How Polygraphs Work and One Reason Why They’re Not Trusted

A lot of high profile people pass polygraph tests…but how accurate are these polygraphs?

By Lydia Richins, Marketing —

Talk of the traditional polygraph test has recently become a rising subject of interest. It’s hard to miss headlines shouting that Stormy Daniels passed a polygraph test about sleeping with Donald Trump. With this news, more attention has turned to the test. Citizens wonder, “How does the polygraph detect lies? Can the results be trusted?”

The Science behind Polygraphs

The polygraph is based on the idea that lying causes stress and stress has physical symptoms that can be measured. Some of the symptoms a polygraph monitors are breathing, heart rate, blood pressure, sweating and twitching. A polygraph proctor starts by asking baseline questions such as “Are you human?” Then as the proctor starts asking serious questions, he or she will compare the response of the new question to the baseline question to find any noticeable changes. Studies have found the polygraph to be 87 percent accurate.

The Doubts behind Polygraphs

Although there are many arguments against the polygraph, the main one is that stress isn’t only manifested when someone is lying. The polygraph could fail someone if they’re feeling fear, rage, embarrassment, or even pain from the cardio cuff. The proctor alone can affect someone’s stress level just by the tone of voice he uses when asking questions. The bias from the proctor can label an innocent subject as guilty.

A Polygraph Alternative

The polygraph has been the king of lie detection for nearly 100 years. However, a new eye lie detector technology might take its place. It’s called EyeDetect®. It’s a small tablet with an eye scanner attached. Subjects take a 30 minute true/false test (as opposed to a two to three-hour polygraph examination) and the scanner measures eye movement and pupil dilation. Then the information is analyzed through the eye detection software technology to verify if there was deception detected. This eye lie detector can detect deception or honesty with the same lie detector test accuracy as a polygraph. However, with EyeDetect, there is not proctor bias and takes one-fifth the time. It truly is the future of lie detection.

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Photo by / Chris Liverani