Do polygraphs work and should we keep using them?

You’ve probably seen this device before.  This is a “polygraph” -- which is more popularly known as a lie detector test. But just how often it can catch you in a lie is shrouded in controversy.

Regardless, thousands of polygraphs are given each year in the US, alone, for everything from government clearance screening to witness verification. And the power of these machine’s results is not taken lightly. People have reportedly lost their jobs and even reputations over a failed exam. But how exactly does this machine work, and is it really as accurate as polygraph examiners claim?

To find out, we decided to put the polygraphs to the test ourselves. Polygraph results haven’t been accepted in most state courts since 1923. Mainly because:

Francis Shen: “The scientific research suggests that the polygraph has significant scientific problems. That is, it may not give us the level of accuracy, specificity, and sensitivity that we think it will, and that could be problematic.”

Still, many defenders contest that even though the polygraph isn’t 100% accurate, neither is DNA testing or eye-witness testimonies.

Lisa Gentile: "Do you intend to answer each question truthfully?"

Jessica Orwig: "Yes."

Now what the examiner may, or may not know, is that I’ve already told my first lie.

Lisa Gentile: "Have you used any illegal drugs in the last three years?"

Jessica Orwig: "No."

Lisa Gentile: "Did you ever commit a serious crime? Were you ever terminated from a job that you did not disclose? In your whole life did you ever do something you're ashamed of? In your whole life did you ever lose your temper? Are the lights on in this room?"

Ok, the test is over. Let's see if she caught my lie.

Lisa Gentile: "You're more relaxed, it goes down. Then when it begins here it goes back up again, so that's a lie."

So, yup, the polygraph caught me.

Now to be clear, this type of test is normally administered for a job interview, meaning the stakes are lower and the accuracy rate is lower. And it caught me anyway. But it’s hard to know if this is the case for your average person.

Even though I worked on controlling my breathing, what really got me was my increased heartbeat, perspiration, and blood pressure. So who knows what would have happened if I spent time learning how to maintain those things? And that uncertainty is pretty much why polygraphs aren't accepted in most states because it's known that people have and can beat the polygraph.

Francis Shen: “I’m of two minds about the polygraph. I have serious reservations about it use. But I can see that it might have some utility in some but not all contexts and I think we need to be pretty conservative and cautious about its use.”

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source http://www.businessinsider.com/do-polygraphs-work-lie-detectors-2018-3