In the ST, a subject is asked to pick a card out of a six-to-eight card pack held face down. The subject chooses and remembers one of the cards and returns it to the pack and is asked to deny that any of the cards were picked. The polygrapher then determines which card was picked from the polygraph results. One of the purposes of the ST is to show the subject that the test is valid. In this study, an ST was used between the first and second presentation of the test questions for 116 examinations. In another 107 examinations, the ST was omitted. Fifty examinations were randomly selected from each group for analysis. In the control question technique, the innocent subject fears the polygraph will falsely indicate deception. This fear is strongest in the first presentation of the test questions, after which there is a gradual decrease in apprehension. As the subject adapts to the procedure, anxiety is less likely to attend control questions, making deceptive responses to relevant questions more prominent in contrast to control-question responses. The ST interferes with subject adaptation and reinforces subject apprehension, obstructing clear distinctions between subject responses to control and relevant questions. This was most noticeable on the measurements of skin resistance. 2 tables and 17 references.