Socioeconomic Status Is Not Related with Facial Fluctuating Asymmetry: Evidence from Latin-American Populations

Abstract

The expression of facial asymmetries has been recurrently related with poverty and/or disadvantaged socioeconomic status. Departing from the developmental instability theory, previous approaches attempted to test the statistical relationship between the stress experienced by individuals grown in poor conditions and an increase in facial and corporal asymmetry. Here we aim to further evaluate such hypothesis on a large sample of admixed Latin Americans individuals by exploring if low socioeconomic status individuals tend to exhibit greater facial fluctuating asymmetry values. To do so, we implement Procrustes analysis of variance and Hierarchical Linear Modelling (HLM) to estimate potential associations between facial fluctuating asymmetry values and socioeconomic status. We report significant relationships between facial fluctuating asymmetry values and age, sex, and genetic ancestry, while socioeconomic status failed to exhibit any strong statistical relationship with facial asymmetry. These results are persistent after the effect of heterozygosity (a proxy for genetic ancestry) is controlled in the model. Our results indicate that, at least on the studied sample, there is no relationship between socioeconomic stress (as intended as low socioeconomic status) and facial asymmetries.

Biological bases of beauty revisited: The effect of symmetry, averageness, and sexual dimorphism on female facial attractiveness

“…For example, measured facial asymmetry shows no association with self-reported health [14], and perceived symmetry shows no relationship with oxidative stress or immune function [13]. Further, socioeconomic status shows no relationship with facial symmetry [24]. In addition, the magnitude of the effect of symmetry is relatively small, with meta-analytic estimates concluding that it contributes the least amount of variance to facial attractiveness, with a mean effect size r of 0.25 [3].…”

Developmental stability and environmental stress: A geometric morphometrics analysis of asymmetry in the human femur

“…Overall, the literature presents confused and contradictory results concerning sex differences of FA. Some studies support the presence of sexual dimorphism in FA (Claes et al, ; Gray and Marlowe, ; Guatelli‐Steinberg, Sciulli, & Edgar, ; Palestis and Trivers, ; Quinto‐Sanchez et al, ; Sladek, Berner, Sosna, & Sailer, ), while others do not (Bailit, Workman, Niswander, & MacLean, ; Hallgrimsson, ; Jung, Woo, & Pak, ; Weisensee, ). Our results did not reveal any statistical differences of the level of femoral FA between male and female centroid size or shape.…”

“…Some studies support variation of FA levels with age (Hallgrimsson, ; Kobyliansky and Livshits, ; Quinto‐Sanchez et al, ) but do not rely on the same arguments to explain it. It seems difficult to attribute these variations to mechanical stress when they concern structures that are not affected by it, such as the skull for instance (without the mandible; Tim, 2000).…”

“…Nevertheless, two types of processes (excluding genetic diseases) are distinguished to explain how DS could be disrupted at a molecular level: (1) inbreeding and heterozygosis; (2) DS heritability. In fact, it seems that DS requires a balance between heterozygosity and homozygosity: too much or too little genetic variability disturbs developmental homeostasis (Alibert et al, ; Ben‐David et al, ; Hershkovitz et al, ; Leamy and Klingenberg, ; Livshits and Kobyliansky, ; Markow and Martin, ; Ozener, ; Ozener and Graham ; Quinto‐Sanchez et al, ; Quinto‐Sanchez et al, ; Schaefer et al, ; Windhager et al, ).…”

Developmental pathways inferred from modularity, morphological integration and fluctuating asymmetry patterns in the human face

“…Approvals provided by the Ethics Committees of the Universidad Nacional Autónoma de México and Escuela Nacional de Antropología e Historia (México), Universidad de Antioquia (Colombia), Universidad Peruana Cayetano Heredia (Perú), Universidad de Tarapacá (Chile), Universidade Federal do Rio Grande do Sul/Universidade Estadual do Sudoeste da Bahia (Brazil), and University College London (UK) were obtained prior the data collection, and an informed consent were signed by each participant before genetic, socioeconomic, and facial phenotypes data was collected. The same sample was used on a recent contribution 34 , 37 , 86 and conforms the main database of the CANDELA consortium 34 , 37 , 66 , 67 , 86 , 87 . All methods and procedures used here were performed in accordance with relevant guidelines and regulations (see below).…”