Digit Ratio (2D:4D; Right-Left 2D:4D) and Multiple Phenotypes for Same-Sex Attraction: The BBC Internet Study Revisited.

Same-sex attraction may be linked to low prenatal androgen (in men) and high prenatal androgen (in women). Digit ratio (2D:4D) is thought to be a negative correlate of prenatal androgen and right-left 2D:4D (Dr-l) to reflect lateralized differences in sensitivity to prenatal androgen. Lower 2D:4D has been reported for lesbians compared to heterosexuals, but links to high 2D:4D in gay men are less clear. The largest study thus far (the BBC Internet study) found no significant difference between the 2D:4D of lesbians and heterosexual women but a higher 2D:4D in gay men compared to heterosexual men. Here we consider the possibility that low and high prenatal androgen is associated with same-sex attraction in men (n = 108,779) and women (n = 87,742), resulting in more than two phenotypes. We examined the associations between 2D:4D, Dr-l, and same-sex attraction scores in the BBC Internet study. In contrast to the earlier report, which considered sexual orientation in categories, there were positive linear associations in men (right and left 2D:4D, but not Dr-l) and negative linear associations in women (right 2D:4D and Dr-l, but not left 2D:4D). There were no curvilinear relationships for right and left 2D:4D. However, Dr-l showed a U-shaped association with same-sex attraction in men. Thus, (1) high prenatal androgen may be implicated in female homosexuality, while both low and high prenatal androgen may be implicated in male homosexuality, and (2) large side differences in sensitivity to androgen may be associated with elevated same-sex attraction in men.

Male facial cues to physical strength in Europe: Medium-strength preference and higher aggressiveness attribution to the weakest.

OBJECTIVES: The capacity to assess male physical strength from facial cues may be adaptive given health and fitness-related associations with muscular strength. Our study complements recent research on strength-related face perceptions of male Maasai by applying the protocol to male European faces and assessors. METHODS: Five distinct facial morphs calibrated for handgrip strength (HGS) were manufactured with geometric morphometrics performing regressions of the Procrustes shape coordinates on HGS in a sample of 26 European men (18-32 years). Young adult men and women (n = 445) rated these morphs on physical strength, attractiveness, and aggressiveness. RESULTS: Facial morphs calibrated to lower HGS were rated as less strong, less attractive, and more aggressive than those calibrated to higher HGS. Medium levels of HGS were associated with the highest attractiveness ratings. CONCLUSIONS: The rating patterns of physical strength, attractiveness, and aggressiveness for European male facial morphs exhibit similarity to previous ratings of Maasai male faces. Therefore, the current findings corroborate the suggestion of a common mechanism for social attributions based on facial cues to physical strength, modulated by local ecology and societal context.

Age-dependent changes in skin features and perceived facial appearance in women of five ethnic groups.

OBJECTIVE: Research documents effects of skin features on assessments of age, health and attractiveness of female faces. Ethnic variation also has been reported for the impact of age-related changes in skin features on face assessments. Here, we investigate women's self-ratings across age cohorts and ethnic groups and discrepancies with (non-expert) assessor ratings of facial appearance together with age-dependent changes in skin features. METHODS: Faces of women 20-65 years from five ethnic groups (each n = 36) were imaged. Participants provided self-ratings of age, health and attractiveness, and were judged on these attributes by members of the same ethnic group (each n = 120). Digital image analysis was used to quantify skin gloss, tone evenness, wrinkling and sagging. Age-dependent changes in ratings and skin features within and between ethnic groups were assessed by comparing information from 10-year cohorts. We also tested whether menopausal status could be predicted by self-ratings, assessor ratings and image-based skin features. RESULTS: Women of all ethnic groups judged themselves younger and higher in attractiveness and health compared to third-party assessors, with the largest discrepancies for age in French women and for attractiveness and health in South African women. In Indian and South African women, specular gloss and skin tone evenness were lower compared to other participants, and sagging was higher in Indian, Japanese and South African women compared to Chinese and French women. Women's menopausal status could be predicted from assessor ratings and image-based skin features but not from self-ratings. CONCLUSION: There are differences between women's self-ratings and assessor ratings of facial appearance. These discrepancies vary with female age and ethnicity. Age and ethnicity effects also are evident in age-dependent changes in skin features within and across ethnic groups, which together with assessor (but not self-) ratings of facial appearance predict menopausal status.

OBJECTIF: l'étude documente les effets des caractéristiques de la peau sur les évaluations de l'âge, de la santé et de l'attractivité des visages féminins. Des variations ethniques ont également été rapportées en ce qui concerne l'impact des changements liés à l'âge dans les caractéristiques de la peau sur les évaluations du visage. Ici, nous étudions les auto­évaluations des femmes à travers les cohortes d'âge et les groupes ethniques et les divergences avec les évaluations (non expertes) de l'apparence du visage ainsi que les changements des caractéristiques de la peau dépendant de l'âge. MÉTHODES: les visages des femmes âgées de 20 à 65 ans issues de cinq groupes ethniques (chacun n = 36) ont été examinés par imagerie. Les participantes ont fourni des auto­évaluations de leur âge, de leur santé et de leur attractivité, et ont été jugées sur ces attributs par les membres du même groupe ethnique (chacun n = 120). L'analyse d'images numériques a été utilisée pour quantifier la luminosité de la peau, l'uniformité du teint, les rides et le relâchement cutané. Les changements dépendants de l'âge dans les évaluations et les caractéristiques de la peau au sein et entre les groupes ethniques ont été évalués en comparant les informations provenant de cohortes sur 10 ans. Nous avons également évalué si le statut ménopausique pouvait être prédit par les auto­évaluations, les évaluations de l'évaluateur et les caractéristiques de la peau basées sur l'imagerie. RÉSULTATS: les femmes de tous les groupes ethniques se sont jugées plus jeunes et plus performantes en termes d'attractivité et de santé par rapport aux évaluateurs tiers, les plus grandes discordances concernant l'âge chez les femmes françaises et l'attractivité et la santé chez les femmes sud­africaines. Chez les femmes indiennes et sud­africaines, la luminosité spéculaire et l'uniformité du teint de la peau étaient inférieures à celles des autres participantes, et le relâchement cutané était plus élevé chez les femmes indiennes, japonaises et sud­africaines que chez les femmes chinoises et françaises. Le statut ménopausique des femmes pouvait être prédit à partir des évaluations de l'évaluateur et des caractéristiques cutanées basées sur l'imagerie, mais pas à partir des auto­évaluations. CONCLUSION: il existe des différences entre les auto­évaluations des femmes et les évaluations de l'apparence faciale par l'évaluateur. Ces divergences varient en fonction de l'âge et de l'origine ethnique des femmes. Les effets sur l'âge et l'origine ethnique sont également évidents dans les changements dépendants de l'âge des caractéristiques de la peau au sein et entre les groupes ethniques, qui, avec les évaluations de l'évaluateur (mais pas de l'auto­évaluation) de l'apparence du visage, prédisent le statut ménopausique.

Perception of strength, attractiveness and aggressiveness of Maasai male faces calibrated to handgrip strength: Evidence from a European sample.

OBJECTIVES: Previous research showed that male and female members of the Maasai from Northern Tanzania judge images of facial morphs calibrated to greater handgrip strength (HGS) higher on strength and attractiveness, but lower on aggressiveness than those calibrated to lower HGS. The accurate assessment of male physical strength from facial information may be adaptive as suggested by the evidence on health and fitness-related benefits linked to high muscular strength. METHODS: This study extends previous work by obtaining European female (n = 220) and male (n = 51) assessments of HGS-calibrated Maasai male faces. Participants rated five facial morphs for strength, attractiveness, and aggressiveness on computer screens. RESULTS: Perceived physical strength increased with morphs calibrated to higher HGS. The lowest and highest HGS morphs were judged lower in attractiveness than the others, and rated aggressiveness decreased in morphs calibrated to higher HGS. CONCLUSIONS: Given the high similarity between the current study findings and those previously reported from intra-population assessments of Maasai faces calibrated to HGS, we suggest that strength and aggressiveness perceptions of facial features associated with male physical strength may be universal. Attractiveness assessments of strength-related information in the faces of (very) strong men were less consistent across populations, possibly attributable to cultural and ecological contexts.

Predictors of female age, health and attractiveness perception from skin feature analysis of digital portraits in five ethnic groups.

OBJECTIVE: Research indicates the impact of skin colour, tone evenness and surface topography on ratings of age, health and attractiveness in women. In addition to subjective assessments, these effects have been quantified with objective measures derived from skin image analysis. Signs of skin ageing may manifest differently across ethnic groups. However, comparisons have been limited to research with two ethnic groups, preventing conclusions about an ethnicity-specific ranking of skin ageing signs. METHODS: We report results from a multi-ethnic and multi-centre study in which faces of women (n = 180; aged 20-69 years) from five ethnic groups were imaged. Facial images were rated for age, health and attractiveness by members of the same ethnic group (each n = 120). Digital image analysis was used to quantify skin colour, gloss, tone evenness and wrinkling/sagging. We assessed associations between face ratings and skin image measurements in the total sample (i.e. all ethnic groups) and separately by ethnicity. RESULTS: Skin image analysis revealed differences between ethnic groups, including skin colour, gloss, tone evenness, wrinkling and sagging. Differences in the relative predictive utility of individual skin features in accounting for ratings of age, health and attractiveness also were observed between ethnic groups. Facial wrinkling and sagging were the best predictors of face ratings in each ethnic group, with some differences in the type (or predictive magnitude) of skin features. CONCLUSION: The current findings corroborate previous reports of differences between ethnic groups in female facial skin and indicate differential effects of skin features on ratings of age, health and attractiveness, within and between ethnic groups. Facial wrinkling and sagging were the best predictors of age and attractiveness ratings, and skin tone evenness and gloss had an additional role in ratings of health.

OBJECTIF: La présente étude montre l'impact de la couleur de la peau, de l'uniformité du teint, et de la texture cutanée sur l'évaluation de l'âge, de la santé et de l'attractivité chez les femmes. En plus d'évaluations subjectives, ces aspects ont été quantifiés à l'aide de mesures objectives provenant d'analyse d'image de la peau. Les signes de vieillissement de la peau peuvent se manifester différemment selon les groupes ethniques. Cependant, les précédentes recherches se limitent à des comparaisons entre deux groupes ethniques, empêchant ainsi de conclure sur un classement des signes de vieillissement cutané par ethnie. MÉTHODE: Nous présentons les résultats d'une étude multiethnique et multicentrique dans laquelle des visages de femmes (n = 180 ; âgées de 20 à 69 ans) de cinq groupes ethniques ont été imagés. Les images des visages ont été évaluées en termes d'âge, de santé et d'attractivité par des membres du même groupe ethnique (n = 120 par groupe). Des algorithmes d'analyse d'image ont été utilisés pour quantifier la couleur de la peau, la brillance, l'uniformité du teint et les rides/affaissement de la peau. Nous avons analysé les corrélations entre l'évaluation des visages et les mesures quantitatives issues de l'analyse d'image sur la totalité de l'échantillon (c'est-à-dire tous les groupes ethniques) et séparément par ethnie. RÉSULTATS: L'analyse d'image a révélé des différences entre les groupes ethniques, notamment en ce qui concerne la couleur de la peau, la brillance, l'uniformité du teint, les rides et le relâchement cutané. Des différences dans la valeur prédictive relative des différentes caractéristiques cutanées dans l'évaluation de l'âge, de la santé et de l'attractivité ont également été observées entre les groupes ethniques. Les rides et l'affaissement du visage ressortent comme les meilleurs prédicteurs de l'évaluation pour tous les groupes ethniques, avec quelques différences dans le type (ou l'ampleur de la prédiction) des différentes caractéristiques cutanées. CONCLUSION: Les résultats actuels corroborent les rapports précédents sur les différences entre les groupes ethniques concernant la peau du visage des femmes. Ils montrent également des effets différentiels des caractéristiques cutanées sur l'évaluation de l'âge, de la santé et de l'attractivité, au sein des groupes ethniques et entre eux. Les rides et l'affaissement du visage ressortent comme les meilleurs prédicteurs de l'âge et de l'attractivité, tandis que l'uniformité et la brillance du teint jouent un rôle supplémentaire dans l'évaluation de la santé.

Mate Retention Behavior and Ejaculate Quality in Humans.

Males of some species use mate retention behavior and investment in ejaculate quality as anti-cuckoldry tactics concurrently while others do so in a compensatory fashion. Leivers, Rhodes, and Simmons (2014) reported that men who performed mate retention less frequently produced higher-quality ejaculates, suggesting that humans use these tactics compensatorily. We conducted a conceptual replication of this research in a sample of 41 men (18-33 years; M = 23.33; SD = 3.60). By self-report, participants had not had a vasectomy and had never sought infertility treatment. We controlled for several covariates known to affect ejaculate quality (e.g., abstinence duration before providing an ejaculate) and found no statistically significant relationships between mate retention behavior and four components of ejaculate quality: sperm velocity, sperm concentration, slow motility, and ejaculate volume. The present results provide little support for the hypothesis that human males deploy mate retention behavior and ejaculate quality investment compensatorily. We discuss the limitations of this study and highlight the need for research to address questions about the nature of anti-cuckoldry tactic deployment in humans, especially concerning investment in ejaculate quality.

Differences between perceived age and chronological age in women: A multi-ethnic and multi-centre study.

OBJECTIVE: Accuracy in assessing age from facial cues is important in social perception given reports of strong negative correlations between perceived age and assessments of health and attractiveness. In a multi-ethnic and multi-centre study, we previously documented similar patterns of female facial age assessments across ethnicities, influenced by gender and ethnicity of assessors. METHODS: Here we extend these findings by examining differences between estimated age from digital portraits and chronological age (Δ age) for 180 women from three age groups (20-34, 35-49, 50-66 years) and five ethnicities (36 images of each ethnicity, assessed for age on a continuous scale by 120 female and male raters of each ethnicity). RESULTS: Across ethnicities, Δ age was smallest in French assessors and largest in South African assessors. Numerically, French women were judged oldest and Chinese women youngest relative to chronological age. In younger women, Δ age was larger than in middle-aged and older women. This effect was particularly evident when considering the interaction of women's age with assessor gender and ethnicity, independently and together, on Δ age. CONCLUSION: Collectively, our findings suggest that accuracy in assessments of female age from digital portraits depends on the chronological age and ethnicity of the photographed women and the ethnicity and gender of the assessor. We discuss the findings concerning ethnic variation in skin pigmentation and visible signs of ageing and comment on implications for cosmetic science.

OBJECTIF: La capacité à évaluer l'âge d'un visage avec exactitude en fonction de ses caractéristiques est important dans sa perception sociale. En effet, des corrélations négatives fortes ont été rapportées entre l'âge perçu d'un visage d'une part, et sa santé et attractivité d'autre part. Dans le cadre d'une étude multi-ethnique et multicentrique, nous avons déjà documenté, dans une démarche similaire, comment la perception de l'âge de visages féminins entre différentes populations, est influencée par le genre et l'origine des évaluateurs. METHODES: Ici nous approfondissons ces premiers résultats par l'étude des différences entre l'âge estimé sur portraits numériques de 180 femmes issues de 3 groupes d'âges (20-34, 35-49, 50-66 ans) et de 5 populations d'origine différente (36 images de chaque population) et leur âge réel (Δ âge), et ce par 120 évaluatrices et évaluateurs de chaque population évaluant l'âge des visages en utilisant une échelle continue. RESULTATS: Au sein des différentes populations d'évaluateurs, le Δ âge le plus faible a été trouvé chez les évaluateurs français et le plus élevé chez les évaluateurs sud-africains. Sur portraits numériques, les femmes françaises ont été perçues comme étant les plus âgées et les femmes chinoises les plus jeunes, par rapport à leur âge réel. Chez les femmes les plus jeunes, le Δ âge a été plus élevé que chez les femmes d'âge moyen et les plus âgées. Ceci a particulièrement été le cas lorsque l'on considère les interactions entre l'âge des femmes évaluées, et le genre et l'origine des évaluateurs, de façon indépendante ou liée, avec le Δ âge. CONCLUSION: Aux travers des différentes analyses, nos résultats suggèrent que l'exactitude avec laquelle l'âge des femmes est évalué sur images numériques de leur visage, dépend de l'âge réel et de l'origine de ces femmes photographiées, ainsi que de l'origine est du genre de l'évaluateur. Nous discutons ces résultats en regard des variations de pigmentation cutanée et de signes visibles de l'âge entre les différentes populations et commentons les implications possibles pour les sciences cosmétiques.

Improvement of Radial Cheek Lines With Hyaluronic Acid-Based Dermal Filler VYC-17.5L: Results of the BEAM Study.

BACKGROUND: Radial cheek lines (RCL) may convey an older, potentially less attractive appearance. OBJECTIVE: To evaluate the effectiveness of hyaluronic acid-based dermal filler VYC-17.5L for correcting RCL. MATERIALS AND METHODS: Fifty-three women (40-65 years) received injections of VYC-17.5L in both cheeks on Day 1 (optional Day 14 touch-up). Effectiveness was evaluated on Day 45 by subject-rated dynamic RCL improvement (Global Aesthetic Improvement Scale [GAIS]; primary end point) and independent, noninjecting investigator-rated GAIS; subject Self-Perception of Age (SPA); subject-assessed satisfaction with and natural look of treatment; and instrument-assessed changes in static and dynamic RCL roughness, amplitude, and texture (secondary end points). Safety assessments included injection site responses (ISRs). RESULTS: On Day 45, 98% of subjects rated RCL as improved or much improved (investigator rated: 95%). Subjects with same or older SPA before treatment (n = 38) perceived themselves as 2.0 and 5.5 average years younger after treatment, respectively. Day 45 mean satisfaction with and natural look of treated areas was 7.9/10 and 7.2/10, respectively. Treatment significantly improved RCL roughness, amplitude, and texture (all p < .001). Most common ISRs were hematoma (35.9%), bruising (30.2%), and irregularities/bumps (22.6%); most ISRs were mild. CONCLUSION: VYC-17.5L effectively corrected dynamic RCL, improved instrument-assessed indicators of skin quality, and resulted in younger age perception.

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. We presented videos of British men's gait-pre-categorized into strong and weak walkers-to male and female members ( n = 100) of the traditional Maasai in northern Tanzania in Africa. Maasai men and women judged the gaits of physically strong men less attractive than those of weak men and judged strong walkers to be weaker than weak walkers. These findings counter results from industrialized societies where participants accurately assessed strength from gait, thus arguing against a universal perception of physical strength from gait information.

Testosterone-dependent facial and body traits predict men's sociosexual attitudes and behaviors.

OBJECTIVES: Strategic Pluralism Theory contends that human mating strategies are calibrated toward short-term (ST) or long-term (LT) mating according to the expression of condition-dependent traits and characteristics of the social and physical environment. Traits reflecting the effects of testosterone have been considered condition-dependent traits that provide information about the calibration of male mating strategy. We investigated the relationship of muscle mass and facial masculinity with attitudes and behaviors reflecting ST and LT mating tactics. METHODS: We measured skeletal muscle mass (SMM) through bioelectrical impedance and facial width-to-height ratio (fWHR) in a sample of Chilean men (n = 206; mean age = 22.52 ± 4.65 SD), and collected information about sociosexual attitudes and past sexual behavior. RESULTS: Our results showed an interaction effect of SMM and fWHR on unrestricted (but not restricted) sociosexual attitudes and past sexual behavior. Individuals with a consistent expression of both traits (ie, high SMM and fWHR or low SMM and fWHR) reported higher levels of unrestricted sociosexual attitudes and a greater number of lifetime and previous-year sexual partners. CONCLUSIONS: These findings suggest that the intensity and consistency of expression of body and facial masculinity is important in signaling male mating tactics and sociosexual attitudes.

Sexual dimorphism in the ontogeny of second (2D) and fourth (4D) digit lengths, and digit ratio (2D:4D).

OBJECTIVE: Sex differences are often reported in digit lengths and digit ratio (2D:4D). However, the ontogeny of these sex differences and their interrelationships are less well known. METHODS: We considered sex differences in the lengths of the 2nd (2D) and 4th (4D) digit and 2D:4D in children aged 2 to 18 years (Sample I, n = 680) and adults aged 18 to 30 years (Sample II, n = 89,246). Digit length was determined by direct experimenter-measurement (Sample I) and direct self-measurement (Sample II). The data were tested with two-factor ANOVA's (sex and year-group). RESULTS: In both samples, there were significant main effects of sex and year-group, and a significant interaction effect on digit length. Digit length was positively related to age in both samples. Boys had longer digits than girls but only after 13 years. Men had longer digits than women and the dimorphism increased from 18 to 30 years. There were significant sex differences in 2D:4D (males < females), but no significant effect of age and no interaction effect of age and sex on 2D:4D in children or adults. CONCLUSIONS: Between 2 and 30 years, the lengths and the sexual dimorphisms of 2D and 4D are dependent on age. In contrast, 2D:4D is not age-dependent. We discuss our findings in the context of the ontogeny of digits and in the light of recent claims on the presence of static allometry in 2D and 4D lengths.

Hair Color and Skin Color Together Influence Perceptions of Age, Health, and Attractiveness in Lightly-Pigmented, Young Women.

OBJECTIVE: Research documents that even subtle changes in visible skin condition affect perceptions of age, health, and attractiveness. There is evidence that hair quality also affects the assessment of physical appearance, as variations in hair diameter, hair density, and hair style have systematic effects on perception. Here, we consider combined effects of hair color and skin color on the perception of female physical appearance. METHODS: In two experiments, we digitally manipulated facial skin color of lightly-pigmented, young women, both between-subjects (Experiment 1) and within-subjects (Experiment 2), and investigated possible interactions with hair color in regard to age, health, and attractiveness perception. RESULTS: In both experiments, we detected hair color and skin color interaction effects on men's and women's assessments. For between-subjects comparisons, participants with lighter hair color were judged to be younger than those with darker shades; this effect was more pronounced in women with light skin color. No such effect was observed for within-subjects variation in skin color. Both experiments showed that smaller perceived contrast between hair color and skin color resulted in more positive responses. CONCLUSION: We conclude that hair color and facial skin color together have an effect on perceptions of female age, health, and attractiveness in young women, and we discuss these findings with reference to the literature on the role of hair and skin in the assessment of female physical appearance. This article is protected by copyright. All rights reserved.

Mate Value Discrepancy and Mate Retention Behaviors of Self and Partner.

OBJECTIVE: This study investigated the relationship between perceived mate value discrepancy (i.e., the difference between an individual's mate value and their partner's mate value) and perceived frequency of mate retention performed by an individual relative to his or her partner. METHOD: In two studies, participants in long-term, exclusive, sexual, heterosexual relationships reported their own, and their partner's, mate value and mate retention. Samples included 899 community members (Study 1) and 941 students and community members (Study 2). RESULTS: In Study 1, we documented that individuals with higher self-perceived short-term mate value, and who perceive their partner to have lower (vs. higher) short-term mate value, perform less frequent Benefit-Provisioning mate retention, controlling for the partner's Benefit-Provisioning mate retention. In Study 2, we documented that individuals who perceive that they could less easily replace their partner, and who perceive their partner could more (vs. less) easily replace them, perform more frequent mate retention (Benefit-Provisioning and Cost-Inflicting), controlling for the partner's mate retention. CONCLUSION: These results highlight the importance of assessing perceived discrepancies in mate value (notably, regarding the replaceability of self and partner with another long-term mate) and perceived mate retention behaviors of self, relative to partner, between men and women in long-term relationships.

Does human ejaculate quality relate to phenotypic traits?

A given man's phenotype embodies cues of his ancestral ability to effectively defend himself and his kin from harm, to survive adverse conditions, and to acquire status and mating opportunities. In this review, we explore the hypothesis that a man's phenotype also embodies cues to fertility or the probability that an ejaculate will fertilize ova. Female mate choice depends on the ability to discern the quality of a male reproductive partner through his phenotype, and male fertility may be among the traits that females have evolved to detect. A female who selects as mates males that deliver higher quality ejaculates will, on average, be more fecund than her competitors. Data on several non-human species demonstrate correlations between ejaculate quality and secondary sexual characteristics that inform female mate choice, suggesting that females may select mates in part on the basis of fertility. While the non-human literature on this topic has advanced, the human literature remains limited in scope and there is no clear consensus on appropriate methodologies or theoretical positions. We provide a comprehensive review and meta-analysis of this literature, and conclude by proposing solutions to the many issues that impede progress in the field. In the process, we hope to encourage interest and insight from investigators in other areas of human mating and reproductive biology. Am. J. Hum. Biol. 28:318-329, 2016. © 2015 Wiley Periodicals, Inc.

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. Here, we investigate men's and women's attractiveness, dominance, and strength assessments from brief samples of male gait. METHODS: Handgrip strength (HGS) was measured in 70 heterosexual men and their gait was motion-captured. Men and women judged 20 precategorized strong (high HGS) and weak (low HGS) walkers on attractiveness, dominance, and strength, and provided a measure of their own HGS. RESULTS: Both men and women judged strong walkers higher on dominance and strength than weak walkers. Women but not men judged strong walkers more attractive than weak walkers. These effects were independent of observers' physical strength. CONCLUSIONS: Male physical strength is conveyed not only through facial and body morphology, but also through body movements. We discuss our findings with reference to studies suggesting that physical strength provides information about male quality in contexts of inter- and intrasexual selection. Am. J. Hum. Biol. 28:913-917, 2016. © 2016Wiley Periodicals, Inc.

Physical strength and dance attractiveness: Further evidence for an association in men, but not in women.

OBJECTIVES: Physical strength provides information about male quality and can be assessed from facial and body morphology. Research on perception of dance movements indicates that body movement also provides information about male physical strength. These relationships have not been investigated for women. METHODS: We investigated relationships of handgrip strength (HGS) and dance attractiveness perception in 75 men and 84 women. RESULTS: We identified positive relationships between HGS and opposite-sex assessments of dance attractiveness for men but not women. CONCLUSIONS: The replication of previous research investigating relationships between dance attractiveness and physical strength in men corroborates the hypothesis that dance movements provide information about male quality. We argue that these relationships are interpretable in contexts of inter- and intra-sexual selection.

Digit ratio (2D:4D), aggression, and dominance in the Hadza and the Datoga of Tanzania.

OBJECTIVES: Digit ratio (2D:4D)-a putative marker of prenatal androgen activity-has been shown to correlate with self-reported physical aggression and dominance behavior, especially in male children and adolescents. This evidence is derived primarily from the study of Western samples. METHODS: Digit ratios, self-reported aggression, and dominance behavior were collected from men and women in two traditional, small-scale societies, i.e., the Hadza and the Datoga of Tanzania. RESULTS: We found significant differences in physical and verbal aggression, anger, and hostility between the two societies with the Datoga reporting higher scores on all four measures. Moreover, self-reported dominance in the Datoga was higher than in the Hadza. The Datoga showed lower left and right hand 2D:4D ratios than the Hadza. Men reported higher physical and verbal aggression and dominance, and had lower 2D:4D ratios than women. A significant negative association between 2D:4D and dominance was found in Hadza women. CONCLUSIONS: We discuss our findings with reference to differences in mating systems between the two small-scale societies and previous findings of Western and other small-scale societies.

Body symmetry and physical strength in human males.

OBJECTIVES: Body symmetry and physical strength in males have been related to aspects of mate "quality"-women seem to prefer men who display both "good genes" (as indexed by high symmetry/developmental health) and fighting ability (as indexed by physical strength). Here we show that fluctuating asymmetry (FA) of the body and physical strength are negatively correlated. METHODS: Body FA (from 12 paired traits) and handgrip strength (HGS; a measure of muscular power and force) were measured in a sample of 69 heterosexual, right-handed men (18-42 years). RESULTS: There were positive correlations of body symmetry with HGS after controlling for the effect of body-mass-index. CONCLUSIONS: We conclude that in males, body symmetry and physical strength are correlated such that symmetric individuals tend to develop higher strength, which may contribute to their success in inter- and intra-sexual selection.

Cognitive simplicity and self-deception are crucial in martyrdom and suicide terrorism.

Suicide attacks and terrorism are characterized by cognitive simplicity, which is related to self-deception. In justifying violence in pursuit of ideologically and/or politically driven commitment, people with high religious commitment may be particularly prone to mechanisms of self-deception. Related megalomania and glorious self-perception are typical of self-deception, and are thus crucial in the emergence and expression of (suicide) terrorism.