For a few years now the probation service has required certain offenders (mostly sex offenders as far as I am aware) to take polygraph or lie detector tests. Recently a number of people have written letters to Inside Time claiming to have voluntarily taken these tests and to have proven that they are being honest when they say they are innocent. However, as much as I hate Jeremy Kyle, I think there are certain lessons we can learn from his show.
Firstly, in the early series of the Jeremy Kyle Show they used to put the accuracy rates of polygraph examinations. They said that it was accurate in 97% of cases. However, in later series they stopped admitting this and now simply say that the accuracy of the tests is disputed. Since the show started they have completed hundreds of lie detector tests, and on each one they usually ask three main questions. The total number of questions asked come well into the thousands. Given that the accuracy rate is 97%, that would mean that 30 questions out of every thousand asked have thrown up false results. And yet, out of all the times that people have protested that the results are wrong, Jeremy Kyle hasn’t once conceded that this might be the case. Well it is the case. Statistically it must be. As a result the damage done to the personal relationships of those who have received inaccurate results is potentially devastating. But what of those who are forced to undertake these tests for probation? What happens if they receive inaccurate results? Not only might their personal relationships suffer. They could also be liable for recall to prison. Let’s imagine that they are asked if they have re-offended since release and they honestly say no but they examiner wrongly says that they are lying. They would almost certainly be recalled. A 3% inaccuracy rate may not sound like much, but that is 3 people out of every hundred who could end up back in prison for absolutely nothing.
Secondly, when someone on Jeremy Kyle says they haven’t slept with anyone other than their partner and passes, but then says they haven’t kissed anyone other than their partner and fails, Jeremy’s response is that they didn’t argue about the accuracy of the test when they passed the first question. This too is misleading. It isn’t 100% right or 100% wrong. The first question could fall into the 97% of accurate results, whilst the second falls into the 3% of inaccurate ones. The fact that one result comes back accurate does not make all other results accurate. But if an offender is ever recalled after failing such a test and challenges the accuracy of the examination when the parole board review the recall, what will they do if faced with the same argument? There is no way to prove that the result for one question is inaccurate or that the result for another is accurate. In fact there is no way to prove any of it.
Finally, when people on Jeremy Kyle are genuinely caught out, the most common excuse is “Well if I’ve done that then I don’t remember it!” What is never pointed out to them is that polygraph examinations actually measure the likelihood that someone is being deceptive. That’s why they’re called lie detector tests. But what that means is that if you truly don’t think you have done something, because you have no recollection of doing it, and you say that you didn’t, then your body will not show any signs of deception and, if the test is conducted accurately, the result will indicate that you are telling the truth. Even if you did do whatever you are accused of, if you can’t remember it, the result should still say that you are being honest when you deny it. However, the same goes for people who do not believe that what they have done is a crime. For example, just fifty years ago it was entirely legal for a man to rape his wife. Fortunately society has put this law right now, but there is still the odd person that believes they have the right to demand sex from their wife whenever they like – even against her will. Those people don’t even see it as a crime at all. So what happens if you ask them if they have committed a crime? Since they honestly believe that what they might have done is not a crime they would say no, and they would honestly believe it. Their body would not show any of the usual signs of deception and the lie detector results would indicate that they are telling the truth. A serious crime will have gone undetected, and the offender would be left to do the same thing again and again. All because too much reliance has been placed upon the polygraph.
These are the very reasons that lie detector evidence is not admissible in criminal court cases. It is simply too unreliable and could indicate that a guilty person is innocent as easily as that an innocent person is guilty. But the increased use of such examinations in the family courts and by probation with those on license is a worrying sign of the times.
This move is only possible because society tolerates it, and society only tolerates it because we have been conditioned to get used to it. Jeremy Kyle has been the main influence in this regard. His brazen disregard of the facts surrounding accuracy, consistency in indication, and result skewing beliefs has led the public to think that they are reliable. This is far from true and it isn’t until something tragic happens that society in general will realise it. My fear is, that will be far too late.