The pre and post-polygraph interviews are used to establish a baseline prior to the examination, and to refine follow-up questions afterward. Pre-examination interviews can be just as useful in standard interrogation. A baseline must be established. Much has been written, some of it inaccurate in fact, about common “tells” that people exhibit when telling a lie. Although these ideas of tells are based in truth, they are not consistent between all people. Just like in poker, every person will have their own little quirks and ticks that can indicate whether they are playing it straight, or about to lay out a whopper of a bluff. Most people do not spend any time trying to defeat these tells or reduce their presence. That is why you see so many people playing poker on television while wearing large, floppy hats, wide sunglasses, and facial hair. Those coverings can reduce the visibility of the player’s tells.
The baseline is established by creating a relaxed atmosphere for the subject. Simple, innocuous questions are asked; questions for which you expect an honest answer. Your age. Your height. Where you were born. The age of your parents. How long you have lived in a specific area. These are all baseline questions. The person may exhibit some form of discomfort or anxiety because they are being questioned, but those traits should be different than when they are exhibiting deceptive behavior. Once you have the baseline, you now know what that person’s normal behavior are and can judge when that behavior changes.
Discomfort and anxiety in and of themselves do not always indicate deception, however. Each person will react differently, but within certain parameters of human behavior. The key is to understand how that person acts and reacts when they are being honest. That is your baseline for further questioning when attempts at deception will be more likely. Even those who believe themselves to be smooth and composed under pressure will exhibit some form of behavior that indicates their deception. It is the job of the trained interrogator to be able to spot them and capitalize upon them during the interrogation. Some are so subtle that they are referred to as “Micro-tells.” A very discriminating eye is required to spot them. This skill generally comes with many years of experience looking into the face of an accomplished liar.
