Cross-cultural perception of strength, attractiveness, aggressiveness and helpfulness of Maasai male faces calibrated to handgrip strength.

Previous research has demonstrated that Maasai and Europeans tend to align in their ratings of the physical strength and aggressiveness of Maasai male faces, calibrated to hand grip strength (HGS). However, perceptions of attractiveness of these faces differed among populations. In this study, three morphs of young Maasai men created by means of geometric morphometrics, and depicting the average sample and two extrema (± 4 SD of HGS), were assessed by men and women from Tanzania, Czech Republic, Russia, Pakistan, China, and Mexico (total sample = 1540).

Unravelling the many facets of human cooperation in an experimental study.

Humans readily cooperate, even with strangers and without prospects of reciprocation. Despite thousands of studies, this finding is not well understood. Most studies focussed on a single aspect of cooperation and were conducted under anonymous conditions.

Facial cues to physical strength are not always associated with facial masculinity: Comparative study of Europeans and Southern Siberians.

Objectives: The aim of our study was to compare morphometric patterns of facial sexual dimorphism with strength-face relationship in members of two distinct populations of European and Central Asian origin: Russians and Tuvans.

Methods: Handgrip strength (HGS) measures and facial photographs were collected from Russian (n = 233) and Tuvan (n = 187) men and women. We digitized 70 landmarks and semilandmarks on full-face and 54 landmarks and semilandmarks on profile photos.

Effects of sex and sex-related facial traits on trust and trustworthiness: An experimental study.

The ability to trust others, including strangers, is a prerequisite for human cooperation. Economically it is not rational to trust strangers, as trust can be easily exploited. Still, generally, the level of trust toward strangers is relatively high.

Factors Associated With Highest Symptoms of Anxiety During COVID-19: Cross-Cultural Study of 23 Countries.

The COVID-19 restrictions have impacted people's lifestyles in all spheres (social, psychological, political, economic, and others). This study explored which factors affected the level of anxiety during the time of the first wave of COVID-19 and subsequent quarantine in a substantial proportion of 23 countries, included in this study. The data was collected from May to August 2020 (5 June 2020).

Perception of Emergent Leaders' Faces and Evolution of Social Cheating: Cross-Cultural Experiments.

The aim of the present study was to investigate whether neutral faces of individuals with different propensities for leadership may convey information about their personal qualities, and are there impacts of sex, population and social environment on the facial perception. This study is based on a previous experiment ( Rostovtseva et al., 2022), where emergent leadership in the context of male group cooperation was investigated in Buryats (Mongolian population of Siberia).

Facial and body sexual dimorphism are not interconnected in the Maasai.

Background: In this paper, we investigate facial sexual dimorphism and its' association with body dimorphism in Maasai, the traditional seminomadic population of Tanzania. We discuss findings on other human populations and possible factors affecting the developmental processes in Maasai.

Methods: Full-face anthropological photographs were obtained from 305 Maasai (185 men, 120 women) aged 17-90 years.

Are There Differences in Experts' and Lay Assessors' Attractiveness Judgments of Non-Professional Men's Dance/Gait Movements?

Research on attractiveness assessments of men's dance has shown that raters derive and integrate information about male mating-related qualities into their attractiveness assessments, but prior studies have focused on lay assessors (i.e., individuals with no professional dance background) rather than dance experts.

Sex differences in cooperativeness-An experiment with Buryats in Southern Siberia.

We report on an experimental study that was set up to reveal differences in the tendencies of men and women to cooperate in same-sex interactions. Former studies on this subject were mostly conducted in industrialized modern societies. In contrast, we tested the cooperation tendency among Buryats, a people from Southern Siberia of Mongolian origin.

Second-to-fourth digit ratio and facial shape in Buryats of Southern Siberia.

Background: The 2nd-to-4th digit ratio (2D:4D) is a putative predictor of a prenatal exposure to sex hormones. 2D:4D is sexually dimorphic (males < females). Studies, linking digit ratio and full facial shapes among Europeans, show that a low 2D:4D is associated with a set of male-specific facial features.

Sexual dimorphism in facial shape of modern Buryats of Southern Siberia.

Objectives: The aim of the present study was to investigate sexual dimorphism in the full facial shape of modern Buryats-people of Southern Siberia of Mongolian origin.

Methods: For this purpose, we have used geometric morphometrics based on standardized full-face frontal photographs. This allowed us to assess and visualize differences in facial shapes between Buryat men (n = 98) and women (n = 89).

Assessment of physical strength from gait: data from the Maasai of Tanzania.

In industrialized societies, male gait provides information about physical strength. Male physical strength may be used by men and women to assess the fighting ability of rivals and the quality of potential mates, respectively. Women more than men discriminate between strong and weak walkers when assessing gait attractiveness.

Polymorphisms of dopamine receptor genes DRD2 and DRD4 in African populations of Hadza and Datoga differing in the level of culturally permitted aggression.

The key regulator in the control of aggressive behavior is dopamine receptors. Association of variants in these genes with aggression has been shown in modern populations. However, these studies have not been conducted in traditional cultures.

Associations of physical strength with facial shape in an African pastoralist society, the Maasai of Northern Tanzania.

Objectives: Previous research has documented associations of physical strength and facial morphology predominantly in men of Western societies. Faces of strong men tend to be more robust, are rounder and have a prominent jawline compared with faces of weak men. Here, we investigate whether the morphometric patterns of strength-face relationships reported for members of industrialized societies can also be found in members of an African pastoralist society, the Maasai of Northern Tanzania.

Serotonergic gene polymorphisms (5-HTTLPR, 5HTR1A, 5HTR2A), and population differences in aggression: traditional (Hadza and Datoga) and industrial (Russians) populations compared.

Background: Current knowledge on genetic basis of aggressive behavior is still contradictory. This may be due to the fact that the majority of studies targeting associations between candidate genes and aggression are conducted on industrial societies and mainly dealing with various types of psychopathology and disorders. Because of that, our study was carried on healthy adult individuals of both sex (n = 853).

Cross-Cultural Investigation of Male Gait Perception in Relation to Physical Strength and Speed.

Previous research documents that men and women can accurately judge male physical strength from gait, but also that the sexes differ in attractiveness judgments of strong and weak male walkers. Women's (but not men's) attractiveness assessments of strong male walkers are higher than for weak male walkers. Here, we extend this research to assessments of strong and weak male walkers in Chile, Germany, and Russia.

Sex difference in attractiveness perceptions of strong and weak male walkers.

Objectives: Men and women accurately assess male physical strength from facial and body morphology cues. Women's assessments of male facial attractiveness, masculinity, and dominance correlate positively with male physical strength. A positive relationship also has been reported between physical strength and attractiveness of men's dance movements.

Polymorphisms of two loci at the oxytocin receptor gene in populations of Africa, Asia and South Europe.

Background: The oxytocin (OT) system is known to be implicated in the regulation of complex social behavior, particularly empathy and parenting. The goal of this study was to estimate the gender and population differences in polymorphisms of two oxytocin receptor gene SNPs, rs53576 and rs2254298, in four populations.

Results: These data were compared with each other and with 14 samples from the corresponding regions retrieved from the 1000 Genomes database.

Androgen Receptor Gene Polymorphism, Aggression, and Reproduction in Tanzanian Foragers and Pastoralists.

The androgen receptor (AR) gene polymorphism in humans is linked to aggression and may also be linked to reproduction. Here we report associations between AR gene polymorphism and aggression and reproduction in two small-scale societies in northern Tanzania (Africa)--the Hadza (monogamous foragers) and the Datoga (polygynous pastoralists). We secured self-reports of aggression and assessed genetic polymorphism of the number of CAG repeats for the AR gene for 210 Hadza men and 229 Datoga men (aged 17-70 years).

Aggression and polymorphisms in AR, DAT1, DRD2, and COMT genes in Datoga pastoralists of Tanzania.

The aim of this study was to analyse the relationships between polymorphisms in four candidate genes (AR, DAT1, DRD2, and COMT) and aggression in men from a traditional society of East African pastoralists, the Datoga. Buss and Perry's Aggression Questionnaire was used to measure aggression. The number of CAG repeats in the AR gene was negatively correlated with physical aggression, anger, and hostility.

Aggression, digit ratio, and variation in the androgen receptor, serotonin transporter, and dopamine D4 receptor genes in African foragers: the Hadza.

The role of genes in the expression of aggression and masculinity traits in humans has been a focus of recent behavioral genetic studies. This is the first study on the variation in aggression, the digit ratio (the ratio between the second and the fourth digits, 2D:4D), the directional asymmetry in 2D:4D (D(R-L)) and polymorphisms of the AR, DRD4, and 5-HTTL genes in simple hunter-gatherers, namely the Hadza of Tanzania (142 adult men). The distribution of AR, DRD4E3, and 5-HTTLPR genotypes and allele frequencies in Hadza was compared to other African populations on which the data were available.

Aggression, conflict resolution, popularity, and attitude to school in Russian adolescents.

The objective of the present study was to examine the effects of aggression and conflict-managing skills on popularity and attitude to school in Russian adolescents. Three types of aggression (physical, verbal, and indirect), constructive conflict resolution, third-party intervention, withdrawal, and victimization were examined using the Peer-Estimated Conflict Behavior (PECOBE) inventory [Bjorkquist and Osterman, 1998]. Also, all respondents rated peer and self-popularity with same-sex classmates and personal attitude to school.

The hormonal basis of reconciliation in humans.

Developing effective behavioral and psychological mechanisms for coping with social stress was very important in human evolution because humans evolved as social beings. The aggressive and post-aggressive behavior of 30 boys aged 7-11 years was observed during free play in summer camp with the standard "post-conflict-matched control" method (de Waal and Yoshihara, 1983). The focals were the victims of the conflict.