Contingency management in the classroom treatment of long-term elective mutism: A case report

An 11-year-old boy with a six-year history of elective mutism in school was successfully treated with operant reinforcement and contingency management techniques. The plan was carried out by the classroom teacher with a minimum amount of management consultation. Twelve-month follow-up reveals continued maintenance of the verbal interaction indistinguishable from that of other children at school which was set as the criterion for terminating the intervention. The plan was carried out in three stages-relationship-building to develop teacher-pupil interaction into a reinforcing event, audible-response eliciting, and generalization throughout the school building and grounds.     

Paradoxical intervention using a polarization model of cotherapy in the treatment of elective mutism: A case study

A case history is presented of a four and-a-half year-old electively mute child who was successfully treated by the authors. The treatment approach involved paradoxical interventions in the context of a polarization model of cotherapy in combination with behavioral techniques in a family therapy framework.     

Concurrent individual and family therapy in a case of elective mutism

In this paper, following a literature review a family containing a child who had been electively mute for four years is described. A concurrent programme of individual and family therapy and the systemic hypothesis which guided these interventions is then presented in detail. Behavioural and psychometric data are presented to illustrate the dramatic improvement which the identified patient showed over the course of treatment. Finally, the probable mechanisms underpinning the child's improvement, and how these differed from our initial expectations, are discussed.     

The stages of acquisition in stimulus fading

Pigeons were exposed to a stimulus fading procedure in which control of responding was transferred from red and black stimuli to lines of different angular orientation. After superimposing one line on the red stimulus and the other line on the black stimulus, the intensity of the lines was gradually increased and that of the red stimulus was gradually reduced. Probes consisting of red and line stimuli presented separately were used during the course of fading to assess control exerted by each element of the compound. As the lines were faded in, they did not acquire control of responding. As red was faded out, control of responding was acquired first by the lower intensity red stimuli in combination with the line stimulus, and finally by the angular orientation of the lines. Probes also determined the point at which the line stimuli, presented alone, would maintain a high degree of stimulus control. The results demonstrated that new stimuli in fading acquire dimensional control of responding in two sequential stages. Acquisition of stimulus control in fading was explained in terms of attenuation of stimulus blocking.     

Degraded contingency revisited: posttraining extinction of a cover stimulus attenuates a target cue's behavioral control

In a Pavlovian conditioning situation, unsignaled outcome presentations interspersed among cue-outcome pairings attenuate conditioned responding to the cue (i.e., the degraded contingency effect). However, if a nontarget cue signals these added outcomes, responding to the target cue is partially restored (i.e., the cover stimulus effect). In 2 conditioned suppression experiments using rats, the effect of posttraining extinction of the cover stimulus was examined. Experiment 1 found that this treatment yielded reduced responding to the target cue. Experiment 2 replicated this finding, while demonstrating that this basic effect was not due to acquired equivalence between the target cue and the cover stimulus. These results are consistent with the extended comparator hypothesis interpretation of the degraded contingency and cover stimulus effects.     

Assessing pharmacological and contingency management interventions with mentally retarded adolescents in a residential treatment program

Two studies were performed using applied behavior analytic methodology to evaluate pharmacological and contingency management interventions with mentally retarded adolescents in a residential treatment facility. In the first study, stimulant (methylphenidate) and beta-blocking (propranolol) medications were compared with an overcorrection procedure to manage the disruptive vocalizing of a 14-year-old female. In the second study. the effects of thioridazine and a reinforcement-response interruption program on stereotypic body-rocking of an 18-year-old male were assessed. Both studies failed to demonstrate a positive response from any of the prescribed medications. Substantial reductions in behavior did occur with application of the contingency management programs. The programs were equally effective whether utilized alone or in combination with medication. Assessment and programmatic issues in the area of clinical behavioral pharmacology are discussed.     

Early and late introduction of probes and stimulus control acquisition in fading

College students learned to name Braille patterns presented visually using a fading procedure in which Braille patterns were superimposed on letter names after which letter names were attenuated. Measurement of acquisition was accomplished by presenting probes—consisting of the Braille stimuli only—throughout fading. Effects of probes upon acquisition were assessed by introducing probes early or late in fading. Fewer fading levels were needed for Braille elements to acquire control when probes were introduced early rather than late. When probes were introduced late, all subjects learned to name the Braille elements as the letters were being faded out. When probes were introduced early, however, most subjects learned to name the Braille elements as they were being faded in. Since virtually no errors occurred during compound-stimulus presentations, the probe procedure did not induce errors during acquisition. Quantitative analysis of probe data suggested that inclusion of probes enhanced the control acquired by the Braille elements during compound-stimulus presentations. The reported effects may have been due to differences in the relative frequency of reinforcement presented during compounds and probes.     

Speech rate as a sticky switch: a multiple lesion case analysis of mutism and hyperlalia

Though it has long been known on the basis of clinical associations and serendipitous observation that speech rate is related to mood and psychomotor baseline, it is less known that speech rate is also related to libido and to immune function. We make the case for a bipolar phenomenon of "psychic tonus," encompassing all these dimensions. The elated, agitated, libidinal, immunofacilitated, and talkative pole is an "approach" disposition primarily activated by the normal left hemisphere-especially, though not exclusively, its frontal lobe. The dejected, lethargic, delibidinized, immunosuppressed, and mute pole is an "avoidance" disposition primarily activated by the normal right hemisphere-especially, though not exclusively, its frontal lobe. In support of this proposed model, we present new evidence, via meta-analysis of previously published single lesion case reports, of a highly significant association between right hemisphere lesions and non-aphasic hyperlalia, and between left hemisphere lesions and non-aphasic mutism.     

Color preference in pigeons: stimulus intensity and reinforcement contingency effects in the avoidance of blue stimuli.

In a procedure intended to determine color preference in pigeons (which partially replicated Catania, Owens, & von Lossberg, 1983), two keys were illuminated by different colors drawn from a set of amber, red, green, or blue stimuli; this was followed by the presentation of grain when either of the two colors was pecked. The grain was illuminated alternately across trials with the colors presented on the keys. In Experiment 1 the intensity of the color stimuli used was not equalized, whereas in Experiment 2 the intensity of the colors was equalized. The low preference for blue found in Experiment 1, as measured by differential key pecking, was not found in Experiment 2. The discriminability of the intensity-equalized colors was confirmed in Experiment 2a, in which equal-intensity color discrimination problems were presented. In Experiment 3, as in Catania et al. (1983), a response-independent reinforcement schedule was used, but with intensity-equalized colors. In contrast to Experiment 2, very low preference for blue was found here and in Experiment 4, which used a within-subject procedure. These findings suggest that pigeon color preference may be a function of intensity, but all controlling variables have not as yet been identified.     

Reinforcement of probe responses and acquisition of stimulus control in fading procedures

Stimulus control of pigeons' key pecking was transferred from colors to lines by the method of stimulus fading. Fading was conducted with the addition of probes consisting of the line stimuli presented alone at each fading level. Probe responding was used to measure stimulus-control acquisition by the lines. Effects of reinforcement and nonreinforcement of probe responding upon acquisition of stimulus control were assessed using a single-organism repeated-acquisition design in which three fades were conducted serially. Probe responding was not reinforced in the first and third fade but was in the second. Reinforcement of probe responding substantially reduced the number of fading levels needed to complete fading. The outcome of a control experiment ruled out the possibility of accounting for these results in terms of the specific stimuli used in each fade or in terms of the sequential exposure to the three discriminations. Although probes permitted measurement of stimulus-control acquisition in fading, a measurement/acquisition interaction was also present.     

The sequential view: From rapidly fading stimulus traces to the organization of memory and the abstract concept of number

The development of the sequential approach to instrumental learning from about 1958 to the present is described. The sequential model began as an attempt to explain a particular class of neglected partial reward phenomena, those in which performance in acquisition and extinction is influenced by the particular sequence in which rewarded and nonrewarded trials occur in acquisition, and it was subsequently applied to a variety of other phenomena. Over time, the sequential model grew, sometimes through the replacement of older assumptions by novel ones, as when retrieved memories replaced stimulus traces, and sometimes simply through the addition of novel assumptions, such as that animals are capable of remembering retrospectively one, two, three or more prior nonrewarded outcomes—the N-length assumption. The most recent assumption added to the sequential model is that on a given trial the animal may utilize its memory of prior reward outcomes to anticipate both the current reward outcome and one or more subsequent reward outcomes. One way to view the sequential model is to say that it is a specific theory in various degrees of competition with other specific theories. Several examples of this are provided. Another way to view the sequential model, a more important way in my opinion, is to see it as a representative of a general theoretical approach, intertrial theory, which differs in fundamental respects from another much more generally utilized theoretical approach, intra-trial theory. I suggest that there is a substantial body of data that can be explained by inter-trial mechanisms but not by intratrial mechanisms. The future may well reveal that the inter-trial mechanisms have greater explanatory potential than the currently more popular intratrial mechanisms.     

Effects of wording and stimulus format on the use of contingency information in causal judgment

There are four kinds of contingency information: occurrences and nonoccurrences of an effect in the presence and in the absence of a cause. Previous studies have shown that these four kinds are not given equal weight in causal judgment. The present research was designed to test two hypotheses about this unequal weighting: that weightings are influenced by the form of the question and other features of the stimulus materials and that unequal weightings occur, in part, because individual differences in the use of contingency information are not evenly distributed across the four kinds of information. Support was found for both hypotheses. However, the effects of question wording were not always as had been predicted, indicating that more needs to be learned about how people interpret the task, instructions, and materials they are given.     

Behavioral momentum and stimulus fading in the acquisition and maintenance of child compliance in the home

The provision of a series of requests to which compliance is highly likely (high-probability requests) immediately antecedent to low-probability requests has been used to establish behavioral momentum of compliance. We evaluated a fading procedure for maintaining high levels of compliance obtained with high-probability requests. Fading involved a systematic reduction in the number of high-probability requests and an increase in the latency between the high- and low-probability requests. High levels of compliance for both "do" and "don't" requests were maintained for 16 weeks in a 5-year-old boy with developmental disabilities after the high-probability request sequence was faded. Similar maintenance was obtained for "do" requests in a 15-year-old girl with developmental disabilities. For this subject, however, the high-probability request sequence was ineffective with "don't" requests. When "don't" requests were phrased as "do" requests, the high-probability request sequence produced high levels of compliance to the low-probability request. High levels of compliance to these "do" requests were maintained for 16 weeks after the high-probability request sequence was faded.     

Evaluation of stimulus intensity fading on reduction of rapid eating in a child with autism

This study assessed the effects of a vibrating pager on reduction of rapid eating. The study also evaluated two strategies for fading the pager, by intensity and by frequency. The pager was successful in decreasing the pace of eating to an appropriate level and the pager prompt was successfully faded. Fading by frequency was ineffective in maintaining an appropriate pace of eating while intensity fading was successful.     

Stimulus fading in the treatment of adipsia

Stimulus fading procedures have repeatedly been demonstrated as effective in shaping a wide variety of new behaviors. Borrowing from this body of research, the behavioral treatment of feeding disorders presents a new area of application for stimulus fading. The purpose of this study is to demonstrate the efficacy of stimulus fading in the treatment of adipsia. Two children who ate solids, but refused all liquids, were participants in the study. Results showed that a five step fading procedure starting with a spoon and thickened liquids, and ending with a cut‐out‐cup, was successful in establishing cup drinking skills for both children. Results of the study suggest that stimulus fading can facilitate feeding skill acquisition. Copyright © 2001 John Wiley & Sons, Ltd.