Biomedical subjects

B A Iwata

Publications and source records attributed to B A Iwata.

At least 19 recordsLinked to original sources

PubMed2000

Response acquisition under direct and indirect contingencies of reinforcement.

We compared the effects of direct and indirect reinforcement contingencies on the performance of 6 individuals with profound developmental disabilities. Under both contingencies, completion of identical tasks (opening one of several types of containers) produced access to identical reinforcers. Under the direct contingency, the reinforcer was placed inside the container to be opened; under the indirect contingency, the therapist held the reinforcer and delivered it to the participant upon task completion. One participant immediately performed the task at 100% accuracy under both contingencies. Three participants showed either more immediate or larger improvements in performance under the direct contingency. The remaining 2 participants showed improved performance only under the direct reinforcement contingency. Data taken on the occurrence of "irrelevant" behaviors under the indirect contingency (e.g., reaching for the reinforcer instead of performing the task) provided some evidence that these behaviors may have interfered with task performance and that their occurrence was a function of differential stimulus control.

Adult↗

PubMed2000

Effects of continuous and intermittent reinforcement for problem behavior during functional communication training.

We evaluated the effectiveness of functional communication training (FCT) in reducing problem behavior and in strengthening alternative behavior when FCT was implemented without extinction. Following the completion of functional analyses in which social-positive reinforcement was identified as the maintaining variable for 5 participants' self-injurious behavior (SIB) and aggression, the participants were first exposed to FCT in which both problem behavior and alternative behavior were reinforced continuously (i.e., on fixed-ratio [FR] 1 schedules). During subsequent FCT conditions, the schedule of reinforcement for problem behavior was made more intermittent (e.g., FR 2, FR 3, FR 5, etc.), whereas alternative behavior was always reinforced according to an FR 1 schedule. Results showed that 1 participant's problem behavior decreased and alternative behavior increased during FCT when both behaviors were reinforced on FR 1 schedules. The remaining 4 participants shifted response allocation from problem to alternative behavior as the schedule of reinforcement for problem behavior became more intermittent. These results suggest that individuals might acquire alternative responses during FCT in spite of inconsistencies in the application of extinction, although even small errors in reinforcement may compromise treatment effects.

Adult↗

PubMed2000

Skill acquisition in the implementation of functional analysis methodology.

Functional analysis methodology is a powerful assessment tool for identifying contingencies that maintain a wide range of behavior disorders and for developing effective treatment programs. Nevertheless, concerns have been raised about the feasibility of conducting functional analyses in typical service settings. In this study, we examined the issue of skill acquisition in implementing functional analyses by evaluating an instructional program designed to establish a basic set of competencies. Eleven undergraduate students enrolled in a laboratory course in applied behavior analysis served as participants. Their performance was assessed during scripted simulations in which they played the roles of "therapists" who conducted functional analyses and trained graduate students played the roles of "clients" who emitted self-injurious and destructive behaviors. To approximate conditions under which an individual might conduct an assessment with limited prior training, participants read a brief set of materials prior to conducting baseline sessions. A multiple baseline design was used to assess the effects of training, which consisted of reading additional materials, watching a videotaped simulation demonstrating correct procedural implementation, passing a written quiz, and receiving feedback on performance during sessions. Results showed that participants scored a relatively high percentage of correct therapist responses during baseline, and that all achieved an accuracy level of 95% or higher following training that lasted about 2 hr. These results suggest that basic skills for conducting functional analyses can be acquired quickly by individuals who have relatively little clinical experience.

Feasibility Studies↗

PubMed2000

Competition between noncontingent and contingent reinforcement schedules during response acquisition.

We examined the extent to which noncontingent reinforcement (NCR), when used as treatment to reduce problem behavior, might interfere with differential reinforcement contingencies designed to strengthen alternative behavior. After conducting a functional analysis to identify the reinforcers maintaining 2 participants' self-injurious behavior (SIB), we delivered those reinforcers under dense NCR schedules. We delivered the same reinforcers concurrently under differential-reinforcement-of-alternative-behavior (DRA) contingencies in an attempt to strengthen replacement behaviors (mands). Results showed that the NCR plus DRA intervention was associated with a decrease in SIB but little or no increase in appropriate mands. In a subsequent phase, when the NCR schedule was thinned while the DRA schedule remained unchanged, SIB remained low and mands increased. These results suggest that dense NCR schedules may alter establishing operations that result in not only suppression of problem behavior but also interference with the acquisition of appropriate behavior. Thus, the strengthening of socially appropriate behaviors as replacements for problem behavior during NCR interventions might best be achieved if the NCR schedule is first thinned.

Adult↗

PubMed2000

A comparison of procedures for programming noncontingent reinforcement schedules.

We compared two methods for programming and thinning noncontingent reinforcement (NCR) schedules during the treatment of self-injurious behavior (SIB). The participants were 3 individuals who had been diagnosed with mental retardation. Results of functional analyses indicated that all participants' SIB was maintained by positive reinforcement (i.e., access to attention or food). Following baseline, the effects of two NCR schedule-thinning procedures were compared in multielement designs. One schedule (fixed increment) was initially set at fixed-time 10-s reinforcer deliveries and was also thinned according to fixed-time intervals. The other schedule (adjusting IRT) was initially determined by participants' baseline interresponse times (IRTs) for SIB and was thinned based on IRTs observed during subsequent treatment sessions. Results indicated that both schedules were effective in initially reducing SIB and in maintaining response suppression as the schedules were thinned.

Adult↗

PubMed1999

Side effects of extinction: prevalence of bursting and aggression during the treatment of self-injurious behavior.

Findings from basic and applied research suggest that treatment with operant extinction may produce adverse side effects; two of these commonly noted are an increase in the frequency of the target response (extinction burst) and an increase in aggression (extinction-induced aggression). Although extinction is often used to treat problem behavior in clinical settings, few applied studies have examined the prevalence of these side effects or their possible attenuation with other operant procedures. An analysis of 41 data sets for individuals who received treatment for self-injurious behavior indicated that extinction bursts or increases in aggression occurred in nearly one half of the cases. The prevalence of bursting and aggression was substantially lower when extinction was implemented as part of a treatment package rather than as the sole intervention.

Adult↗

PubMed1999

Examination of ambiguous stimulus preferences with duration-based measures.

Items that produced ambiguous results in an approach-based preference assessment were reassessed using a duration-based assessment. The reinforcing effects of three items on free-operant responding were subsequently tested. The results suggested that the duration-based assessment produced slightly more differentiated results and that predictions about reinforcer value, based on this assessment, were accurate.

Adult↗

PubMed1999

DRO contingencies: an analysis of variable-momentary schedules.

We conducted several comparative analyses to determine the relative effectiveness of variable-momentary differential-reinforcement-of-other-behavior (VM DRO) schedules. Three individuals who had been diagnosed with mental retardation participated. Results of functional analyses indicated that their self-injurious behavior (SIB) was maintained by social-positive reinforcement. Two individuals participated in a two-stage comparative analysis within multielement and multiple baseline designs. Fixed-interval (FI) and variable-interval (VI) DRO were compared in the first stage; VI DRO and VM DRO were compared in the second. All three schedules effectively reduced the participants' SIB. Treatment for the 3rd individual was conducted in a reversal design to examine the effects of VM DRO when it was implemented in isolation, and results indicated that the procedure was effective in reducing SIB. These findings suggest that VM DRO schedules may represent attractive alternatives to traditional FI schedules because momentary schedules do not require continuous monitoring and may result in higher rates of reinforcement.

Adult↗

PubMed1999

Correspondence between outcomes of brief and extended functional analyses.

We compared results obtained from 50 sets of functional analysis data from assessments of self-injurious behavior (SIB), 35 of which showed clear response patterns and 15 of which were undifferentiated, with those obtained from two abbreviated methods of assessment: (a) a brief functional analysis, consisting of the first session of each condition from the full functional analysis, and (b) a within-session analysis, in which data from the brief analysis were regraphed to show minute-by-minute changes in response rates during a session. Results indicated that outcomes of the brief and within-session analyses corresponded with those of the full functional analyses in 66.0% and 68.0% of the cases, respectively. Further examination of results indicated a tendency for the brief analysis to identify a large proportion of positive cases (both true and false positives) and for the within-session analysis to identify a large proportion of negative cases (true and false negatives).

Adult↗

PubMed1999

Effects of session duration on functional analysis outcomes.

We examined the extent to which variations in session duration affected the outcomes of functional analyses. Forty-six individuals, all diagnosed with mental retardation and referred for assessment and treatment of self-injurious or aggressive behavior, participated in functional analyses, consisting of repeated exposure to multiple test conditions during 15-min sessions. For each set of assessment data, new data sets based on session durations of 10 and 5 min were prepared by deleting data from the last 5 and 10 min, respectively, of each session. Each graph (N = 138) was then reviewed individually by graduate students who had previous experience conducting and interpreting functional analyses, but who were blind to both participant identity and session duration. Interpretations of behavioral function based on the 10- and 5-min data sets were then compared with those based on the 15-min data sets. All of the 10-min data sets yielded interpretations identical to those based on 15-min data sets. Interpretations based on the 5-min and 15-min data sets yielded three discrepancies, all of which were the result of increased response rates toward the latter parts of sessions. These results suggest that the efficiency of assessment might be improved with little or no loss in clarity by simply reducing the duration of assessment sessions.

Adult↗

PubMed1999

False-positive maintenance of self-injurious behavior by access to tangible reinforcers.

Results of a functional analysis indicated that the hand mouthing of a woman with developmental disabilities was maintained by multiple sources of control (sensory stimulation and access to a leisure item). Further assessment revealed that access to several other items also produced high rates of hand mouthing. However, direct observation conducted in the woman's home indicated that none of these items was delivered contingent upon hand mouthing. When the consequence observed most frequently in the home was incorporated into the functional analysis, rates of hand mouthing were no higher than they were during an alone condition. We concluded that hand mouthing, although maintained by automatic reinforcement, was also susceptible to social contingencies when exposed to them during assessment, thereby producing a partially false-positive outcome.

Adult↗

PubMed1999

Multicomponent assessment and treatment of cigarette pica.

We conducted a multicomponent assessment and treatment for 4 individuals who engaged in cigarette pica. During Phase 1, three stimulus preference assessments were conducted to identify (a) the reinforcing component of the cigarette, (b) potential alternative reinforcers that may be used during treatment, and (c) whether the alternative reinforcer would compete effectively with cigarettes. Results were successful in identifying the reinforcing component of the cigarette and suggested the feasibility of using alternative reinforcers during treatment to eliminate cigarette pica. During Phase 2, the effects of two treatment procedures were evaluated. Noncontingent reinforcement (NCR) with the alternative edible reinforcer reduced the pica of 2 of the participants, but effects were not maintained when the initial dense schedule of NCR was thinned. Subsequently, differential reinforcement of alternative behavior with the alternative edible reinforcer was effective in reducing pica for 3 participants. An evaluation of nine treatment procedures failed to identify an effective intervention for the remaining participant; consequently, preventive measures were designed to minimize occurrences of cigarette pica.

Adult↗

PubMed1999

Effects of reinforcement for alternative behavior during punishment of self-injury.

A number of variables influence the effectiveness of punishment and may determine the extent to which less intrusive forms of punishment may be used as alternatives to more intrusive interventions. For example, it has been suggested that response suppression during punishment may be facilitated if reinforcement is concurrently available for an alternative response. However, results of basic research demonstrating this finding have not been replicated with interventions more commonly prescribed as treatments for problem behavior. We evaluated the effects of relatively benign punishment procedures (reprimands or brief manual restraint) on the self-injurious behavior of 4 individuals who had been diagnosed with mental retardation, when access to reinforcement for alternative behavior (manipulation of leisure materials) was and was not available. In all cases, punishment produced greater response suppression when reinforcement for an alternative response was available.

Adult↗

PubMed1999

Analysis of activity preferences as a function of differential consequences.

Individuals who do not possess the verbal skills to express meaningful choice in the absence of its consequences may have difficulty indicating their preference for protracted activities that are unavailable until some time in the future (e.g., taking a walk, riding a bike). When we examined the preferences of 4 individuals with developmental disabilities by showing them pictorial representations of various activities, their initial choices showed no clear preferences. In a subsequent condition, selecting a photograph resulted in brief access to the depicted activity. When selections produced differential consequences (i.e., access to the activity), clear preferences emerged. In addition, 3 individuals' preferences were later shifted to an initially less preferred but more socially desirable option by superimposing additional reinforcement contingencies for engaging in the less preferred activity. Results are discussed in terms of the conditions under which choice functions as an indicator of preference and how those conditions may be altered to improve the quality of choice making without limiting access to preferred options.

Adult↗

PubMed1999

Relative versus absolute reinforcement effects: implications for preference assessments.

We compared results obtained in two previous studies on reinforcer identification (Fisher et al., 1992; Pace, Ivancic, Edwards, Iwata, & Page, 1985) by combining methodologies from both studies. Eight individuals with mental retardation participated. During Phase 1, two preference assessments were conducted, one in which stimuli were presented singly (SS method) and one in which stimuli were presented in pairs (PS method). Based on these results, two types of stimuli were identified for each participant: High-preference (HP) stimuli were those selected on 75% or more trials during both preference assessments; low-preference (LP) stimuli were those selected on 100% of the SS trials but on 25% or fewer of the PS trials. During Phase 2, the reinforcing effects of HP and LP stimuli were evaluated in reversal designs under two test conditions: concurrent and single schedules of continuous reinforcement. Two response options were available under the concurrent-schedule condition: One response produced access to the HP stimulus; the other produced access to the LP stimulus. Only one response option was available under the single-schedule condition, and that response produced access only to the LP stimulus. Results indicated that 7 of the 8 participants consistently showed preference for the HP stimulus under the concurrent schedule. However, when only the LP stimulus was available during the single-schedule condition, response rates for 6 of the 7 participants were as high as those observed for the HP stimulus during the concurrent-schedule condition (1 participant showed no reinforcement effect). These results indicate that, although the concurrent-schedule procedure is well suited to the assessment of relative reinforcement effects (preference for one reinforcer over another), absolute reinforcement effects associated with a given stimulus may be best examined under single-schedule conditions.

Adult↗

PubMed1999

On the relation between object manipulation and stereotypic self-injurious behavior.

Results from a number of studies have shown an inverse relationship between stereotypic behavior and object manipulation. The purposes of this study were to determine whether techniques similar to those used previously (prompting and reinforcement) would be effective in increasing object manipulation under both prompted and unprompted conditions, and to ascertain whether increases in object manipulation would result in decreases in stereotypic self-injurious behavior (SIB). Two individuals with developmental disabilities who engaged in SIB maintained by automatic reinforcement participated. Results showed that object manipulation increased from baseline levels when experimenters prompted participants to manipulate leisure items, but that object manipulation was not maintained under unprompted conditions, and rates of SIB stayed within baseline levels. We then attempted to increase object manipulation further by (a) reinforcing object manipulation, (b) blocking SIB while reinforcing manipulation, and (c) preventing SIB by applying protective equipment while reinforcing object manipulation. Reinforcing object manipulation alone did not affect levels of object manipulation. Blocking effectively reduced attempts to engage in SIB for 1 participant but produced no increase in object manipulation. When the 2nd participant was prevented from engaging in SIB through the use of protective equipment, rates of object manipulation increased dramatically but were not maintained when the equipment was removed. These results suggest that stimulation derived from object manipulation, even when supplemented with arbitrary reinforcement, may not compete with stimulation produced by stereotypic SIB; therefore, direct interventions to reduce SIB are required.

Adult↗

PubMed1999

Rapid assessment of the effects of restraint on self-injury and adaptive behavior.

We evaluated the effects of restraint on occurrences of self-injurious behavior (SIB) and adaptive responses exhibited by 2 individuals across eight response-effort conditions: baseline (no restraints); restraint sleeves without stays; restraints with 5, 10, 15, 20, or 25 thin metal stays; and restraints with five thick metal stays. From this analysis, we identified a restraint level for each participant that reduced SIB but did not inhibit adaptive responding.

Adaptation, Psychological↗

PubMed1998

Temporal distributions of problem behavior based on scatter plot analysis.

The scatter plot is a commonly used assessment tool for identifying temporal patterns in the occurrence of behavior problems. However, the extent to which such patterns are frequently observed is unknown because little research has evaluated the general utility of the scatter plot. We conducted a large-scale analysis of within- and across-day occurrences of problem behavior by conducting continuous observations of 20 individuals living in four residential facilities. Data were recorded during 30-min intervals throughout participants' waking hours for 30 days by direct care staff and were converted into scatter plot formats. Five sets of data were excluded from further analysis due to poor interobserver agreement (below 80%). Visual analysis of the remaining 15 scatter plots indicated that none showed any reliable temporal pattern of responding. However, when the data were transformed into aggregate "control charts" based on statistical process control procedures, 12 of the 15 sets of data revealed one or more 30-min intervals during which problem behavior was more likely to occur. Results are discussed in terms of the practicality of applying statistical analyses to scatter plot data and of collecting data for the length of time needed to show statistical significance. It was concluded that detailed functional or descriptive analyses, which would reveal cause-effect or correlational relationships between behavior and specific environmental events, may be both more precise and more efficient forms of assessment.

Adolescent↗