Don't remember reading about this before but I think it was to measure perspiration as he ran his fingers along the bottom of my fingers before attaching the devices) and then he starts telling me the questions he'll ask. Since this is a 'sex history' polygraph, I didn't think I had anything to worry about since I had been honest and truthful in my relating of my past. The questions were all pretty normal except 1 which may or may not have been a control question. The odd thing was that there were really no control questions such as the one listed in "The Lie Behind..." before the test started.