THE THEORETICAL basis for the empirically derived pattern of rostral, or face, dominance which is elicited by multiple simultaneous cutaneous stimuli has not yet been established. Several theories have been proposed; none has been completely satisfactory. The major physiological modes of action advanced have been cortical suppression,1 as activated by "specific" areas, and the direct interaction of the first and second cutaneous sensory systems.2 Even if it is allowed that suppression is an experimentally proved physiological phenomenon, the time required for effective suppression, as established in animal studies, is incommensurately long compared with clinical extinction. The sensory interaction theory appears plausible, but it has not yet been experimentally shown to be operative either in multiple ipsilateral or in simultaneous bilateral stimulation.
Psychologically, "inattention," organismic, and gestalt theories have been formulated to account for the observed phenomenon of extinction. These formulations appear too descriptive and too general to be