The Truth and Lies of Lie Detecting – by Len Nieuwoudt

Posted on January 22nd, 2018
Categories: News

A popular lie about lie detection is that it is able to detect lies. In fact, lie detectors, or polygraph machines can’t detect lies, but actually measure nervous excitement. Why do we say a polygraph can’t detect when someone is lying? Because that would suggest that every person is the same, and there is one magic ingredient engrained in all of us which, when triggered, acts as a dead giveaway. It’s simply not the case.

A polygraph machine operates on the premise that if a person is telling the truth, he or she will remain calm. We always hear about polygraph tests all the time in court cases, police investigations and even when someone applies for a job. The goal of lie detection is to test whether a person is telling the truth or not when answering specific questions.

When someone sits down for a polygraph test, three to six devices are attached to the tips of his or her fingers. A polygraph is a piece of equipment, which records numerous “poly” signals deriving the devices on a single piece of moving paper, or the graph. These sensors normally record the following:

  • The individual’s pulse;
  • The individual’s perspiration;
  • The person’s blood pressure; and
  • The individual’s breathing rate.

At times, a polygraph can also record aspects such as leg and arm movement.

How Is A Polygraph Test Conducted?

When a lie detection test starts, the technician usually asks four to five simple questions as a way of establishing the norms of the individual’s signals. The real questions then follow. Throughout the questioning process, all of the individual’s signals are recorded on the graph paper.

Both throughout and after the polygraph, the technician can study the graphs to determine whether the individual’s vital signs have changed exponentially on some of the inquiries. Generally, a big change, like higher blood pressure, sped up heart rate or increased perspiration can be indicative that the individual is lying.

When seasoned and professional examiners makes use of a polygraph machine, they can rather accurately detect lying in a person with incredible accuracy. However, as the examiner’s interpretation is subjective, and due to different individuals responding differently to lying, a lie detection test isn’t perfect.

Why Would You Want to Employ a Polygraph Test in Your Business?

Many employers use polygraph tests in their businesses, for many reasons. It’s not to say that you don’t trust your workforce, or that you suspect them. You could even use this method as part of a recruitment drive when looking to hire candidates who will be in a position of authority, or who will be working with sensitive information for your business.

There are a number of other reasons why businesses use polygraph testing in their operations too, including:

  • Having sufficient suspicion an employee was involved in illegal activity;
  • The employee in question has access to the property where the incident took place;
  • The employer is struggling with an increase in alcohol, drug or fraudulent behaviour within the company;
  • The employer is in the process of promotions to management positions and needs to know that they can trust employees with high-level confidential information; and
  • To instill a high level of honesty within the business and to enforce the company’s policies and procedures with regard to company information.

It’s important to note, under no circumstance can you force an employee to take a polygraph test unless they give written consent. In asking if they would take the test, you need to inform the person that it’s voluntary, and they can stop at any time.

The results of the polygraph test can’t be used as the only evidence when trying to prove guilt, it needs to be used as a means of confirming the evidence you gathered already. As there are currently no laws protecting employees when it comes to lie detection, these results alone will not be sufficient in a hearing.

As the rate crime is increasing, businesses all over the world are doing everything they can to ensure the business as well as its intellectual property is protected. One of the ways to achieve this is to introduce the use of lie detection into the work environment. This helps make businesses a stronger unit in an insecure world and sift out any nervous excitement that might be hindering business operations.

Author Bio:

Len Nieuwoudt’s years’ of experience since 1989, in the SAPS(South African police Service) and the security industry his company Secure Polygraph Solutions was established in 2012. When Len isn’t performing lie detector tests he like to ride his bike on long journeys in and around South Africa.