Physiological and Behavioral Indicants of Activation

The present study demonstrates that various central and peripheral physiological variables are similarly altered by experimentally induced changes in activation while being dissimilarly altered during the course of a trial by unknown factors. That is, both general and specific physiological changes are demonstrated in a single experiment. Activation level was experimentally altered by having S (a) react to light flashes under threat of shock, (b) react to flashes without any such threat, and (c) passively observe light flashes. Evoked cortical potentials, heart rate, skin conductance, and muscular tension were similarly affected by these experimental conditions, but the variables showed differential changes over time. It was concluded that these physiological processes simultaneously reflect both generalized arousal and directionally fractionated activity.