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Biomedical subjects

E G Carr

Publications and source records attributed to E G Carr.

29 records · Page 2Linked to original sources

Speech versus sign comprehension in autistic children: analysis and prediction.

Autistic children have severe problems in acquiring language. For this reason, special techniques have been developed to teach them speech and sign language. It is not known, however, whether these children will profit more from speech or sign training. The research literature implies that verbal imitative ability may predict language learning characteristics particularly in the speech modality. In view of this possibility, two groups of autistic children--good versus poor verbal imitators--were studied within the context of a receptive label acquisition task. Good imitators acquired receptive speech whereas poor imitators typically did not. Both groups acquired receptive signs. The results were discussed in terms of the role that imitative ability may play with respect to language acquisition in this population.

Adolescent↗

Acquisition of sign language by autistic children. II: Spontaneity and generalization effects.

Autistic children typically do not use their language repertoire in order to communicate. Six autistic children who exhibited poor communication skills were trained to use their sign repertoire to make spontaneous requests of adults. Training consisted of imitative prompting, fading, and differential reinforcement, and included aspects of incidental teaching. The children displayed an increase in the rate and variety of spontaneous sign requests (Experiment 1). Generalization of spontaneity across adults (Experiments 1 and 2) and settings (Experiment 2) was also observed. We suggest that spontaneity may be facilitated when language is brought under the control of broadly defined stimuli such as adult attention rather than narrowly defined stimuli such as the presence of specific objects or verbal prompting in the form of questions. Finally, response generalization was observed as well (Experiment 1). Specifically, as spontaneity increased, self-stimulatory behavior decreased. This result may be accounted for in terms of reinforcer competition, reinforcer consistency, or discriminative stimulus effects.

Adolescent↗

Escape as a factor in the aggressive behavior of two retarded children.

This study sought to identify some of the variables controlling the severely aggressive behavior of two retarded children. In Experiment 1, each child was presented with several demand and nondemand situations. Aggression was frequent in the demand situations and rare in the nondemand situations. When a stimulus correlated with the termination of demands was introduced, aggression fell to a near zero level. In Experiment 2, for one child, a variety of preferred reinforcers was introduced into the demand situation contingent on correct responding. Aggression abruptly decreased to a low level. Experiments 3 and 4 involved the second child. In Experiment 3, this child was permitted, in one condition, to leave the demand situation if he emitted a nonaggressive response. Aggression decreased to a low level. In Experiment 4, he was prevented, in one condition, from leaving the demand situation in spite of high levels of aggression. Aggression fell to a near zero level. In Experiments 3 and 4, he was permitted, in several conditions, to leave the demand situation following aggressive behavior. Aggression increased to a high level. The results suggested that: (1) aggression can sometimes function as an escape response; and (2) escape-motivated aggression can be controlled by: (a) introducing strongly preferred reinforcers to attenuate the aversiveness of the demand situation; (b) strengthening an alternative, nonaggressive escape response; or (c) using an escape-extinction procedure.

Adolescent↗

Teaching autistic children to use sign language: some research issues.

Three questions are raised with respect to the use of sign language as an alternative system of communication for nonverbal autistic children. First, does teaching a child to sign facilitate speech development? The data suggest that following simultaneous communication training, mute children are not likely to learn to talk; however, a combination of simultaneous communication training and separate vocal training may have a synergetic effect on speech development. In contrast, children who initially have good verbal imitation skills apparently show gains in speech following simultaneous communication training alone. Second, what is the upper limit of sign acquisition? Data suggest that abstract concepts, syntax, and generative skills can be taught. Procedures used in the operant conditioning of speech may prove useful in training complex signing skills. Third, does sign acquisition result in a general improvement in adaptive functioning? It appears that following sign training, some children do show increases in spontaneous communication, decreases in self-stimulatory behavior, and improvement in social skills. However, these outcomes are often difficult to interpret. Some data are described that help clarify the relationship between sign training and general behavioral improvement.

Adaptation, Psychological↗

Elimination of echolalic responding to questions through the training of a generalized verbal response.

Echolalia, the parroting of the speech of others, is a severe communication disorder frequently associated with childhood schizophrenia and mental retardation. Two echolalic children, one schizophrenic and one retarded, were treated in a multiple-baseline design across subjects. Each child was taught to make an appropriate, non-echolalic verbal response (i.e., "I don't know") to a small set of previously echoed questions. After such training, this response generalized across a broad set of untrained questions that had formerly been echoed. The results obtained were the same irrespective of the specific experimenter who presented the questions. Further, each child discriminated appropriately between those questions that had previously been echoed and those that had not. Followup probes showed that treatment gains were maintained one month later. The procedure is economical, in that it produces a rapid and widespread cessation of echolalic responding.

Adolescent↗

Acquisition of sign language by autistic children. I: Expressive labelling.

There has been growing interest in teaching sign language to autistic children who have failed to develop speech. However, controlled experimentation in this area is nonexistent. In the present study, four nonverbal autistic children were taught expressive sign labels for common objects, using a training procedure that consisted of prompting, fading, and stimulus rotation. The efficacy of the procedure was demonstrated in a multiple-baseline design across objects. The results were reliable, replicable across children, and generalizable across therapists. A stimulus control analysis demonstrated that, for three of the children, correct signing was controlled solely by the visual cues associated with the presentation of a given object and was independent of respect to the known perceptual and linguistic deficits of autistic children.

Adolescent↗

Stimulus control of self-destructive behavior in a psychotic child.

This study attemped to isolate some of the stimulus variables that controlled the self-destructive behavior of a psychotic child. In Experiment 1, the child was exposed to several demand and nondemand situations. In Experiment 2, the situation containing demands was modified so that demands now occurred in the context of a positive, ongoing interaction between the child and the adult therapist. The rates of self-destructive behavior underwent several orderly changes: (1) Rates were high in demand situations and low in nondemand and modifieddemand situations; (2) rates decreased sharply when a stimulus correlated with the termination of demands was introduced; and (3) rates of self-destruction typically showed gradual increases within each of those sessions which contained only demands. These results were interpreted as suggesting that (1) self-destruction, under certain circumstances, may be conceptualized as an escape response which is negatively reinforced by the termination of a demand situation and (2) certain modifications of the social environment may provide discriminative stimuli for behaviors other than self-destruction, thereby decreasing this behavior.

Animals↗

Control of echolalic speech in psychotic children.

Immediate echolalia, a common language disorder in psychotic children, was studied in a series of replicated single-subject designs across six schizophrenic and five normal children. In Experiment 1, each child was presented with several questions and commands, some of which set the occasion for specific, appropriate responses and some of which did not. The former were referred to as discriminative stimuli and the latter, as neutral stimuli. The psychotic children tended to echo the neutral stimuli while responding appropriately to the discriminative stimuli; the normal children, in contrast, typically echoed neither type of stimulus. In Experiment 2, three psychotic children were taught appropriate responses to each of several neutral stimuli. Following this training, the children generally responded appropriately to these stimuli without echoing. A plausible interpretation of these results is that the neutral stimuli were initially incomprehensible or meaningless to the children (whereas the discriminative stimuli were comprehensible or meaningful) and that verbal incomprehensibility may be one important determinant of immediate echolalia. Finally, the results are noteworthy in that they isolate a sufficient treatment variable (i.e., the reinforcement of alternative, nonecholalic responses) for eliminating instances of this language anomaly.

Adolescent↗

Temporal inhibition: effects of changes in rate of reinforcement and rate of responding.

Pigeons were trained to key peck on several multiple schedules in which the first of two components was always a simple fixed-interval schedule. The rate of responding at the beginning of the constant fixed-interval schedule was found to decrease with increases in the rate of reinforcement associated with the other component of the multiple schedule, but remained unchanged with decreases in the rate of responding associated with the other component. These results were interpreted as being consistent with the view that the presence and magnitude of the temporal inhibitory effects observed in a given fixed-interval schedule are a function of the properties of reinforcing stimuli, rather than of changes in the rate of responding associated with the time interval immediately preceding the fixed interval in question.

Journal Article↗