Home Page > Reading Room
"How to Beat the Lie Detector" by Chicago attorney William Scott Stewart appeared in the November 1941 issue of Esquire magazine. It might be the earliest article ever published about polygraph countermeasures. More than sixty years later, the author's criticisms of the polygraph and its use remain highly relevant. In the article text below, page numbers are indicated in curly braces for citation purposes. To discuss this article, see the message board thread, How to Beat the Lie Detector.

Note: at the time this article was written, the "Control Question Test," which is today the most commonly used polygraph technique, had not yet been developed, and the Relevant/Irrelevant technique was used instead. Counter-countermeasures have been developed for some of the techniques Stewart suggests, for example, that of moving one's big toe inside one's shoe, and the word association test described at the end of the article has fallen out of use. Those interested in how to beat a lie detector "test" should download's free book, The Lie Behind the Lie Detector.


How to Beat the Lie Detector

Armed with these directions for fooling
the quack who operates it, you need not
fear this modern instrument of torture



In the first place, it's the bunk. In spite of what the newspapers and the so-called experts would have you believe, there's no machine on earth capable of detecting a lie.

The popular conception of a "lie detector" machine--and a belief sponsored by the propaganda of those who live off the racket--is that of an Almighty contraption that rings a gong every time a lie is told, a machine whose instrument gauge points a "naughty-naughty" finger at any one who dares to fib to it. You'd hardly think it necessary to say "There ain't no such animal," and yet in this age when the public is ready to believe anything and everything so long as it's labeled "scientific," quacks are finding an easy market for their pretended infallible crime cure-all, the lie detector. Some of those guilty are being passed up, while the innocent are often made to suffer.

Because this fraud upon the credulous public is growing to such proportions that everyone--not only those who are booked at the police station--is open to attack by the lie detectors, everyone owes it to himself to have some understanding of the operation of the machine, and to have some plan of combating it when it forces itself upon him.

Really "there ought to be a law" prohibiting the use of the lie detector; but even if passage of such a law could be brought about over the objections of the favorite sons who make nice, fat livings with their mechanical Charlie McCarthys, that law would probably be about as effective as the sterile laws prohibiting the third degree today--and you don't have to rely on the movies to know that police methods are unhampered by restrictions on the third degree. As a matter of fact, the lie detector is nothing but the third degree dressed up in white tie and tails. Warden Lawes gave an apt definition of their usefulness when he said, "Those lie detector gadgets are all right...provided you have a couple of stool pigeons working behind the scenes."

The effectiveness of the machine depends largely on the victim's fears or belief in its infallibility, so if you understand something about how the lie detector works, and about the law concerning your relations with it, you've accomplished the first step in beating the fraud.

There are a number of machines in use today. The most modern one combines those which were formerly used separately. Called the polygraph, meaning "many-graph" instrument, this lie detector is a hybrid--not so pure, and not so simple. None of the parts was intended by the inventor to be passed off as a detector of lies. It's made up of the cardiograph, which records the pulse wave; the sphygmograph, which records the blood pressure; the galvanograph, which records the galvanic reflex (which closely follows the activity of the sweat pores); and the pneumograph, which records the respiratory movements. The whole thing is sometimes called the pneumo-cardio-sphygmo-galvanograph. The name alone is enough to scare you into reverent belief in its powers--and that's where the fun begins for the other fellow.

When you're strapped into the contraption, a rubber tube is placed around your chest, and a blood pressure cuff, of the type ordinarily used by physicians, is fastened about your upper arm. This cuff is then inflated to a pressure about midway between the systolic and diastolic blood pressures. Rubber tubes approximately a quarter of an inch in diameter lead from both the pneumograph and the cuff into metal tambours to which two stiluses are attached. At the tip of each stilus is a small cup, filled with ink, which feeds the pens as they fluctuate with each pulse beat or respiratory movement. The recordations are made upon slowly moving graph paper, driven by a small synchronous electric motor.

Then the guesswork begins. Those who operate the machines write that the value of the deception test depends upon the bodily responses to certain mental stimuli, and that, therefore, there must be no irrelevant factors. If outside influences can't be eliminated, say the instructors, they must be kept constant throughout the examination and allowed for in the interpretation. Wherever a movement is made, voluntarily or involuntarily, that movement must be noted and discounted in the diagnosis. The normal breathing will affect the blood pressure instrument, and that should be noted. If the subject is not normal in all respects, that must be taken into consideration. When you get right down to it, the lie detector report is just one man's opinion of what a lot of jumpy marks on graph paper mean in relation to your guilt or innocence. Influenced, of course, by his guess, based upon what he has heard about you, and deductions he draws from how you appear and act. Everyone thinks himself quite shrewd at detecting liars. That "you can't fool me" attitude explains why first-rate con men work best on bankers.

If you're brought face to face with one of these modern torture machines, as a suspect in a criminal case, remember that you need not submit to any test by any machine. You have a constitutional right to refuse to incriminate yourself. This, of course, is pretty well known, but the operators of the machine lead you to believe that an innocent person has nothing to fear and that a guilty person will not dare to refuse for fear his refusal will be accepted as evidence of guilt. Neither of these premises is true. If you're brought to trial, the prosecutor is not permitted under the rules of evidence to let the court or jury {158} know that you refused to take a lie detector test. And if you're innocent, shun the machine like a plague. It might guess wrong.

The courts, with good reason, have refused to admit lie detector reports as evidence, and have not recognized the operators as properly qualified expert witnesses. Those who support the machine claim that this attitude of the law is reactionary, but the fact that the courts have admitted X-rays, photographs, blood tests, fingerprinting, chemical analysis and all other advances made by science shows they are ready to accept witnesses as soon as a reasonable degree of certainty is reached. The judges would have run to meet the machine long ago if it could have delivered. There can be no certainty in the pseudo-science of lie-detecting. Today, before an X-ray picture is allowed in court, it must be proved that the machine was in order at the time the picture was made. Before a lie detector report will ever be acceptable, proof will have to be made as to two machines: the polygraph and the human machine. So long as it is true that twenty per cent of us humans are out of line in some way which will have a direct bearing on the polygraph, the lie detector will have no legal foundation. Just as approval is withheld by the American Medical Association when the advertiser claims too much for his product, the lie detector should not have your approval...or mine...or the approval of the courts.

This legal protection of the victim is all very well and good where the courts are involved, for you can simply refuse to take the test and settle the whole question. Too few people realize this, however, and outside of court the lie detector has become a racket. The machine is now being used by big firms in an effort to detect thefts and other misconduct among employees, and the laboratories are getting huge annual fees for doing a hundred other bits of detective work--sifting out charges of infidelity made by one spouse against another, testing the truth of the claim of a mother as to the paternity of her child, searching into the truth or falsity of claims for damages or for insurance. It is highly unfair to demand, for instance, that a person who claims a loss under an insurance policy be required to submit to a lie detector test--especially when the operator is collecting from the insurance company. No such requirement is in any policy, and the law does not sanction it, but most ordinary people don't know enough to refuse to take the test. Then too, there is a large class of people not in a position to refuse to take the test. Bank employees, for instance, would lose their jobs on the spot if they refused to submit to tests when money is missing--so they must take their chances with a machine which all too often makes tragic mistakes.

So there you are--forced to take a lie detector test, not by law, but by the ignorance of your empolyer who subscribes to the "service" on the assurance of the psuedo-scientists [sic]. Some employers are sold on the value of the protection afforded them, brought about by the knowledge among employees that regular check-ups are to be made. The "service" includes washroom placards to this effect.

Okay, you say? You have nothing to fear? Take a look at this actual case, and see whether or not you think you can count on the machine to give you a fair shake.

A young woman was brutally assaulted by a man who broke into her hotel bedroom in Chicago. Having been knocked suddenly senseless with a brick, she could not identify her assailant. Suspicion attached to a young colored man named Nixon, who worked in a parking lot adjoining the hotel. Nixon was arrested by the Chicago police, but he denied his guilt. He was taken to the Scientific Crime Detection Laboratories and given a lie detector test. The wise man in charge said he was not guilty, so, since Nixon refused to confess and there was no evidence, he was released. Later the police arrested another suspect, this time a white man, a resident of the hotel named McCall. An elevator man told the police that on the night of the attack he had taken McCall from his own floor up to that on which the girl lived. Here was the guilty man, thought the police, even though McCall insisted on his innocence. McCall was given the lie detector test, and the operator said he was lying when he protested his innocence. So, with that confirmation, the police beat a confession out of him. When McCall went to trial, he denied his guilt and testified that his confession was false and had been forced from him. The girl couldn't identify him, but the police helped the jury out by adding a bit of framed testimony about finding the key to the girl's room in McCall's pocket. McCall was sentenced to Joliet Penitentiary for life.

When the investigation of the case had just begun, the Chicago police had sent Nixon's fingerprints around the country. McCall had already started on his term of imprisonment when the Chicago police received a wire from the police in California, saying that Nixon's fingerprints showed that he had been guilty of a similar assault and murder of a woman and her child in California. The Chicago police re-arrested Nixon, and, when he was informed of the California charge, he not only confessed to the Chicago crime but described the manner in which he had gained entrance to the girl's room, took the police to the scene, and convinced them that he could not have known the details without having committed the crime. When Nixon was found guilty, McCall, an innocent victim of the lie detector, was released--but not before he had spent six months of his term.

When Nixon's confession was given publicity, it came out that the girl had confided to a friend that she was sure it had been a Negro who had raped her. But when the police presented McCall's confession, the girl was glad to be convinced she had been mistaken, and never revealed her first reaction until Nixon confessed. Everyone knows that police feel justified in concocting evidence against anyone they think is guilty. If the lie detector is to be relied upon as a basis from which to frame a case, no one is safe.

The guilty Nixon had come out of his lie detector test with a clean slate. Physicians later discovered that he had a low emotional center at the base of his brain. The operators "explained" their fatal mistake by saying that that physical abnormality had thrown off their gauges. But just think--no one of us is the perfect physical specimen. You may have an abnormality in the thyroid that makes you hyper-apprehensive, or any number of little reactional traits that will have their effect on the machine. The operators, in most cases, are half-smart policemen seeking to better their position, broken down investigators and private detectives. Even if they were competent physicians and had the time and equipment to examine you thoroughly, their diagnosis of your mental condition would still be subject to error.

In the legal journals, Wilson and Inbau report that confessions have been attained in seventy-five per cent of the cases in which the polygraph indicated deception. They don't say how the confessions were obtained. Actually the police don't want to be bothered with the lie detectors when they have other evidence. The testimony of a Chicago Police Captain before the Wickersham Committee is typical of the police opinion of the lie detectors. The Captain, when asked why he didn't make more use of the lie detector, held up his clenched fist and said, "This is the best lie detector." Actually the police resort to the laboratories only when they have merely a suspicion. The machine might complicate matters by saying innocent to a guilty man. Not many police have book learning, but they learn a great deal from experience. Most of them know that the lie detector is a fake. They use the lie detector as they use anything and everything, legal or illegal, which they believe will help them build a case, where they have only a suspicion, plus a great desire to solve a crime. If their suspicions are borne out by the lie detector, the police feel justified in beating the victim to a pulp, if necessary, to get a confession. They have "science" on their side if the suspect should die of his injuries: they can "prove" that a guilty man got what was coming to him--"in an attempt to escape." So what are those seventy-five per cent confessions worth? Are they not a case against the lie detector and the third degree, rather than a case for the machines? We might ask, too, of what value are the statistics which show that only 12 mistakes in diagnosis of innocence or guilt have been verified out of the 2,171 tests made by the Scientific Laboratory in Chicago (from January 1, 1935, to June 1, 1938)? How were those results which are not supposed to be mistakes determined to be correct? Was it after a trial, based on a confession obtained by the third degree? If you will think for a moment you will perceive how impossible it would be to obtain reliable statistics. Guilty men who are turned out are not always later apprehended, and the guiltless who are punished often maintain their innocence in vain throughout their term, or go to their deaths as the machine's victims.

Merely because an occasional thief is caught and made to confess should not justify the use of the machine on hundreds of innocent employees, any more than would the intrusion of our homes by the police be justified merely because lawbreakers are sometimes protected by the law which keeps the officers out. While the so-called gangster has ways of beating the machine, it's the poor and defenseless who are victims of such illegal practices. Don't let ignorance put you on the spot.

Another of the cases from the record of failures of the machine will show you how a basic knowledge of the lie detector might protect the guilty, while the poor, good, trusting innocents are taken for a ride. A messenger for the Brinks Express Company in Chicago, a fellow by the name of Hummel, handled money for so long he got attached to it and decided to take a few samples home with him one day. He walked off with quite a sum, and while he was in hiding he decided, just in case, to read up on the lie detector. He was finally arrested in the East, and brought back to Chicago. But he denied his identity, even in the face of overwhelming evidence. He took a lie detector test--he showed a clean slate, lied brazenly. He knew from his reading that the operators watch for a deep breath just before a lie and a sigh of relief afterwards, so by voluntary control of his breathing he beat the machine. He was convicted and later told of how he tricked the operator.

When you've examined the record and realized that the whole game is a racket, you've actually blasted the lie-detector's first line {160} of offense. If you can sit in the torture chamber, strapped into the model electric chair, confronted by the solemn operator and all his psychological tricks to scare you and gain your confidence, and still be convinced in your own mind that the system is the bunk, you're in good enough control of your senses to beat the machine. Your first impulse will be to try to conceal all emotion, but that is exactly what not to do. The physical effort required to conceal emotion shows up and could often be detected without a machine. So, in beating the lie detector, conceal no emotions; intensify them as much as possible, even on those preliminary innocent questions calculated to obtain your normal reaction. When you're asked a harmless question, think about something unpleasant. Deviations in the chart are not great in any case, and if you cause the needle to act up on innocent questions the operator will be baffled, whether he admits it or not.

It is really not necessary , in order to beat the machine, that you interfere with the operator, but by doing so you will be keeping your mind occupied with your own business. The blood pressure machine is influenced not only by the respiratory mechanism which the operator tries to register and allow for, but also by sensory impressions or sudden changes in the repose of the muscles. The operator, of course, will be watching for voluntary changes and actions in order to make note of them and allow for them in his interpretations, but if you bite the inside of your mouth or tongue on a question of no importance, unbeknown to the operator, he will begin to wonder what's the matter with his machine. You can make sudden muscular movements inside the skin, or twitch your leg in such a manner that the operator will see no outward sign of movement. Try moving your big toe inside your shoe, for instance. It's easy. Or, to confuse the test from the start, you might tense your muscles when the rubber is wrapped around your arm. If you appear to relax in spite of this tenseness, the operator will set his gauge to a false medium.

Of course, one who sets out to beat the machine should never admit that such is his purpose. Operators have little ways of testing, and naturally try to bluff the victim into thinking they know that an effort is being made to fool the machine. These operators maintain that such effort shows guilt, but pay no attention to that. Talk to the operator as little as possible. Remember that he is not your friend, no matter what he says. He may pretend to be alone with you, and yet in all probability his room is wired for sound and a stenographer in another room is taking down every word that is said.

If, in spite of your nonchalance, the operator thinks you are trying to fool him, you'll be given the word association test. The operator explains that he is going to mention a word, and that you should answer with the first word which comes to your mind, such as dog-cat, soldier-army, girl-dress, etc. Then, while you're still hooked up to the machine, the operator calls off a list of words, noting the time required for the response and the emotion, as indicated by the machine. About three key words, connected with the crime, are included in the list, and the test is repeated at leat three times with these words included. The theory is that a guilty suspect will reject in his own mind the real word which a key word suggests, and that in search of another he'll consume time as well as energy.

The way to beat the association test is simply to blurt out the first word you think of in association, whether you think the word is good or bad. Suppose you're suspected of a murder. The body was found in a park, so when one of the key words given you is "park," naturally the first word you think of, wheter you're guilty or innocent, is "murder." When you answer "murder" outright, the experts are sunk, for the whole test is based on the assumption that a guilty person will try hard to conceal the fact that he knows what the crime charged is all about. That assumption is about as sensible as many they make. Anybody but an expert knows that even an innocent person will try to gain a favorable report on the test, so, therefore, innocent and guilty alike will hesitate to give words connected with the crime. If a suspect indicates that he knows the details of the crime, the experts have no way of knowing whether he got information firsthand or through the newspapers or questioning.

Seeing that you appear to be not afraid of his machine, the operator will be naïve enough to think you innocent, when all the time you are nervous and scared. But, if the operators had good sense, and were honest, they would not be such racketeers.

No one should approve of the use of the lie detector any more than he would sanction the revival of primitive ordeals or Middle Age tortures. Think of what a sad human tragedy it would be if anyone who could purchase a few diagnostic instruments, some scalpels, forceps and a white coat, could hang out his shingle and commence medical practice on suffering patients! Yet anybody can buy or build a polygraph and practice on the unsuspecting public! The machine today is a fraud upon the public's credulity, not only because it is unreliable, but because it is an adjunct to the third degree. It should not be tolerated in civilized society! III Home Page > Reading Room