Have you heard the rumors online that polygraph exams might not provide accurate results? There are stories littered across the internet stating people have proven methods for beating the polygraph and that the lie detector test found them acting deceptive when they were telling the truth. Is there any substance to these claims?

The reality is the outcome of the polygraph exam can affect your career, livelihood, and reputation if you experience a failed result. Is it worth taking a polygraph, or should you risk it and comply with your employer’s polygraph policy?

After all, according to “The Employee Polygraph Protection Act of 1988” (EPPA), you have the right to refuse a polygraph request by your employer. What are the chances you could fail the lie detector test if you’re innocent, and what happens if you receive a failed result? Is there any way to beat a polygraph exam and influence the results?

This post answers all these questions and gives you a real insight into what to expect from the exam and why it might not be accurate.


Understanding How Polygraph Technology Works

The polygraph is a highly-refined device developed over more than a century by doctors, psychiatrists, and human behavioral specialists. The first modern devices, invented by John Larson, appeared in the early 1920s, with Larson’s colleague, Leonard Keeler, advancing the technology and its functionality.

The “Keeler” polygraph became the industry standard for the device for nearly 70 years before being replaced by systems incorporating software and computerized technology into the device in the 1990s. Today’s modern polygraph device is a finely-tuned apparatus operated by well-trained professional examiners.


Instrumentation and Software

The polygraph incorporates instrumentation and software that measure and track the body’s physiological responses. The instrumentation involves corrugated rubber tubes placed across the chest and abdomen to measure heart rate and respiration.

A blood pressure cuff and sensors are mounted to the fingertips to collect data on skin and sweat gland activity. Some models also incorporate the use of motion sensor pads on the examinee’s seat to detect movement.

These instruments connect to a control box, feeding data to software on the examiner’s laptop. The information displays in chart format, giving a real-time reading of the examinee’s physiological response to the examiner.


The Examiner

The polygraph examiner undergoes extensive training at university and polygraph school before undertaking an internship with a polygraph company where they sit in on real tests. When they complete their training, the examiner starts conducting tests themselves.

The examiner has the role of ensuring the company hosting the polygraph policy complies with the regulations outlined by the EPPA. They also assist with making the examinee comfortable in the test environment, answering their questions about the procedure to put them at ease.


The Fight-or-Flight Response

The polygraph device operates by looking for activation of the “Fight-or-Flight” (FoF) response in the examinee when they answer questions directed by the examiner. Our peripheral nervous system is host to the autonomic nervous system, which has two parts – the parasympathetic nervous system (PSNS) and the Sympathetic nervous system (SNS).

It’s the SNS that’s responsible for initiating the FoF. It does so to protect us from a threat, preparing us to escape it or stand and confront it. The SNS activates the FoF during the polygraph test when we have to lie to protect ourselves from the possibility of being caught out doing something wrong.

The polygraph device and examiner look for the activation of the FoF by the examiner when asking them questions, assessing their reaction through the software to determine if the subject is lying or acting “deceptively.”


The History of Inaccuracies in Polygraph Testing

The introduction of the polygraph device was a game-changer for law enforcement in the 1920s and 1930s. Finally, detectives had the means to prove if a suspect was lying or telling the truth in their statements. The device was so successful it led to a marked increase in conviction rates during the next 40 years.

When coupled with the progression of questioning techniques, the polygraph proved invaluable for law enforcement organizations to get criminals off the streets. However, the 1950s and 1960s saw an uptick in alleged criminals stating the [polygraph was inaccurate and questioning techniques used by examiners we unethical.

In several cases, polygraph results led to the wrongful conviction of innocent people, causing the US government to reconsider its role in law enforcement cases. Around this time, the polygraph also entered the private sector, with employers using the device to assist them with pre-employment screening and on-the-job testing of their candidates and employees.

Unfortunately, like with law enforcement, employers began to misuse the device. They would use the polygraph to prevent hiring undesirable candidates and fire employees they didn’t want at their organization.

These unethical practices led to President Ronald Reagan implementing the EPPA in his last stint in office. Many experts suggested that the Keeler polygraph only produced accurate results 60% to 70% of the time, creating speculation about the device’s efficacy and the results it produced.

The early 1990s saw computerized systems and software integration into the polygraph. Over decades of development, polygraph accuracy dramatically improved, but the law didn’t change to accommodate these improvements.

The modern polygraph is by no means a flawless device, and there are a few reasons why it might produce inaccurate test results.


5 Reasons Why a Polygraph Test May Not Be Accurate


#1 A Nervous Examinee

The examinee presents a weak link in the polygraph process. Everyone reacts differently to the pressure placed on their nervous system during the test. Some people are more anxious than others, to the extent of developing an anxiety disorder, requiring them to be medicated by a physician.

If the examinee is a naturally nervous person, they’ll experience a higher degree of anxiety surrounding the polygraph exam. As a result, they’re at risk of activating the fight-or-flight (FoF) response when they aren’t trying to be deceptive.

The pressure of the exam scenario might get to them, making them feel on edge and providing conflicting results and inaccuracies. However, most polygraph software modules and trained examiners can spot the difference between anxiety and deception in the polygraph results.

So, it’s highly unlikely that a nervous examinee could influence the outcome of the polygraph results, producing an inaccurate result. However, this scenario has occurred in the past, so we can’t rule it out completely.


#2 The Use of Countermeasures

Countermeasures are strategies deployed by the examinee before or during the polygraph exam. It’s possibly the most frequently and widely discussed component of beating polygraph exams and causing inaccurate results.

There are several technical terms for countermeasures used by professional examiners. However, for the sake of keeping this post as simple as possible for the layman, we can consider them to occur in three categories.

  • Information-based countermeasures.
  • Physical countermeasures.
  • Drug-based countermeasures.

Let’s unpack each of these to understand how they might cause inaccuracies in polygraph results.

Information-based countermeasures involve the practice of researching strategies like countermeasures online and in other resources in an attempt to beat the polygraph. For instance, the examinee might learn how to deploy techniques during the lie detector test to cause suppression of the FoF to the extent that the polygraph device doesn’t pick it up.

Physical countermeasures involve the practice of completing physical actions that interfere with the body’s response to the FoF. As a result, the polygraph device picks up mixed signals from the examinee, helping them escape deception detection by the examiner.

Drug-based countermeasures are the most commonly used strategy in trying to evade deception detection by the polygraph and examiner. Drugs like beta-blockers and Xanax help reduce levels of anxiety in the body. By ingesting these drugs before the exam starts, the examinee creates suppression of the FoF response, allowing them to evade deception detection.

However, the reality is that no countermeasures are proven to be effective against the modern polygraph. In the era of the Keeler polygraph device, there was evidence suggesting these countermeasures were effective. However, the sensitivity of modern software makes it all but impossible to use them in the exam and not have the examiner notice this behavior.


#3 Exterior Influences on the Testing Environment

The examination environment involves the examinee sitting to the side of the examiner, with a video recording device monitoring them from the front. No one is allowed in the exam room apart from the examinee and examiner.

However, the employer has the right to request to watch the polygraph session through a two-way mirror, provided they receive permission to do so from the examinee before the polygraph test. However, this practice introduces another element into the environment that could potentially sway results.


#4 Instrumentation Malfunctions

There’s a possibility that the instrumentation connected to the examinee could malfunction during the exam procedure, changing the results or failing to pick up the activation of the FoF in the examinee. Such a malfunction could sway the outcome of the exam results, either skewing them towards failure or passing.

However, after each polygraph session, the examiner maintains their instrumentation, ensuring it’s in working order. If they connect faulty instruments to the examiner, the software program assessing the physiological data will notify the examiner that they need to replace or service it.

It’s highly unlikely that malfunctioning equipment would be the cause of inaccuracies in the polygraph, but it’s not outside of the realm of possibility.


#5 An Inexperienced Examiner

The examiner is the final component of the polygraph process that may cause a failed result. If the examiner lacks the training or experience to assess polygraph results, they may interpret them incorrectly.

For instance, the examinee may be using a countermeasure like Xanax, and the examiner doesn’t have the skills to notice this behavior in the examinee or on the software module. However, this is highly unlikely that a professional examiner would make this mistake.

Polygraph examiners are highly-trained individuals. As mentioned, they undergo extensive training at university, in polygraph school, and through their internship. Examiners are well-versed in identifying the use of countermeasures by the examinee, and they know what to look for during the test.

While the examiner is a human and prone to making mistakes, it’s highly unlikely this would be the case. The examiner records the session, both visually and through their laptop software. If they’re uncertain of the outcome of the exam, they’ll ask a colleague to review the session and data.

The examiner doesn’t reach a conclusion on the session directly after the test. They’ll take the data back to their office to review it to see if they missed anything. During this review, their colleagues will assess the data if the original examiner is uncertain of the results.


How Accurate Is the Modern Polygraph?

The modern polygraph is a huge advancement over the Keeler model. Incorporating software and computers into the polygraph device considerably changed its accuracy. Experts suggest that the modern polygraph is up to 97% accurate.

However, there’s still that 3% possibility of it producing inaccurate results. The purpose of the polygraph is not to assess the examinee to see if they are lying. It checks their physiological feedback during questioning to see if the examinee indicates “deceptive” behavior.

In other words, is the examinee displaying behavior indicating they’re trying to hide something?


Can I Beat a Polygraph Exam?

Plenty of stories on Reddit and other online message boards state the polygraph is inaccurate, and examinees managed to beat it. However, there’s no firm evidence to suggest these people are telling the truth about their experience with the polygraph exam process.

If you ask a trained examiner or polygraph manufacturer about the accuracy of their software, they’ll claim it’s next to impossible to beat the polygraph, especially when combined with proven, effective questioning procedures.

The examinee would require total control over their nervous system and the fight-or-flight response to beat the polygraph. Since the FoF is an autonomic system, you can’t control it or the way it responds to environmental stimuli.

In short, you would need total control over your emotions to beat the polygraph, and people with this capability don’t exist


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