Not all forms of communication are created equal. For establishing trust, video is better than audio (with no video), and audio is better than a chat window. The logic of this hierarchy seems intuitive: People communicate as much, if not more, with how an idea is conveyed, than with what it said. Shifty eyes and raised shoulders can reveal anxiety; intonation can convey passion. The more non-substantive information the medium can convey, the more data a listener has to decide how trustworthy the speaker is.
via mashable.com