Graziano & Raulin
Research Methods (9th edition)
Examples of Single-Subject
Research
from the Literature
(Note that each of these studies has more than one participant, but in each study they were analyzed separately, as in single subject designs.
Example # 1
Smith, R. G., & Churchill, R. M. (2002). Identification of environmental determinants of behavior disorders through functional analysis of precursor behaviors. Journal of Applied Behavior Analysis, 35, 125-136.
Summary
The functional analysis of behavior (observing target behavior and its contingencies) has long been a major method of evaluating behavioral problems. Once a functional analysis is completed, treatment most likely entails manipulating the contingencies to strengthen or weaken the target behavior. However, this usual functional analysis procedure is seriously limited when the problem behavior poses risks for the person, as is the case with self injurious behavior (SIB). In order to analyze it, the target behavior of SIB must be allowed to occur so it and its contingencies can be observed. In that process, the person is at risk for injury due to the SIB.
In this study, the researchers focused, not on the problem behavior, such as SIB, nor on the contingencies following the behavior. Rather, they explored the possibility of looking at the behavior precursors--what the person does just prior to the appearance of the problem behavior, which may be responsible for evoking the problem behavior.
Four adults with severe cognitive disabilities and self-injurious behavior were observed individually under four different conditions in a time-series design. The four sequential conditions were:
- Alone - The participant is alone and no contingencies are applied
- Attention - when SIB occurs, the participant receives 5 seconds of staff attention (i.e. statements of concern or reprimand)
- Play - Participant has play and game materials around; every 30 seconds staff presents a non-contingent remark, such as "How are you doing?"
- Demand - Every 30 seconds staff give participant a command to perform some simple task. Verbal praise was given contingent on completion of the task.
Each participant was observed individually in each condition across a time series design. Observers made their recordings on a hand-held computer. The dependent variables (i.e., the target behaviors) were the particular problem behavior of each person (i.e., head-banging, aggression).
The results showed that, for each person, the problem behavior varied with the precursor condition, occurring more in some conditions and less in others. That is, under some conditions, the problem behavior was very low. The researchers concluded that by focusing the functional analysis on precursor conditions, it may be possible to identify the conditions under which the problem behavior is most and least likely to occur. In this way, the analysis need not include a high rate of the behavior in order to identify its contingencies. Some of the problem behavior will occur, but not as much as it does in more traditional functional analysis. This may be a way of reducing the risk of such behaviors as SIB during functional analyses.
Example # 2
Slifer, K. J,, Koontz, K. L., & Cataldo, M. (2002). Operant-conditioning-based preparation of children for functional Magnetic Resonance Imaging. Journal of Applied Behavior Analysis, 35, 191-194.
Summary
MRI diagnoses of brain pathology is an important medical tool. The procedure most often involves cooperation of the patient, who must minimize disruptive head movements while carry out simple tasks on command. This is often difficult for children. In this study, four children, ranging in age from 7 to 10 years old, were trained using operant conditioning techniques to control disruptive head movement and to follow directions and respond effectively while in a simulated MRI procedure.
Each child moved through a multiple baseline procedure, followed by reinforcement for motor control, followed by reinforcement for accuracy in task responding. In the baseline condition, the child was given instructions, shown how to lie still, and how to respond to the tasks. In the next phase, the child was reinforced with verbal feedback, praise, and a small prize for reduced head motion. In the final phase, the child was reinforced for correct responding to the task. Note that reinforcement was contingent on motion control and performance accuracy.
Across conditions, there was a sharp improvement in head-motion control and performance accuracy as a function of the reinforcement contingencies. That is, these children became much better at cooperating during the mock MRI procedure. The researchers conclude that such training may be useful in real clinical situations to improve the validity and reliability of MRI diagnoses of children. This was a laboratory setting, using a simulated MRI procedure. Further research is needed in actual MRI settings.
Example # 3
Charlop-Christy, M. H., Carpenter, M., Loc, L., LeBlanc, L. A., & Kellet, K. (2002). Using the Picture-Exchange-Communication System (PECS) with children with autism: Assessment of PECS acquisition, speech, social communicative behavior, and problem behavior. Journal of Applied Behavior Analysis, 35, 213-231.
Summary
This research evaluates the effectiveness of a communication-training system (PECS), which is often used to teach non-speaking children with autism to communicate through a series of picture cards. Although commonly used, the procedure had not yet been effectively evaluated. This study attempted an evaluation.
In the PECS training, children are given a Velcro board and a series of cardboard pictures. Through the use of basic behavioral technology, such as differential reinforcement, shaping, and stimulus control, the child is taught to select appropriate cards and place them on the board in the desired order, thus constructing "picture sentences." In this research, three children with autism were observed across a multiple baseline design that consisted of: Pre-Training Baseline; PECS Training; Post-Training; and Follow-up.
The dependent measures were: the occurrence of spontaneous speech; the length of speech utterances; the proportion of time intervals in which the child had eye-contact with the teacher; the proportion of time intervals in which tantrums and disruptive out-of-seat behavior occurred.
The results showed that across the multiple baseline conditions, (1) all three children mastered the PECS procedure in a relatively short period, (2) all increased their amount and length of spontaneous speech; and (3) all showed a reduction of tantrum and other disruptive behavior. They concluded the PECS system is useful and effective.
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