motivated rather than unmotivated senders, in accor-
dance with the hypothesis.
However, this result has been found for within-
study comparisons and has generally not been found
when comparing between studies. Here, the reliable
difference found is that motivated participants appear
less truthful than those with no motivation to succeed.
It matters little if a highly motivated speaker is lying
or not; what matters is the fear of not being believed.
Research further indicates that motivation in itself
affects how the sender is perceived differently for dif-
ferent media: Motivation reduces senders’ video and
audiovisual appearance of truthfulness but has no
effect on how truthful a sender sounds.Is seems as if
motivation makes people resemble a visible stereo-
type of a liar. If so, motivational effects on credibility
might be most apparent in video-based judgments.
In conclusion, the accumulated evidence suggests
that people who are motivated to be believed appear
deceptive, whether or not they are lying.Interaction
In some studies, the deceptive and truthful senders are
alone, talking to a camera. In other studies, an experi-
menter, blind to the veracity of the person in front, asks
a standardized set of questions. Sometimes, the inter-
action partner is attempting to judge the veracity (such
as in a mock police interview or interrogation); on
other occasions, an observer may be making this judg-
ment. The latter occurs, for example, when the interac-
tion partner is the experimenter and the observer is the
receiver assessing veracity on the basis of the video-
taped interaction. In principle, social interaction might
influence the receiver’s veracity judgments and/or the
receiver’s success at detecting deception.
The literature produces clear evidence that receivers
are inclined to judge their interaction partners as truth-
ful much more often than observers do. The overall
pattern in the literature further suggests that observers
are better than interaction partners at discriminat-
ing lies from truths. It seems as if people do not
want to believe that someone has just lied to them
without their spotting it. Alternatively, the reluctance
to attribute deception to interaction partners could be
the result of not wanting to insinuate that the partner
is a liar.
In summary, research suggests that lies told in
social interactions are better detected by observers
than interaction partners.Expertise
Usually, those making veracity judgments in decep-
tion research are college students. They have no spe-
cial training and may have no interest in or reason for
succeeding in the task. Reasonably, people with more
experience would be better at judging deceit, and to
assess this possibility, researchers have also tested
presumed deception detection experts. These are indi-
viduals whose occupations expose them to lies, and
they include law enforcement personnel, judges, psy-
chiatrists, job interviewers, and customs officials.
The results are clear-cut. The “experts” are not
experts at lie detection—there is no reliable difference
in deception detection accuracy compared with novices.
The accumulated research further suggests that experts
are more skeptical than nonexperts, meaning that they
are less inclined to believe that people are truthful.
Having been targets of deceit in their professional
roles, these experts may have overcome the usual
unwillingness to infer that certain people are liars.
However, it should be noted that the experimental set-
ting that the experts have been tested in may not make
possible a fair representation of their expertise. For
example, police officers very rarely assess veracity on
the basis of one, short videotaped interview and with-
out having access to evidence. Therefore, the conclu-
sion that experts are not better than laypeople at
detecting deception may be premature. Future research
is needed to shed light on experts using their expertise
in a more ecologically valid setting.Beliefs About Deception
The most often stated reason for the low accuracy
rates found in deception research is that there is a dis-
parity between what actually is indicative of decep-
tion and what people believe to be indicative of
deception. As hinted at earlier, there is a stereotypical
belief concerning a liar’s behavior. A belief is a feel-
ing that something is true or real; it can be strong or
weak, correct or incorrect. The beliefs that a person
holds are often reflected in his or her behavioral dis-
positions; that is, beliefs guide action. Hence, if one
wants to learn about deception detection, it is impor-
tant to study people’s beliefs about deception.
Two different methods have been used to investi-
gate people’s beliefs about cues to deception: surveys
and laboratory-based studies. In the surveys, partici-
pants have typically been asked to work through a list210 ———Detection of Deception in AdultsD-Cutler (Encyc)-45463.qxd 11/18/2007 12:41 PM Page 210