The interaction of instruction components with cybernetic feedback effects in the voluntary control of human heart rate

The effect of activation versus inhibition of feedback on perceived control of EEG activity

This study explores a model in which perceived control is affected by multiple sources of feedback at three different stages of the control sequence--person, response, and outcome. Behavior that enhances feedback is termed activation, while behavior that diminishes feedback is termed inhibition. The study tests the hypothesis that activation at any stage of the sequence leads to greater perceived control than inhibition. Eighty subjects increased or decreased their brain-wave activity (EEG) by making a tone go either on or off, using either an active or a passive strategy. Following 10 60-second trials, subjects rated their perception of control over their EEG activity. The hypothesis that making a tone go on (activation of the outcome) leads to a greater perception of control than making the tone go off (inhibition of the outcome) was confirmed only when subjects decreased their EEG activity. Perceived control was not significantly correlated with actual control, supporting the expectation that they are separately mediated. The results did not support the hypothesis that increasing EEG activity or using an activity strategy would lead to a greater perception of control than decreasing EEG or using a passive strategy. These findings are interpreted as evidence that attention to feedback may be necessary for the predicted bias in perceived control to occur, and that activation and inhibition should be operationalized as the absolute presence versus absence of feedback in testing the hypothesis for the first two stages of control.

Voluntary heart rate deceleration: a critical evaluation

This experiment was designed as a test of the view that the human heart rate (HR) deceleration response can be brought under voluntary control, when some form of exteroceptive feedback is available. Sixteen female volunteers were randomly assigned to two groups. The first group received instructions to decrease their HR plus a continuous negative (failure) binary feedback, while the second group received only the instructions. Each subject was given four sessions of HR deceleration training. Two identical tests were presented, one before and the other after the series of training sessions. These tests were divided into two parts. In the first part, subjects attempted to decrease their HR while undergoing an ischemic arm pain stress. In the second part, subjects performed a 40-trial HR discrimination task. The results indicate that all subjects decrease HR during both rest and voluntary control periods within each training session, but there are no significant group differences, no improvement in HR deceleration control over the four training sessions, and no difference in performance between rest and voluntary control periods. Similarly HR, blood pressure (BP), and the HR x BP product levels during the ischemic stress condition and the HR discrimination performance do not show group differences. It is suggested that the HR deceleration response may not meet the criteria generally applied to the definition of a voluntary response.