I can only recommend the book ‘Spy the Lie: How to spot deception the CIA way‘ by Philip Houston & co. In spite of the title it is a book written by real professionals of deception identification and the approach is very interesting.
Basically the approach is “in order to determine whether a person is being untruthful, we need to look and listen for the first deceptive behavior to occur within the first five seconds after that stimulus is delivered“.
Then in addition, to be valid this deceptive behavior needs to come as a cluster with a second deceptive behavior following closely. “A cluster is defined simply as any combination of two or more deceptive indicators, which, you’ll remember, can be either verbal or nonverbal. So a cluster might be one verbal and one nonverbal, or two nonverbals, or two verbals and one nonverbal, and so on. What do you do if there’s just a single deceptive behavior in response to the stimulus? You ignore it.”
The difficult side of the approach is that “The strategic principle is that if you want to know if someone is lying, you need to ignore, and thereby not process, truthful behavior“, because there will be a lot of truthful behavior at the same time as well.
Have a read of the book, it is great learning in everyday life.
