Facial shapes in Frankfurt Horizontal and natural head positions: a methodological study

Annals of Human Biology. 2025. Vol. 52. No. 1. Article 2536162.

Mezentseva A., Rostovtseva V., Komarova A., Korotkova A., Dashieva N., Marina L. Butovskaya

Background: Head orientation during photography can distort facial shape, but this is
rarely considered in cross-population studies focusing on facial morphology and its
perception.
Aim: To assess how head positioning (Frankfurt Horizontal [FH] vs. natural position
[NP]) affects facial shape and trait perception across two ethnic populations.
Subjects and methods: Facial photographs were collected from Buryats of Mongolian
descent (N = 148) and Russians of European descent (N = 155). Geometric morphometrics
were used to compare the facial shapes in the FH and NP positions. Independent rater
groups with similar population origins, Kalmyks (N = 162) and Russians (N = 242),
evaluated perceived aggressiveness and attractiveness based on these portraits.
Results: Head orientation significantly altered facial shape, particularly among the
Buryat group. Despite the larger facial sexual dimorphism in the Buryat group, sex
differences were more pronounced in FH across both samples. Correlations between
facial shape and body metrics (height, Body Mass Index, and body fat mass) were
stronger in FH. Ratings of male aggressiveness and female attractiveness were
consistently influenced by head position across both rater populations and sexes.
Conclusion: Head positioning introduces systematic bias into facial shape analysis and
perception. Failure to control for this factor may compromise study comparability and
distort meta-analytic findings.

Keywords: perception, cross-cultural studies, Facial shape, Geometric morphometrics, Photo methods

Publication based on the results of: From Antiquity to Modernity: Epistemology of the Development of Spiritual and Material Cultures in Non-Western Societies (2025)