Are Lie Detector Tests Fool-Proof?

Everyone loves watching crime shows on television. One of the coolest things about these shows is the way they gather evidence. I’ve always been interested about the accuracy of those lie detector tests that they use. The results aren’t admissible in court, but police still use them to interrogate their suspects. But how do these things even work? I’m a pretty good liar, would I be able to pass one?

When you first get hooked up to a polygraph, they stick four to six sensors onto your body. These record your breathing rate, pulse, blood pressure, and perspiration. The theory is that when people lie, their bodies react to it.

When the test begins, the person administering it will ask a series of baseline questions. These are questions that they know the person won’t lie about. Like name, family member’s names, simple things like that. This is to record what a person’s body looks like when it is telling the truth. has a whole bunch of useful information about this.

Then the real questions start. The examiner will ask the things that the detectives want to know, and all of the responses are recorded into a log. The polygraph will be recording all of the sensor data onto a rolling chart. Anything like a faster heart, higher blood pressure, or increased perspiration can be seen as an indication of lying.

A highly experienced examiner will be able to read the results and determine with a good amount of accuracy whether or not the subject was lying. Although this isn’t a fool-proof method.

Like I said at the beginning, I’m a pretty good liar. People have been known to fool these machines. Military members are trained to do it. The machine can only record your body’s response to the questions. If you actually believe you’re telling the truth, it won’t know that you’re lying. This is how sociopaths can beat these machines. They actually believe in what they say.

You can’t use the results of these tests in a court of law, either. They are simply tools that the police can use in order to gauge whether or not they are heading in the right direction. It’s also pretty handy to use on spouse or family member. There are even lie detector apps out there that claim to be able to record the same things. Although you’ll never really get the same accuracy with an app as you would an actual polygraph. It could still be fun to play around with.

Some places offer their services to the general public as well. A lie detector test is not only for the police. You can book an appointment and go have a conversation with a licensed professional and talk about your lie detecting goals. Do you want to catch a cheating spouse? Find out what happened to your lawn mower? Just remember, that these things are not 100% accurate. They are just the most accurate thing we have so far to find out when someone is lying.