Per Philip Yaffe in 2011, "In the 1960s Professor Albert Mehrabian and colleagues at the University of California, Los Angles (UCLA), conducted studies into human communication patterns. When their results were published in professional journals in 1967, they were widely circulated across mass media in abbreviated form. Most people forgot about what they really meant because the figures were so easy to remember. Hence, the myth that communication is only 7 percent verbal and 93 percent non-verbal was born."
"The fact is Professor Mehrabian's research had nothing to do with giving speeches, because it was based on the information that could be conveyed in a single word. Subjects were asked to listen to a recording of a woman's voice saying the word "maybe" in three different ways to convey liking, neutrality, and disliking. They were also shown photos of the woman's face conveying the same three emotions. They were then asked to guess the emotions heard in the recorded voice, seen in the photos, and both together. The result was that the subjects correctly identified the emotions 50 percent more often from the photos than from the voice."
"In the second study, subjects were asked to listen to nine recorded words, three meant to convey liking (honey, dear, thanks), three to convey neutrality (maybe, really, oh), and three to convey disliking (don't, brute, terrible). Each word was pronounced three different ways. When asked to guess the emotions being conveyed, it turned out that the subjects were more influenced by the tone of voice than by the words themselves."
"Professor Mehrabian combined the statistical results of the two studies and came up with the famously misused—rule that communication is only 7 percent verbal and 93 percent non-verbal. The non-verbal component was made up of body language (55 percent) and tone of voice (38 percent). Actually, it is incorrect to call this a "rule," being the result of only two studies. Scientists usually insist on many more corroborating studies before calling anything a rule. An exception can never prove a rule; it can only disprove it."
In the words of Professor Mehrabian himself in 2009, "Total Liking = 7% Verbal Liking + 38% Vocal Liking + 55% Facial Liking. Please note that this and other equations regarding relative importance of verbal and nonverbal messages were derived from experiments dealing with communications of feelings and attitudes (i.e., like-dislike). Unless a communicator is talking about their feelings or attitudes, these equations are not applicable."