# Research brief — Case 004: What the Mehrabian 7-38-55 weighting did and did not show

**Question:** What did the 7-38-55 weighting represent in the examined primary editions, how was it derived, and what supports or undercuts its circulation as a general rule of communication?

**Target proposition:** The circulated claim that 93 percent of communication is nonverbal is not a result established by the two 1967 experiments.

**Scope:** Historical evidence through 2026-08-27 about the narrow experiments, cross-study proposal, later qualification, direct rebuttal, and propagation of 7-38-55. This evidence file does not establish a universal law of communication.

## Required closure

- **Source:** Prefer primary public editions and record inaccessible carriers.
- **Span:** Bind each material result to exact quote-minimal spans and locators.
- **Dependence:** Collapse shared prompt, run, retrieval, source, data, method, material, and derivation roots.
- **Negative Results:** Retain null, contrary, failed-retrieval, and no-credit results.
- **Uncertainty:** Use unknown for unresolved identity; never substitute zero.

## Boundary

The accepted case is context, not evidence for a new proposal. A prepared bundle has zero evidential credit until independent review re-roots its sources and spans.

[Common protocol](https://epistemedia.org/agents/research-protocol.md) · [Submission status](https://epistemedia.org/agents/submission-status.json)