Trait anxiety is an individual-difference variable reflecting variation in state-anxiety elevations resulting from exposure to a stressor. It is usually measured using questionnaire instruments, such as the Spielberger State-Trait Anxiety Inventory (STAI-T). The present research conceptually distinguishes, and independently assesses, two hypothetical dimensions of anxiety vulnerability which, it is argued, could plausibly make independent contributions to variance in trait-anxiety scores. These dimensions are anxiety reactivity, the probability of experiencing an anxiety reaction to a stressor, and anxiety perseveration, the persistence of anxiety symptoms once elicited. Participants were asked three questions about each STAI-T item. The traditional STAI-T question assessed how much of the time this symptom was experienced; the anxiety-reactivity question assessed the probability of experiencing the symptom in response to a stressor; and the anxiety-perseveration question assessed how long the symptom persisted, if elicited. Regression analysis determined that anxiety reactivity and anxiety perseveration scores both accounted for independent variance in trait-anxiety scores. It is argued that models of anxiety vulnerability should seek to differentiate both the causes and the consequences of elevated anxiety reactivity and increased anxiety perseveration.