It’s a scenario familiar to all parents: You put your child down in her crib so you can do the dishes or get some other household chore done. She immediately becomes hysterical. You can hardly focus on the task at hand with all of her crying. Eventually abandoning your fruitless efforts, you start walking toward her and she puts her arms up, begging to be held. As soon as you give in and scoop her up into your arms, the crying stops. Peering at her cheeks, you notice there isn’t even a hint of tears. Believe it or not, your child just deceived you. 
According to Dan Ribacoff, a private investigator, credibility assessment expert, and polygraph examiner, children learn to deceive their parents when they’re as young as 2 months old. “[Children] learn at a very young age, ‘Hey, I’d rather be in mommy’s warm arms than in this cold bed,’” he says. So they turn on the fake waterworks to get what they need.
Why We Lie
Ribacoff defines deception as anything that might be seen as deliberately misleading: lying, trickery, and even telling “white lies” to make oneself look better. According to Ribacoff, there are three main reasons people lie: “They don’t want to hurt you, they don’t want to look bad, or they want to scam you.”
“In an average 10-minute conversation, a person will lie at least one time.”
For instance, if you ask someone what they think of your new jacket, they might hate it but tell you they like it to spare your feelings. Or someone who wants to look more impressive in front of peers or a romantic prospect might say they are the manager of a business when they’re really just assistant manager. And then there’s someone like Bernie Madoff, who can create an entire scheme just to defraud others. 
While it might seem like a big jump to go from innocently commenting on someone’s clothing to Bernie Madoff, it’s all part of the same process. “Deception is part of survival,” Ribacoff says, “and that instinct is built in.” In fact, he says that deception is so ingrained in us, “In an average 10-minute conversation, a person will lie at least one time.” And so finding out whether you’re being lied to becomes a survival mechanism as well. “Everyone needs to know if they’re being told the truth,” Ribacoff says. “You have to protect yourself against being victimized by people that will deceive you.” 
The ability to discern truthfulness keeps you from spending a lot of money on a product that turns out to be a scam or from meeting someone from the internet in person who may be a serial killer. Everyone has human intuition that alerts them if they think someone isn’t being completely honest.
Trust your gut. Or not.
But too often, Ribacoff says, we want to believe the best about people, so we wind up suppressing that intuition. “We have human intuition built into us from caveman days—fight, flight, freeze, or surrender,” he says. “And people wind up killing that [intuition], and that’s how they become victims. They’ll actually turn their own radar systems off.”
“When you give me the truth, your brain is not working very hard, because it’s accessing information that is already there or not there. When you want to lie, your brain must work harder.”
So how can you tell if someone is being dishonest? Ribacoff says that there are physiological changes that happen in your body when you lie. The polygraph machine is an instrument that was created to measure these changes. 
“The polygraph is actually several medical instruments that were put together to detect physiological changes that take place in the human body when a person lies,” Ribacoff says. “The truth is in your memory. Your memory is like the hard drive in your computer—record found, no record found,” he explains. “When you give me the truth, your brain is not working very hard, because it’s accessing information that is already there or not there. When you want to lie, your brain must work harder. You have to create the lie, usually by accessing information that is already in your brain, and mixing the two: lie and truth. And then you have to express the lie in a way that seems credible.”
Brains and Lies
Ribacoff says that magnetic resonance imaging (MRI) scans show that when someone tells the truth, they use only about seven parts of their brain. But when they lie, they have to use about 15 parts of their brain.
“Your brain really goes into ‘rev the engine’ mode when you lie.”
He compares the experience of watching a polygraph machine work to watching a mechanic check a car engine. “Your brain really goes into ‘rev the engine’ mode when you lie,” he says. 
In fact, the human brain and a car motor are actually quite similar in what they need to operate. Just as an engine needs fuel, oxygen, and cooling to run properly, the brain needs blood, oxygen, and cooling. “When you lie, you call for more blood, your blood pressure increases, your heart rate [increases], your oxygenation of that blood has to increase,” Ribacoff says. “And your sweat glands have to activate, otherwise your brain will overheat.” These bodily changes, all medical in nature, are how the polygraph does its work. “You can’t feel it, you can’t control it. But we can measure it.” Obviously, you’re not going to be able to hook everyone you suspect of lying up to a polygraph machine. Even if you could, you wouldn’t want to. The process is tedious. A lot of preparation goes into a polygraph interview, and the test often has to be done three to five times. And although it’s not true that a polygraph machine can be “beat,” it is possible to deceive an inexperienced examiner.
“There’s only one reason to try to beat a polygraph test: You’re lying!”
“There is no way to beat a polygraph instrument,” Ribacoff says. “[But] you can defeat the examiner.” The internet is full of misinformation on how to “beat” a polygraph. “Really, none of it works, because an experienced examiner will see that [the behavior is] not natural,” says Ribacoff, adding, “because there’s only one reason to try to beat a polygraph test: You’re lying!”
Low-Tech Detection
So for someone who doesn’t have a polygraph, how can they detect mistruths in someone they’re talking with? Ribacoff says there are a lot of telltale signs that can give someone away. All of these behaviors are what polygraph examiners look for when interviewing a subject. To start with, latency, hesitancy, and repeating the question usually means the subject is trying to fabricate their answer. “Repeating the question allows for time to fabricate the lie,” Ribacoff says. “A lot of ‘ums’ and ‘non-ums’ [show] hesitation also.” 
There’s body language clues, like if a person is sweating or shaking or if they cross their arms. That’s usually out of a self-conscious desire to protect themselves. “If someone’s sitting in front of you, they will actually lean back and perhaps stretch their legs out, to try to get maximum distance between you and them,” Ribacoff says. “If I ask you a question, and within five seconds you shift positions in your chair, I’ve made you uncomfortable.” All of these signs are ways to polygraph with your eyes and ears. Ribacoff adds that someone who’s lying will often either not answer the question or blame someone else. “Touching your nose also means, ‘what I’m telling you stinks,’” Ribacoff says. “These are all ways that humans are programmed. The sensory portion of the brain goes towards the nostrils when you say something that smells like crap.” 
The best way to detect deception, however, is through written or spoken language. Examiners will often ask for written statements and look for the details a person includes or neglects to include. This process is called SCAN – Scientific Content Analysis. Ribacoff told the story of a woman who was accused of causing serious harm to her husband but kept referring to him as “Mr. Smith.” “Who the hell calls their husband ‘Mr. Smith?’” This lack of pronouns, he says, allowed her to dehumanize the situation. Even with these telltale signs, finding the truth can be complex. For Mary (not her real name), a former judge and arbitrator in the Chicago area, finding the truth in the courtroom was her profession. In a courtroom, she says, “each side is doing its best to distort the truth in its favor. …This is very unlike the medical scenario, where everyone is trying to find the right answer and working collaboratively to find it… So in the trial arena, the fact finder is always very suspect of anyone who has something to win or lose in the trial.” For Mary, it was rare to see visual or auditory signs that made it clear someone was lying. 
“Personally, I always found it difficult to just decide that someone was telling a lie by just looking at them and listening to their testimony in a vacuum,” she says. “A number of court reporters over the years thought that they could make that determination. I never questioned them about their opinions. But I’ve always wondered whether their position in the courtroom was helpful. By that, I mean their actual physical position, because they are in front of the witness and watching them as they transcribe their testimony.”
“People want to confess.”
Mary says that knowing whether she made the right decision over credibility assessments was one of the most difficult aspects of her job. “At the end of the day, it was very hard to say, ‘I got that right,'” she says. “You have to just make your best judgment, and I imagine I got it wrong from time to time. I imagine most people get it wrong from time to time.” Still, Ribacoff maintains that if you take your time and are patient, you can get to the truth eventually. Guilt is a powerful motivating factor, and people want to share the truth. “People want to confess,” Ribacoff says. “There’s a saying in SCAN: ‘Everybody wants to tell you everything, you just have to be able to get them to tell you.’”
