Observe other people's facial expressions

Usually, the color of a person's cheek will change with the change of mood. Among them, the most obvious is the red and white.

Blushing is also an expression of anger. When people are angry, their cheeks turn red instantaneously instead of spreading slowly from the center of their cheeks. When people in anger want to restrain their anger and aggressive impulse, their cheeks will become pale. When people are frightened, their cheeks will become pale.

The change of cheek skin color is caused by the autonomic nervous system, which is difficult to control or hide, but what he has to hide may be shame or panic itself.

In addition, the length of expression can also reflect the mark of lying. It includes the following three aspects: the pause time of the expression, the starting time (the time spent when the expression starts) and the disappearing time (the time spent when the expression disappears).

Long pause expressions are likely to be fake, such as 10 seconds or more, and even 5 seconds pause expressions may be untrue. In addition to the extremely strong emotional feelings, such as ecstasy, rage, grief, etc., the natural expression will not exceed 4-5 seconds. Moreover, even if it's very emotional, its expression can't last long. Only symbolic and mocking expressions exist for a long time.

There is no fixed standard for the starting time and disappearing time of an expression. If the surprised expression is true, the starting time, pause time and disappearing time may be very short, less than one second in total.