Can you fail a lie detector test if you are nervous?

In this blog post, we talk about lie detectors, also known as polygraphs. We debate whether you can fail a lie detector test if you are nervous, and give you some tips to prepare for a polygraph test. 

Can you fail a lie detector test if you are nervous?

Even if the practice of lying detector testing fascinates everyone, after almost a century of scientific research, the veracity of the results of polygraph tests cannot be confirmed. Thus, you can fail a lie detector test if you are nervous, calm or even if you didn’t know you were taking a lie detector. 

Moreover, a report from 1983, coordinated by psychologist Leonard Saxe at the request of the American Congress, which led to a national ban on polygraph testing in the private workplace, concludes that there is too little scientific evidence to provide an empirical validity of the procedure.

In fact, the procedure is a set of closed-ended questions – “YES” or “NO” – to the interviewee, which is connected to a polygraph machine. The test lasts an average of three hours, and the examiners have to go through, together with those tested, three stages:

1.  the pre-test phase, where the legal reasons for the procedure are exposed, the type of questions that will be asked, and the legal consent of the interviewee is obtained; then calibrate the device by interacting with the test person, in fact, creating and maintaining a psychological contact between the polygraphist and the test person;

2.  the testing phase, which addresses the interview questions, as well as a set of independent questions, the answer to which is predetermined and which can provide a benchmark of emotional stability;

3.  the post-test interview, where certain questions whose answers did not record a relevant emotional register can be repeated. Also in this third stage, the polygraphist forms an opinion about the success or failure of the test.

Of course, the relevance of this test is hidden in the appropriate phraseology of the questions and in the psychological connection between the two parties involved in the interview. And hence the problem.

Failing a lie detector test

In 1955, Darrel Parker, a Nebraska forester whose wife had been killed by an unknown perpetrator, was invited to the Lincoln police station under the pretext of discovering new clues about the investigation. Once there, he was taken to an interrogation room and connected to a polygraph device whose dials remained hidden.

He was joined in the room by John Reid, a former Chicago police officer. Darrel was questioned for nine hours, and with each question he answered, the police officer accused him of lying, which the suspect could not deny because he did not have access to the polygraph needles. 

Moreover, Reid created a whole scenario of criminal motivation: the lack of affection and sexual interaction in the marriage of the two. After nine hours, Darrel confessed his deed: yes, he had killed her! The next day, however, he denied everything, but the jury sentenced him to life in prison.

John Reid became famous, and his organization, John E. Reid and Associates, became a world leader in training polygraph experts and canonizing interview procedures. 

Moreover, according to the information provided on the official website of the institution, their expertise has a success rate of 99%, and their methods are recognized and appreciated by courts in the United States. Their clients include the FBI, the CIA and other state services.

However, according to a survey conducted by the New Yorker in 2013, more than a quarter of the more than 300 people exempted from the DNA testing procedure gave false confessions, and experts believe that the polygraph test and interrogations may lead, indeed, to erroneous confessions.

Therefore, the question is: is there any safe way to investigate, interrogate, or test with the polygraph (or a combination of the three) that can clearly prove when a person is lying? No, because neither the polygraph test nor the interrogation procedures record the lie, but the physiological and psychological reaction to certain stimuli and the variables depend on several factors: accuracy and quality of testing, professionalism of the investigator, physiological reactions of the respondent, etc.

Is a lie detector accurate?

Basically, there are doubts about the manifestations of subjects with low IQ, social irresponsibility, hyper anxiety, the accuracy of the device, the competence of the examiner, the nervousness of the subject, too many questions, fatigue, inadequate phraseology, inadequate control questions, physical and mental discomfort, fear of physical pain, negligence, resentment towards the examination, personal problems that may interfere with the investigated deed, the pressure exerted by the sleeve that measures blood pressure and/or pulses, etc.

However, the need and utility of the polygraph are hidden elsewhere, namely, in the obsession with infallibility. The judiciary system must not make mistakes, otherwise trust in it will collapse. 

More or less scientific procedures for detecting lies have been recorded since the time of Erasistrate (300-250 BC), a physician from ancient Greece, whose way of identifying false testimony was correlated with the pulse of the respondent. 

Then, in the Middle Ages, by the Method of the Order, the suspect was subjected to a series of tortures accompanied by a draconian and biased interrogation. The 18th-19th centuries record studies of the physiological reaction of the body subjected to emotional stimuli (fear), and the invention of devices that can record subtle variations in the pulse – the plethysmograph and hydro sphygmograph, because, in the end, in 1921, John Augustus Larson to invent the polygraph.

Therefore, finding out the truth is one of the constant efforts of humanity, which, when discussing the judiciary, has never lightly accepted the appropriation of the old Latin saying: errare humanum est !, even if the road to infallibility has been (and is) sprinkled with an endless stream of good intentions and, inevitably, mistakes.

Of course, in the end, we must also consider the commercial component, that of the public show. In society, after the initial shock of a tragedy and the waves of petitions for the reintroduction of the death penalty dissipate, entomological curiosity intervenes the need to find out, to categorize, to understand and to find the right taxonomies for those who live with us and who fascinate and horrify at the same time.

Can you fail a lie detector test?

The polygraph has been misled repeatedly, and many of its principles and the arguments underlying the allegations are based on sheer pseudoscience. The polygraph can measure certain parameters and those in particular with the reliability and margin of error that we mentioned earlier.

University of Maryland physicist and professor Robert Lee Park once commented ironically: ‘The polygraph discovers abrupt increases in heart rate, blood pressure and sweating. Therefore, this machine is a very reliable detector of org**ms. But does it detect lies? Only if one is faking an org**m. ‘

To trick the polygraph, simply press your toes hard against the ground or concentrate on performing complex mathematical operations, so your stress levels and nerves would be so high whenever you would overshadow the test. 

The lie detector, in short, is not a reliable instrument to know the truth, or at least in its entirety and use it for a certain purpose, such as in a trial. It can serve to pressure, intimidate, or lead one to believe that a reliable result has been obtained to make the accused confess but never support the full weight of a sentence in the outcome of a test.

Would you be ready for a polygraph interview?

To get to the polygraph you have to overcome several filters. It is very unlikely that from the first appointment in a company they will make this evaluation. Regularly, you must first talk with Human Resources, then with the person in charge of the area in which you want to work and finally with a specialist who manipulates and interprets this instrument.

Polygraph interviewing is common in government organizations, but not in the private sector. It is expensive and it needs a specialist to perform it, for the same reason not all candidates come to it. 

Companies that handle high-value securities or jewellery or materials are the ones that apply it: they need total trust in their employees. For what positions? Drivers, custodians…

However, it can be used for any position. If one day, by the chance of fate, you are about to do such a test, it is essential that you clarify everything. How many questions, which ones, why. You must sign a document in which you agree.

Everything discussed in the session stays there. In the end, the polygraph designer will only present a report stating whether or not the person is fit to work in the company.

So take it easy, you are free to tell the truth. You even need to do it. 

It is uncomfortable? Maybe at first yes.

Invasive? Yes, that is why you must sign and consent to whether or not you accept this type of interview.

Legal? Yes.

Infallible? Not.

Funny? It depends.

Strange? Clearly.

Different from any other selection process? Of course.

FAQ on Can you fail a lie detector test if you are nervous

Conclusions

In this blog post, we talked about lie detectors, also known as polygraphs. We debated whether you can fail a lie detector test if you are nervous, and gave you some tips to prepare for a polygraph test. 

Is there any safe way to investigate, interrogate, or test with the polygraph (or a combination of the three) that can clearly prove when a person is lying? 

No, because neither the polygraph test nor the interrogation procedures record the lie, but the physiological and psychological reaction to certain stimuli and the variables depend on several factors: accuracy and quality of testing, professionalism of the investigator, physiological reactions of the respondent, etc.

Even if the practice of lying detector testing fascinates everyone, after almost a century of scientific research, the veracity of the results of polygraph tests cannot be confirmed. Thus, you can fail a lie detector test if you are nervous, calm or even if you didn’t know you were taking a lie detector. 

If you have any questions or comments on the content, please let us know!

References

M. Ganapati, D. Prakash, M.S. Ramadurg, Scientific and legal procedure of polygraph test, Journal of Bio-Innovation, vol. 2, no. 1, 2013, ISSN 2277-8330.

Commission for the Evaluation of the Scientific Evidence of the Polygraph, Lie detectors and detection,

Scientific Validity of Polygraph Testing: A Research Review and Evaluation; A Technical Memorandum. Washington, D. C.: U.S. Congress; Office of Technology Assessment, November 1983

Reid.com

newyorker.com