Conditional discrimination in mentally retarded subjects: programming acquisition and learning set.

In Experiment 1, 3 subjects with retardation were exposed to two visual-visual arbitrary matching-to-sample problems each day. One conditional discrimination was presented under trial-and-error conditions, and the other was presented under a component training procedure. The latter began by establishing the comparison discrimination and its rapid reversal. The successive discrimination between the sample stimuli was established through differential naming. Then, sample naming was maintained in conditional discrimination sessions in which the same sample was presented in blocks of consecutive trials. Block size was decreased across sessions until sample presentation was randomized as in trial-and-error training (but with naming maintained). Two subjects initially learned only with component training. The performance of the 3rd subject was inconsistent across conditional discriminations. One of the successful subjects ultimately learned rapidly and consistently with trial-and-error procedures. Experiment 2 sought to demonstrate learning set in the other 2 subjects. Elements of the component training procedure were withdrawn over successive conditional discriminations. Ultimately, 1 subject nearly always learned under trial-and-error conditions, and the other learned under trial-and-error conditions combined with differential sample naming.     

A developmental study of form discrimination in pre-school children

Using a matching-from-sample technique the discriminative ability of a group of pre-school children was tested twice, at mean ages 3-8 and 4-9, in relation to an independent test of their comprehension of the notion “same”. A sequence of three stages is described, for both shape and orientation discrimination; in the first, characterized by a large number of errors, the child appears to respond largely in terms of proximity of a comparison figure to the standard; in the second his responses reflect gross aspects of similarity between the figures in the comparison set, in that several matches are made to one standard all of which have certain attributes in common with it. Finally correct and unique choices are made. Attributes used in differentiating figures are described, and a number of theoretical and methodological problems are discussed.     

Reinforcement of spaced responding in a simultaneous discrimination

Pigeons were exposed to three stimuli simultaneously with responses reinforced according to differential-reinforcement-of-low-rate schedules. Responses to one stimulus (the positive stimulus) that were spaced appropriately resulted in food presentation. The variables manipulated were the time parameter of the schedule (5, 10, 20, 30 sec) and the consequences of responding to the other two stimuli (the negative stimuli). The percentage of the total responses that occurred to each stimulus was independent of the schedule value but was dependent on the consequences of responding to the negative stimuli. If responses to both reset the schedule timer, responding was confined largely to the positive stimulus. If responses to neither had scheduled effects, the birds were more likely to respond to those stimuli. Responding to one negative stimulus could be selectively attenuated by having responses to that stimulus alone reset the timer. With the schedule time value held constant, the absolute rate of responding to the positive stimulus was either stable or decreased with maintained exposure; it did not change as a function of increases or decreases in responding to the negative stimuli. Rather than interacting and affecting each other, responses to the three stimuli were controlled independently by their relation to reinforcement. There was no evidence that responses to the negative stimuli mediated the spacing of responses to the positive stimulus.     

Stimulus function in simultaneous discrimination

In discrimination learning, the negativity of the stimulus correlated with nonreinforcement (S-) declines after 100 training trials while the stimulus correlated with reinforcement (S+) is paradoxically more positive with lesser amounts of discrimination training. Training subjects on two simultaneous discrimination tasks revealed a within-subjects overlearning reversal effect, where a more-frequently presented discrimination problem was better learned in reversal than was a discrimination problem presented less frequently during training.     

The effects of fading,feedback, and feedback plus instruction on the perfomance of institutionalized retarded children in number retention exercises

Summary Three feedback training procedures, fading, feedback and feedback plus instruction, were used in conjunction with reinforcement contingencies to assess the performance of 12 mentally retarded boys in number rentention exercises. The fading and the feedback plus instruction procedures were the only ones to yield highly significant effects: none of the procedures led to any substantially improved performance in transfer exercises. Advantages of fading over the more traditional procedure (less errors, ability to learn difficult exercises) are discussed, as are the problems arising in the application of this method. Analysis of the exercises showed that premature removal of the additional colour cues in the fading procedure resulted in a substantial reduction of the number of correct responses, especially in the difficult exercises, and that the feedback procedure was particularly unsuccessful in difficult exercises. Methodological problems encountered in previous retention studies were indicated and an attempt made to overcome them.

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Zusammenfassung Kombiniert mit Belohnungen, die nur für richtige Antworten erfolgten, wurden drei Rückmelde-Trainingsverfahren: Fading, Feedback und Feedback plus Instruction angewandt, um 12 geistig retardierte Jungen an Zahlen-Konservations-Aufgaben zu trainieren. Nur die Fading- und Feedback plus Instruction-Techniken zeigten hoch signifikante Trainingsgewinne, doch keine der Techniken führte zu bedeutenden Verbesserungen bei Transferaufgaben. Die Vorteile der Fading-Technik gegenüber mehr traditionellen Verfahren (weniger Fehler, Erlernen schwierigerer Aufgaben) wurde ebenso erörtert wie Probleme ihrer Anwendung. Aufgabenanalysen zeigten, daß erstens verfrühtes Ausblenden der zusätzlichen Farben bei der Fading-Technik zu einem starken Absinken der Anzahl der richtigen Antworten besonders bei schwierigen Aufgaben führt; und daß zweitens die Feedback-Technik beim Erlernen schwieriger Aufgaben besonders geringen Erfolg hat. Methodologische Probleme bei vorausgegangenen Konservationsexperimenten wurden aufgezeigt, und es wurde versucht, diese methodologischen Probleme zu lösen.

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This paper is based on a thesis submitted by the author to the University Mannheim as partial fulfillmant of the requirements for the degree of Master of Science (Diplom). The writer is greatly indebted to Dr. Norman H. Stein for his guidance throughout the planning and execution of the study and to his helpful suggestions and criticisms. The writer is also indebted to Dr. Byron J. Ward for making subjects available at Syracuse State School, and to the teachers of the Association for Retarded Children in Syracuse, New York. The study was conducted during a one year stay at Syracuse University. The financial support of the Studentenwerk Mannheim for tuitions and living expenses and a travel grant of the Fulbright Commission is gratefully acknowledged.