On Dutch TV they will be starting to broadcast ‘Lie to Me’, a TV series (see Wikipedia). The series is founded on the idea that it is possible to tell a lie from seeing a few ´tell-tale signs’. Watching downwards indicates you’re guilty. Biting your lip indicates lying. That sort of stuff. Paul Ekman and his colleague Friesen did research on this idea back in the 1970’s which is still the only evidence, as far as I am aware of, that the idea holds any real value.
Personally, I find it very hard to believe that people are such bad liars that they can be spotted so unambiguously. But then again, I have my doubts about physiological lie detection tests too. Even if everything is done properly (including additional testing to detect masking efforts) they will still have a 5% fault margin I’m told by a guy doing such tests. What then to make of a lip bite? There is a world of gestures and signs on our two lips, see for example this entry in the ‘nonverbal dictionary’ (here). I am not too fond of that dictionary, again because of its total lack of appreciation of ambiguity and human resourcefulnes. But it shows a nice collection of ‘lip signs’.
There is simple too little known about the usefulnes of behavioral clues to detect lies. To what extent can people control their behavior? Can they suppress it? Is it ‘unconscious’ or unwilling? Is it entirely beyond the will of a crook acting a saint? Can people mask the behavior? Or throw up a smokescreen of ‘tell tale signs’? Does everyone show these signs in the same manner? What about men and women? Children and adults? Japanese and Nigerian people? People from Boston or New York? Married or unmarried? Parents or not?
In addition, to what extent can observers, like the main characters in Lie to Me suppress their personal opinion. Will they not be influenced by the power of suggestion and spot that what they wish to see? If I think a man is guilty I will easily notice his every downward glance, won’t I. The eye of the beholder is not an innocent eye.
Please, good people of the world. Watch ‘Lie to Me’ for your entertainment, but do not think it is based on scientific evidence.