From: jcs
The polygraph examination process is a technique used in investigations, often involving a combination of psychological strategies and physiological monitoring to assess a subject’s truthfulness [00:00:28]. It is not considered a foolproof system, but its effectiveness can be increased in certain conditions [00:10:40].
Pre-Test Phase
Before the actual polygraph test begins, several steps are taken to prepare the subject and gather information:
- Information Gathering The polygrapher obtains the examinee’s version of the facts regarding the specific issues under investigation [00:12:09]. This includes details about the events leading up to a disappearance [00:13:16].
- Managing Anxiety and Credibility It is considered normal for a person to be nervous about taking a polygraph test, even if they have nothing to hide [00:09:48]. The polygrapher often attempts to establish their credibility, stating their extensive training (e.g., “10 weeks for training,” “best school in the country,” “best training that they offer in the United States”) and use of “most validated testing” methods [00:09:59].
- Psychological Pressure and Reassurance
- Investigators may exert psychological pressure by suggesting that other law enforcement agents also suspect the subject’s involvement in a crime [00:07:08]. This aims to amplify the subject’s apprehension for the upcoming test [00:07:21].
- The investigator might predict the subject’s future thoughts or anxieties, suggesting they will regret not having disclosed more information [00:07:48].
- A technique known as “passive accusation” may be used, where the interrogator indirectly accuses the subject while praising them for seemingly trivial actions [00:08:52]. For example, a polygrapher might say, “A lot of dads don’t get second pairs of clothes and cook eggs and give them snacks at night” to suggest the subject is a “good dad” while maintaining underlying suspicion [00:09:08].
- Psychological pressure can be disguised as routine questioning, such as asking the subject to list ways someone could “disappear” or be murdered [00:13:56]. This is framed as ensuring the subject understands the questions that will be asked during the test [00:14:06].
Directed Lie Polygraph Test
The type of polygraph discussed is a “directed lie polygraph,” where the subject is instructed to intentionally lie on certain questions [00:18:04].
This test consists of three types of questions:
- Known Truth Questions These are simple, easy-to-answer questions (e.g., “Are you sitting down?” or “Are you wearing shoes?“) [00:18:20].
- Purpose 1: To provide a baseline reading of the subject’s physiological responses when telling the truth, which should elicit minimal bodily reactions [00:18:27].
- Purpose 2: To “disconnect the examinee’s thought patterns” between questions, effectively “resetting their cerebration” for a more accurate reading [00:18:36].
- Control Questions These are questions where the subject is explicitly told to lie (e.g., “Before 2018, did you ever lose your temper with someone you cared about?” and the subject says “no”) [00:18:44]. These questions are designed so that the truthful answer would almost certainly be “yes,” making a “no” answer a deliberate lie [00:18:54].
- Relevant Questions These questions directly relate to the crime or specific issues under investigation [00:19:01]. The examinee is expected to answer these truthfully [00:19:05].
Interpretation: A guilty subject is expected to show a significantly stronger physiological reaction to the relevant questions than to the control questions, even though they might be lying on both [00:19:07]. This is attributed to the immediate threat posed by the relevant questions [00:19:15].
During the Test
During the polygraph, the subject is given instructions on how to remain still and how to answer questions [00:11:00]. The polygrapher typically confirms that the subject understands they will only be asked previously discussed questions and intends to answer truthfully [00:21:29].
Post-Test Phase and Results
After a portion of the test is complete, the polygrapher may provide feedback. This often includes initial compliments to boost the subject’s confidence, followed by a dramatic “reveal” of the results [00:20:01].
A common interrogation technique is to tell the subject they are a “bad liar” based on their reactions during the control questions (even if the polygraph is not “on” during that part) [00:20:17]. This is intended to amplify the subject’s anxiety and encourage a confession, as it suggests any lies about the main questions will be easily detected [00:20:51]. The polygrapher states that the results will reveal the truth, making “two” people in the room (the polygrapher and the subject) aware of it, before sharing it with others [00:21:11].
If a subject “fails” the polygraph, they are directly informed of the results and told that their dishonesty is “completely clear” [00:23:32]. This usually leads into further interrogation and psychological analysis to encourage a confession [00:23:42].
Limitations
Polygraphs are not considered “fool-proof,” meaning they can potentially be beaten [00:10:40]. However, a “heightened state of anxiety” can make it considerably more challenging and unlikely for a deceptive individual to pass [00:10:44]. A polygraph can be failed if the subject does not follow instructions (e.g., remaining still, answering correctly) or chooses to lie about the relevant questions [00:10:54]. It is explicitly stated that if a subject is guilty, it would be “really stupid” to take a polygraph test [00:11:14].