990). It has been clearly recognized that these people, as others, have the right to express and satisfy their preferences within their daily situations. There also has been increasing support for the notion that allowing people to satisfy their preferences may have beneficial effects on their behavior, performance, and quality of life (Bambara, Koger, Katzer, & Davenport, 1995; Dyer, Dunlap, & Winterling, 1990; Favell, Realon, & Sutton, 1996; Felce & Perry, 1995). A number of studies have assessed presenting choices and identifying preferences within daily situations with people with severe and profound developmental disabilities. Choices have been presented between food and drink items within meals or snacks (Parsons, McCarn, & Reid, 1993; Reid & Parsons, 1991; Sigafoos, Roberts, Couzens, & Kerr, 1993), between leisure and food items during free time (Schepis & Reid, 1995), and between different tasks or work strategies (alone or with a peer) during work periods (Bambara, Ager, & Koger, 1994; Lancioni, Oliva, Andreoni, & Pirani, 1995; Lancioni, Oliva, Meazzini, & Marconi, 1993; Mithaug & Mar, 1980; Parsons, Reid, Reynolds, & Bumgarner, 1990). The findings from these studies (a) support the notion that people with severe and profound developmental disabilities can express preferences on a variety of daily events, and (b) encourage the extending of the assessment of preferences to other relevant areas. One of those areas concerns vocational arrangements. People with severe and profound developmental disabilities usually are presented either one or a few tasks to be repeated many times throughout the day (Bates, Renzaglia, & Clees, 1980; Dunlap & Plienis, 1991; Sweeney & LeBlanc, 1995); however, task variation could be more effective in promoting alertness and motivation, and could be preferred over task repetition. Furthermore, data from the instructional literature seem to suggest that the use of task variation can facilitate learning, reduce deviant behavior, and improve mood (Cuvo et al., 1980; Dunlap, 1984; Dunlap & Dunlap, 1987; Dunlap & Koegel, 1980; Winterling, Dunlap, & O’Neill, 1987). The present study assessed preferences between task variation and task repetition with four adults with profound developmental disabilities. All participants were instructed on the tasks to be performed using a computer-aided system familiar to them. For task repetition, the system continued to present instructions on the same task. For task variation, the system presented different instructions representing different tasks. Periods in which participants were exposed to both task conditions were followed by periods in which participants were allowed to choose between task conditions. In addition to assessing participants’ preferences for task conditions, the study also checked whether participants had different work performance (i.e., correct responding and ontask behavior) in the two task conditions.
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METHOD Participants Participants were two men (Participants 1 and 2) and two women (Participants 3 and 4) whose ages ranged between 24 and 31 years. They were involved in special programs concerning basic self-help skills, orientation and mobility, and independent occupation in a center for persons with multiple disabilities. All four participants were congenitally deaf, with functional vision, and profound developmental delays. The Vineland Adaptive Behavior Scales showed age equivalents of about 3 years on daily living skills, and less than 1 year on socialization, for each participant. They could eat independently, were toilet trained, washed themselves with help, and put on clothes without fastening buttons. They could carry out a variety of simple vocational tasks (e.g., assembling two-piece objects, placing objects into containers, and sorting objects), and engage in those tasks when shown objects or pictorial representations related to them. All participants performed some tasks daily and would normally receive tangible reinforcement (e.g., small food items) for their performance. During their nonoccupational periods, they were generally sedentary. Setting, Tasks, and Task Sessions Three rooms and a reception area in front of the rooms, located in a vocational and research unit in which participants had often worked, served as the setting. There were 30 tasks that participants had already demonstrated competence performing. These tasks, which were not available outside experimental sessions, required 7 to 18 responses and could be performed usually in less than 2 minutes (e.g., assembling 7 two-piece objects, sorting 18 objects into three groups, putting 8 combs in bags, placing 9 brushes in boxes). For the task variation condition, a session involved 10 different tasks that could change across days. For the task repetition condition, a session involved 10 presentations of the same task. The task available changed every four or five sessions. Five tasks from the pool of 30 were used for these sessions. During each session, the task instructions (representations of objects needed for the tasks) were interspersed with six representations of food reinforcers. Apparatus Two versions of a computer-aided system were used in two adjacent rooms, one for task variation and one for task repetition. Each version consisted of a screen for the display of pictorial representations, a mat sensor placed on the floor in front of the screen and connected to a computer, and a reinforcer dispenser (see Lancioni, Oliva, Raimondi, & Ciattaglia, 1989). At the start of a session, the participant walked to the screen and, by stepping on the mat sensor, caused the first task representation to appear on the screen. This was the first of two
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representations used for a task, and showed objects (e.g., soap bottles) to be taken from a large table. After taking these objects, the participant returned to the screen, and by stepping on the mat sensor caused the second task representation to appear. This showed, for example, boxes for the soap bottles. The participant was to walk to the boxes on the table and put the bottles in the boxes. The subsequent return to the screen caused the appearance of either the first representation of a task or the representation of a food reinforcer. In the latter case, the participant would obtain a favorite food item (as reinforcer for the performance of the previous task) from a reinforcer dispenser connected to the system.
Experimental Design The study included five phases. The first phase served to establish “objectsignals,” objects to be used as cues for the two task conditions and a control condition (i.e., a combination of food items and visual and vibrotactile stimuli of known reinforcing value). During the second phase, participants were assigned the two task conditions an equal number of times. This gave participants equal exposure to the conditions before choosing between them (third phase) and also allowed a check of participants’ performance in the two conditions. The control condition was also assigned a number of times so participants had regular exposure to it. During the third phase, participants could choose between the two task conditions and, sometimes, between one of the task conditions and the control condition. Choice trials that included the control condition were used to examine whether participants engaged in reliable choice behavior. The control condition was allegedly the more favorable alternative since it allowed access to reinforcing items and did not require any effort (see Lancioni et al., 1995, 1996). Participants were therefore expected to choose the control condition when it was presented. The fourth and fifth phases replicated the second and third phases. Phase I: establishing object-signals. The object-signals were a wooden box, a piece of rope, and a dish or plastic bag. Each object-signal had an identical match that was placed either above one of the screens used for task instructions, or on the tray with items used for the control condition. When given an object-signal, participants were to go to the screen or tray where the match was and put one next to the other. For Participants 1 and 3, a match of the wooden box was above a screen with a black frame used to show instructions for task variation; a match of the rope was above a screen with a light-blue frame used to show instructions for task repetition; and a match of the dish was on the tray with food, a flash light, and a vibrator. This tray with reinforcing items served as a control condition. For Participants 2 and 4, a match of the box was above
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the screen with the light-blue frame; and a match of the rope above the screen with the black frame. A match of the plastic bag was on the tray with reinforcing items. Sessions included 10 to 20 trials and lasted less than 15 minutes. For each block of 10 trials, 8 were for object-signals related to the screens for the two task conditions and 2 for the object-signals related to the tray with reinforcing items. An object-signal was never presented more than twice in succession. A correct response was defined as participants going directly to the screen or tray where the match of the object-signal was and matching the two. Correct responses were followed by praise and edibles. A total of 100 consecutive correct responses was required. Phase II: experimenter’s assignment. The experimenter assigned each task condition 22 times and the control condition 16 times by giving the participants an object-signal. The wooden box for Participants 1 and 3, for example, meant that they had to (a) reach the screen with the black frame used for task variation where the match for the box was, (b) put the box next to its match, and (c) begin a task variation session. Each task condition was assigned once or twice a day. There was a break of at least 1.5 hours between assignments. No experimenter feedback was provided for task performance during sessions. Participants obtained food reinforcers as indicated by the representations of those reinforcers on the screen. The assignment of the control condition allowed participants to walk to the room containing the tray with reinforcing items and have access to them for 4 minutes. Phase III: participants’ choice. This phase included 38 choice trials. A choice trial consisted of the presentation of two object-signals. The object-signals were in a container (in the reception area), and participants were to take one of them. Of the 38 choice trials, 24 concerned the two task conditions; 14 concerned one of the task conditions and the control condition. The left-right position of the object-signals of each choice varied systematically. The choice of task variation or task repetition led to a task variation session or a task repetition session. The choice of the control condition led to a 4-minute access to the tray with reinforcing items. Phase IV: experimenter’s assignment. Participants were assigned task and comparison conditions as in Phase II, but the room previously used for task variation was now used for task repetition and vice versa. Phase V: participants’ choice. The differences from Phase III were the change of rooms between task conditions and the presence of 28 to 30 choice trials concerning task conditions.
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Data Collection and Reliability The experimenter who assigned conditions and presented choices also collected the data. The measures recorded during task sessions were (a) number of task-related responses carried out correctly (e.g., number of combs placed in bags correctly) and (b) on-task behavior. Other measures were the responses with object-signals (Phase I) and the alternatives selected during choice trials. On-task behavior was recorded by momentary time interval sampling (Sattler, 1988). At the end of each 10-second interval, a positive score was recorded if participants were using task material, walking, or looking at the screen. Interrater agreement was collected during about 25% of the sessions (for the first two measures), on about 20% of the responses with object-signals, and 70% of the choices. The percentages of agreement on the responses with objectsignals and correct task responses were computed on single sessions by dividing the smaller number of responses by the larger number of responses and multiplying by 100%. The percentages of agreement for on-task were computed on single sessions by dividing agreements (determined on a point-by-point basis) by agreements plus disagreements and multiplying by 100%. The percentages of agreement on alternatives chosen were computed on groups of 10 choices with the formula agreements divided by agreements plus disagreements and multiplied by 100%. Interrater agreement on correct task-related responses and on-task behavior varied between 86% and 100% with means exceeding 94%. Interrater agreement on the other measures varied between 90% and 100% with means exceeding 98%.
RESULTS During Phase I, participants received 128 to 212 (M 5 168) trials on the object-signals. Figure 1 shows participants’ choice data during Phases III and V of the study. During both phases, Participants 1, 2, and 3 preferred task variation over task repetition. They chose the former on 79 –100% of the choice trials. Participant 4, in contrast, preferred task repetition, choosing this condition on 96% and 93% of the trials of the two phases, respectively. With regard to the control condition, participants chose it in all except one of the trials in which it was presented. Contrary to the clear preferences expressed either for task variation or task repetition, participants did not differ in performance in the two task conditions during Phases II and IV (when they had equal exposure to the two conditions). Figure 2 shows that the percentages of correct task-related responses varied between 93 and 100. Figure 3 shows that the percentages of on-task behavior were nearly or above 90 for Participants 1, 2 and 3, and slightly above 60 for Participant 4. The mean length of sessions was about 20 minutes with differences of about 1 minute between conditions.
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FIGURE 1. The four blocks of bars show the participants’ choice percentages for the two task conditions in Phases III and V of the study. The first two bars of each block (one black and one striped) represent the percentages of Phase III, the last two bars the percentages of Phase V.
DISCUSSION The results showed that the four participants had clear preferences; three preferred task variation and one task repetition. In the trials in which the control condition was presented together with a task option, they consistently selected the control condition (i.e., the allegedly more favorable alternative), suggesting reliable choice behavior. The data of this study can be taken as additional evidence of the possibility of enabling people with severe and profound developmental disabilities to express preferences about important daily events. The absence of performance differences in the two task conditions seems to contrast with the strong preferences expressed by all participants. It may be that participants’ familiarity with the tasks and the presence of regular reinforcement ensured a relatively stable responding and work interest in both task conditions. The preference for task variation expressed by Participants 1, 2, and 3 could have been due to the stimulus changes occurring within the sessions. These changes may have served to promote alertness and activity and prevent or minimize the risks of boredom (cf. Egel, 1980; Koegel & Egel, 1979; Morris, Martin, & Nowak, 1981; Sweeney & LeBlanc, 1995). A possible (although very unlikely) alternative explanation for such a preference could be that the task repetition condition involved less attractive/relevant tasks for participants. This
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FIGURE 2. The four blocks of bars show the participants’ percentages of correct task-related responses within the two task conditions in Phases II and IV of the study. The first two bars of each block represent the percentages of Phase II, the last two bars the percentages of Phase IV.
explanation is in clear contrast with the efforts made (in cooperation with staff) to include in this condition tasks considered fairly characteristic of participants’ repertoire. The knowledge that people with profound developmental disabilities have clear preferences about occupational conditions and that these preferences can be assessed may encourage important practical initiatives. For example, new choice opportunities could be built in the people’s daily occupational contexts and efforts could be made to accommodate their preferences in those contexts (cf. Houghton, Bronicki, & Guess, 1987; Parsons et al., 1993; Reid & Parsons, 1991). These initiatives would be perfectly in line with the increasing consensus on the right of all people (irrespective of their disabilities) to express and satisfy personal preferences (Bannerman et al., 1990; Halle, 1995; Lancioni et al., 1996). Obviously, the assessment of preferences and the arrangement of conditions respecting those preferences would require extra time and attention from work and care centers. The arrangement of those conditions may require new ways of preparing the task material and special instruction systems to help the people move from one task to another (Lancioni et al., 1989; Moore, Agran, & Fodor-Davis, 1989; Sowers, Verdi, Bourbeau, & Sheehan, 1985). All this would
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FIGURE 3. The four blocks of bars show the participants’ percentages of on-task behavior within the two task conditions in Phases II and IV of the study. The first two bars of each block represent the percentages of Phase II, the last two bars the percentages of Phase IV.
have significant practical and economical consequences that need to be analyzed and eventually accepted (cf. O’Shea & Kennelly, 1996).
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