Heart rate control under conditions of augmented sensory feedback.

Five human Ss were presented with a high frequency tone on the emission of each short inter-heartbeat interval and a low frequency tone on the emission of each long inter-heartbeat interval. Under these conditions, all Ss learned within a short period of time to produce significantly lower heart rates in the presence of one visual stimulus than in the presence of another. On the basis of this finding, it is suggested that an important determinant of where a given response falls on the voluntary/involuntary continuum is the availability of specific feedback from the response in question.