But in digital communications such as the testing with phone, email using Internet using computers just uses typing WORDS. However, a human communication is composed of not only words, but also sensitivity-like non-verbal one. Non-verbal information like the human voice, gesture, and emotion rather than verbal one is more useful to understand the user's inclination exactly. However it is quite difficult to catch the meaning of non-verbal information without looking at recording video of the person non-verbal behavior.
Discrepancy may also arise if the sender's message does not fit the receiver's perception of social norms for the particular situation. Although these difficulties and discrepancy are occurred in human communication, the non-verbal information gives cues for solving the difficulties and discrepancy of communication.