Alpha-adrenergic, beta-adrenergic, and cholinergic responses are often considered important activation components when conceptual and empirical analyses are made of single physiological variables and of patterns of cardiovascular reactivity; these autonomic distinctions are also of particular significance in autonomic blockade studies. A Model of Cardiovascular Activation Components is introduced that relates these components to both the measured cardiovascular variables and the protocol of autonomic blockade studies. It is pointed out that a restricted form of the complete model is often implicitly used in cardiovascular psychophysiology. The differential consequences of an erroneous employment of the restricted model are discussed for single and dual blockade protocols. Critical evaluations of autonomic blockade as a tool in cardiovascular psychophysiology are examined and are proposed to be often the consequence of the restricted model assumptions. Lastly, the utility of the Activation Components Model for a componential description of tasks and for componential intertask relationships is illustrated with data from the literature.