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Biomedical subjects

J L Feld

Publications and source records attributed to J L Feld.

3 recordsLinked to original sources
PubMed1981

Expectancies of reinforcement control in biofeedback and cognitive performance.

This study investigated the effects of expectancies concerning the controllability of outcomes in a biofeedback task. Forty-eight college undergraduates were subjects. Frontal (forehead) electromyographic (EMG) responses were measured during baseline (no treatment), pretreatment, and test sessions. During pretreatment, subjects were assigned to one of three groups. Using a fictitious blood vessel control task, the success group received false feedback and instructions that conveyed that outcomes had been successfully controlled. The failure group received feedback and instructions that conveyed that outcomes had not been controlled. A control group was given no specific task. During the subsequent test stage, all subjects were asked to reduce frontal muscle tension levels through relaxation while assisted with true EMG feedback. Relative to the success and control groups. EMG levels of the failure group reflected more rapid acquisition of frontal muscle relaxation. However, performance on a cognitive task was not affected by the pretreatment. It was concluded that expectancies generated during the false feedback pretreatment were related to later biofeedback performance. The results were discussed in terms of concepts of locus of control and theories of learned helplessness and reactance.

Adolescent↗
PubMed1978

Role of incentives in the training of the frontal EMG relaxation response.

Male college students were assigned to a feedback condition in which an auditory signal was correlated with forehead electromyographic (EMG) responses or to a control condition in which a constant low tone was provided. Within each condition, half of the subjects were provided with an incentive for successful reductions of EMG levels from session to session. In the control condition incentives were actually given on the basis of performance of yoked feedback partners. The remaining subjects in each condition (no incentive) were instructed that the incentive was available for reliable participation in the experiment. Feedback subjects acquired lower EMG levels than control subjects, and the yoked-incentive subjects acquired lower levels than no-incentive subjects in the control condition. There were no major differences in EMG levels attributable to locus of control orientation. The results are discussed mainly in terms of implications of incentive variables for reinforcement analyses of biofeedback effects and the validity of the locus of control construct in this application.

Adolescent↗