Indexador

A 5‐yr‐old mentally retarded spina bifida child was taught to walk with the aid of crutches. This behavior was developed through fading of physical prompting within a 10‐step successive approximation sequence. Preliminary training to establish gait consisted of developing use of parallel bars through fading of physically modelled responses within a six‐step successive approximation sequence. Use of parallel bars ceased during an extinction period and completely recovered upon being primed with one “free” reinforcement. Systematic use of natural reinforcers was employed as an aid in maintaining use of crutches.

Discriminative responding in pigeons was studied under multiple variable‐interval extinction and variable‐ratio extinction schedules, as deprivation was varied. Generally, the greater the accuracy of discrimination that developed during training, the smaller the effect of deprivation upon subsequent performance. This was true both in terms of changes in response rates, and in the relationship between response rates during food reinforcement and extinction. When discrimination was inaccurate, increases in deprivation resulted in disproportionate increases in responding during extinction, as compared to increases during food reinforcement components of the schedule. The results suggest that as stimulus control (accuracy) of responding increases, discriminative performance becomes less and less susceptible to influence by deprivation.

A program may have a low error rate but, at the same time, require little of the student and teach him little. A measure to supplement error rate in evaluating a program has recently been developed. This measure, called the blackout ratio, is the percentage of material that may be deleted without increasing the error rate. In high blackout‐ratio programs, obtaining a correct answer is contingent upon only a small portion of the item. The present study determined if such low response‐contingent material is read less thoroughly than programmed material that is heavily response‐contingent. Eye movements were compared for two versions of the same program that differed only in the choice of the omitted words. The alteration of the required responses resulted in a version with a higher blackout ratio than the original version, which had a low blackout ratio. Eighteen undergraduates received half their material from the high and half their material from the low blackout‐ratio version. The order was counterbalanced. Location and duration of all eye fixations in each item were recorded by a Mackworth Eye Marker Camera. On high blackout‐ratio material, subjects used fewer fixations, shorter fixation time, and shorter scanning time. High blackout‐ratio material failed to evoke the students' attention.

Resumo não informado pela fonte indexada.

Resumo não informado pela fonte indexada.

Resumo não informado pela fonte indexada.

Resumo não informado pela fonte indexada.

Resumo não informado pela fonte indexada.

Resumo não informado pela fonte indexada.

Resumo não informado pela fonte indexada.