Most people will have to take a lie detector test at some point in their lives. They can be used in employment screening and by law enforcement.

A polygraph examiner records physiological reactions such as blood pressure, pulse and respiration as you answer questions. This is to differentiate between honest and dishonest responses.

False positives

Most polygraphs are based on measuring the body’s physical responses under controlled conditions while questions are asked. There are a number of different ways that you can affect the results to look like you’re lying, such as biting your tongue, using antiperspirant or even inflicting pain (like putting a tack in your shoe) to artificially raise blood pressure and perspiration.

Unfortunately, these methods aren’t foolproof and many examiners can spot covert attempts to beat the test. Some medical conditions also interfere with the test, such as mental illness or certain drugs. For this reason, it’s important that you disclose any medications you’re taking to the examiner before testing.

False negatives

Some people are able to pass polygraph tests despite being guilty of wrongdoing. This may be because they are extremely nervous during the test or because they have a natural tendency to answer questions honestly. This can skew the results and cause them to be inconclusive.

Some people use countermeasures to try and manipulate their responses, such as taking sedatives before the test or using antiperspirant on their skin to control sweating. This can skew the results, but it isn’t foolproof.

Mental illness and drugs can also skew the results and can make it difficult to accurately assess whether someone is lying or telling the truth. This can be dangerous and can lead to a miscarriage of justice.I recommend this website for more Octopus Referral.

Excessive stress

Whether you’re taking the test for a job interview or criminal case, being nervous can make your body react in ways that signal lying. This may include sweating, increased heart rate, and jittery movement.

These physical reactions are recorded by the machine and compared to your base readings. If they’re significantly higher than your baseline, the examiner will consider it an anomaly and assume you’re lying.

To avoid this, it’s a good idea to ask the examiner for questions to be repeated, and to take your time. Trying to rush will only cause you to become more anxious and may affect your results.

Mental illness

Psychiatric conditions, such as schizophrenia and schizoaffective disorder, can affect how the body responds during a lie detector test. These disorders can cause an increased heart rate, blood pressure and perspiration – all of which are interpreted by the polygraph as signs that a person is lying during a test.

This is why it’s important to understand that the polygraph doesn’t distinguish between lying and a stress response. Biting the tongue or putting a tack in the shoe won’t help to lower blood pressure or raise perspiration levels during the test. Neither will using hypnosis or imagining the truth while answering questions. Ultimately, there is no way to beat a polygraph test without first diagnosing and treating underlying mental illness.


Whether you’re accused of a crime or trying to get a job, being told you need to take a polygraph test is unnerving. But while the infamous polygraph pen has become a pop culture icon, most psychologists agree that these tests can’t detect lies.

Nevertheless, there are ways to fail a lie detector test that involve drugs and other medical conditions. Anti-anxiety medications, for example, can cause changes in heart rate and blood pressure that aren’t picked up on by the polygraph. These changes can skew results and make them less accurate. The same goes for some other drugs like cocaine, amphetamines, and methamphetamine.

Other medical conditions

Certain medical conditions, such as COPD (chronic obstructive pulmonary disease) or asthma, can also affect the results of a polygraph test. These conditions can lead to shortness of breath, which is often misinterpreted as a sign that you are lying. Additionally, some medications used to treat these conditions, such as albuterol, can increase heart rate and cause nervousness and shakiness.

Cardiovascular disorders, like hypertension, can also impact polygraph tests by keeping blood pressure higher than usual. However, this shouldn’t be interpreted as a sign of stress or deceit by an examiner. Additionally, trying to use tricks like biting your tongue or putting a tack in your shoe to control your perspiration will most likely fail.