Is possible discover a liar?

The piece of news I selected is about the possibility of discover a liar. Generally, people think that the best form to know if someone is telling us the truth is looking directly to the eyes and see if they move the look when speak, but according with the experts mention in the article don't exist basis to make these assertions. The psychologist Richard Wiseman says that trust in this idea could be a problem because the people can control easily their look and deceive to others looking directly to eyes when in fact is making a big lie. Wiseman explain that a best form to discern if someone is saying the truth is  to listen to the person's voice and words, because the liar tend to use more "uhm and ahhs" and don't refer to themselves so much. However, neither is a perfect way to discern untruths. Judi James, an expert body lenguage, think the same that Wiseman and declare that the body-lenguage clues never can tell us exactly what is thinking a person. The piece of news was write because David Cameron, Prime Minister of the United Kingdom, declare have a skill to discern untruths, however the experts coincide in that he can't trust in this, bacause don't exist basis. For that, James advise that he need some coaching to don't make mistake in world conferences and financial meetings.

http://www.theguardian.com/science/shortcuts/2012/sep/26/telling-truth-look-into-eyes