The Role of Contingencies and Stimuli in a Human Laboratory Model of Treatment of Problem Behavior.

Behavioral momentum theory posits a paradoxical implication for behavioral interventions in clinical situations using Differential Reinforcement of Alternative Behavior (DRA): When alternative reinforcers are presented within the same context as the problem behavior, the added reinforcers may decrease the frequency of the behavior but also increase its persistence when the intervention ends. Providing alternative reinforcers in a setting that is distinctively different from that in which the target behavior occurs may avoid or reduce this increase in persistence. The present experiment compared behavioral persistence following standard DRA versus DRA in a different context that was available after refraining from target behavior (Differential Reinforcement of Other Behavior, DRO). We arranged a human laboratory model of treatment intervention using computer games and token reinforcement. Participants were five individuals with intellectual disabilities. Experimental phases included (a) an initial multiple-schedule baseline with token reinforcement for target behaviors A and B, (b) an intervention phase with alternative reinforcement using a conventional DRA procedure for A and a DRO-DRA procedure for B, and (c) an extinction phase with no interventions and no tokens. Response rates as proportion of baseline in the initial extinction phase were greater for A than for B for three of five participants. Four participants whose response rates remained relatively high during the extinction phase then received a second extinction-plus-distraction test with leisure items available. Response rates were greater for A than for B in three of four participants. The results indicate that DRO-DRA contingencies may contribute to reduced post-intervention persistence of problem behavior.

The potential influence of stimulus overselectivity in AAC: information from eye tracking and behavioral studies of attention with individuals with intellectual disabilities.

This paper examines the phenomenon of stimulus overselectivity, or overselective attention, as it may impact AAC training and use in individuals with intellectual disabilities. Stimulus overselectivity is defined as an atypical limitation in the number of stimuli or stimulus features within an image that are attended to and subsequently learned. Within AAC, the term stimulus could refer to symbols or line drawings on speech-generating devices, drawings or pictures on low-technology systems, and/or the elements within visual scene displays. In this context, overselective attention may result in unusual or uneven error patterns such as confusion between two symbols that share a single feature, or difficulties with transitioning between different types of hardware. We review some of the ways that overselective attention has been studied behaviorally. We then examine how eye tracking technology allows a glimpse into some of the behavioral characteristics of overselective attention. We describe an intervention approach, differential observing responses, that may reduce or eliminate overselectivity, and we consider this type of intervention as it relates to issues of relevance for AAC.

Use of a differential observing response to expand restricted stimulus control.

This study extends previous work on the use of differential observing responses (DOR) to remediate atypically restricted stimulus control. A participant with autism had high matching-to-sample accuracy scores with printed words that had no letters in common (e.g., cat, lid, bug) but poor accuracy with words that had two letters in common (e.g., cat, can, car). In the DOR intervention, she matched the distinguishing letters of the overlapping words (e.g., t, n, r) immediately prior to matching the whole words. Accuracy scores improved, and accuracy remained high when DOR requirements were withdrawn.

Reducing overselective stimulus control with differential observing responses.

Overselective stimulus control refers to discriminative control in which the number of controlling stimuli is too limited for effective behavior. Experiment 1 included 22 special-education students who exhibited overselective stimulus control on a two-sample delayed matching task. An intervention added a compound identity matching opportunity within the sample observation period of the matching trials. The compound matching functioned as a differential observing response (DOR) in that high accuracy verified observation and discrimination of both sample stimuli. Nineteen participants learned to perform the DOR and two-sample delayed matching accuracy increased substantially for 16 of them. When the DOR was completely withdrawn after 10 sessions, accuracy declined. In Experiment 2, a more gradual withdrawal of DOR requirements showed that highly accurate performance could be maintained with the DOR on only a proportion of trials for most participants. The results show that DOR training may lead to a general improvement in observing behavior.

Matching-to-sample assessment of stimulus overselectivity in students with intellectual disabilities.

A delayed matching-to-sample task with multiple sample stimuli was used to evaluate stimulus overselectivity in 70 individuals attending residential special-education schools. A Mental Age Equivalent score (MAE) was obtained for each student using the Peabody Picture Vocabulary Test. Twenty-one participants failed to complete matching-to-sample pretests (mean MAE = 3.70 years). Results on the multiple-sample test for the remaining 49 participants indicated no overselectivity for 14 students (mean MAE = 7.44 years) and were consistent with overselectivity for 35 students (mean MAE = 5.28 years). Performances of students with overselectivity were more variable than those with no overselectivity. The MAE scores were related to both matching-to-sample performance and stimulus overselectivity.

Equivalence classes with requirements for short response latencies.

Five adult humans were tested for emergent conditional discriminations under rapid-responding contingencies. During four-comparison matching-to-sample baseline training (AB and AC), limited-hold contingencies for responding to samples and comparisons were gradually restricted to the shortest duration consistent with at least 95% accuracy and no more than 5% failures to respond. The final limited-hold values were 0.4-0.5 s for samples and 1.2-1.3 s for comparisons; mean response latencies were 0.15-0.28 s for samples and 0.59-0.73 s for comparisons; inter-trial intervals were 0.4 s. With these fast-responding requirements, test blocks presented 72 probe trials interspersed among 72 baseline trials, all without programmed differential consequences. Four equivalence test blocks (BC and CB probes, which tested simultaneously for both symmetry and transitivity) were followed by four symmetry (BA and CA probes) test blocks. Three subjects' results documented emergent performances indicative of equivalence classes despite fast-responding requirements that severely limited the time available for mediating vocal or subvocal responses. For these three subjects, mean latencies were slightly shorter in baseline trials than in probes, and shorter on symmetry than on equivalence probes. These differences, however, were usually less than the differences among mean latencies on the different types of trials within the baseline and probed performances.

Overselective stimulus control in residential school students with intellectual disabilities.

Overselective stimulus control was assessed in 29 students at residential schools for individuals with developmental disabilities. Overselectivity testing included three different delayed identity matching-to-sample tasks. Sample stimuli for the Form/Color Test were nine possible combinations of three colors and three forms. On each trial, the S+ stimulus was identical to the sample, one S- was the same color as the sample but a different form, and the other S- was the same form but a different color. Sample stimuli for the Two-Sample Test were two alphanumeric characters. The S+ stimulus was identical to one of the sample stimuli, and two S- stimuli were characters different from both samples. Sample stimuli for the Faces Test were six digital images of adult faces. On each trial, the S+ stimulus was identical to the sample, one S- stimulus was a non-matching face to which one sample feature had been added (e.g., an identical hat or scarf), and the other S- stimulus was an unaltered non-matching face. All participants were also tested with the Peabody Picture Vocabulary Test III (PPVT) and the Autism Diagnostic Observation Schedule (ADOS). Results indicated overselective stimulus control on at least one test for 18 of the 29 participants. Overselectivity (a) was distributed across a range of PPVT mental age equivalent scores from <1.75 to 8.83; (b) was more likely in individuals with higher ADOS scores; (c) was most likely on the Two-Sample Test; and (d) was found in five individuals on more than one of the tests. Thus, overselective stimulus control may occur across a range of characteristics typical for students who attend residential special-education programs.

Behavioral assessment of joint attention: a methodological report.

This paper describes a highly structured assessment protocol with objective behavioral measures for joint attention responding and initiation. The assessment was given to 26 children diagnosed with autism spectrum disorders and 21 typically developing children, aged two to four years. Interobserver agreement was high for all behavioral measures. Children with autism had relatively minor deficits in joint attention responding and more severe deficits in joint attention initiation, relative to typically developing children. These results replicate those reported in previous research. The protocol can be used reliably to assess behavior indicative of joint attention responding and initiation in typically developing children and children with autism.

A sorting-to-matching method to teach compound matching to sample.

Individuals with developmental disabilities may fail to attend to multiple features in compound stimuli (e.g., arrays of pictures, letters within words) with detrimental effects on learning. Participants were 5 children with autism spectrum disorder who had low to intermediate accuracy scores (35% to 84%) on a computer-presented compound matching task. Sample stimuli were pairs of icons (e.g., chair-tree), the correct comparison was identical to the sample, and each incorrect comparison had one icon in common with the sample (e.g., chair-sun, airplane-tree). A 5-step tabletop sorting-to-matching training procedure was used to teach compound matching. The first step was sorting 3 single pictures; subsequent steps gradually changed the task to compound matching. If progress stalled, tasks were modified temporarily to prompt observing behavior. After tabletop training, participants were retested on the compound matching task; accuracy improved to at least 95% for all children. This procedure illustrates one way to improve attending to multiple features of compound stimuli.

Stimulus Overselectivity in Autism, Down Syndrome, and Typical Development.

Stimulus overselectivity refers to maladaptive narrow attending that is a common learning problem among children with intellectual disabilities and frequently associated with autism. The present study contrasted overselectivity among groups of children with autism, Down syndrome, and typical development. The groups with autism and Down syndrome were matched for intellectual level, and all three groups were matched for developmental levels on tests of nonverbal reasoning and receptive vocabulary. Delayed matching-to-sample tests presented color/form compounds, printed words, photographs of faces, Mayer-Johnson Picture Communication Symbols, and unfamiliar black forms. No significant differences among groups emerged for test accuracy scores. Overselectivity was not statistically overrepresented among individuals with autism in contrast to those with Down syndrome or typically developing children.

Stimulus Fading and Response Elaboration in Differential Reinforcement for Alternative Behavior.

A hallmark of applied behavior analysis is the development of function-based interventions for problem behavior. A widely recommended function-based intervention is differential reinforcement of alternative behavior (DRA), in which reinforcement is contingent upon socially acceptable alternatives to problem behavior (e.g., teaching communication skills). Typically, DRA is introduced under rich schedules of reinforcement. Although effective for initiating behavior change, rich schedules are often impractical in the natural setting. In this study, we evaluated the extent to which a stimulus fading program could be employed to elaborate alternative behavior (mands) in two individuals diagnosed with an Autism Spectrum Disorder. For both participants, problem behavior was reduced substantially upon implementation of the DRA procedure. Further, problem behavior rates remained low and mand rates decreased to more practical levels as the DRA behavioral requirements increased during the fading program. The fading approach demonstrated in this paper may be a useful component of intervention packages for clinicians.

Functional analysis of problem behavior: A systematic approach for identifying idiosyncratic variables.

When inconclusive functional analysis (FA) outcomes occur, a number of modifications have been made to enhance the putative establishing operation or consequence associated with behavioral maintenance. However, a systematic method for identifying relevant events to test during modified FAs has not been evaluated. The purpose of this study was to develop and evaluate a technology for systematically identifying events to test in a modified FA after an initial FA led to inconclusive outcomes. Six individuals, whose initial FA showed little or no responding or high levels only in the control condition, participated. An indirect assessment (IA) questionnaire developed for identifying idiosyncratic variables was administered, and a descriptive analysis (DA) was conducted. Results from the IA only or a combination of the IA and DA were used to inform modified FA test and control conditions. Conclusive FA outcomes were obtained with 5 of the 6 participants during the modified FA phase.

A statewide survey assessing practitioners' use and perceived utility of functional assessment.

The field of applied behavior analysis emphasizes the importance of conducting functional assessment before treatment development for problem behavior. There is, however, little information regarding the extent to which practitioners are using functional assessment in applied settings for individuals with developmental disabilities (DD). The purpose of the current study was to conduct a survey to assess the degree to which various types of functional assessment are implemented in agencies that serve individuals with DD in Massachusetts. Practitioners were asked to indicate their perception about and use of the various categories of functional assessment (e.g., indirect assessment, descriptive assessment, and functional analysis). From the 205 respondents who completed the survey, the most frequently used functional assessment was descriptive assessment. Results indicated that although the majority (67.8%) of practitioners believe functional analysis to be the most informative assessment tool for selecting behavioral treatment, only 34.6% of respondents indicated that they typically use functional analysis to inform the development of a behavior plan.

Quantitative assessments of sensitivity to reinforcement contingencies in mental retardation.

Sensitivity to differences in reinforcement contingencies was examined in 6 individuals with mental retardation. A concurrent operants procedure was implemented in the context of a computer game. Participants selected two different types of animated figures displayed concurrently in the left and right portions of a touchscreen monitor. Over a series of conditions, the relative rates or magnitudes of reinforcers following selections of the two options were changed in ratios of 5:1, 3:1, 1:1, 1:3, and 1:5. Sensitivity was quantified by application of the generalized matching equation. Results included individual differences in sensitivity and differential sensitivity to rate and magnitude variation. The results suggest that comprehensive assessments of potential reinforcers may benefit from including tests of delivery parameters.

Reinforcer rate effects and behavioral momentum in individuals with developmental disabilities.

Behavioral momentum theory states that behavioral resistance to change is positively related to reinforcer rate and independent of response rate under most circumstances. We examined behavioral momentum in humans with developmental disabilities. The experimental procedures were implemented as a computer game. Different rates of positive reinforcement were programmed in two alternating components signaled by distinctive cues. For 10 participants who successfully completed testing, resistance to disruption by an alternate source of reinforcement was greater in the component with the higher reinforcer rate, although the magnitude of the difference varied among individuals. These results confirm reinforcer rate effects consistent with behavioral momentum under laboratory conditions and with the largest number of human beings with developmental disabilities studied to date.

High-probability stimulus control topographies with delayed S+ onset in a simultaneous discrimination procedure.

Experimenters and teachers use discrimination learning procedures to encourage reliable attending to stimulus differences defined as relevant for their purposes. Put another way, the goal of discrimination training is to establish high-probability stimulus control topographies that are coherent with experimenter or teacher specifications. The present research was conducted to investigate a novel procedure for encouraging stimulus control topography coherence. Participants were 13 adolescents with severe intellectual handicaps. During an initial Condition A, all were exposed to a simultaneous discrimination procedure. Participants could select a form alternating with a black field (S+) or an identical form that did not alternate (S-). Accuracy scores were typically low, and there was little evidence of coherent stimulus control topographies. Subsequently, the procedure was changed. During Condition B, every trial initially presented two identical nonalternating S- forms (Trial State 1). If the participant made no selection for 5 s, one of the forms began to alternate with the black field, and he or she could make the S+/S- discrimination (Trial State 2). Selections during Trial State I prolonged the delay to Trial State 2 until there had been no response for 5 s. During Condition B, S+/S- discrimination accuracy scores improved rapidly and markedly for most participants. Reinstating Condition A often resulted in diminished accuracy scores. This study thus (a) demonstrated a novel procedure for encouraging stimulus control topography coherence and (b) provided support for the interpretation that intermediate accuracy scores may be due to different topographies of stimulus control that co-occur in the same discriminative baseline.

Persistence of stereotypic behavior: examining the effects of external reinforcers.

Basic research has shown that behavioral persistence is often positively related to rate of reinforcement. This relation, expressed in the metaphor of behavioral momentum, has potentially important implications for clinical application. The current study examined one prediction of the momentum metaphor for automatically reinforced behavior. Participants were 3 children who had been diagnosed with an autism spectrum disorder and who engaged in stereotypic behavior maintained by automatic reinforcement. Results suggested that stereotypic behavior was more resistant to disruption following periods of access to preferred stimuli delivered on a variable-time schedule than following periods without access to preferred stimuli. The implications of these findings for the treatment of automatically reinforced behavior are discussed.

Stimulus control topography coherence theory: foundations and extensions.

Stimulus control topography refers to qualitative differences among members of a functional stimulus class. Stimulus control topography coherence refers to the degree of concordance between the stimulus properties specified as relevant by the individual arranging a reinforcement contingency (behavior analyst, experimenter, teacher, etc.) and the stimulus properties that come to control the behavior of the organism (experimental subject, student, etc.) that experiences those contingencies. This paper summarizes the rationale for analyses of discrimination learning outcomes in terms of stimulus control topography coherence and briefly reviews some of the foundational studies that led to this perspective. We also suggest directions for future research, including pursuit of conceptual and methodological challenges to a complete stimulus control topography coherence analysis of processes involved in discriminated and generalized operants.

Toward a behavioral analysis of joint attention.

Joint attention (JA) initiation is defined in cognitive-developmental psychology as a child's actions that verify or produce simultaneous attending by that child and an adult to some object or event in the environment so that both may experience the object or event together. This paper presents a contingency analysis of gaze shift in JA initiation. The analysis describes reinforcer-establishing and evocative effects of antecedent objects or events, discriminative and conditioned reinforcing functions of stimuli generated by adult behavior, and socially mediated reinforcers that may maintain JA behavior. A functional analysis of JA may describe multiple operant classes. The paper concludes with a discussion of JA deficits in children with autism spectrum disorders and suggestions for research and treatment.

Merging separately established stimulus classes with outcome-specific reinforcement.

This study extended previous research on equivalence relations established with outcome-specific reinforcers to include the merger of separately established stimulus classes. Participants were four adults. Conditional discriminations AC and BC were trained first. Correct selections of C1 (C2, or C3) in the presence of A1 or B1 (A2 or B2, or A3 or B3) were followed by red (blue, or white) tokens; tokens were exchanged for value added to three participant-selected gift cards. Outcomes on equivalence tests for three-member classes ABC were positive. DF and EF were trained with the same reinforcing consequences, and tests were positive for three-member classes DEF. Results of class merger tests with combinations of stimuli from the ABC and DEF classes (AD, FB, etc.) were immediately positive for two participants, demonstrating six-member classes ABCDEF with reinforcers as nodes. Merger tests for a third participant were initially negative but became positive after brief exposure to unreinforced probe trials with reinforcers as comparison stimuli. Following class merger, tests for matching the reinforcers to samples and comparisons were also positive. Class-merger test results were negative for a fourth participant. The results provide the first demonstration of eight-member equivalence classes including two outcome-specific conditioned reinforcing stimuli.