Changes in Facial Shape throughout Pregnancy—A Computational Exploratory Approach

Urszula Maria Marcinkowska,Natalia Nowak-Szczepanska,Danuta Kornafel,Dariusz P Danel,Sławomir Kozieł,Anna Ziomkiewicz-Wichary

doi:10.3390/sym13101944

Abstract

Facial cognition serves an important role in human daily interactions. It has been suggested that facial shape can serve as a signal for underlining biological condition, and that it is correlated with, among others, health, fertility, and attractiveness. In this study, 14 women were photographed during three consecutive trimesters of pregnancy, and the levels of their facial sexual dimorphism, asymmetry, and averageness were computed. Facial sexual dimorphism in first trimester was higher than in the second trimester (F(2, 22) = 5.77; p = 0.01; ηp2 = 0.34, post-hoc Tukey HSD test p = 0.007). Similar pattern was visible for asymmetry (F(2, 22) = 3.67; p = 0.04; ηp2 = 0.25, post-hoc Tukey HSD test p = 0.05). No statistically significant changes in measurement of averageness were observed. Results from Bayesian complementary analyses confirmed the observed effects for sexual dimorphism. The evidence for trimester differences in asymmetry and averageness was inconsequential. Based on the preliminary results of this exploratory study, we suggest that previously found decrease in observed facial attractiveness during pregnancy can be related to the decrease in computed facial femininity (possibly mediated by the changes in facial adiposity).

Highlights

Published: 15 October 2021Facial features are important to human social interactions [1,2] they can serve as cues to multiple character traits and biological quality, i.e., sexual openness [3], social status [4], maternal tendencies [5], or health [6].Investigating variation in facial features and perception can provide important insight into human daily interactions
While the facial averageness did not differ significantly between the trimesters (F(2,22) = 1.70; p = 0.21; ηp 2 = 0.13; for all post hoc pairwise comparisons between trimesters p > 0.23; Figure 1A), statistically significant differences were found for the asymmetry (F(2,22) = 3.67; p = 0.04; ηp 2 = 0.25; Figure 1B) and sexual dimorphism (F(2,22) = 5.77; p = 0.01; ηp 2 = 0.34; Figure 1C)
In the case of asymmetry, the highest values were observed for the T1 while the lowest for the T2

Summary

Introduction

Published: 15 October 2021Facial features are important to human social interactions [1,2] they can serve as cues to multiple character traits and biological quality, i.e., sexual openness [3], social status [4], maternal tendencies [5], or health [6] ( see [7] for no effect in women).Investigating variation in facial features and perception can provide important insight into human daily interactions. Facial features are important to human social interactions [1,2] they can serve as cues to multiple character traits and biological quality, i.e., sexual openness [3], social status [4], maternal tendencies [5], or health [6] ( see [7] for no effect in women). Previous research has established that several aspects of facial appearance are frequently associated with attractiveness across different groups of judges and cultures. These globally attractive features include symmetry, averageness, and pronounced sexual dimorphism in women—see [8] for a theorethical review.

Methods

Results

Discussion

Conclusion