Facial symmetry and severity of gender dimorphism in its proportions in the isanzu people, traditional farmers of East Africa

Abstract

In modern scientific literature on sexual selection, a significant place is occupied by scientific works that examine the relationship between indicators of fluctuating asymmetry of the face, the expression of sexual dimorphism and individual attractiveness and reproductive success. The present study is devoted to analysis of the data of the ethno-psychological research of representatives of Isanzu tribe - one of the traditional agricultural societies of East Africa (Tanzania). An assessment of the degree of symmetry of the faces of men and women of Isanzu tribe, as well as the expression of characteristics of sexual dimorphism in face proportions was the purpose of this study. On the basis of the evaluation of photographic images of 159 men and 56 women of Isanzu tribe we analyzed and compared the following indexes: indexes of fluctuating asymmetry and sexual dimorphism of the face, finger index, the ratio of waist to hips, the ratio of shoulders to hips, and finally indicators of the age in which expression of fluctuating asymmetry reaches its maximum level. The results of the analysis indicate that faces of men and women of Isanzu tribe do not differ in the level of fluctuating asymmetry, male faces are characterized by pronounced masculine traits; as for the calculation of indexes, we did not detect any age differences based on fluctuating asymmetry index, whereas masculine index tends to increase linearly with increasing age