The psychological literature contains evidence that the Semantic Differential (SD) (Osgood, Suci and Tannenbaum, 1957) is capable of differentiating psychiatric groups from normal controls on the basis of checking style. There were three specific aims of this present study. The first was to gain further confirmation of the ability of the SD to distinguish psychiatric patients from normal subjects. The second was to see whether the sex of the subject affected his checking style and thirdly, the writer wished to see whether the actual concepts used with the SD affected response tendency. However, before these three hypotheses are discussed in detail an introduction to the SD and a review of the important literature on the instrument are in order.