Journal of Experimental Psychology: General Copyright 1981 by the American Psychological Association, Inc. 1981, Vol. 110, No. 3, 381-397 0096-3445/81/1003-0381S00.75A critical assumption in the rationale for the clinical application of voluntary control
over central nervous system (CNS) activity is that there exists a direct relationship
between specific CNS activities and specific subjective mood states. The experiment
reported here was based on the idea that a joint manipulation of both cognitive and
physiological (i.e., alpha electroencephalographic [EEG]) variables would provide information
required for an explication of the processes involved in subjective mood
change. Three main variables were considered in the present experiment. First, the
instructions were designed to induce a "set" or expectations for either positive or
negative changes in subjective mood. Second, the type of feedback (alpha or not alpha)
was varied. Those in the not-alpha feedback condition received feedback contingent
on the absence of alpha activity, whereas those in the alpha feedback condition received
feedback contingent on the presence of alpha activity. Third, an estimate of each
individual's baseline alpha density was obtained, and on this basis subjects were classified
as high-baseline or low-baseline subjects. Baseline alpha density, alpha density
during training, and subjective mood were all considered as continuous variables.
The results of the present study indicate that biofeedback of the cortical alpha rhythm
is neither a sufficient nor a necessary condition for changes in subjective mood. In
addition, the type of instructions designed to set subjects for positive or negative alterations
in subjective states is predictive of changes in subjective state reported during
alpha biofeedback training as well as of success at controlling and changing EEG
during feedback training. The data presented here permit a direct examination of the
actual relationship of EEG changes to changes in subjective mood state. Similar shifts
in subjective mood state can be obtained with either increases or decreases in alpha
activity. Further, both positive and negative subjective experiences can be associated
with increases in alpha activity.
