Polygraphology - a critique

[Erik Narramore]

Jeremy Bamber 'passed' a 'lie detector test' conducted by a UK-based polygraph examiner, Terry Mullins.

The polygraph expert, Terry Mullins, admits that any verdict expressed on a polygraph examination result is only one part of the picture.  He also admits that there is a high error rate with polygraph examinations, though he does not explain how this 'error' rate was calculated, and given that a polygraph examination cannot possibly diagnose lie-telling and truth-telling anyway, it is difficult to see how an error rate can be calculated in the first place.  If you stop to think about it, Mr Mullins is showing his disingenuousness when he talks about 'error rates'.  He is trying to undergird the reliability of these tests on some sort of empirical basis.

Against this background, a polygraph examination result is not the be-all and end-all in any situation.  Even if the result is a 'Pass', a convicted and confessed paedophile should always have his computer checked by the police where there is otherwise proper reason to do so.

A sceptic may ask whether supporters should stop believing in Jeremy Bamber's innocence if he failed a polygraph examination, but the situation cannot arise as Jeremy is deemed to have Passed, so the question cannot be answered, can it, or it is purely theoretical.  I assume had that situation arisen in reality, the person you directed the question at would have had to consider things in the round, and more questions could be asked: Does Mr Mitchell maintain his innocence, despite the test result?  Etc.

Personally, I think polygraphology is pseudo-scientific rubbish and I would be appalled if such 'tests' were ever used by the courts to determine matters of fact.  It would do no good anyway.  Anybody who fails one of these tests would surely interrogate the machine and the examiner, and demand a copy of the results and hand them to another expert to be re-interpreted.  As I have had to keep reminding a certain user on here, the opinions and findings of experts are always open to interpretation.

[Erik Narramore]

There is a Campaign Team podcast on the topic of the polygraph test, which Jeremy passed with flying colours.

Here we are:

https://www.youtube.com/watch?v=OL9TLqeyV3U&t=51s

This podcast is quite interesting.

I have commented above with my view on polygraphology and in this thread I will touch on some of the obvious flaws and pitfalls in any applied discipline that attempts to draw forensic conclusions based on theories about psychophysiology.

In a nutshell, I can't take polygraph testing seriously - but I am not an expert.  My layman's scepticism only deepened as I listened to Mr Mullins explain his methods in this podcast.  It's not so much a criticism of Mr Mullins, rather a criticism of the discipline to which he is clearly committed and out of which he seems able to draw sweeping conclusions about the case.

One eye-catching claim the CT and the polygraph expert are making is that Jeremy graded in the top 5% of  examinees, implying (in their view) a conclusive result and that he must be telling the truth.

[Erik Narramore]

If - for the sake of argument - we assume for a moment that polygraph tests are valid and can be relied on, the reason Jeremy was able to pass is that he has constructed an alternate narrative of the case that he has come to believe, because he has to, either because it is true, or because he is guilty and needs to believe in this alternate narrative.  In the latter case, the alternate narrative could be a projection of his own guilty conscience.

All liars, petty and serious, engage in a form of double-think in which they know what they say is not true but they also believe in it.  That may sound odd, but if you think about it, it makes sense.  If you've done something wrong, you may easily come to convince yourself that you didn't do it.  Liars on this scale often come to sincerely believe in a completely alternative world and in effect become schizoid and delusional.

Of course, that's just speculation in the case of Jeremy.  In any event, polygraphology is too simple.  It does not take account of psychological nuances.  It is easy to imagine an innocent person failing a polygraph because innocent people are, by the very nature of their innocence, doubtful about facts and may be nervous and so on.  Equally, a guilty person is nervous, but knows what he has done and this knowledge may give him the confidence to ride through a fine-tuned test of his physiological responses.  Or it may not.  We're left in the same place with the same questions.  A polygraph result is practically useless.

[Erik Narramore]

As stated above, the biggest problem with polygraph examination is evidential redundancy.  They don't tell us anything dispositive.  Whether a subject passes or fails, we are left with the same questions that we started with.

There is also the more mundane flaw that there is no credible body of scientific findings that tells us there is a commonality of physiological and psychological responses among lie-tellers and truth-tellers respectively.  One person can be nervous and be telling the truth; another person can be cool, calm and confident and still be lying.  There is too much variation, due to the existence of infinite variables.

[Erik Narramore]

When somebody does something terrible, they will often construct an entirely alternate narrative that they come to believe in.  That sounds weird and paradoxical, and I can understand if you are sceptical about the idea, even scoff at it.  It's not necessarily common experience.  But I do think a lot of people genuinely believe their own lies, especially if the extent of the lie is deep and has been maintained for a very long time.

It has nothing to do with rationalisation or justification.  It is simply a lie.  Sometimes (as it will be in this case, if Jeremy is guilty) it is virtually an entirely constructed false alternate reality - a fantasy world.  It starts with the offender lying to himself.  Dissimulation and fabrication can be an essential survival strategy, especially in high security prisons, but in some cases it may become the basis of an offender's reality, in his own head.  Thus, paradoxically, a lie becomes true.

The reason I labour the point is that it could go some way to explain why Jeremy has passed the polygraph test.  This point is independent of his guilt or innocence, though it's obviously more useful for guilters and sceptics to consider.  By the time he took the polygraph, Jeremy had served 20 or more years in custody.  Think about it.  That's 20 years to construct an alternate narrative that he then promotes aggressively and, quite possibly, comes to genuinely believe in.  Hence, he comes across as genuine and his fine-tuned physiological responses betray nothing other than that he is a truthful subject.  And in a sense, he is telling the truth, even if he is guilty!

Of course, here I am putting aside my scepticism of the whole field of polygraphology.  I am adopting the assumption that the polygraph is valid, and on that premise, I am considering how a guilty person could pass it with flying colours - albeit it would still raise questions about the usefulness of the test (even if the methodology is valid).

An additional point, which is related, is that if Jeremy is guilty but has a guilty conscience about it (i.e. he is either not a clinical psychopath or no longer a psychopath, he is psychologically normal), then this guilty conscience may be projected through his aggressive defence of his claimed innocence.

[Erik Narramore]

Mullins is an engaging interviewee and knowledgeable and expert in his field.

However, the CT podcast deepened my scepticism of his field.  A major point is that there was no prior psychological evaluation of Jeremy in preparation for the polygraph test.  This was not Mullins' fault, rather it was due to restrictions put on him by the Prison Service, which seems petty.

Another point is that I got the impression from Mullins' answers that the underlying science of polygraphology is pretty vague and it's mainly based on psychology and cognitive science.  At one point, he refers to 'cognitive load', which seems like a woolly metaphor for something.  I am not sure either psychology or cognitive science can be considered science in a proper sense.

Finally, I'm not sure it is known what all the questions were.  Apparently 12 questions were put to Jeremy but we only know three of them.  Why is that (assuming I am correct)?

All this got me thinking about the conditions under which a rigorous polygraph test could be completed and what questions I would ask Jeremy.  I may add more on that at some point.  Don't have time for it now.

[Erik Narramore]

I don't have any expertise in this area, but I've always assumed that so-called 'lie detector tests' can't be relied on as evidence.  I know that's the case in English criminal courts.

I also assume that 'lie detector tests', as such, don't exist anyway.  It's just a popular term.  The test measures physiological responses, but that is all it can tell us.  A polygraph examiner is assuming he can then draw interpretations from the results, but that sounds pretty ropy to me.  You can't reliably detect when somebody is lying by measuring heart rate, blood pressure, etc., or in the case of body language experts, by simply observing somebody.  The human mind and its interplay with the body are just too complex for that kind of simplification.

It's perhaps impossible to detect lying anyway, because even a liar can, in a sense, be telling the truth.  A determined liar may be saying what he or she has convinced themselves to be true.  Jeremy could be guilty but at the same time genuinely believe he is innocent, and he may have had a black-out, etc., etc.  We just don't know, because we can't peer into his mind.  Paradoxically, liars are often the most truthful people of all.  Can a so-called 'lie detector test' detect this psychological quirk?  If it can't, then it's categorically not a lie detector test.

Furthermore, there's an underlying objection to lie detector tests: they are based on the premise that human beings are machines.  Admittedly, in a sense, we are machines, but we also have souls.  You can't open a window into the human soul.  You don't know if somebody is really lying or not.  Not for absolute sure.  It's more a question of whether what somebody says can be relied on, and you can only know that through an examination of evidence and facts.  If Jeremy has a low or high pulse while he's discussing his dead family, I don't see what that can really tell us.  Statistically it may or may not be consistent with physiological behaviour under truth, but then how are those statistics derived?  How were the test subjects measured in the first place?

It's all circular and I personally take the view it's garbage.  If Jeremy has passed such a test, I'm not sure what that tells me beyond that he's quite a controlled person.  It doesn't follow that he's guilty or innocent.  In fact, the result could be interpreted either for or against him, depending on how you interpret the surrounding evidence.

[Erik Narramore]

I think polygraph examinations ('lie detector tests') are nonsense and establish nothing one way or the other; I would even say they are dangerous, for a number of reasons, including that they would dumb-down the criminal justice system if they are allowed to creep into police investigations and courtroom evidence.

However, the footage linked below is relevant to the Forum because it shows Luke Mitchell, convicted of murder, and his mother submitted to polygraph examinations conducted by Terry Mullins.

Make of it what you will.

One important point for context: some people wonder why Luke has his eyes shut throughout his examination.  Both Dr. Lean and Mr Mullins have explained that Luke was advised to do this by Mr Mullins because prison officers could see what was going on in the vestibule in which the test was being conducted and were pulling faces at him!  Are we to believe this?  Don't ask me, I'm just the parrot.

The polygraph examination of Corrine Mitchell, conducted by Terry Mullins on 23rd. February 2012 (location unknown):

https://www.youtube.com/watch?v=dS5gs81NvOc

The polygraph examination of Luke Mitchell, conducted at HMP Shotts, Scotland, by Terry Mullins, on 25th. April 2012:

https://www.youtube.com/watch?v=boKXAggpHoQ