Lie Detector Tests: Are They Admissible in Court?

Lie detector tests have their uses. The police use them in a variety of cases. Lie detector tests, also called polygraph tests, have been around and in use for decades.

Before you submit to a lie detector test, though, you might want to pause and think about whether that’s the best idea if you’re suspected of having committed a crime. You can always refuse such a test. You might also be curious about whether the results of such a test are admissible in court.

We’ll answer that question in the following article.

What Exactly is a Lie Detector Test?

A lie detector test, as the name indicates, is a test that determines with reasonable accuracy whether you are telling the truth or not when you are asked direct questions about something. Also known as a polygraph, this test measures your body’s involuntary physiological changes when you are asked questions about something and when you respond to those questions.

Your body will react through factors like your skin’s conductivity, whether you perspire or not, and whether your heart rate rises or remains the same. The person interrogating you will start with some harmless baseline questions, and they will then move on to queries about the crime that you have supposedly committed. 

Are They Always 100% Accurate?

Lie detector tests sound great, in theory. If the police or investigators could ask someone whether they committed a murder, for instance, and the person failed the lie detector test, they would know they had caught the culprit right there.

In reality, lie detector tests sometimes fail. There are ways that people have beaten these tests, and these countermeasures render such tests fallible, to say the least. This does not mean that the tests fail all the time, but if someone is able to control their physiological responses, they might be able to beat the test and further establish an alibi, even if they actually committed the crime.

Are They Admissible in Court?

Lie detector tests are sometimes admissible in court, but not always. Some states allow the results to be used against a defendant, while some do not. Some detectives, criminologists, and other individuals who try to catch criminals feel that they are a useful tool, while others don’t think they have any real practical application.

These tests have inspired controversy since the moment they were first introduced into the law enforcement community. In a state where the results are allowed in court, they might be just one of the factors that the prosecution will use to try and convince a jury of a defendant’s guilt.

However, because they have been proven not to work so many times, they need to be put into the proper context. Most juries would not convict a suspected criminal based on the results of such a test alone.

Anyone who is asked to take such a test can refuse. Not every suspected criminal knows that, though, which is why so many of them still submit to these tests.