of prespecified verbal and nonverbal behaviors and for
each particular behavior (e.g., gaze aversion and head
movements), rate the extent to which they believe that
this behavior is indicative of deception. The second
method is used in studies where participants first
watch videotapes of deceptive and truth-telling senders
and then judge these in terms of veracity. Most studies
on beliefs about deception have employed college
students as participants, but there is also research on
experts’ beliefs about deception (e.g., police officers,
customs officers, prison guards, prosecutors, and
judges).
The available research shows that the beliefs held
by experts and lay people are very similar. In terms of
nonverbal cues, the evidence suggests that both
experts and lay people consider nervous behaviors to
indicate deception. For example, both experts and lay
people believe that eye contact decreases during lying,
but research on objective cues to deception has shown
that this particular cue is not a reliable predictor of
deception. Furthermore, both experts and lay people
have indicated a strong relationship between decep-
tive behavior and an increase in bodily movements,
which is also incorrect. In terms of verbal indicators
of deception, both experts and lay people believe that
truthful messages are more detailed than deceptive
ones, and to some extent, research on objective cues to
deception supports this belief. Researchers have in
addition studied cross-cultural beliefs about deception
and found that people around the world believe that
deception can be spotted in the eye behaviors of the
sender, such as gaze aversion. As regards accuracy in
cross-cultural deception judgments, the available
research shows that, as expected, deception is even
harder to detect when the sender and receiver are not
from the same cultural or ethnic group.
In sum, research on beliefs about deception has
shown that the beliefs are similar for experts and lay
people and that these beliefs to a rather large extent
are misconceptions about how liars actually behave.Training to Detect Deception
In a number of published studies, researchers and
scholars have tried to train people in detecting deceit.
The training programs have differed markedly in con-
tent and duration, but information about the mismatch
between beliefs about deception and actual indicators
of deception seems commonplace. Often, feedback on
the veracity judgments made has been provided aswell. In general, training has been shown to signifi-
cantly increase the accuracy of lie detection—a small
but detectable increase is most often found. However,
even if an increase is found, it usually is from, say,
55% to 60%, which is still of limited practical value.
Furthermore, the long-term effect(s) of training is not
as yet known. Unfortunately, the one group of partic-
ipants that has been the hardest to train to become bet-
ter in the deception detection task is police officers.Limitations and Future Challenges
When deception detection research has been criticized,
it is often the type of lies studied that has come under
attack. For example, most of the lies studied have not
been about transgressions, so some critics have argued
that the lies told are not high-stake lies; others argue
that the social aspects of lying and lie detecting are too
constrained in experimental settings; and legal scholars
point out aspects of the forensic world that have
not been examined in research contexts. Deception
researchers have tried to answer the critics by, for
example, studying murderers’ and other criminals’ lies
in police interviews, lies that could harm children, and
lies to lovers. Researchers have also begun to study nat-
uralistic deceptive interactions, jurors’ credibility judg-
ments, and police officers’ assessments of veracity after
conducting the interviews themselves.
In experiments, the receivers come across one brief
message and must judge the veracity of that message
on the spot, with no time or opportunity to collect
additional information. Outside the laboratory, how-
ever, additional information is important. When asked
to describe their discovery of a lie, people rarely state
that the discovery was prompted by behaviors dis-
played at the time of the attempted deception. Rather,
they say that lie detection took days, weeks, or even
months and involved physical evidence or third par-
ties. In police interviews, for example, the evidence in
the case may be used as a tool to detect deception.
Future studies will be needed to examine the impact
on lie detection of these and other forms of extra-
behavioral information. At present, across hundreds of
experiments, the typical rate of deception detection in
adults remains just above the level of chance.Pär Anders Granhag and Leif A. StrömwallSee alsoDetection of Deception: Nonverbal Cues; Detection
of Deception: Reality Monitoring; Detection ofDetection of Deception in Adults——— 211D-Cutler (Encyc)-45463.qxd 11/18/2007 12:41 PM Page 211