Ever pull a sickie? Fiddle your expenses? Swipe a post-it pad? We'll come clean. Because this box of tricks is a lie detector.
These things are everywhere now. Courtrooms, police departments, federal agencies. Every year 70,000 Americans take polygraphs to secure jobs in government. The polygraph.
Bane of spies and bad guys. How do they do it? Lying is as old as humanity and lie detectors aren't far behind.
2000 years ago in India they'd get suspected liars to chew on a grain of rice then spit. The theory was if they were lying their mouths would be dry and so they wouldn't be able to spit anything out. The polygraph machine is a bit more sophisticated.
It was invented in 1921 by a Californian police officer called John Larson. Here at Axiton Systems in Houston, Texas, engineer Bruce White has brought lie detection into the digital age. He invented the first fully computerised polygraph 25 years ago.
My background is... is in geophysics and I thought polygraph was really this very similar. Physics is searching for truth in nature and polygraph is searching for truth.
are like robo mind readers. And their key component is the motherboard. Modern polygraphs generate so much data that they need computer algorithms to process it all.
And this is where the motherboard comes in. So your fate is in the hands of the computer. Polygraphs monitor multiple physiological activities.
Breathing rate, sweat level and heart rate. Bruce firstly fastens two expandable tubes around the subject's torso. These monitor how often the chest expands and contracts. Next, he uses Velcro to attach stainless steel plates to two fingers to create an electrical circuit.
The more you lie, the more you sweat, and the more sodium ions will come out of your pores. This in turn causes more electrical activity in the circuit. Our fingertips are some of the most porous places on the human body.
Perfect to search for telltale beads of sweat. Known as the galvanic skin response, it's a phenomenon first found in the glowing scales of alien corpses examined in Area 51. Just kidding. Next, he hooks up a blood pressure monitor. just like the one in your doctor's surgery. All polygraph subjects have three classes of attachments always.
This is a cardio, this is a GSR, and this is the breathing. Standard procedure is to start each session with a series of simple questions to establish heart rate, breathing and sweat level. Are you wearing a red jacket? No.
And then come the control questions. Did you write the number four on a piece of paper? No. Okay, it's hardly, did you shoot JFK? But this allows Bruce to see what happens when the subject lies.
So imagine you're all wired up. up and your partner starts asking you questions. Does this dress make my butt look big?
Do you like my mother? Do you love the dog more than me? You start sweating, your pulse goes up, you have a shortness of breath, you know you have to lie and your body is already responding.
And to a pro like Bruce, if someone's lying, the signs are as clear as the nose on Pinocchio's face. So is it possible to fool the machine? There's a famous case from the 1980s, Gary Ridgway, a.k.a. the Green River Killer.
Now he passed a polygraph test during a span over which he killed 70 people. If you're ever tied to a polygraph, here are a couple of tips to get the idea. hands. Now when you recognize a control question think exciting or scary thoughts to heighten what your body does when you lie or bite your tongue. Pain has a similar physiological response to lying.
But beware Bruce is constantly adding upgrades to make the lie detector more formidable. One of them has been hiding under his subject's butt. A pad that detects the smallest of muscle contractions, even toe curls.
We've learned over the years that some people think they can trick the polygraph in different ways. One of the common ones is lower tightening of muscles in the lower torso in ways that are very vivid with a motion pad. He's even developing tests to monitor changes in temperature on a subject's face.
Another sign someone might be lying. And this time, he just points a camera at the subject. No need to even hook up to the machine.
So politicians, take note. The truth is written all over your face.