Genetic and phenotypic cues associated with facial attractiveness and health

Facial attractiveness plays a crucial role in human mate choice, with individuals from both sexes using facial attractiveness cues to some degree when choosing a partner. Although some of the general facial attractiveness preferences have been studied in cross-cultural populations, most of the research focused specifically on Western populations. Most previous studies also approached facial attractiveness solely from a psychological point of view. One notable exception was a recent study by Roberts et al. (2005) in which the authors linked the Human Leococyte Antigen (HLA) system to cues for health and facial attractiveness in males. This study provides fascinating evidence that genes involved in the immune response also signal attractiveness and health. But is this true cross-culturally and across genders? Roberts et al. (2005) used a British population, who compared to other populations worldwide, have relatively few pathogens that routinely challenge their immune response. The first objective of our study was to test the role of the HLA system in an African female population with a high pathogen load. We found that common HLA alleles, that seemingly provide resistance against common pathogens, play a more important role in health measures than heterozygosity per se. However, our results showed these individuals were not necessarily rated more attractive. So which facial cues do individuals from our study population find attractive in the opposite sex? According to this study individuals from both sexes prefer neotenous features in the opposite sex. Interestingly, we found no preference for facial symmetry and only a slight preference for femininity in females. Our findings support the hypothesis by Boothroyd et al. (2005) that preference for femininity is a by-product of preference for neotenous cues. To test if ethnic preference could not play a confounding role in facial attractiveness ratings of the ethnically mixed South African population, we tested ethnic recognition in two abundant South African ethnic groups. Our results showed that individuals from both sexes could not reliably assign ethnicity to facial images of the two groups. Ethnic preference could therefore not play a role in our study. But mate choice does not only depend on cues displayed by the person being observed. Conditional dependent factors, inherent to the observer, influence how choosy they are of potential partners and therefore how attractive they rate members of the opposite sex. We tested the role of three condition dependent factors, age self-perceived attractiveness and relationship status in both sexes. We observed no significant difference in choosiness between males and females. Male choice therefore plays a more important role in human mate choice than previously expected. Furthermore, our study showed that condition dependent factors affect choosiness differently in males and females. Females are generally more sensitive to condition dependent factors, especially self-perceived attractiveness, while males showed no correlation between any of the condition-dependent factors and choosiness. Since HIV is so prevalent in the South African population, we also tested the role of self esteem in predicting sexual risky behaviour. Our results showed that high self-esteem males were more likely to be sexually active after the age of 18, but that males with low self-esteem were more likely to start sexual activity prematurely. We observed no significant correlation for females. These results indicate that HIV prevention campaigns should focus more on behavioural outcomes other than abstinence, instead of challenging the cultural norms, as indicated by the behavior of high self-esteem individuals. In conclusion, this dissertation is based on the first comprehensive study of genetic and conditional cues associated with facial attractiveness and health in an African population. This African population, with its high pathogen load, high diversity and novel cultural background provided many novel findings, which would hopefully contribute to a more universal view of human mate choice.Dissertation (MSc (Genetics))--University of Pretoria, 2006.Geneticsunrestricte

African perceptions of female attractiveness

Little is known about mate choice preferences outside Western, educated, industrialised, rich and democratic societies, even though these Western populations may be particularly unrepresentative of human populations. To our knowledge, this is the first study to test which facial cues contribute to African perceptions of African female attractiveness and also the first study to test the combined role of facial adiposity, skin colour (lightness, yellowness and redness), skin homogeneity and youthfulness in the facial attractiveness preferences of any population. Results show that youthfulness, skin colour, skin homogeneity and facial adiposity significantly and independently predict attractiveness in female African faces. Younger, thinner women with a lighter, yellower skin colour and a more homogenous skin tone are considered more attractive. These findings provide a more global perspective on human mate choice and point to a universal role for these four facial cues in female facial attractiveness.Publisher PDFPeer reviewe

Facial Adiposity, Attractiveness, and Health: A Review

The relationship between facial cues and perceptions of health and attractiveness in others plays an influential role in our social interactions and mating behaviors. Several facial cues have historically been investigated in this regard, with facial adiposity being the newest addition. Evidence is mounting that a robust link exists between facial adiposity and attractiveness, as well as perceived health. Facial adiposity has also been linked to various health outcomes such as cardiovascular disease, respiratory disease, blood pressure, immune function, diabetes, arthritis, oxidative stress, hormones, and mental health. Though recent advances in the analysis of facial morphology has led to significant strides in the description and quantification of facial cues, it is becoming increasingly clear that there is a great deal of nuance in the way that humans use and integrate facial cues to form coherent social or health judgments of others. This paper serves as a review of the current literature on the relationship between facial adiposity, attractiveness, and health. A key component in utilizing facial adiposity as a cue to health and attractiveness perceptions is that people need to be able to estimate body mass from facial cues. To estimate the strength of the relationship between perceived facial adiposity and body mass, a meta-analysis was conducted on studies that quantified the relationship between perceived facial adiposity and BMI/percentage body fat. Summary effect size estimates indicate that participants could reliably estimate BMI from facial cues alone (r = 0.71, n = 458)

Skin Blood Perfusion and Oxygenation Colour Affect Perceived Human Health

Skin blood perfusion and oxygenation depends upon cardiovascular, hormonal and circulatory health in humans and provides socio-sexual signals of underlying physiology, dominance and reproductive status in some primates. We allowed participants to manipulate colour calibrated facial photographs along empirically-measured oxygenated and deoxygenated blood colour axes both separately and simultaneously, to optimise healthy appearance. Participants increased skin blood colour, particularly oxygenated, above basal levels to optimise healthy appearance. We show, therefore, that skin blood perfusion and oxygenation influence perceived health in a way that may be important to mate choice

Facial shape analysis identifies valid cues to aspects of physiological health in Caucasian, Asian and African populations

Facial cues contribute to attractiveness, including shape cues such as symmetry, averageness and sexual dimorphism. These cues may represent cues to objective aspects of physiological health, thereby conferring an evolutionary advantage to individuals who find them attractive. The link between facial cues and aspects of physiological health is therefore central to evolutionary explanations of attractiveness. Previously, studies linking facial cues to aspects of physiological health have been infrequent, have had mixed results, and have tended to focus on individual facial cues in isolation. Geometric morphometric methodology (GMM) allows a bottom-up approach to identifying shape correlates of aspects of physiological health. Here, we apply GMM to facial shape data, producing models that successfully predict aspects of physiological health in 272 Asian, African and Caucasian faces ? percentage body fat (21.0% of variance explained), body mass index (BMI; 31.9%) and blood pressure (BP; 21.3%). Models successfully predict percentage body fat and blood pressure even when controlling for BMI, suggesting that they are not simply measuring body size. Predicted values of BMI and BP, but not percentage body fat, correlate with health ratings. When asked to manipulate the shape of faces along the physiological health variable axes (as determined by the models), participants reduced predicted BMI, body fat and (marginally) BP, suggesting that facial shape provides a valid cue to aspects of physiological healthpublishersversionPeer reviewe

Facial-based ethnic recognition: insights from two closely related by ethnically distinct groups

Sherpa Romeo blue journal; open accessPrevious studies on facial recognition have considered widely separated populations, both geographically and culturally, making it hard to disentangle effects of familiarity with an ability to identify ethnic groups per se.We used data from a highly intermixed population of African peoples from South Africa to test whether individuals from nine different ethnic groups could correctly differentiate between facial images of two of these, the Tswana and Pedi. Individuals could not assign ethnicity better than expected by chance, and there was no significant difference between genders in accuracy of assignment. Interestingly, we observed a trend that individuals of mixed ethnic origin were better at assigning ethnicity to Pedi and Tswanas, than individuals from less mixed backgrounds. This result supports the hypothesis that ethnic recognition is based on the visual expertise gained with exposure to different ethnic groups

Common HLA Alleles Associated with Health, but Not with Facial Attractiveness

Three adaptive hypotheses have been proposed to explain the link between the human leucocyte antigen (HLA) genes, health measures and facial attractiveness: inbreeding avoidance, heterozygote advantage and frequency-dependent selection. This paper reports findings that support a new hypothesis relating HLA to health. We suggest a new method to quantify the level of heterozygosity. HLA heterozygosity did not significantly predict health measures in women, but allele frequency did. Women with more common HLA alleles reported fewer cold and flu bouts per year, fewer illnesses in the previous year and rated themselves healthier than women with rare alleles. To our knowledge, this is the first study to show a positive correlation between HLA allele frequency and general health measures. We propose that certain common HLA alleles confer resistance to prevalent pathogens. Nevertheless, neither HLA heterozygosity nor allele frequency significantly predicted how healthy or attractive men rated the female volunteers. Three non-mutually exclusive explanations are put forward to explain this finding

Looking like a leader-facial shape predicts perceived height and leadership ability.

Judgments of leadership ability from face images predict the outcomes of actual political elections and are correlated with leadership success in the corporate world. The specific facial cues that people use to judge leadership remain unclear, however. Physical height is also associated with political and organizational success, raising the possibility that facial cues of height contribute to leadership perceptions. Consequently, we assessed whether cues to height exist in the face and, if so, whether they are associated with perception of leadership ability. We found that facial cues to perceived height had a strong relationship with perceived leadership ability. Furthermore, when allowed to manually manipulate faces, participants increased facial cues associated with perceived height in order to maximize leadership perception. A morphometric analysis of face shape revealed that structural facial masculinity was not responsible for the relationship between perceived height and perceived leadership ability. Given the prominence of facial appearance in making social judgments, facial cues to perceived height may have a significant influence on leadership selection

Cross-cultural agreement in facial attractiveness preferences : the role of ethnicity and gender

Previous work showed high agreement in facial attractiveness preferences within and across cultures. The aims of the current study were twofold. First, we tested cross-cultural agreement in the attractiveness judgements of White Scottish and Black South African students for own- and other-ethnicity faces. Results showed significant agreement between White Scottish and Black South African observers’ attractiveness judgements, providing further evidence of strong cross-cultural agreement in facial attractiveness preferences. Second, we tested whether cross-cultural agreement is influenced by the ethnicity and/or the gender of the target group. White Scottish and Black South African observers showed significantly higher agreement for Scottish than for African faces, presumably because both groups are familiar with White European facial features, but the Scottish group are less familiar with Black African facial features. Further work investigating this discordance in cross-cultural attractiveness preferences for African faces show that Black South African observers rely more heavily on colour cues when judging African female faces for attractiveness, while White Scottish observers rely more heavily on shape cues. Results also show higher cross-cultural agreement for female, compared to male faces, albeit not significantly higher. The findings shed new light on the factors that influence cross-cultural agreement in attractiveness preferences.VC was supported by a South African National Research Foundation Scarce Skills Postdoctoral Fellowship (Grant nr: 76454).http://www.plosone.orgam201

MHC Class II Heterozygosity Associated With Attractiveness of Men and Women

The genes of the Major Histocompatibility Complex (MHC), which plays a fundamental role in the immune system, are some of the most diverse genes in vertebrates and have been connected to mate choice in several species, including humans. While studies suggest a positive relationship between MHC diversity and male facial attractiveness, the connection of MHC diversity to other visual traits and female attractiveness is still unclear. The purpose of this study was to investigate further whether MHC heterozygosity, indicating genetic quality, is associated with visual traits affecting mate preferences in humans. In total 74 Latvian men and 49 women were genotyped for several MHC loci and rated for facial and, in men, also body attractiveness. The results indicate a preference for MHC heterozygous female and male faces. However, the initially positive relationship between MHC heterozygosity and facial attractiveness becomes non-significant in females, when controlling for multiple testing, and in males, when age and fat content is taken into account, referring to the importance of adiposity in immune function and thus also attractiveness. Thus overall the effect of MHC heterozygosity on attractiveness seems weak. When considering separate loci, we show that the main gene related to facial attractiveness is the MHC class II DQB1; a gene important also in viral infections and autoimmune diseases. Indeed, in our study, heterozygous individuals are rated significantly more attractive than their homozygous counterparts, only in relation to gene DQB1. This study is the first to indicate a link between DQB1 and attractiveness in humans