[Paleopsych] Science News: Deception Detection
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Deception Detection: Science News Online, July 31, 2004
Psychologists try to learn how to spot a liar
"Is he lying?" Odds are, you'll never know. Although people have been
communicating with one another for tens of thousands of years, more
than 3 decades of psychological research have found that most
individuals are abysmally poor lie detectors. In the only worldwide
study of its kind, scientists asked more than 2,000 people from nearly
60 countries, "How can you tell when people are lying?" From Botswana
to Belgium, the number-one answer was the same: Liars avert their
"This is . . . the most prevalent stereotype about deception in the
world," says Charles Bond of Texas Christian University in Fort Worth,
who led the research project. And yet gaze aversion, like other
commonly held stereotypes about liars, isn't correlated with lying at
all, studies have shown. Liars don't shift around or touch their noses
or clear their throats any more than truth tellers do.
For decades, psychologists have done laboratory experiments in an
attempt to describe differences between the behavior of liars and of
people telling the truth. Some researchers, however, are now moving
away from those controlled conditions and are inching closer to
understanding liars in the real world. The researchers are examining
whether several behaviors that have emerged as deception signals in
lab tests are associated with real-life, high-stake lies. The
psychologists are also testing how well professional sleuths, such as
police and judges, can detect deceptions.
One thing, however, is certain: There is no unique telltale signal for
a fib. Pinocchio's nose just doesn't exist, and that makes liars
difficult to spot.
By studying large groups of participants, researchers have identified
certain general behaviors that liars are more likely to exhibit than
are people telling the truth. Fibbers tend to move their arms, hands,
and fingers less and blink less than people telling the truth do, and
liars' voices can become more tense or high-pitched. The extra effort
needed to remember what they've already said and to keep their stories
consistent may cause liars to restrain their movements and fill their
speech with pauses. People shading the truth tend to make fewer speech
errors than truth tellers do, and they rarely backtrack to fill in
forgotten or incorrect details.
"Their stories are too good to be true," says Bella DePaulo of the
University of California, Santa Barbara, who has written several
reviews of the field of deception research.
Liars may also feel fear and guilt or delight at fooling people. Such
emotions can trigger a change in facial expression so brief that most
observers never notice. Paul Ekman, a retired psychologist from the
University of California, San Francisco, terms these split-second
phenomena "microexpressions." He says these emotional clues are as
important as gestures, voice, and speech patterns in uncovering
But not all liars display these signals, and one can't conclude people
are lying because they don't move their arms or pause while telling
their stories. These could be natural behaviors for them, not signs of
lying. "They are statistically reliable indicators of deception," says
Timothy Levine of Michigan State University in East Lansing, but that
doesn't mean they're helpful in one-on-one encounters.
People don't seem to be very good at spotting deception signals. On
average, over hundreds of laboratory studies, participants distinguish
correctly between truths and lies only about 55 percent of the time.
This success rate holds for groups as diverse as students and police
officers. "Human accuracy is really just barely better than chance,"
Some researchers think, however, that the design of the laboratory
studies is responsible for the poor rates of lie detection. "People
are very good liars when nothing is at stake," says Aldert Vrij of the
University of Portsmouth in England. "But a lab setting is not real
In most experiments, researchers tell the subjects whether or not to
lie, and the lies have no effect on their lives. There's no
significant reward for a liar who's believed or punishment for a judge
"There is definitely a lack of real-life stuff in this field of
research," says Vrij.
Vrij has been looking at lies told not by participants in an
experiment but by actual suspects in police-interrogation rooms. A
major difficulty in using real-life lies is that the researchers
themselves often don't know the truth. To overcome that obstacle, Vrij
obtained police-recorded videotapes in which 16 suspects in the United
Kingdom, charged with offenses such as arson and murder, told both
lies and truths about their alleged involvement in the crimes. The
police used forensic evidence, witness accounts, and the suspects'
eventual confessions to determine the actual events.
Before learning the police conclusions, Vrij's team analyzed the
videotapes for signs of the suspects' nonverbal reactions to
questioning, such as gaze aversion, blinking, and hand-and-arm
movements. They also looked at verbal cues, such as pauses in speech
and speech disturbances, including "ahs," stutters, and incomplete
The differences between lying and truth telling were largely
individual: Some suspects looked away more while lying than while
telling the truth, and others increased their degree of eye contact,
for example. The only general difference Vrij found between liars and
truth tellers is that the liars blinked less frequently and paused
longer while speaking.
In contrast to participants in the lab studies, the crime suspects
didn't show any overall increase in speech disturbances or decrease in
hand-and-arm movements. Because of the intense nature of a police
interrogation, stressed truth tellers may display the same behaviors
as liars do, Vrij speculates.
He is currently exploring lie detection from the side of the
interviewer rather than the suspect. He showed 99 police officers
tapes of real-life lies and truths and found that the officers were,
at 65 percent accuracy, slightly better than lab-study participants at
discerning the difference. But police are "still far away from
perfect," Vrij points out.
He attributes the police officers' slightly better performance
primarily to the nature of the lies they hear during an interrogation.
"More is at stake, and that gives the lies away more," he says.
Most recently, Vrij has tested whether the police officers' accuracy
rates are consistent in multiple tests. In this study, 35 police
officers took four tests derived from interviews of either liars or
truth tellers, and 70 percent of the professionals' calls were
Although the officers again outperformed participants in lab studies,
no individual officer stood out. "Our early findings indicate that
none was consistently good or consistently bad," Vrij says. "Nobody is
80 percent overall."
Wizards of detection
Other researchers, however, present evidence that highly skilled human
lie detectors do exist. The scientists have been trying to identify
such people and figure out how they recognize lies.
In a now-famous study from more than a decade ago, about 500 Secret
Service agents, federal polygraphers, and judges watched 10 1-minute
video clips of female nurses describing the pleasant nature films they
were supposedly watching as they spoke. Half the women were instead
watching what Ekman calls "terribly gruesome" medical films. The
legal-system professionals were asked to determine the truth by
reading the women's faces, speech, and voices.
Ekman and his coauthor Maureen O'Sullivan of the University of San
Francisco motivated the women to lie by telling them that because
nurses shouldn't be bothered by gory images, their believability
related to their future career success.
Most of the observers uncovered lies at only about the level of
chance. One group, however, outperformed the others. The Secret
Service group had a better-than-chance distribution, with nearly
one-third of the agents getting 8 out of 10 determinations correct,
the San Francisco psychologists reported in 1991.
O'Sullivan now says that her further studies of federal agents,
forensic psychologists, and other groups of professionals indicate
that a very small percentage of people are extremely good at spotting
a phony. "We always found one or two people who were very good," she
Over the past decade, she has given a series of tests to more than
13,000 people from all walks of life, including therapists, police
officers, law students, artists, and dispute mediators. In the first
test, college students either lie or tell the truth about a strongly
held opinion, such as their views on abortion or the death penalty.
The researchers motivate the students by instituting a system of
rewards and punishments, although for ethical reasons, the study
participants know that they can withdraw at any time.
The subjects are told that if they are judged to be lying, even if
they're not, they'll be locked in a dark room about the size of a
telephone booth for 2 hours and subjected to intermittent blasts of
noise. "We actually didn't do that, but that was the threat," says
If a student is believed, he or she earns $50 to $100. These rewards
and punishments, Ekman says, "cross a certain threshold so that you
generate similar behavior and emotional clues" in the experiment and
in real life.
Observers who judge the students' opinions correctly 90 percent of the
time or better move on to two more tests. The motivation for the
students to lie remains the same.
In the first of these tests, students describe their participation in
a mock crime scenario. The second test again uses nurses lying or not
lying about watching nature films. Human lie detectors who get 80
percent correct on both the additional tests are "ultimate wizards" of
lie detection, says O'Sullivan.
She has identified only 15 people as ultimate wizards, about 0.1
percent of the people who have taken the series of tests. "People who
are extraordinarily good are extraordinarily good, no matter what the
lie is," says Ekman. Another 16 people are "penultimate wizards,"
getting 80 percent on either the mock-crime test or the nature-film
test, but not on both.
O'Sullivan has asked the wizards questions about their lie-detection
processes. "All of them pay attention to nonverbal cues and the
nuances of word usages and apply them differently to different
people," she says. "They could tell you eight things about someone
after watching a 2-second tape. It's scary, the things these people
notice," she says.
O'Sullivan compares these skillful observers to Agatha Christie's
fictional Miss Marple, who could instantly judge the veracity of
someone by comparing him or her to people she'd already encountered.
Bond, however, doubts that O'Sullivan's experiments can be
successfully applied to real-life liars. The system of rewards and
punishment doesn't make the laboratory environment similar to a
police-interrogation room. "A dark room and noise is not comparable to
the threat of lethal injection," Bond says.
He also suggests that the supposed lie-detection wizards are just
people who happen by chance to do well on all three of O'Sullivan's
tests. O'Sullivan, however says that's unlikely.
Bond and DePaulo recently reviewed 217 studies going back 60 years
that together include tens of thousands of subjects. The analysis
found no evidence of significant differences between people in their
ability to detect lies in various scenarios, Bond says.
Ekman and O'Sullivan speculate that if they could only study enough
people, they might learn specific techniques that good lie detectors
use. Then, it might be possible to deconstruct their skill and teach
it to others, such as police officers, the researchers say.
Vrij, for instance, reports in the April Applied Cognitive Psychology
that he has increased people's accuracy by a few percent by teaching
them to make quick assessments of behaviors such as the frequency of
hand movements. However, Levine speculates that even a bogus program
can succeed by simply getting people to pay attention.
"Training may increase your hit rate a little bit in the long run, but
you're still missing a lot," Levine says.
But because witnesses, hard facts, and physical evidence are often
scarce, Ekman says, "it's worth training people to be as accurate as
they can be."
Bond, C., et al. A world of deception. (unpublished
manuscript--submitted to Journal of Cross-Cultural Psychology, but not
Ekman, P., and M. O'Sullivan. 1991. Who can catch a liar? American
Psychologist 46(September):913-920. Available at
Mann, S., A. Vrij, and R. Bull. 2004. Detecting true lies: Police
officers' ability to detect suspects' lies. Journal of Applied
Psychology 89(February):137-149. Abstract.
Mann, S., A. Vrij, and R. Bull. 2002. Suspects, lies, and videotape:
An analysis of authentic high-stake liars. Law and Human Behavior
26(June):365-376. Abstract available at
Park, H.S., T.R. Levine, et al. 2002. How people really detect lies.
Communication Monographs 69(June):144.
Vrij, A. In press. Why professionals fail to catch liars and how they
can improve. Legal and Criminological Psychology.
Vrij, A., et al. 2004. Rapid Judgments in assessing verbal and
nonverbal cues: Their potential for deception researchers and lie
detection. Applied Cognitive Psychology 18(April):283-296. Abstract
DePaulo, B.M., and W.L. Morris. In press. Discerning lies from truths:
Behavioral cues to deception and the indirect pathway of intuition. In
Deception Detection in Forensic Contexts, Granhag, P.A., and L.
Stromwall, eds. Cambridge: Cambridge University Press.
Ekman, P. 1997. Lying and deception. In Memory for Everyday and
Emotional Events, Stein, N.L., P.A. Ornstein, B. Tversky, and C.
Brainerd, eds. Mahway, New Jersey: Lawrence Erlbaum Associates.
Ekman, P. 1996. Why don't we catch liars? Social Research
63(Fall):801-807. Available at
Frank, M.G., and P. Ekman. 1997. The ability to detect deceit
generalizes across different types of high-stake lies. Journal of
Personality and Social Psychology 72(June):1429-1439. Available at
Levine, T.R., and S.A. McCornack. 2001. Behavioral adaptation,
confidence, and heuristic-based explanations of the probing effect.
Human Communication Research 27(October):471-502. Abstract available
Levine, T.R., et al. 2000. Norms, expectations, and deception: A norm
violation model of veracity judgment. Communication Monographs
Levine, T.R., H.S. Park, and S.A. McCornack. 1999. Accuracy in
detecting truths and lies: Documenting the "veracity effect."
Communication Monographs 66(June):125.
Vrij, A. In press. Guidelines to catch a liar. In Deception Detection
in Forensic Contexts, Granhag, P.A., and L. Stromwall, eds. Cambridge:
Cambridge University Press.
Department of Psychology
Texas Christian University
TCU Box 298920
Fort Worth, TX 76129
Bella M. DePaulo
Department of Psychology
University of California, Santa Barbara
Santa Barbara, CA 93106
P.O. Box 5211
Berkeley, CA 94705
Department of Communication
4 Huntington Street
New Brunswick, NJ 08901
Department of Communication
Michigan State University
482 Comm Arts Building
East Lansing, MI 48824
Department of Psychology
University of San Francisco
2130 Fulton Street
San Francisco, CA 94117
Department of Psychology
University of Portsmouth
King Henry Building
King Henry I Street
Portsmouth PO1 2DY
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