Physical attractiveness is the extent to which a person's physical features are considered aesthetically pleasing or beautiful. The term often implies sexual attractiveness or desirability but can also be distinct. Many factors influence one person's attraction to another, with physical aspects being one of them. Physical attraction includes universal perceptions common across human cultures, such as facial symmetry, as well as socioculturally dependent attributes, and personal preferences unique to each individual.
In many cases, humans subconsciously attribute positive characteristics, such as intelligence and honesty, to physically attractive people, a psychological phenomenon called the halo effect. Research done in the United States and United Kingdom found that objective measures of physical attractiveness and intelligence are positively correlated, and that the association between the two attributes is stronger among men than among women. Evolutionary psychologists have tried to answer why individuals who are more physically attractive should also, on average, be more intelligent, and have put forward the notion that both general intelligence and physical attractiveness may be indicators of underlying genetic fitness. A person's physical characteristics can signal cues to fertility and health, with statistical modeling studies showing that the facial shape variables that reflect aspects of physiological health, including body fat and blood pressure, also influence observers' perceptions of health. Attending to these factors increases reproductive success, furthering the representation of one's genes in the population.
Heterosexual men tend to be attracted to women who have a youthful appearance and exhibit features such as a symmetrical face, full breasts, full lips, and a low waist–hip ratio. Heterosexual women tend to be attracted to men who are taller than they are and who display a high degree of facial symmetry, masculine facial dimorphism, upper body strength, broad shoulders, a relatively narrow waist, and a V-shaped torso.
General contributing factors Generally, physical attractiveness can be viewed from a number of perspectives; with universal perceptions being common to all human cultures, cultural and social aspects, and individual subjective preferences. The perception of attractiveness can have a significant effect on how people are judged in terms of employment or social opportunities, friendship, sexual behaviour, and marriage.
Some physical features are attractive in both men and women, particularly bodily and facial symmetry, although one contrary report suggests that "absolute flawlessness" with perfect symmetry can be "disturbing". Symmetry may be evolutionarily beneficial as a sign of health because asymmetry "signals past illness or injury". One study suggested people were able to "gauge beauty at a subliminal level" by seeing only a glimpse of a picture for one-hundredth of a second. Other important factors include youthfulness, skin clarity and smoothness of skin, and "vivid colour" in the eyes and hair. However, there are numerous differences based on gender.
A 1921 study of the reports of college students regarding those traits argued that static traits, such as beauty or ugliness of features, hold a position subordinate to groups of physical elements like expressive behaviour, affectionate disposition, grace of manner, aristocratic bearing, social accomplishments and personal habits.
Grammer and colleagues have identified eight "pillars" of beauty: youthfulness, symmetry, averageness, sex-hormone markers, body odor, motion, skin complexion, and hair texture. Traditionally in Samoa, body fat was acceptable or attractive.
Facial features An Italian study published in 2008 analyzed the positions of the 50 soft-tissue landmarks of the faces of 324 white Northern Italian adolescent boys and girls to compare the features of a group of 93 "beautiful" individuals selected by a commercial casting agency with those of a reference group with normal dentofacial dimensions and proportions. The research found that, in comparison with the reference group, the attractive adolescents tended to have the following characteristics: the ratio between the volume of the forehead and that of the total face was larger; the nasal volume was smaller; the distance between outer canthi was larger; total facial height and depth were reduced. Some tendencies differed by age and sex: the facial volume was smaller in older attractive boys than in their peers, but bigger in attractive girls; the faces of older attractive adolescent boys were less rounded (bigger ratio between facial area and volume), but the reverse was true for girls of any age; attractive older boys had smaller angles of facial convexity with more acute profiles, while in girls the reverse pattern was found; the nasolabial angle was reduced in girls, but in older boys the effect was reversed; older attractive boys tended to have more prominent chins. The study concluded that attractive adolescents had more neotenous and juvenile features, but older attractive boys also showed tendencies towards sexual dimorphism.
Contrary to common misconception, one study finds that non-severe facial scarring increases male attractiveness for short-term relationships.
Symmetry
Symmetrical faces and bodies may be signs of good inheritance to women of child-bearing age seeking to create healthy offspring. Studies suggest women are less attracted to men with asymmetrical faces, and symmetrical faces correlate with long-term mental performance and are an indication that a man has experienced "fewer genetic and environmental disturbances such as diseases, toxins, malnutrition or genetic mutations" while growing. Since achieving symmetry is a difficult task during human growth, requiring billions of cell reproductions while maintaining a parallel structure, achieving symmetry is a visible signal of genetic health.
Studies have also suggested that women at peak fertility were more likely to fantasise about men with greater facial symmetry, and other studies have found that male symmetry was the only factor that could significantly predict the likelihood of a woman experiencing orgasm during sex. Women with partners possessing greater symmetry reported significantly more copulatory female orgasms than were reported by women with partners possessing low symmetry, even with many potential confounding variables controlled. This finding has been found to hold across different cultures. It has been argued that masculine facial dimorphism (in men) and symmetry in faces are signals advertising genetic quality in potential mates. Low facial and body fluctuating asymmetry may indicate good health and intelligence, which are desirable features. Studies have found that women who perceive themselves as being more physically attractive are more likely to favour men with a higher degree of facial symmetry than are women who perceive themselves as being less physically attractive. It has been found that symmetrical females and males have a tendency to begin to have sexual intercourse at an earlier age, to have more sexual partners, and to have more one-night stands. They are also more likely to engage in infidelity. A study of quarterbacks in the American National Football League found a positive correlation between facial symmetry and salaries.
Body scent
Double-blind studies found that women prefer the scent of men who are rated as facially attractive. For example, both males and females were more attracted to the natural scent of individuals who had been rated by consensus as facially attractive. Additionally, it has also been shown that women have a preference for the scent of men with more symmetrical faces, and that women's preference for the scent of more symmetrical men is strongest during the most fertile period of their menstrual cycle. Within the set of normally cycling women, individual women's preference for the scent of men with high facial symmetry correlated with their probability of conception. Men's body odor is also affected by their diet, with women expressing preferences for male body odor associated with increased dietary fruit, vegetable and protein content, and reduced carbohydrate content.
Genetics
Studies have explored the genetic basis behind such issues as facial symmetry and body scent and how they influence physical attraction. In one study in which women wore men's T-shirts, researchers found that women were more attracted to the bodily scents in shirts of men who had a different type of gene section within the DNA called major histocompatibility complex (MHC). MHC is a large gene area within the DNA of vertebrates which encodes proteins dealing with the immune system and which influences individual bodily odors. One hypothesis is that humans are naturally attracted by the sense of smell and taste to others with dissimilar MHC sections, perhaps to avoid subsequent inbreeding while increasing the genetic diversity of offspring. Furthermore, there are studies showing that women's natural attraction for men with dissimilar immune profiles can be distorted with use of birth control pills. Other research findings involving the genetic foundations of attraction suggest that MHC heterozygosity positively correlates with male facial attractiveness. Women judge the faces of men who are heterozygous at all three MHC loci to be more attractive than the faces of men who are homozygous at one or more of these loci. Additionally, a second experiment with genotyped women raters, found these preferences were independent of the degree of MHC similarity between the men and the female rater. With MHC heterozygosity independently seen as a genetic advantage, the results suggest that facial attractiveness in men may be a measure of genetic quality. General genetic heterozygosity has been demonstrated to be related to attractiveness in that people with mixed genetic backgrounds (i.e., mixed race people) are seen as more attractive than people with more genetically similar parents (i.e., single race people). However, some studies have not found that mixed race individuals are rated as more attractive, and one found that only certain mixes were rated as more attractive; this study argued that equating race with genetics was incorrect and argued for social influences as the cause.
Youthfulness
A 2010 study by American dating site OkCupid on 200,000 of its male and female users found that heterosexual women—except those during their early to mid-twenties—are open to relationships with both somewhat older and somewhat younger men; they have a larger potential dating pool than men until age 26. At age 20, women, in a "dramatic change", begin sending private messages to significantly older men. At age 29, they become "even more open to older men". Male desirability to women peaks in the late 20s and does not fall below the average for all men until 36. Other research indicates that women, irrespective of their own age, tend to be more attracted to men who are the same age or older.
For the Romans especially, "beardlessness" and "smooth young bodies" were considered beautiful to both men and women. For Greek and Roman men, the most desirable traits of boys were their "youth" and "hairlessness". Pubescent boys were considered a socially appropriate object of male desire, while post-pubescent boys were considered to be "ἔξωροι" or "past the prime". This was largely in the context of pederasty (adult male interest in adolescent boys). Today, men and women's attitudes towards male beauty have changed. For example, body hair on men may even be preferred (see below).