Two factor analytic studies were conducted on a revised long form and a short form of the Activation-Deactivation Adjective Check List, a self-report test of transitory activation or arousal states. Although previous research indicated that the check list is composed of four independent activation factors, the present research instead suggests two general bipolar activation dimensions. However, certain evidence indicates that the concept of four separate activation factors cannot be completely abandoned. A third study showed high measurement reliability on two kinds of estimates.
Robert E Thayer (Thu,) studied this question.