# Figure 32: Natural laughter by the voluntary contraction of the two large zygomatics and the lower palpebral orbicularis

- By: Guillaume-Benjamin-Amand Duchenne (de Boulogne) (French, 1806–1875)
- By: Adrien Tournachon (French, 1825–1903)
- Date: c. 1856, printed 1862
- Medium: Albumen print from glass plate negative
- Classification: Photograph
- Dimensions: Image: 15.1 x 11 cm (5 15/16 x 4 5/16 in.); Paper: 22.7 x 17 cm (8 15/16 x 6 11/16 in.); Mounted: 41 x 27.6 cm (16 1/8 x 10 7/8 in.)
- Credit line: Severance and Greta Millikin Trust
- Museum: [Cleveland Museum of Art](https://clevelandart.org/art/2018.9)
- Rights: [Public domain (CC0)](https://creativecommons.org/publicdomain/zero/1.0/)
- Picture: https://openaccess-cdn.clevelandart.org/2018.9/2018.9_web.jpg
- Who can see it: Tweens profiles and older (museums give no ratings; placed by Invisible Network from the museum's own words)

Duchenne embarked on the first scientific, systematic exploration of the physiology of human facial expression and hoped, through photographs of the experiments, to teach artists how to portray those emotions. Here, he has photographed a subject’s natural smile and described the muscles creating it. In subsequent photographs, he used an electrode to contract one of the muscles that convey that same emotion.