Charles Darwin · 1916 · theoretical treatise and naturalistic observation · n=?

The expression of the emotions in man and animals / by Charles Darwin.

Cited 35 times in the scientific literature.

Level 5 - mechanism / opinion, no new human data

Level 5 by design analogy; historical theoretical treatise and observational natural history.

OpenAlex W4245222255 · doi:10.5962/bhl.title.4820 · record verified 2026-08-26

What was done

This historical work presents Charles Darwin's natural history observations and theoretical framework regarding emotional expression across humans and non-human animals. The text outlines discussions on the physiology and psychology of blushing (including inheritance, bodily distribution, cross-cultural occurrence, and triggers such as shame, shyness, and modesty), anatomical diagrams of facial musculature, and comparative photographic and illustrated observations of expressive behaviors in domestic animals, birds, primates, and humans.

What was found

The abstract represents a table of contents and figure list rather than an experimental report; no numerical data or statistical analyses are reported. The work synthesizes qualitative naturalistic observations to describe principles governing expressive movements, their evolutionary inheritance, and the specific unity of human races in expressive behavior.

Why it matters

This foundational treatise established the evolutionary study of emotion and nonverbal communication, proposing that human affective displays and physiological responses share homologous origins with animal behaviors.

Limits

The record consists of 19th-century qualitative naturalistic observations, historical case descriptions, and theoretical synthesis lacking modern experimental controls, standardized measurement, or statistical testing. The abstract provides only chapter headings and illustration captions rather than experimental findings.

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