Right before Walkin kills Hopper in the movie True Romance he makes a statement about lying. I think that he says there are X number of ways to tell if someone is lying, he calls them “Pantomimes”. How many are there and What are they?
Excessive blinking is one of them.
Covering your mouth as you speak is one of them.
Shaking your head “no” while saying “yes” is one of them.
Not meeting someone’s eyes is one.
I’m sure there are a few others and Desmond Morris covered this topic on his show “The Human Animal” which comes on TLC every once in a while. They aren’t definite proof that someone is telling a lie but it can be useful in life.