Deception Detection for Interviewers

The Psychology of Lies: Behavioral Science Perspectives on Conducting Successful Interviews

There are plenty of myths about the “science” of lie detection.

Despite what popular books on nonverbal behavior may say, there’s no scientific evidence that crossed arms or legs indicate a non-receptive person, or that deceivers touch their noses, evert their eyes, or cover their mouths.

Unfortunately, deception detection isn’t so simple, say behavioral scientists who actually study communication and deceit using scientific methods. Spotting a lie, it seems, is an inexact science.

So how can investigators improve their chances of discovering deceit during investigative interviews? To tackle this topic and overcome popular misconceptions, I asked three leading research psychologists who specialize in the study of deception to share their insights on how to catch a liar.

The Experts:

David Matsumoto, San Francisco State University
Aldert Vrij, University of Portsmouth (UK)
Caroline Keating, Colgate University

Deception detection researcher Paul Ekman established that basic emotions are universal, as are their expressions.

Why Humans Are Good Deceivers and Lousy Detectors

According to Caroline Keating, we’re better liars than we are lie detectors. This point is echoed in various academic studies, which suggest that most people are no better than 50/50 at detecting deception by observing verbal and nonverbal cues.

Research conducted by Paul Ekman and Maureen O’Sullivan, published in Psychological Science in 1991, suggests that even professionals involved in fighting crime (such as law-enforcement and judges) veer only a little better than chance at detecting deception.

According to David Matsumoto, later research by Ekman and O’Sullivan demonstrated that law enforcement personnel were able to tell when people were lying about whether they committed crimes, but not about their opinions on various topics. Of the law enforcement professionals tested by Ekman and O’Sullivan, the Secret Service were the most able at detecting deceit, averaging a 65% success rate.

The bottom line is that even if law enforcement as a whole is better at detecting deception than the general public, that isn’t a particularly impressive statistic.

Most people are no better than 50/50 at detecting deception by observing verbal and nonverbal cues.
But there’s hope yet for lie detection science.

Matsumoto points out a problem with academic research on the topic: Many experiments are based on low-stakes lies. In the real world, lies that concern investigators or potential employers are usually high stakes—in other words, liars in the interrogation room have a lot more to lose than study participants.

How to be a Good Liar

Naturally, some people are bad liars; but professional investigators are concerned with the gifted ones. It stands to reason that to be a good lie spotter, the investigator needs to know what makes a good liar.

Sometimes the investigator may need to be good a liar himself in order to go undercover or pretext.

According to Keating, good liars are ultimately good actors. Her advice on how to lie convincingly is to “rehearse” in order to reduce anxiety; she also suggests creating plausible responses by interweaving deception with truth. Good lying, like good acting, is an art that requires a plausible story, well-practiced.

There are, however, pathological types that make natural liars: psychopaths and pathological liars such as those suffering from Münchausen syndrome. Pathological liars may tell lies with ease, but they are usually unmasked over time by inconsistencies, which earn them stigmatized reputations.

Psychopaths, on the other hand, are natural chameleons that mimic the behavior expected of them but have little or no emotional attachment.

The latter condition is thought to result from structural differences in the frontal lobe and amygdala—areas of the brain that are responsible for regulating emotion. In essence, psychopaths have little fear or anxiety but are natural actors. Keating notes that their “lack of stress” enables them as deceivers.

Good lying, like good acting, is an art that requires a plausible story, well-practiced.

Like the psychopath that simulates love for another when it serves him, good liars uses a measure of control over emotional appearances to overcome discovery, says Keating. The possibility that a liar will be unmasked naturally creates the desire to avoid the issue, but a savvy liar can take the offensive.

For instance, he may mimic anger or hurt in response to an accusation that’s true. The seeming natural response would be anxiety or embarrassment, but a good liar can turn the tables, emotionally speaking.

A final quality of good liars, according to Keating, is self-deception. She cites the story of Colonel Oliver North, who tried to hide evidence of U.S. arms sales to Iran and illegal funding of the Contras. North knew he was breaking the law, but he was acting on behalf of senior government officials—on some level, he believed he was doing the right thing.

Lying to himself, according to Keating, may have enabled him to lie about his actions more convincingly.

Self-deception reduces anxiety by justifying the lie. Presumably the Russian SVR agent presenting as an American businessman, the Al Qaeda operative engaged in terrorism, and the investigator pretexting during a fraud investigation are all enabled by a belief of inherent righteousness.
Caroline Keating suggests that anxiety lies at the root of high-stakes lies—if unmasked, the deceiver faces stiff consequences. But the researcher’s dilemma is that high-stakes lies—and the anxiety associated with them—are hard to ethically replicate in the laboratory.

There is, therefore, hope that in real-world scenarios, fear may betray the deceiver’s self-control more inexorably than it does in the dispassionate environment of the behavioral-science lab.

Catching Liars Through Cognitive Taxation

Aldert Vrij suggests we throw out all notions of specific nonverbal cues and rather look for narrative inconsistencies when mining for lies. To that end, he provides several guidelines based on a synthesis of psychological and social science research. Most notably, Vrij supports the proposition of “imposing cognitive load.”

The idea here is that lying requires extra psychological effort at creating a plausible story, whereas the truth doesn’t, because the teller is simply recalling, not inventing. According to Vrij, an interviewer can exploit this fact through several strategies (as summarized below):

1. Ask for details.

The more details the interviewee provides, the more chance of inconsistency. This fact alone may cause the guilty interviewee to be reluctant about answering questions or to give short or vague responses. If the interviewee is reluctant or vague in responding to a question, the interviewer should pursue the subject further.

Vrij suggests borrowing from the techniques of “cognitive interviewing”—developed to enhance eyewitness’ memories—because they are useful in encouraging the subject to report details. Such techniques include asking the subject to describe his story with richness and imagery and to reassure him that no detail is without significance or is too trivial.

While inconsistency, vagueness and hesitancy can be signs of deception, details provide the practicality of more information that can be cross-referenced and validated.

2. Encourage the subject to describe events in reverse order.

Because a lie is a fabrication, it may be more challenging for the liar to describe events in reverse order, because such act creates extra “cognitive load.” Vrij cites research in which subjects watched videos in which they had to distinguish a liar from a non-liar.

Subjects detected the liar 42% of the time when the lies where sequential but 60% of the time when the liar had to describe what happened in reverse order.

3. Ask unexpected questions.

Just as Caroline Keating suggests that the would-be-liar rehearse responses to possible tough questions, Vrij suggests asking “unexpected questions” as a counter-measure. To be successful, the interviewer must be able to develop relevant questions that the interviewee doesn’t anticipate.

Vrij cites experiments that show that liars produce fewer details when responding to unanticipated questions than truth-tellers.

4. Conduct an information-seeking interview rather than a confrontational interview.

Vrij is critical of the popular Reid method of interviewing, which progresses from interview to accusation. (Some researchers have asserted that success-rate claims in texts on the topic are unverifiable and un-replicable.) Basically, the Reid method presumes guilt and incrementally increases pressure on the subject to make a confession.

In contrast, Vrij promotes the information-seeking interview, in which the interviewer aims to build rapport and plays a sympathetic role in order to coax out facts. Vrij cites a recent meta-analysis of several field studies (as well as laboratory studies), which found that information-seeking approaches yield more information and cues to deceit than confrontational approaches.

Evidently, information-seeking interviewing is a war-proven approach: Ali Soufan, A CIA interrogator, describes using information-seeking interviews with good success on Al-Qaeda suspects in developing intelligence in his book, The Black Banners.

5. Strategic Use of Evidence (SUE)

Vrij advocates an approach developed by Maria Hartwig in her doctoral dissertation, which studied the presentation of evidence in interrogations. Hartwig’s research showed that the non-accusatorial interview— asking open-ended questions and presenting evidence late in the interview—revealed more inconsistencies and contradictions than if the evidence were introduced early.

Furthermore, when interrogation trainees formulated indirect questions specific to the evidence without revealing their own knowledge of the evidence, their ability to detect deception significantly increased. (Such questions are also introduced at a late stage in the interview.)

A later study on SUE showed that trainees utilizing the SUE method produced 85% accuracy vs. 56% over a control group of interrogators not trained in SUE in determining the veracity of statements made by interviewees.

Catching Liars Through Emotional Leakage

Paul Ekman is widely credited with establishing that basic emotions are universal, as are their expressions.

Some anthropologists (such as Margaret Mead) theorized that facial expressions and emotional expressions were learned behaviors with culturally relevant meanings. Ekman’s research took him to Papua New Guinea, where he discovered an isolated primitive tribe whose members were able to accurately describe the meaning of facial expressions from pictures of Westerners.

Ekman is best known for his work on micro expressions—facial expressions that last a faction of a second and are believed to be involuntary. The proposition that these fleeting expressions reveal the true emotion of the subject led Ekman to suggest the ability to posit micro-expressions as a means of truth detection.

Ekman and his colleagues David Matsumoto and Mark Frank then developed a micro expressions training tool called METT—utilized by the TSA and other federal agencies—which has been further expanded independently by both Ekman and Matsumoto.

Matsumoto has been at the forefront of academic scholarship on nonverbal behavior and cross-cultural psychology. He heads a company called Humintell that provides seminars and training material on recognizing and interpreting micro-expressions.

When I asked what actions investigators can take to improve their sensitivity to deception, Matsumoto said this:

“Get trained on the VALIDATED indicators of veracity and deception, both verbal and nonverbal.”

“Learn to strategize their interviewing techniques to maximize the potential for them to receive CLEAR verbal and nonverbal signals to interpret.”

Caroline Keating concedes that micro-expressions betray a person’s true feelings, but she adds this caveat: “You almost need a video camera running in slow motion to see them,” (although Matsumoto counters that a person can be trained to see them in real time). Keating recommends scanning for anxiety and attempts at self-control when looking for deception but also recognizes that individuals have different baseline behaviors and different levels of response.

For instance, one person may be naturally anxious in most situations, while another may become anxious when asked questions that he believes may falsely incriminate him. There are also liars who show little anxiety because they are well rehearsed in their deceit, are self-deceived, or suffer pathological conditions.

The bottom line: a guilty person facing the possibility of unmasking should be anxious, but so, too, could an innocent person fearing for his freedom…and there are exceptions to every rule. To deal with variations in behavior between people, Keating suggests the importance of interpreting behavior by gauging the individual’s “baseline” behavior.

Parting Wisdom

Popular science is not the same as real science, nor is real science on complex human behavior fully resolved. Unfortunately, popular beliefs on nonverbal behavior and lie detection have managed to leak into texts on police interviewing and interrogations.

Nonetheless, behavioral science is making headway, and savvy investigators should pay attention. Ultimately, an interview with a suspect relies on psychological strategizing that aims to unmask the truth.

Deceit betrays itself by behavioral and narrative inconsistencies. Looking for incongruences in a subject’s story and behavior is common sense, but investigators can improve their chances of discovering lies by aligning their strategies with advances from the behavioral sciences. Watching for involuntary micro-expressions and the theory of cognitive load are two such advances that can aid an investigator’s tactics and observations.

There are many variables in human behavior. The investigator must consider all possibilities when interpreting the significance of a statement, pause, contradiction, gesture or hesitation. The goal shouldn’t be to become a psychological X-ray machine, because that’s currently impossible.

Instead, the investigator should aim to acquire verifiable intelligence, and/or, if the intelligence merits it, a true confession. The tips offered in this article provide the investigator with insights from world-class researchers in the field on how to achieve those goals.

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