Verbal Versus Non-Verbal Communication

You may not have heard of Albert Mehrabian, an Armenian-Iranian professor of psychology at UCLA, but you’ve almost certainly heard of his work. He studied human communication, and he performed experiments in the 1960s on the relative importance of words, tone, and physiology in verbal communication.

Words, tone and facial expression can all matter, but their importance depends on the message and situation. Mehrabian’s famous percentages concern judgments of feelings and attitudes in particular experimental conditions. They are not a formula for all communication, and they do not show that body language always outweighs words.

Mehrabian’s experiments

Mehrabian was interested in how humans communicate, and whether verbal or non-verbal cues play a more vital role in conveying messages to one another. The idea behind the experiments he came up with was to judge the relative impact of three different factors on verbal communication:

1. Words spoken (i.e. what is said)
2. Tone of voice (i.e. how the voice sounds)
3. Physiology (e.g. body language, facial expressions, etc.)

The experiments examined judgments of attitude from limited cues rather than ordinary full conversations. One study compared recorded words with vocal delivery, including combinations in which the word and tone suggested different attitudes. A warm tone is an audio cue; a smile was not part of that word-versus-tone recording.

The second experiment compared photos of facial expressions and vocal tone captured on a tape recording. Participants had to judge whether the overall effect of the communication was positive or negative based on the combination of facial expressions and tone. From combining the results of these two studies, Mehrabian found:

• 7% verbal liking in the combined equation
• 38% vocal liking in the combined equation
• 55% facial liking in the combined equation

Over-interpretation

The problem with Mehrabian’s work is that it is frequently over-interpreted and used to make claims that are not actually supported. You’ll hear people claim that “body language makes up 55% of all communication” or that “non-verbal communication is more important than verbal communication.” In fact, this isn’t the case for several reasons.

First, remember that the experiments were performed with the participants listening to single, isolated words without context, which is not at all how humans typically experience communication. Secondly, the physiology factors that were consider were facial expressions, not body language as is commonly claimed. Most importantly, the experimental findings applied only to incongruent situations. This means that when physiological cues and verbal cues do not match, people disproportionately base their judgements on non-verbal rather than verbal communication. The same thing is not necessarily true in other situations.

The real takeaway lesson from these studies should not be “non-verbal communication is more important than verbal communication,” it should be “for clear communication, verbal and non-verbal cues need to match”. So, if you want to convey excitement about a project when you’re presenting, then your tone and body language should be positive as well as the words that you are using.

A final key factor that often goes completely overlooked is that these experiments equated communication to each speaker’s feelings and attitudes. In other words, Mehrabian’s speakers weren’t talking about facts or objective information, but instead their own subjective likes and dislikes.

For example, a flat tone after someone says they are having a good time may prompt you to ask how they are feeling. It does not prove that their words are false. A factual claim, such as a statement about the shape of the Earth, needs evidence about the world rather than a judgment based on the speaker’s enthusiasm.

Apply the lesson without a universal formula

In a workplace conversation, a mismatch between words and delivery is a reason to ask a question, not proof that you know what someone feels. A flat tone could reflect fatigue, concentration, a communication difference or discomfort. Avoid treating eye contact, smiling or posture as a universal test of honesty or engagement.

Illustrative example: a colleague says a deadline is fine but hesitates before answering. You might ask, “Is there a concern about timing or resources that we should discuss?” That makes room for clarification without accusing them of hiding a feeling.

Make factual requirements explicit in words, especially decisions, quantities and deadlines. Use tone and expression to support the message, then check understanding. For a practical process, read effective listening.

The direct source for the scope of the percentages is Mehrabian’s explanation of Silent Messages. The figures should not be generalized to technical instructions, every culture or every communication channel.