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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.

What is the most important part of speech as communication? It seems obvious that the answers would be the words that the communicator speaks, as they convey information most consistently. But according to Mehrabian, tone and physiology are even more important than words. Put another way: body language speaks volumes louder than words ever can!

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.)

Mehrabian aimed to compare the relative importance of verbal and non-verbal communication in face-to-face conversations. In the first experiment he ran, participants observed a person saying a single word and then judged whether that word was meant in a positive or negative way. The experimenters varied the communication so that sometimes both the word and the tone was positive (e.g. the word “dear” delivered with a smile), sometimes both were negative, and sometimes the word and tone were incongruent (i.e. the word was positive, but the delivery was negative). From the judgement of the participants over whether the communication was overall positive or negative, Mehrabian worked out how much of the judgement was due to the tone versus the word.

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% of meaning came from the words used
  • 38% of meaning came from the tone of voice
  • 55% of meaning came from physiological cues like facial expressions

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.

Think of it this way: if you were at a party and you asked someone if they were having a good time, and they said yes while using a flat tone of voice and not making eye contact, then you’d naturally assume that they were not really having a good time. But if someone tried to tell you that the Earth was flat, it wouldn’t matter how upbeat they sounded or how excited they were, you still wouldn’t believe them. That’s because the person at the party was talking about their feelings, where non-verbal cues are important for your judgements, but the flat earth enthusiast was talking about facts, where you are more focused on the content of their speech.

Other body language studies

Of course, none of this is meant to refute that body language and other non-verbal cues are important in communication. It’s just that Mehrabian’s studies don’t really show what they are often claimed to show. But there have been many other studies over the years that have looked at verbal and non-verbal communication.

A notable example by Argyle and colleagues from 1970 used video tapes to show participants communicators who were either dominant or submissive, and it found that non-verbal cues and especially body posture contributed 4.3 times more to their judgements than did verbal cues.

On the other hand, a 1992 study by Hsee and colleagues analyzed how clinicians make judgements about the emotional states of their clients. They found that participants made judgements about another person’s emotional state based more on that person’s self-report and facial expressions than on their tone of voice. This could be because clinicians are trained to listen more than most people and are very attentive to subtle cues like facial expressions.

So what does all of this mean in practice? Essentially, effective communication requires a combination of words, tone, and physiology that are all in harmony. When you share information, especially if you are talking about your personal feelings, you needn’t be stiff and formal. In fact, you’ll communicate more clearly if you allow your body posture and your tone of voice to convey the same meaning as your words.

Next week we’re going to talk about the reverse of communicating effective – how to listen effectively. Come back soon for that!