Forensic Psychology For Dummies (45 page)

Some people assume that a guilty person is likely to be more nervous when lying and shows his stress through displaying more hand movements, slower speech and general fidgeting. But studies show that the opposite is the case. A person under pressure of maintaining the lie is concentrating harder on the lie, with the result that he displays
less
non-verbal leakage than you may expect. On the other hand, a person who’s telling the truth is so often concerned to show that he’s telling the truth that his body language may become more animated and exaggerated.

Body language
is a gripping metaphor for communicating through gestures, facial expressions and other bodily movements. But these movements are not a
language
in the same way the written and spoken word is. They can add emphasis, as when people thump the table, but these movements and gestures do not provide an account of what is claimed that can be open to logical scrutiny of how plausible it is.

Micro-twitches

Paul Ekman, has spent over 40 years studying how people express emotions, focusing on the small changes in facial muscles that go with what a person’s feeling. These
micro-twitches
often last only a fraction of a second and you can see them best from watching a slow-downed video recording. Ekman claims that micro-twitches show what a person is feeling even when trying to hide their emotions. They are not really part of body language because they are only visible under very special scrutiny.

Giving a false smile to hide what you’re really feeling is the most obvious micro-twitch. Ekman’s theory claims that although the muscles round the mouth are indicating pleasure the facial muscles around your eyes are showing the opposite.

As a result of Ekman’s research micro-twitches are now being used for detecting lying and deceit.The problem is that these tiny facial muscles can only show strong emotions, such as anger, fear or surprise. If strong emotions can be proved to link directly to truthfulness or lying, micro-twitches can be valuable in detecting deception. For example, the suspect may be asked how he feels about his victim, and says that he liked her, while his wrinkling nose is indicating disgust. Or, when the suspect is asked directly if he’s lying and he denies it, but the micro-twitches around his mouth are showing that he himself doesn’t believe in what he’s saying.

Paul Ekman warns against the danger of ignoring the value of micro-twitches as a way of detecting lying, calling it the ‘Othello Error’. Remembering how Othello in Shakespeare’s play refuses to believe Desdemona’s protestations of innocence, totally ignoring her anguished face, and then killing her out of jealousy – so the investigator needs to bear in mind that the workings of the facial muscles have a part to play in helping get at the truth when you’re interviewing a suspect in a crime investigation. The practice of observing micro-twitches as a way of detecting malicious intent is now being used in public places such as airports. However, this practice is being questioned on the grounds that a particular facial expression can be because of a person’s culture in which such expressions are normal, as much as being a sign of what the person’s thinking and feeling. There are also people who have a general dislike of authority and show this dislike in their facial expressions despite being innocent of any crime.

Aldert Vrij and his colleagues carried out an experiment for observing the rate of blinks before and after a person was telling a lie. Vrij found that the relative differences in the rates were much larger for liars than truth-tellers. As the experiment was small, having only 13 people in each group, the results are open to question.

Paralinguistic cues

What a person’s telling you, and the actual meaning of what they’re saying, is often less to do with
what’s
being said than
how
it’s being said. Because these aspects of speech run parallel to one another, they’re called
paralinguistic cues
, such as:

Indulging in pauses, of varying length and frequency.

The number of mispronunciations or inappropriate words.

Speed of delivery, either very fast or very slow.