Revisiting the baby schema by a geometric morphometric analysis of infant facial characteristics across great apes

Kawaguchi, Y., Nakamura, K., Tajima, T. and Waller, B.M. ORCID: 0000-0001-6303-7458, 2023. Revisiting the baby schema by a geometric morphometric analysis of infant facial characteristics across great apes. Scientific Reports, 13 (1): 5129. ISSN 2045-2322

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Infants across species are thought to exhibit specific facial features (termed the “baby schema”, such as a relatively bigger forehead and eyes, and protruding cheeks), with an adaptive function to induce caretaking behaviour from adults. There is abundant empirical evidence for this in humans, but, surprisingly, the existence of a baby schema in non-human animals has not been scientifically demonstrated. We investigated which facial characteristics are shared across infants in five species of great apes: humans, chimpanzees, bonobos, mountain gorillas, and Bornean orangutans. We analysed eight adult and infant faces for each species (80 images in total) using geometric morphometric analysis and machine learning. We found two principal components characterizing infant faces consistently observed across species. These included (1) relatively bigger eyes located lower in the face, (2) a rounder and vertically shorter face shape, and (3) an inverted triangular face shape. While these features are shared, human infant faces are unique in that the second characteristic (round face shape) is more pronounced, whereas the third (inverted triangular face shape) is less pronounced than other species. We also found some infantile features only found in some species. We discuss future directions to investigate the baby schema using an evolutionary approach.

Item Type: Journal article
Publication Title: Scientific Reports
Creators: Kawaguchi, Y., Nakamura, K., Tajima, T. and Waller, B.M.
Publisher: Springer Science and Business Media LLC
Date: 2023
Volume: 13
Number: 1
ISSN: 2045-2322
Rights: © The Author(s) 2023. Tis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit
Divisions: Schools > School of Social Sciences
Record created by: Laura Ward
Date Added: 05 Apr 2023 08:39
Last Modified: 05 Apr 2023 08:39

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