Is a Lie Detector Test Accurate?


The polygraph (also known as a lie detector test) measures changes in heart rate, breathing, and perspiration. It is based on the theory that liars have different physiological reactions than truth tellers do.

The accuracy of a polygraph depends on how it is administered. Some experts say that it is only accurate if the questions are well-formulated and the examiner is well-trained.


A polygraph (or “lie detector”) is an instrument that monitors changes in a person’s blood pressure, heart rate, respiration, and perspiration — reactions that supposedly occur when someone is lying. It’s a form of psychological arousal testing that is often used by employers to evaluate job applicants, police departments to interrogate suspected criminals, and lovers and spouses to settle alleged infidelity.

However, the accuracy of a lie detector test is disputed by many scientists. According to a recent Wired article, the technology is “pseudoscientific hokum” and is often subject to racial bias. In addition, experts warn that the tests can be tainted by the examiner’s personal bias and prior suspicions. This can lead to false positives, which are mistakes that suggest that the subject is lying even when they’re not.

Types of questions

When a person takes a polygraph test, the examiner asks both “control” questions (such as age, eye color and height) and “relevant” questions related to a crime under investigation. The physiological responses recorded during these questions are compared with each other to determine if the subject is lying.

While some medical conditions and certain medications can make a person’s responses less reliable, these factors don’t allow people to lie during the test. However, sociopaths and psychopaths may be able to control their reactions to some of the questions.

In these cases, the examiner will have to ask more relevant questions in order to find a match. This can result in longer test times. Some people also may be forced to answer questions that are embarrassing to them or otherwise difficult.


A polygraph or “lie detector” is a device that monitors changes in a person’s physiological responses to determine whether they are telling the truth. It is often used to screen job applicants and interrogate criminal suspects.For more info, do visit this website Lie Detector Test Price.

The test is based on the assumption that liars will display more stress-related signs than truth tellers, such as increased heart rate, blood pressure, and perspiration. A examiner will ask a series of questions that include both relevant and control (irrelevant) questions. The examiner will then watch as the subject’s responses are recorded on a graph.

While the results of a lie detector are not admissible in court, it can help investigators build their case. However, it is important to know that the test can be skewed by certain medications and medical conditions.

False positives

Lie detectors are prone to false positives, which can occur when someone lies while actually telling the truth. This is a big reason why they are generally not admissible in court.

The test relies on interpreting the subject’s physiological responses to questions. However, this can be influenced by several factors. For example, when a person is nervous or anxious, their heart rate and blood pressure may elevate. This can cause them to appear deceptive on the polygraph results.

Also, the examiner’s preconceptions can influence the results as well. For example, if the examiner believes that you are guilty, they will likely ask more difficult questions that will elicit an elevated reaction from your body. This will also affect the accuracy of the results. Therefore, it is important to find a trained and experienced examiner to administer the test.


Since the early 20th century, a number of techniques have been used to try to detect deception. Most of these involve measuring physiological indicators like heart rate, breathing rate, and galvanic skin response (sweating). In most cases, a subject will answer a series of questions while the polygraph is assessing their responses. These questions typically include relevant, irrelevant, and emotionally charged control questions.

While many people claim to be able to beat the test, it is not very easy. There are a few tricks that can be used, but most of them won’t be very effective. Biting your tongue or putting a tack in your shoe won’t change your blood pressure or perspiration levels, and imagining the truth when lying won’t work either because it won’t establish differences between lies and the truth.