The facts you veed to know about Lie Detectors and their reliability

There are times when you need to ascertain if somebody is telling the truth or not. There are people who are good at telling lies. Sometimes, there are also cases of one person’s word against another. A lie detector test or a polygraph test can be helpful in these instances. The test is considered to be essential for matters that concern security, crimes, and personal affairs.

What is a Lie Detector Test?

Lie detector tests, commonly referred to as polygraph tests, measure and analyze key body reactions through a series of “yes or no” questions. Based on the person’s body reactions as he answers the questions, these tests can tell whether a person is telling the truth or is lying.

The body reactions refer to the physiological functions of the body. These are subconscious reactions to circumstances. These are conditions that a person cannot control all at the same time.

The main physiological functions that the lie detector tests measure are:

  • Respiratory activity (by placing rubber tubes or sensors on the chest and abdominal area)
  • Cardiovascular activity (by wearing a pressure cuff)
  • Sweat glands activity (by attaching metal plates to the fingers)

Any changes in these activities such as faster heart beats, higher respiratory rate, increased sweat activity, or the combination of those may indicate that a person is telling a lie.

How are the Tests Done?

In order to obtain results with high accuracy from lie detector tests, the entire process is subdivided into three phases:

  1. Pre-test Phase
  2. Chart Collection Phase
  3. Analysis

During the pre-test phase, this is where the reactions of the examinee are ‘calibrated’. This phase provides the baseline reactions of the examinee when he is telling the truth and when he is lying.

The examinee is first asked questions that are emotionally neutral to assess how he reacts normally. This may be obvious things that relate to the examinee such as his name and gender.

Next, the examinee may be asked about things that will prompt him to tell a lie so the examiner can record the response of the person when he is lying.

In the chart collection phase, the examiner asks a series of questions that are particular to the incident or situation that is under investigation.

The person’s reactions to these incident-specific questions are then compared to his responses to the baseline questions. Higher biologic reactions to answers to key questions may suggest that the person is telling a lie.

Lastly, in the test analysis phase, the examiner then makes a decision on whether the person is lying or not.

Can You Make the Truth a Lie?

It may be important to note that lie detector tests are not foolproof systems. In certain circumstances, their results may also be affected by different factors such as:

  • The subjective analysis of the examiner. Sometimes, it may result to false positives (a truthful person being judged as deceptive) or false negatives (a deceptive person being falsely identified as being truthful)
  • The methods through which a person can beat the test. There are sites claiming that a person can mask his reaction when lying. Here are two of the common methods that supposedly influence the results of polygraph tests:
    • By leveling up his baseline reaction – this is done by holding breath for a few seconds before answering the questions. This way, his baseline reactions will always have higher scores in the charts no matter what questions may be presented to him later on.
    • By creating distractions such as biting the cheek or anything that induces pain – pain alters the body’s reactions as the examinee answers the questions. His body would then have mixed reactions to both the pain and the questions he is being asked.
  • The impact of anxiety while taking the test. It is understandable to be stressed when you are asked to take a polygraph test. But, you have to know that the results of the test could be adversely affected if you are in an anxious state. The results could show that you are lying even if you are actually telling the truth.

There are ways to compensate for these factors that could affect the results of polygraph tests. You can minimize the possibility of inaccurate results by taking the following steps:

  • Choosing the right lie detection services provider.

You need to find a company that has established a track record in the industry and has skilled examiners with years of experience doing these tests.

Those who have the education and experience in polygraph tests know how to detect and handle any situation that may affect the accuracy of the test results.  Also, these experts can analyze the chart results more accurately.

  • Be familiar with the latest technology in digital polygraphs and advanced techniques.

Newer machines are more accurate than the earlier polygraph machines. Scientists and psychologists have worked together to come up with new machines and methods to make the results of polygraph tests more accurate.

The company you hire to do your polygraph tests should have machines and equipment that employ the latest technology for increased accuracy and reliability of results. More sensitive digital polygraphs or electronic sensors are now being used by some lie detection companies.

Despite the doubts that surround the use of lie detection systems, the American Polygraph Association emphasizes that the accuracy of these tests can reach as high as 90%. With advancements in technology, it can be expected that more machines and techniques will be designed to significantly increase the overall accuracy and reliability of polygraph tests.