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Concept

7-38-55 Rule

The 7-38-55 rule is Albert Mehrabian's finding that when words conflict with tone of voice and body language about feelings, listeners weight words about 7%, tone 38% and body language 55%; negotiators use it as a reminder to trust tone over words when they disagree.

Psychologist Albert Mehrabian's experiments in the 1960s studied how people read expressions of feeling and attitude when the verbal and non-verbal signals clashed. Chris Voss cites the ratio in Never Split the Difference as a practical check at the table: a 'yes' said in a flat, hesitant voice is not a real yes. The rule is widely misquoted as meaning that words carry only 7% of all communication, which Mehrabian himself did not claim; the studies were narrow and do not apply to ordinary factual messages. The useful lesson is narrower and sound: when words and delivery disagree, pay attention to the delivery and gently name the mismatch.

A real-life example

In a supplier meeting in İstanbul, a sales manager hears 'Sure, that timeline works' said with a sigh and eyes on the table. Rather than moving on, she says 'It sounds like part of you has doubts about that date.' The supplier admits a machine is due for maintenance that week, and they set a realistic date before anything is signed.

How to use it

  1. 1When someone agrees, watch whether their tone and posture match the words.
  2. 2If they don't match, label it calmly: 'It sounds like there's some hesitation.'
  3. 3Don't treat the ratio as a law of communication; use it only as a prompt to check for mixed signals.