This a great question, and we’re going to address it. But let me start by saying, the answer is, “Probably not, and you should be calling a lawyer.”
In this post we’re going to discuss some common myths and misconceptions about lie detectors and give some inside baseball on what’s really going on during a polygraph examination.
Lie detector tests have been the subject of controversy since their introduction in the early twentieth century. William Moulton Marston introduced an early polygraph machine that tested blood pressure and heart rate. (Side note: He also created the comic book heroine Wonder Woman, and her lasso of truth.
Which, incidentally, was much more accurate than his polygraph.) His theory was that subjects would become nervous when lying, and thus would demonstrate increased heart rate and blood pressure.
In 1921, John Larson invented a lie detector he called the Cardio-pneumo-psychogram, that he used with the Berkeley, CA police department. Although Berkeley PD touted their successes with the device, criminal courts were skeptical of their efficacy.
In the U.S. Supreme Court case Frye v. United States, the Court held that polygraph evidence did not meet the standard to be “sufficiently established to have gained general acceptance in the particular field in which it belongs,” and concurred with the lower court’s decision to exclude the “deception test” evidence.
The Frye standard is still used today by many jurisdictions to determine if scientific testimony and evidence should be admissible at trial.
In Colorado, the rule for admissibility of evidence can be found in People v. Schreck. The Schreck case held that Colorado Rule of Evidence 702 is the correct standard to determine if scientific evidence should be admitted by the Court. The Court can also consider other factors such as Daubert factors to determine whether evidence is sufficiently reliable.
Key Takeaways: Should You Take a Lie Detector Test in Colorado?
- In most Colorado criminal cases, the safest answer is usually no. Speak with a defense lawyer first.
- Polygraph results are generally not admissible in Colorado courts because their reliability is widely disputed.
- Police often use lie detector tests as an investigative tool to gather statements, admissions, or inconsistencies.
- Even truthful people can fail a polygraph due to stress, anxiety, medical conditions, or examiner interpretation.
- Anything you say before, during, or after the test can potentially be used against you in a criminal investigation.
- Never agree to a lie detector test without first consulting an experienced criminal defense attorney.
How Do Lie Detectors Work?
The lie detector tests of today measure and record several physiological indicators that may be associated with stress responses. Polygraphs can measure blood pressure, pulse, respiration, and skin conductivity while the subject answers a series of questions.
The basic premise is that deceptive answers will produce physiological responses that can be differentiated from those associated with non-deceptive answers. The polygraph then records these physiological changes on a graph, which a trained polygrapher will interpret to determine whether the responses indicate purposeful or knowing deception.
Are Lie Detectors Accurate?
Do lie detectors actually work? The accuracy of lie detectors has been a topic of debate among scientists, psychologists, and legal experts for over 100 years. Polygraph proponents contend that polygraph tests are a useful tool for detecting deception. Some polygraphers claim accuracy rates over 90%.
Critics of lie detectors correctly state that the scientific community at large has not universally accepted polygraphs as a reliable tool. Some scientific studies that suggest the accuracy of polygraphs can be rather low, especially when considering the potential for false positives and false negatives.
The basic principle of a lie detector test is interesting, but the tests are limited by the subject, the accuracy of the instrument and the training and experience of the examiner.
As technology advances, there are opportunities to improve deception detection devices. The recent introduction of Artificial intelligence (AI) to polygraph exams could potentially lead to increased accuracy. One AI based deception detector is called AVATAR (Automated Virtual Agent for Truth Assessments in Real-Time) .
The AVATAR system has been used at border crossings and in airports to detect deception of travelers. It claims to have a rate of 80-85% accuracy. The AVATAR system employs physiological, kinesic, vocalic, linguistic and ocular detection to detect deception, and uses a proprietary AI algorithm to learn for future examinations.
Even with advanced methods like AVATAR, the human element can’t be ignored. Typically, if deception is detected by AVATAR, an alert will notify security screeners that the person should be subjected to additional screenings.
Common Reasons Polygraphs Can Be Inaccurate
| Factor | How It Affects Results |
|---|---|
| Anxiety or nervousness | Can trigger stress responses |
| Medical conditions | May alter physiological readings |
| Examiner interpretation | Results depend heavily on examiner skill |
| Faulty baseline responses | Can skew comparisons |
| Countermeasures | May create inconclusive outcomes |
Can You Beat a Lie Detector Test?
I think we’ve all heard rumors that there are sure-fire ways to beat a lie detector test. One common strategy is to employ certain countermeasures to throw off the readings of the machine. The countermeasures can range from physical tactics to mental techniques intended to alter one’s physiological responses during the test.
One common strategy is to flex parts of your body during the initial questions to give an elevated response on baseline questions.
While there is anecdotal evidence of individuals successfully beating polygraph tests, these methods are unreliable and not guaranteed to work.
Moreover, experienced examiners may be trained to detect and counteract such tactics, potentially leading to the test being deemed inconclusive or indicative of deception. A good examiner isn’t just looking for the feedback from the lie detector itself, but also the visual keys and behavior of the subject.
How to Pass a Lie Detector Test
Here is a practical step-by-step way people generally prepare for a polygraph test:
Understand how the test works
The machine records physiological responses such as breathing, pulse, blood pressure, and skin conductivity. The examiner compares your responses to different types of questions.
Get a good night’s sleep before the test
Being well rested helps keep your body responses more stable and reduces unnecessary stress.
Listen carefully during the pre-test interview
The examiner will explain the process and review the questions with you beforehand. Pay attention and make sure you understand what is being asked.
Stay calm and breathe normally
Try to maintain a steady breathing pattern and avoid sudden changes in posture or movement during the test.
Focus on the question being asked
Answer clearly and briefly, usually “yes” or “no.” Avoid overthinking or adding extra explanations unless asked.
Use simple mental calming techniques
Many people silently count, focus on their breathing, or think about neutral topics to stay relaxed and avoid spikes in stress.
Avoid obvious physical movements
Examiners monitor body movement closely, so fidgeting or shifting around can make the results harder to interpret.
Answer truthfully and consistently
The most reliable way to avoid abnormal physiological reactions is to respond honestly and keep your answers consistent.
Are Lie Detectors Admissible in Court?
The admissibility of lie detector test results in court varies widely by jurisdiction. The U.S. Supreme Court allows the individual states to determine their admissibility in Court. In Frye v. U.S., a D.C. Circuit Court case took on the admissibility of lie detectors, then called a “deception test”.
The Court found that evidence must be “sufficiently established to have gained general acceptance in the particular field in which it belongs.” In Frye, the Court determined that the lower court was correct in excluding the results of the test as it did not meet the standard.
The Frye standard is still used today in many jurisdictions to determine the admissibility of scientific evidence. Currently, a little less than half of States allow polygraphs to be admitted as evidence in Court.
In Colorado, polygraphs are not admissible at trial. Colorado law follows the Schreck standard which says for scientific evidence to be admissible it must comport with Colorado Rules of Evidence 702, “If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise.”
| Jurisdiction/Scenario | Admissible in Court? |
|---|---|
| Colorado criminal trials | Generally No |
| Private defense investigation | Possibly useful strategically |
| Police investigations | Commonly used |
| Plea negotiations | Sometimes referenced informally |
| Federal/other states | Varies by jurisdiction |
If polygraphs aren’t admissible in Court, why do Police give them?
Now, this is the big question. Police use polygraphs as an investigative tool. But not always in the way you’re thinking. Police are allowed to lie to you. And they do all the time. The investigative technique is to use the polygraph test to psychologically influence you to talk and provide them more evidence.
Here are a few ways they use the test beyond the actual findings:
- They might use your refusal to take the test to tell you that it clearly means you are lying. They then use this to attempt to get you to talk more about what happened.
- Any questions they ask during the test are to elicit information/evidence for their case. They are looking for admissions and inconsistencies in your statement.
- The post-test interview: Police will tell you that you failed the test (whether you did or didn’t) to get you to talk more and try to get you to, “come clean, because the test proves you are lying.” This technique can be incredibly effective, and I have personally seen it used successfully in cases I handled as a prosecutor.
When in doubt, TAKE THE FIFTH. Tell law enforcement clearly that you want an attorney and that you are exercising your right to remain silent. If you ever find yourself in the position of being questioned by law enforcement, call the best defense lawyer you can afford, and do exactly as they counsel.
Lie Detector Myths vs Facts
| Myth | Reality |
|---|---|
| Lie detectors are always accurate | Accuracy is heavily debated |
| Innocent people always pass | Truthful people can fail |
| Results guarantee conviction | Polygraphs are usually inadmissible in Colorado |
| Refusing makes you guilty | Refusal alone is not proof of guilt |
| You can easily beat the test | Countermeasures are unreliable |
Should You Agree to Take a Lie Detector Test?
Whether you should take a lie detector test is an important decision that should not be made without the assistance of counsel. One thing to consider is a private polygraph to see the results outside of the presence of law enforcement.
It can be a useful tool, but I’ve had my clients take private lie detectors less times than I can count on one hand. In a couple of cases, I had my clients pass a private test and show that to the DA as part of the negotiation process that ultimately resulted in a dismissal. However, it is a rare fact pattern in which that this technique will be successful.
The decision where to take a lie detector test should consider understanding of the test’s limitations, the potential for false readings, and the possible outcomes. Most importantly, don’t ever take a polygraph without consulting legal counsel first. An experienced criminal defense attorney can advise you of the potential outcomes and the pros and cons of taking a test.
Frequently Asked Questions
How accurate are lie detector tests?
Lie detector tests are not 100% accurate. While some studies suggest polygraph tests can detect deception under certain conditions, their accuracy varies depending on the examiner, the testing method, and the individual being tested. Because false positives and false negatives can occur, courts generally do not consider polygraph results to be conclusive evidence.
Do lie detector tests really work?
Polygraph tests may detect physiological changes associated with stress or deception, but they cannot determine with certainty whether someone is telling the truth. Factors such as anxiety, fear, medical conditions, or the testing environment may influence the results. For that reason, polygraph examinations are generally considered investigative tools rather than definitive proof of deception.
Should you take a lie detector test?
Whether you should take a lie detector test depends on the circumstances of your case. In many criminal investigations, taking a polygraph without first consulting a criminal defense attorney may not be in your best interest. An attorney can evaluate the potential risks and benefits before you decide whether to participate.
Can a lie detector test be wrong?
Yes. A lie detector test can produce inaccurate results. A truthful person may fail a polygraph, and a deceptive person may pass one. Because polygraph testing measures physiological responses rather than lies themselves, the results are not considered infallible.
Are lie detector tests admissible in court?
In most cases, polygraph results are not admissible in court because of ongoing concerns about their reliability. Some jurisdictions allow polygraph evidence only under limited circumstances, such as when both parties agree to its admission before the test is administered. The rules vary by jurisdiction and the specific facts of the case.
Do you have to take a polygraph test?
Generally, no. Most people are not legally required to take a polygraph test during a criminal investigation. Law enforcement officers may request that you take one, but participation is often voluntary. Before agreeing to a polygraph examination, it is advisable to consult with an experienced criminal defense attorney.
How long does a lie detector test take?
A typical lie detector test lasts two to four hours, although the exact length varies. The examination usually includes a pre-test interview, an explanation of the testing process, the polygraph examination itself, and a post-test discussion of the results.
What questions are asked during a polygraph test?
A polygraph examination generally includes several types of questions, including background questions, control questions, and questions directly related to the investigation. Before the examination begins, the examiner typically reviews the questions with the person being tested so there are no surprises during the test.
Can you fail a lie detector test even if you are telling the truth?
Yes. It is possible to fail a lie detector test even when telling the truth. Stress, nervousness, anxiety, medical conditions, medications, or other physiological factors may affect the body’s responses and contribute to inaccurate or inconclusive results.
Can you beat a lie detector test?
There is no reliable or guaranteed way to beat a lie detector test. Many commonly suggested countermeasures have not been proven effective and may be recognized by experienced examiners. Attempting to manipulate the examination could also affect the examiner’s evaluation of the results.
Can anyone take a lie detector test?
In most cases, yes. Private polygraph examinations are available for many individuals, and law enforcement agencies may also request polygraph testing during certain investigations. However, whether a person should take a polygraph depends on the purpose of the examination and the legal circumstances involved.
How should you prepare for a polygraph test?
If you are asked to take a polygraph test, you should get adequate rest, follow any instructions provided by the examiner, answer questions honestly, and avoid attempting to manipulate the results. If the examination relates to a criminal investigation, you should speak with a criminal defense attorney before agreeing to the test.
When are lie detector tests used?
Lie detector tests are commonly used during criminal investigations, internal employment investigations, certain pre-employment screenings for law enforcement or government agencies, and some private matters. Although polygraph examinations may assist investigators, the results alone generally do not determine whether someone is guilty or innocent.
