“…Certainly each of the 10 items listed above reflects stimulus-seeking motivation and preference for sensory variability. This fits with the high risk taking of the extrovert (Lynn & Butler, 1962), his more frequent alternation behavior (Eysenck & Levey, 1965), greater alcohol and cigarette consumption (Eysenck, 1963), greater extent of physical movement (Rachman, 1961), less stimulus-deprivation tolerance (Petrie, Collins, & Solomon, 1960), and greater pain tolerance as compared with introverts (Lynn & Eysenck, 1961).…”