Critical procedural variables related to the physiological effects of progressive relaxation: a review.

Twenty-five investigations of the physiological effects of progressive relaxation training were classified according to whether relaxation was found to be superior or equivalent to control conditions. The two sets of studies differed significantly on number of training sessions and in the use of taped vs live administration of training, and they tended to differ in the use of normal vs patient samples. The likelihood of producing significant physiological reductions via progressive relaxation appears to be greater when multi-session, subject-controlled training is conducted with subjects for whom physiological activity contributes to a presenting. clinical problem.     

The ambiguous-cue problem: The effects of reduced similarity between trials and the schedule of reinforcement

In a series of seven experiments pigeons were trained on the two-choice ambiguous-cue problem that contains PA and NA trials. On PA trials choice of P (the positive stimulus) was reinforced and choice of A (the so-called ambiguous stimulus) was not reinforced; on NA trials choice of A was reinforced and choice of N (the negative stimulus) was not reinforced. When the two types of trials were distinguished by only the presence of P or N and each trial was terminated by one response, subjects quickly attained high levels of performance on NA trials but showed only chance levels of performance on PA trials. PA performance was markedly improved when a variety of additional stimuli distinguished the two types of trials and when a variety of schedules of intermittent reinforcement were employed; these manipulations had little effect on NA performance.     

Probabilistic contingency theories of animal conditioning: A critical analysis

Seven contingency theories of classical and instrumental conditioning were defined in relation to the contingency matrix and to six separate probabilities which can be derived from this matrix. These theories were compared on the basis of formal similarities and differences, and were judged against three separate empirical variables which have been discussed in the contingency literature: the duration of the intertrial interval, partial reinforcement, and negative contingencies between the two events of conditioning. All previous theories had some difficulty predicting the effects of one or more of these variables upon animal conditioning. Also, some formulas make the unusual prediction that there will be less conditioning when there is more than one conditioning trial. The paper concluded with an extensive discussion of the problems that are created by conditioning events with temporal extension; events which are then categorized by a contingency matrix which has no temporal character. Some possible solutions to the problems were discussed.     

Individual differences in speed of phonemic analysis, visual analysis, and reading.

College student subjects (Ss) classified phrases as making sense or not according to sound in one condition, according to visual appearance in another, and in abasic task in which either strategy would yield right answers. Ss who were relatively fast in the visual condition were faster at the basic task than Ss who were relatively fast in the sound condition. Other results suggested that the former Ss used a visual strategy in the basic task while the latter used a phonemic strategy.