Encyclopedia of Psychology and Law

processes (or approaches) that might answer that

question. According to the emotional approach(some-

times called the affective approach), the three most

common types of emotion associated with deception

are guilt, fear, and excitement. A liar might feel guilty

because he or she is lying, might be afraid of getting

caught, or might be excited about the possibility of

fooling someone (“duping delight”).

According to the cognitive complexity approach

(sometimes called cognitive load or working memory

model), the lie should be possible to detect from the

liars’ nonverbal behavior because it is more difficult to

lie than to tell the truth. The liars have to come up with

believable answers, avoid contradicting themselves,

and tell a lie consistent with what the interviewer

knows or might find out. Additionally, they have to

remember what they have said, in order to declare the

same things again if asked to repeat their statement.

The attempted control approach emphasizes that

liars may be concerned that their lies will be detected

by, for example, nonverbal behaviors and will there-

fore try to suppress such behaviors. In other words,

they will try to make a convincing impression by, for

example, suppressing their nervousness and masking

evidence of thinking hard. However, when controlling

their body language, liars may overcontrol their behav-

ior, therefore exhibiting body language that will appear

planned, rehearsed, and lacking in spontaneity. For

example, liars may believe that bodily movements will

give their lies away and will consequently avoid any

movements not strictly essential, resulting in rigidity.

All three processes may occur simultaneously.

That is, liars could—at the same time—be nervous,

have to think hard, and try to control themselves.

Which of these processes is most prevalent depends

on the situation. In high-stake lies, nervous responses

are more likely to occur. In complicated lies, indica-

tors of increased cognitive load are more likely to

occur. Attempts to control behavior, voice, and speech

may especially occur in motivated liars.

Before turning to the outcomes of reviews about

nonverbal behavior, it should be emphasized that the

approaches only suggest that the presence of signs of

emotions, content complexity, and impression manage-

ment may be indicative of deceit. None of these

approaches claim that the occurrence of these signs

necessarily indicates deception. Truth tellers might

experience exactly the same processes. For example,

innocent (truthful) suspects might very well be anxious

if they worry about not being believed in a police inter-

view. Because of that fear, they may show the same

nervous reactions as liars who are afraid of being

caught. The lie catcher is then put in a difficult position:

Should the nonverbal behaviors be interpreted as signs

of guilt or of innocence? The behavior does not provide

the answer. The false accusation of a truth teller on the

basis of the emotional reactions displayed has been

labeled the Othello error, after Shakespeare’s play.

Nonverbal Behavior

and Deception in General

The most notable result of research to date is that non-

verbal behaviors generally do not correlate strongly

with either deception or truthfulness; very few reliable

nonverbal cues to deception have been found.

There is evidence that liars tend to speak in a higher-

pitched voice,which might be the result of experienced

arousal. However, differences in pitch between liars

and truth tellers are usually small and detectable only

with technical equipment. Furthermore, sometimes

liars’voices sound tenser than truth tellers’ voices,

another result of arousal. Speech errors(e.g., word

and/or sentence repetition, sentence incompletion, slips

of the tongue) occur more often during deception, and

response latency is longer before giving deceptive

answers. There is also evidence of message duration

being shorter for liars, who also tend to make fewer

illustrators(hand and arm movements modifying what

is said verbally). The decrease in movements might be

the result of lie complexity or overcontrol of behavior.

Moreover, compared with truth tellers, liars tend to

sound vocally less expressive, more passive, and more

uncertain.This might all be the result of overcontrol of

behavior. Liars also sound less involved and come

across as being less cooperativeand tending to make

more negative statements.This might be caused by a

negative emotion felt by the liar.

Perhaps the most remarkable outcome of the liter-

ature reviews is the finding that several signs of ner-

vousness, such as gaze aversion (avoidance of eye

contact) and fidgeting, are generally unrelated to

deception. One reason why nervous behaviors do not

seem to be systematically related to deception is that

truth tellers could be nervous as well. Another reason

could be that in most deception studies, people are

requested to lie or tell the truth for the sake of the

experiment, and in such studies, liars might not be

aroused enough to show cues of nervousness.

Summarizing the literature, there seem to be a

greater number of reliable verbal cues to deception

than nonverbal cues. This contradicts most police

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