Electromyograph biofeedback with high absorption subjects : attentional demand, mental set and informational components

No Thumbnail Available
Dekker, James D.
Zimmerman, Jay S.
Issue Date
Thesis (Ph. D.)
Other Identifiers

Previous research by Quails and Sheehan (1979, 1981b, 1981c) has found an interaction effect between absorptive capacity and relaxation in frontalis EMG biofeedback and no-feedback (instructions only) conditions. High absorption subjects were able to relax more completely under biofeedback conditions while low absorption subjects relaxed more ably under no-feedback conditions. They theorized that this outcome was the product of the attentional demand characteristics of these conditions. That is, attention demanding conditions were believed to interfer with the imaginal thinking of high absorption subjects, thereby disrupting relaxation. Low absorption subjects, however, were believed to utilized attentional demand to compensate for their limited attention deployment capabilities. In contrast, in reinterpreting these findings, Tellegen (1981) maintained that the mechanism underlying these results was not attentional demand, but was mental set (experiential or instrumental set). Both Qualls and Sheehan and Tellegen, nevertheless, agreed that biofeedback does not play an informational role.This study examined the relative contributions of attentional demand, mental set, and the feedback of muscle activity to the relaxation of high absorption subjects. Thirty-one male and female college students were distributed into three conditions: frontalis EMG biofeedback with instrumental set, metronome with experiential set, and nosignal (instructions only) with experiential set. All subjects were given six sessions of relaxation.Results showed no between condition differences in EMG output or imagery production either within or across sessions. The primary significant finding was a within sessions EMG reduction which occurred for all groups. It was concluded that attentional demand, mental set and the physiological information supplied by biofeedback play a limited role in the relaxation of high absorption subjects. The findings relative to the informational role of biofeedback were qualified by the possible operation of a floor effect, since normal subjects were used. Further, the findings relating to attentional demand, when' interpreted in light of Qualls and Sheehan's results, suggested that attentional demand may only be important in the relaxation of high absorption subjects when highly interfering. This followed from the assumption that the attentional demands used in the present study may not have been as interfering as those utilized by Qualls and Sheehan.