Are Lie Detector Tests Reliable? Here’s What Science Says

From crime dramas to real-life courtrooms, polygraphs have captured our imagination for decades. But can a machine really tell if you’re lying?

Whether you’re a true crime buff or someone who’s actually facing a polygraph test, you’ve come to the right place. We’re about to dive deep into the world of lie detectors, unraveling the science, busting myths, and yes, even sharing some tips on how to ace that test (for educational purposes only, of course).

So, strap in as we explore the truth about lie detectors!

What is a Lie Detector Test?

A lie detector test, also known as a polygraph, is a device and procedure that can (allegedly) detect when someone’s lying while answering questions by picking up on a variety of physiological indicators in the body. 

Specifically, polygraphs monitor:

1. Your heart rate (Is your heart racing like you just ran a marathon?)
2. Blood pressure (Are you about to pop a vein?)
3. Breathing rate (Are you huffing and puffing like the Big Bad Wolf?)
4. Skin conductivity (Are you sweating bullets?)

The idea is that when you lie, these physiological markers change without your being aware of it. So while you might seem cool as a cucumber on the surface, your subconscious bodily responses might give you away! 

The kicker, of course, is that these changes can happen for all sorts of reasons. Maybe you’re nervous about the test itself, or you really need to pee, or you’re thinking about that embarrassing thing you did in third grade. The polygraph doesn’t know the difference—it just sees that your body is reacting.

That’s why examiners typically employ strategies involving control questions in addition to relevant questions (remember that from science class?). 

 Here are a couple common methods:

1. The Guilty Knowledge Test: This is one type of polygraph test where the examiner asks multiple-choice questions about a crime. The theory is that the guilty person would react to the correct answer being spoken aloud by the examiner, which can be compared to and differentiated from their baseline response to the incorrect answers. It’s like a really high-stakes game of “Who Wants to Be a Millionaire?”

2. The Control Question Test: This is the more common type. The examiner asks relevant questions about the issue at hand and control questions about other misdeeds. The idea is that innocent people will be more stressed by the control questions, while guilty people will be more stressed by the relevant ones. It’s like comparing apples and oranges, but with more sweat involved.
   
3. The Jimmy Kimmel Test: Alright, this isn’t actually a thing, but we really wanted to share this hilarious (and adorable) Jimmy Kimmel segment:

But even with these more rigorous methods, are lie detector tests foolproof?

Well, let’s just say if they were, we’d probably be using them a lot more often…

The Science Behind Lie Detectors

Alright, so the polygraph test is based on the idea that lying causes stress, and stress causes physiological changes. Sounds logical, right?

Here’s the rub: according to a landmark review^{1https://nap.nationalacademies.org/catalog/10420/the-polygraph-and-lie-detection} by the National Academy of Sciences (NAS) in 2003, there is very weak evidence for the validity of lie detector tests. Reviewing approximately 80 polygraph studies, the NAS found:

• The majority of studies were of poor scientific quality
• No statistical evidence for claims of over 90% accuracy made by proponents of polygraphs
• Even when studies did point towards polygraphs providing a better-than-chance detection rate, the level of error was still so high that they wouldn’t exactly be reliable pieces of evidence in a courtroom. Imagine being told that your parachute only has a 60% chance of opening up when you go skydiving—you wouldn’t take those odds, would you?

Dr. Leonard Saxe, a professor who specializes in deception detection, summed it up best in an interview with the American Psychological Association^{2https://www.apa.org/monitor/julaug04/polygraph.html} : “there is no unique physiological reaction to deception.” As such, any device predicated on measuring physiological responses will probably never be a foolproof lie detector!

Can You Outsmart a Lie Detector? (For Science, of Course!)

We’ve all thought about it: Can you pull a fast one on a polygraph? 

Well, given what we know about the rather dubious accuracy of lie detectors, there’s probably a pretty good chance you’d be able to fib your way through one without even trying anything special. 

But what if you wanted to really improve your odds?

While we absolutely don’t condone lying or trying to cheat on any official tests, we think it’s important to understand the limitations of polygraphs. So, let’s explore some methods people have tried to “beat” the test (for educational purposes, of course):

1. The Tack in the Shoe Trick: Some people believe that causing yourself physical discomfort (like a tack in your shoe) during control questions can elevate your physiological responses, making them similar to your responses during relevant questions. 

2. Mental Countermeasures: This involves trying to alter your mental state during the test. Some people try to think of calming thoughts during relevant questions and exciting thoughts during control questions.
   
3. Controlled Breathing: Some believe that controlling your breathing can help regulate other physiological responses.
   
4. The “I’m Just Nervous” Defense: Some people claim that being generally anxious about the test can throw off the results. It’s like blaming your sweaty palms on the spicy food you had for lunch.
   

Unfortunately, many of these methods are well-known to polygraph examiners. In fact, they’re trained to look for signs of countermeasures. It’s like trying to cheat on a test when the teacher knows all the tricks in the book.

So, while it might be theoretically possible to “beat” a lie detector, it’s not as easy as Hollywood makes it seem. And let’s be real, if you’re spending that much energy trying to outsmart a machine, maybe it’s time to rethink your life choices!

P.S. Are you looking to improve your people skills and make the most of your career? Check out our course: [Decode Push to Pschool]

Lie Detectors in the Wild: Who’s Using Them and Why?

So, we’ve talked about what lie detectors are and how they work (or don’t work). But who’s actually using these things in the real world? Let’s take a look: 

Law Enforcement

Many police departments incorporate polygraphs into their investigative toolkit. Ironically, though, these results typically don’t hold up in court. Imagine having a crystal ball that whispers secrets, but you can’t tell the judge what it said.

Here’s a clip of George Anthony, father of Casey Anthony^{3https://www.biography.com/crime/casey-anthony-muder-trial-timeline-facts} , undergo a lie detector test: 

Government Agencies

The FBI, CIA, and NSA have integrated polygraphs into their hiring process. Picture a job interview where “Where do you see yourself in five years?” is replaced by “Have you ever considered selling state secrets?”

Private Companies

Some businesses, particularly in security and pharmaceuticals, use polygraphs for pre-employment screening. Think of it as a high-stakes game of “Two Truths and a Lie,” where your career hangs in the balance.

TV Shows

From daytime talk shows to reality dating programs, polygraphs have become the go-to drama amplifier. But remember, folks: just because it makes for good TV doesn’t mean it’s good science.

Now, here’s where things get interesting:

The Employee Polygraph Protection Act of 1988 threw a wrench in the works for most private employers. This legislation essentially told businesses, “Sorry, you can’t use this dubious technology to decide who gets to man the drive-thru.”

Government agencies, however, still take polygraphs seriously in their hiring process. But even they’re not blind to the limitations. Former FBI agent Joe Navarro, in his book What Every Body is Saying^{4https://www.amazon.ca/What-Every-BODY-Saying-Speed-Reading/dp/0061438294#:~:text=Joe%20Navarro%2C%20a%20former%20FBI,and%20look%20for%20deceptive%20behaviors.} , argues that non-verbal cues often speak louder than polygraph results.

When it comes to the courtroom, polygraph results are generally inadmissible in most U.S. states. Presenting polygraph evidence is akin to bringing a Ouija board to a legal battle—it might be intriguing, but it won’t sway the judge.

In the end, while lie detectors continue to be used in various settings, their results are often viewed skeptically. Rather than a foolproof “lie detector,” they’re perhaps more accurately described as a “stress detector with a hefty side of uncertainty.” The polygraph, it seems, tells us more about our fascination with uncovering deception than it does about the lies themselves.

When Lie Detectors Lie: Famous Polygraph Fails

Still think lie detectors are legit? These infamous cases might make you think twice:

The Spy Who Fooled the Machine

Aldrich Ames, a CIA officer turned Soviet double agent, passed two polygraph tests while secretly working for the other side. Despite reportedly being “terrified” at the idea of the tests, the KGB’s advice of “just relax” was all it took for Ames to pass the test. 

The Green River Killer’s Lucky Break

Gary Ridgway^{5https://www.cvsa1.com/blog/killer-passes-polygraph-innocent-man-fails-killer-goes-on-to-kill-again/} , the notorious Green River Killer, sailed through a polygraph test in 1984. Meanwhile, another suspect failed miserably. Plot twist: Ridgway was the real killer, confessing almost 20 years later when DNA evidence caught up with him. Oops!

The BTK Blunder

In 1986, Bill Wegerle^{6https://www.paramountpressexpress.com/cbs-news-and-stations/shows/48-hours/releases/?view=10900-for-almost-20-years-a-husband-and-father-was-for-almost-20-years-a-husband-and-father-was-suspected-of-murdering-his-wife-but-the-murderer-was-the-quo} failed two polygraph tests after his wife’s murder, making him the prime suspect. Almost two decades later, DNA evidence revealed the real killer was Dennis Rader, the infamous BTK serial killer. Talk about a case of polygraph prejudice!

These cases show that while polygraphs might make for dramatic TV, in real life, they’re about as reliable as a weather forecast for next month. Sometimes they catch the bad guys, sometimes they don’t, and sometimes they point the finger at the wrong person entirely. 

The Future of Lie Detection

As we’ve seen, traditional polygraphs have more holes than Swiss cheese. But fear not, truth seekers! Science marches on, and researchers are exploring new frontiers in lie detection. Let’s peek into the crystal ball:

1. fMRI Lie Detection: Some researchers are using functional magnetic resonance imaging (fMRI) to observe brain activity during lying. Early studies show promise, but this technology is still in its infancy and not yet ready for widespread application.
2. EEG-based Methods: These techniques examine electrical activity in the brain. By analyzing brainwave patterns, researchers hope to identify neural signatures associated with deception.
3. Thermal Imaging: This approach focuses on changes in facial temperature when a person lies. The theory suggests that specific temperature variations might indicate deceptive behavior.
4. Voice Stress Analysis: This method scrutinizes vocal patterns to detect lies. By examining subtle changes in voice frequency and pitch, analysts attempt to identify stress indicators associated with deception.
5. AI and Machine Learning: Researchers are harnessing artificial intelligence to analyze a combination of physiological and behavioral cues. These advanced algorithms process vast amounts of data to identify patterns potentially indicative of lying.

While some of these methods show promise, they’re still very far away from representing anything close to a foolproof lie detector. 

As fast-paced as science is, it’s important to remember that lying is a complex cognitive process underlied by widely varying emotions, feelings and motivations. There’s no single “lie response” in the brain or body—and there might never be!

How to Prepare for a Polygraph Test

So, you’ve got a date with a polygraph. Maybe it’s for a job, maybe it’s for an investigation, or maybe you’ve been binge-watching too much true crime TV. Whatever the reason, here’s how to prepare:

1. Get a Good Night’s Sleep: Being well-rested can help you stay calm.
   
2. Avoid Caffeine and Stimulants: These can affect your physiological responses. Save that double espresso for your victory lap after the test.
   
3. Wear Comfortable Clothing: You’ll be sitting for a while, so comfort is key.
   
4. Be Honest: The best way to pass a lie detector test is to tell the truth. Revolutionary concept, we know!
   
5. Understand Your Rights: In many cases, you have the right to refuse a polygraph. Know the laws in your area.
   
6. Practice Calm Breathing: Deep, slow breaths can help manage stress. Think yoga, or other mindful activities.
   
7. Don’t Overthink It: The more you obsess, the more anxious you’ll be. It’s a polygraph, not mind control.
   
8. Be Prepared for Personal Questions: Polygraphs often include very personal queries.
   

Remember, polygraph examiners are trained to spot attempts at deception or countermeasures. The best strategy? Honesty. It’s not just the best policy, it’s also the easiest to remember!

Frequently Asked Questions (FAQs) About Lie Detector Tests

The Moment of Truth

While polygraphs can detect stress responses that might indicate lying, they’re far from foolproof. Here’s what we’ve learned:

• Scientific evidence for the accuracy of polygraphs is weak, with studies showing they perform only slightly better than chance (at best).
• Common polygraph methods include the Guilty Knowledge Test and the Control Question Test. 
• While there are techniques people claim can “beat” a lie detector, these are not reliable and are often detected by examiners. 
• Polygraphs are used by law enforcement, government agencies, and some private companies, but their results are generally not admissible in court. 
• Famous cases like Aldrich Ames and Gary Ridgway highlight the potential for polygraphs to fail in high-stakes situations. 
• New technologies like fMRI, EEG, and AI are being explored for lie detection, but are still in early stages. 
• Preparing for a polygraph test involves being well-rested, avoiding stimulants, and most importantly, being honest. 

All in all, polygraphs are, at best, more of a tool in the toolbox of truth-seeking rather than a magic wand that reveals all.

You know what else is in that toolbox? Understanding body language, facial expressions and human behavior in general! When you understand people, it’s like having a built-in lie detector. 

So, are you curious about detecting lies without a machine? Check out our article on 9 Things You Should Know About Liars.