Instruction-following behavior of a retarded child and its controlling stimuli

A combination of positive reinforcement and fading of physical guidance was used to teach a profoundly retarded boy specific responses to specific verbal instructions. The design consisted of a multiple baseline of probe data across different verbal instructions. The subject started responding correctly to each verbal instruction as that item was trained in a multiple-baseline order. Generalization did not occur to items that had not yet been trained, nor did it occur to items included to assess generalization. Probes of variations in the verbal instructions, conducted after training was completed, revealed that generalization was minimal except in those cases where the variation consisted of the verb only, the noun only, the noun plus preposition, or where the verb of the instruction was presented last. Training a profoundly retarded 11-yr-old subject to respond to specific verbal instructions did not adequately facilitate the development of a generative instruction-following capability, nor did all verbal elements of the instruction control a specific response.     

Response restriction and substitution with autistic children.

Few studies to date have examined time reallocation in naturalistic, multiresponse human repertoires when one or more responses are restricted. For this experiment, free-operant baseline levels of six responses were measured for four autistic children. The high-probability responses were made unavailable, one at a time, such that subjects had access to five, four, three, and two responses in successive restriction conditions. A return to the six-response free-operant baseline condition completed the experiment. Results were compared to predictions made by four time-reallocation models. These results were described accurately only by the selective substitution model. Further analyses examined alternative explanations for the individual reallocation patterns obtained. An expanded selective substitution definition is proposed that may characterize orderly patterns observed in multiresponse repertoires under restriction conditions more accurately than the other existing models.     

Establishing mirror-image discriminations with progressively delayed extra-stimulus prompts.

Progressively delayed extra-stimulus prompts were used to help normal preschool children discriminate left-right mirror-image stimuli. Two issues were addressed, the attention guiding properties of the prompts and the necessity for their gradual elimination. The study consisted of four experiments in which one or multiple prompt conditions were used. Each condition involved three prompts: a reference prompt for indicating the S+ and two superimposed prompts, one on the S+, and one on the S-. The prompts required subjects to respond to the orientation of the S+ (Orientation condition) or to the location of the reference prompt (Location condition); or allowed them to respond to the discriminative shapes of the superimposed prompts (Shape condition). The results showed the following. First, most subjects rapidly learned to respond to the Orientation prompts. Second, delayed orientation prompting was always successful regardless of how the prompts were eliminated. Delay training was never successful in either of the other two conditions. Third, the Orientation condition did not reliably produce learning unless the delayed prompting procedure was used.     

Timeout and concurrent fixed-ratio schedules with human subjects

Human subjects given choices among 10 different pairs of concurrent fixed-ratio schedules preferred the smaller ratio. After a preference had been determined, timeout of increasing duration followed the completion of the preferred schedule. The larger the fixed-ratio difference, the longer the timeout necessary to produce the shift to the previously nonpreferred ratio. Responses by two of three subjects were unaffected by changes from response-dependent to response-independent pay.     

Matching to complex stimuli under non-reinforced conditions: Errorless transfer from identity to arbitrary matching tasks

The present study investigated whether preschool children exposed to identity-matching tasks involving colour-form (CF) complex stimuli acquire arbitrary relations among those colours and forms. The children were first trained on an identity-matching task with green and yellow as samples and as comparisons (C-C task). Subsequent tests showed that the children matched: (1) samples green lambda and yellow pi, with comparisons green and yellow (CF-C), respectively; (2) samples black lambda and black pi, with comparisons green lambda and yellow pi (F-CF); (3) samples black lambda and black pi, with comparisons green and yellow (F-C); and (4) samples green and yellow, with comparisons black lambda and black pi (C-F). Other findings suggested that the F-C and C-F outcomes were likely only if the children were exposed to both CF-C and F-CF conditions. The results extend previous studies on emergent discriminations based on the elements of complex stimuli. The emergence of both form-colour and colour-form matching to sample permits an inference of symmetry, one of the properties of stimulus equivalence.     

Discrimination training of mirror-image stimuli with a delayed-prompt technique: some critical dimensions of extra-stimulus prompts

Research on fading and delay procedures has shown that extra-stimulus prompts frequently fail to help children learn difficult discriminations. The present study analyzed two delay conditions for an extra-stimulus prompt to help preschoolers discriminate mirror-image stimuli as a function of the configurations and locations of the prompts. All subjects were selected on their ability to discriminate the task stimuli in the presence of a third stimulus, a replica of the S+ and an arrow pointing to that stimulus; and on their inability to do so without these stimuli. Experiments 1 and 2 compared these prompt configurations (S+ replica, arrow) when presented equidistant from the task stimuli. Experiment 3 analyzed the contribution of the replica configuration in terms of its location, in between stimuli or immediately above the S+. Experiment 4 investigated the extent to which the results of the previous experiments could be influenced by the methodology for the assessment of prompt control. The results consistently demonstrated that most subjects did not learn the task unless the extra-stimulus prompt had the same configuration as the S+ and was located equidistant from both task stimuli.     

Establishing generalized verb-noun instruction-following skills in retarded children

A transfer of stimulus control procedure was used to establish generalized verb-noun instruction-following skills in two severely retarded boys. Each of 12 verbs was trained, in a multiple baseline order, to criterion with each of 12 nouns in the form of verb-noun verbal instructions. Throughout training, reinforced probes were conducted on both trained and untrained verb-noun combinations. As training progressed, both subjects began to respond correctly to untrained verb-noun instructions. Eventually, a verb needed to be trained in combination with only one noun before generalization occurred to the as-yet-untrained 11 verb-noun instructions involving that verb.     

THE EFFECTS OF DIFFERENT REINFORCEMENT CONDITIONS ON THE TEST PERFORMANCE OF MULTIHANDICAPPED DEAF CHILDREN1

The present study explored the effects of different reinforcement conditions on the number of correct responses on the Raven Progressive Matrices. Four groups of 11- to 18-year-old multihandicapped deaf children matched on the basis of mean age and pretest scores were used. The groups were randomly assigned to any of four posttest conditions: end-of-session reinforcement, noncontingent reinforcement, delayed reinforcement, and immediate reinforcement. The mean posttest score of subjects tested under the immediate-reinforcement condition was significantly higher than that of any other group. No significant differences were observed between the mean posttest scores of the three other groups. The practical implications of using reinforcement procedures for testing purposes are discussed.