What to expect from a polygraph?

October 13, 2018 1:45 AM

I asked this question. The school reported it to the police, and I am now in the middle of a police investigation I never really expected. I have been told to expect a polygraph exam as part of the process (I have already given a statement).

I'm looking up the literature on it (and am well aware of its criticisms), but want to know what to expect from the actual process of taking one. I was just told to expect monitoring of vitals, and a three-hour long exam. I'm also nervous about giving contradictory information because it was seven years ago and I blocked out a lot of things.

NB this is Singapore, polygraphs are apparently standard and admissible evidence. The accused will be taking one as well, presumably, and we have both surrendered devices for forensic examination.

posted by ahundredjarsofsky to Law & Government (6 answers total)

I work in a polygraph-adjacent field, so I defer to the real experts. However, my understanding is that polygraphs are generally designed for—and work best on—people with limited knowledge of the process. Too much research or preparation ahead of time can skew results. A general overview would be, yes, a three-hour exam while they monitor vital signs. Expect a number of unrelated questions at the start to set a baseline for your responses.

In the US, at least, polygraphers for these type of investigations tend to be well-trained, professional, and experienced. They would set aside time at the start for getting you settled and explaining what’s going to take place.

In terms of contradictory answers, you say what you know and tell the polygrapher when you’re unsure. It is not your job to keep your story straight—it’s you job to take each question as it comes and give as honest as response as possible (including saying, “I’m not sure,” or, “I don’t remember.”)

Ok, MeFi hates polygraphs, and I’m sure people are going to come in with different hot takes, but this is my general sense of how polygraphs play out in my corner of the universe.
posted by whitewall at 4:34 AM on October 13, 2018 [2 favorites]

To the extent that polygraphs do anything at all, they measure (very roughly) how stressed-out and anxious you are during the questioning. The idea is that anxiety is a sort of proxy variable for mendacity. It's spurious, but that's what the concept is.

So if you want to "pass" your test, you should do what you can to make sure that you are in a physically calm, relaxed state before and during the questioning. Lots of stretching and deep, slow breaths are probably in order.
posted by Anticipation Of A New Lover's Arrival, The at 7:16 AM on October 13, 2018

I have worked for almost thirty years in child welfare investigations-working closely with law enforcement all that time, and of course constantly part of sec abuse investigations-and I have NEVER heard of a polygraph of an alleged victim of abuse. I suppose that could vary based on jurisdiction, or that there may be facts that would support this-but on the face of it, this seems like a bizarre step to take.
posted by purenitrous at 7:04 PM on October 13, 2018

Response by poster: Thanks whitewall & Anticipation. purenitrous, I'm trying to get a legal information session with the local equivalent of RAINN. My sense is that polygraphs are probably standard for Singapore in the interest of treating both parties equally (e.g. we were both required to surrender our devices) for a criminal case (I'm not interested in civil charges). I can withdraw consent for the polygraph at any time but I'm guessing that won't go over so well in court if it comes to that. The officer pointed out that I had given her contradictory information in the initial phone call and actual statement, so maybe that's why they are proposing one. Not to mention that unless forensics turns something up, there are zero other witnesses to my case.
posted by ahundredjarsofsky at 9:33 PM on October 13, 2018

I don't know about the polygraph part, but I'm wondering if it might help your emotional wellbeing if you try to let go of any idea that your testimony will produce any particular results (don't worry about trying to convince anyone that they have to believe you) and instead of focus on this as a chance to just to tell your story for the record. Focus on reporting the facts of your experience as best you can. If the truth is that you don't remember, that is just the fact, it's OK. If the fact is that you said one thing before and you think that the first statement was incomplete or even wrong, then tell them why your answer changed but don't worry about whether they believe you - just focus on putting the facts on the record.

Hopefully, this perspective will help you be calmer and less anxious about what is going to happen and that will have the extra benefit of also helping the polygraph be more accurate. Certainly for me, self-talk about "all you have to do is tell your story" would be more effective than focusing on how the polygraph might be reading my body.

Also, where I live, you can have an advocate from the rape crisis center be in the room with you when being interviewed by the police for moral support. They are trained not to interfere in the process but they can make it feel safer, especially if you are being interviewed by male police officers. If it sounds helpful, you might ask when you talk about your local support agency.
posted by metahawk at 1:32 PM on October 14, 2018 [3 favorites]

In general, polygraph tests consist of yes/no questions only. The first part of the session will be the interviewer explaining how it all works, show you the equipment, tell you what questions they're going to ask. They'll explain what they mean by those questions, you'll say how you will answer, and explain why (tell them what happened, etc). For example if they asked "is the sky blue?" and you were confused by the fact that it was overcast today and you can't see a window from where you're sitting, you'd explain to the interviewer why it's hard to answer that clearly, and they'd explain they meant the ideal sunny day sky and you'd agree on maybe a different phrasing. Then when it's time to do the test, they'll connect the monitors (pulse, breathing, etc) and because you talked they'd modify the question to "is a cloudless sky blue?" and you'd say "yes", but at that point you're only giving one word answers, yes or no. The interview is in a lot of ways the important part because that's when you explain what they need to know. The actual polygraph part may be very short, nothing to get worked up over.
posted by aimedwander at 6:02 PM on October 14, 2018 [1 favorite]