ON LIE DETECTION
By JOHN W. DEAN
|Friday, Mar. 15, 2002|
Is President Bush being truthful with the American people about the war on terrorism? Is Vice President Cheney being honest about why he doesn't want to release the names of people with whom his energy task force met, in the course of developing our national energy policy? Did Jeffrey Skilling lie about his activities at Enron when testifying before Congress? Are Andrea Yates's doctors really telling the truth about her mental condition before she drowned her children?
No doubt, just as I have, you have heard a lot of public - and private - commentary on these and many other questions that ask who is, and is not, being truthful about any of myriad matters. This business of discerning the truth, or uncovering lies, is a part of daily life.
Aldert Vrij, a professor of psychology at the University of Portsmouth, in England, is a leading expert on lie detection. His book Detecting Lies and Deceit: The Psychology of Lying and the Implications for Professional Practice represents the state of the art - and that term is apt, for lie detection is mostly art and a little science.
This study, published last year for law enforcement professionals, digests the psychological literature addressing the significant advances made during the last decade in understanding why people lie, and how those lies can be detected.
Untrained People Are Not Good Lie Detectors
Contrary to popular belief, studies show that most people are much better at lying than they are spotting liars. It seems we are not good lie catchers because we don't have the knowledge necessary to make our judgments more accurate.
Remarkably, after training, some law enforcement people are quite good at detecting liars. None are better than U.S. Secret Service agents - who tested at 90% accuracy in identifying lies. In contrast, untrained law enforcement people could do no better than pure chance - scoring less than 50% accuracy in identifying lies.
Interestingly, people who are best at intuitively spotting liars are long-term, hard-core prisoners. Vrij explains why: Criminals live in a culture where deception is the norm, and their very survival in that world depends upon their having the ability to sort truth from lies.
No such demands are placed on most people. Also, we most typically encounter lies in social situations, where it is inappropriate -- or unnecessary if not embarrassing -- to probe for the truth. We simply make a mental note and move on. No wonder, then, that most of us are relatively bad lie detectors.
Polygraph Testing: Helpful, But Not Definitive
As for polygraph tests, studies demonstrate they are only as good as the tester. Yet while polygraphs are never a sure thing, they can help. For instance, Vrij notes that when Richard Jewell became the main suspect in the Atlanta bombing during the 1996 Olympic Games, he underwent 15 hours of testing, which determined he was innocent and aided in his exoneration.
On the other hand, notorious spies like FBI agent Donald Hansen, and CIA agent Aldrich Ames, both sold secrets to the FBI for years even though they were given regular polygraph tests by their agencies. In fact, Vrij learned, Ames was actually put to the test by his KGB handlers - who exposed him to a known KGB agent to make sure he could lie successfully when confronted with the routine polygraph question of whether he had recently had been in contact with a KGB officer. Ames passed with flying colors.
How to Fool A Polygraph
I'd always wondered how liars beat lie-detector tests. Generally, the ability to lie is established when the polygraph examiner asks the control questions - which determine the interviewee's normal levels of palm sweating, blood pressure and respiration rate.
Later, after the control questions are done, changes from normal in these physiological measures are used to determine if a person is aroused when answering a question, which is supposedly indicative of lying. So those who seek to lie do so most successfully when they fiddle with the normals - convincing the polygraph examiner that their normal state is more aroused than, in fact, it is. Setting the normals incorrectly allows later lies, since the arousal these lies cause will be taken as merely normal for the subject.
There are a number of such "countermeasures" that can be used to defeat the polygraph machine, if taken during the control questioning. Among the more common are tongue biting, foot tensing by pressing your toes against the floor, counting backwards from seven, or employing other mental distractions. While a good examiner can spot at least some such countermeasures, the wily prevaricator can fool even the best, for mental countermeasures, especially, are difficult to detect.
An Expert Liar Furnishes a Cautionary Tale
Vrij reports a cautionary tale for the lie detector business. Floyd "Buzz" Fay, a man who had been falsely convicted of murder based on a failed polygraph examination, sought his own type of revenge. During his two and a half years of wrongful imprisonment, he made himself a polygraph expert. Then he coached 27 men (who admitted to Fay their guilt) how to beat a control question based test.
After only twenty minutes of instruction, 23 of the inmates beat the machine. For good reason, polygraph tests are generally not admissible as evidence in the United States.
Scientific journals do report promising new developments in neuroscience research using modern technology, such as the latest in magnetic resonance imaging equipment, which might be able to improve lie detection in the future. But today, in the real world we have not progressed a long way since ancient times in China when suspected liars had to chew on rice powder and spit it out - if it remained dry, it meant a liar had been caught.
Tomorrow may be another story. Meanwhile, psychologists are making their own progress.
Characteristics Of Good Liars
Perfect liars, according to Vrij, are rare. A perfect liar shows absolutely no verbal or non-verbal clues of his or her deception. In contrast, most liars do show clues. Good liars are those who show only a few, or very subtle, behavioral clues when dissembling - clues that are difficult to discern, especially to the untrained eye. Or their false statements contain none of the indicia of lying.
For example, Vrij found that during his research, liars who sat still while being interviewed - but lied through their teeth, by pre-arrangement - typically gave observers the impression they were being honest. Yet they were not perfect liars because they usually showed unnatural rigidity when lying, or unwittingly gave some other clue.
The observer who is aware of the lying can catch such signs - and so, conceivably can the observer who does not know of the lying beforehand, but who is trained to detect it.
Clueless lying is not easy. And liars get caught, Vrij states, "because it is cognitively too difficult to continue lying, or because they way in which they deal with their emotions gives away to their lies." Good liars are those people who are not so affected - who do not have a strong emotional response, whether of shame, jubilation, or anxiety, to lying.
Vrij catalogues seven traits found in good liars. Good liars, he says, tend to be (1) well prepared, (2) original, (3) able to think quickly, (4) eloquent, (5) able to call up good memories, (6) devoid of feelings of fear, guilt or "duping delight" (conspicuous pleasure) when lying, and (7) possessed of good acting skills.
Needless to say, we all know many people who have all these traits. Ironically, and disturbingly, these traits are also essential for those who enter public office, as well.
So how do we spot the liars?
Catching Liars: Some Basic Principles
Vrij's studies show that while people can be trained to improve their skill at catching liars, this remains very much an art. And as with any art, some people will be better than others.
Moreover, some aspects of the art are easier to practice than others. In many of the studies Vrij reports, I noticed that most people are better at determining the truth than they are at spotting the falsehoods. It seems we are intuitively better at recognizing truth.
While I cannot begin to do justice in a few paragraphs to the work of Vrij and others, I can share what I took away from this work.
First, non-verbal signs like lack of eye contact, fidgeting, stuttering, pauses, slow speech, a higher-pitched voice, body stiffening, or emotional facial expressions are not necessarily signs of lying. No one should conclude any of these actions alone identifies lying, for each can indicate many other things instead.
Also, good liars often exhibit none of these traits when they lie. As Vrij explains, "there is no typical non-verbal behavior that indicates deception." Indeed, studies indicate that non-verbal behavior tells us the least about a person's truthfulness - a finding that is opposite to widespread public assumptions that a liar can best be caught through a stutter, tic, or evasive eye movement.
Second, television and (most) witness boxes in courtrooms are not designed to facilitate observing liars. Typically, television gives only a head shot, and many witness boxes often show the witness only from the chest up. Yet Vrij instructs that "looking at movements of the hands, fingers, legs and feet can be particularly useful in detecting lies ... the observer has to scrutinize the potential liar carefully and observe them almost literally from head to foot." Vrij notes that "eye movements do not give reliable information about deception."
Third, healthy suspicion uncovers lies. Law enforcement is suspicious; that's their job. Journalists should be more suspicious when public officials make dubious statements. The "trust me, I know what I'm talking about" posture of many public officials should be questioned more often. Those in public life should have the ability to back up their contentions with evidence, and the public should demand they do so more often.
Fourth, lies are flushed out by probing. In public affairs, this means the surrogates like members of Congress or journalist must do the probing.
Unfortunately, tough probes are typically avoided, particularly when televised. As Vrij's studies show, however, when interrogators "keep on asking questions about the topic" when they suspect a lie, it becomes increasingly difficult for the liar to lie about the topic.
This is because liars must avoid self-contradictions. To do so, they have to constantly remember what they have said on a given subject, while at the same time continuing to contain their emotions while lying. Doing both at once is a challenge even for a good liar.
Repeated questioning, however, is tricky. Studies also show that the liar who repeats the lie can actually gain credibility with observers. Perhaps that is because the repetitive questioner seems to be harassing the subject of questioning - or because the liars who are able to be consistent, thereby bolster the audience's natural inclination to believe rather than doubt.
Fifth, liars are more likely caught when others are well informed. As lawyers know, or painfully learn at some stage, during a trial a lawyer should never ask a question to which you don't know the answer. Lawyers try to learn all the answers ahead of time through depositions - which are often taken in civil cases for no reason other than to tie down the answer of a witness or party, so that their answer at trial will either be predictable, or able to be impeached with a deposition transcript. Depositions also educate the interrogator to know when the witness is lying.
The same holds true in public interrogations of officials: If the interrogator knows the answer, he can frequently determine the truthfulness of the witness. Unfortunately, most members of Congress take little time to prepare to interrogate witnesses, and only a few journalists undertake such efforts.
Finally, Vrij's analysis of the nature of verbal statements that are indicative of lying is most revealing. While liars don't provide standard verbal clues, there are verbal criteria that can help discriminate between fact and fiction.
For example, Vrij notes that "[l]iars make more negative statements, give more implausible answers, give shorter responses, make fewer self-references and give more indirect replies." While the presence of one - or even many - of these factors is not proof that a lie has been told, they are flags that can raise suspicion.
A few classic whoppers confirm the point: "I'm not a crook" (R. Nixon - negative, brief, indirect and by that time, implausible), "I was out of the loop" (George H. W. Bush - negative, brief, indirect, and implausible given that he was Vice President at the time), "I didn't have sexual relations with that woman" (W. J. Clinton - negative, brief, indirect in that it does not mention Ms. Lewinsky by name, and in light of his admitted affair with Gennifer Flowers, somewhat implausible too).
A more recent example is this one: "I got to know Ken Lay [in 1994] when he was the head of the - what they call the Governor's Business Council in Texas.... I decided to leave him in place, just for the sake of continuity." (George W. Bush - indirect and implausible, but at least self-directed and relatively lengthy, showing traits of a good liar; and those who were well-informed quickly documented the lie).
We should improve our ability to tell lies from the truth - at minimum by putting public officials to the test more often.