http://news.bbc.co.uk/2/hi/health/5316916.stm

No amount of coaching or media training can co-ordinate the hand gestures and facial expressions to fully cover up what a person knows not to be true.
For example, each politician has their own signature tells which a trained eye can use to detect moments of stress during a speech or press conference, claims Dr Collett.

Tony Blair unconsciously fiddles with his little finger whenever an opponent makes him anxious.

George Bush, on the other hand, bites the inside of his cheek at anxious moments.

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In some cases, the politician may be aware of the effect of the movement itself.

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George Bush walks like a body builder, hanging his palms to the rear as though laden down by huge muscle, to imply that he's larger than he actually is, says Dr Collett.


So. Does this mean we should all start studying the psychology of movement to determine which politician we can trust? Since obviously they do lie.

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Dictionary of Body language cues
http://members.aol.com/nonverbal2/entries.htm#Entries

Deception:

RESEARCH REPORTS:

1. Deliberate control of body movement and the mental energy required to fabricate a lie have been suggested to explain the general research finding that fewer body movements occur with deception (Vrij et al. 1966).

2. Lower rates of head nodding "are associated with deceitful communication" (Mehrabian 1972:102).

3. Three ". . . extensive reviews of the data . . . showed that several nonverbal cues are, in fact, consistently related to deception" (Burgoon et al. 1989:270). "Deceivers display increased pupil dilation [see EYES], blinking rates, and adaptors [i.e., self-touching], more segments of body behavior, and fewer segments of facial behavior" (Burgoon et al. 1989:271).

4. Paul Ekman suggests that one should ". . . never reach a final conclusion about whether a suspect is lying or truthful based solely on either the polygraph or behavioral clues to deceit" (Ekman 1992:238; ).

5. People make "fewer hand movements during deception compared to truth-telling" (Vrij et al. 1997:97).