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Symmetry...

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Monday, May 3, y

Symmetry Preferences

- Koinophilia • Idea that, when sexual creatures seek a mate, they prefer that mate not to have any unusual, peculiar, or deviant features

• In these composite face studies, facial attractiveness increases in proportion to the number of faces in the composite

• Preference for the average - Indicator of health-normal looking= nothing wrong

- Hormonal Markers • Levels of testosterone and estrogen in males and females affect a number of social features that can be used

- Male Facial Structure • Testosterone promotes - Lateral growth of the cheekbones, mandible, and chin - Forward growth of the brow bridges - Lengthening of the face

- Facial Hair • In humans, the presence or absence of head and facial hair provide strong social/sexual signals

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• Facial hair is generated at puberty in the presence of testosterone and rate of beard growth is positively related to androgen levels

• Males with facial hair are rated as being more masculine, strong, potent, dominant, and courageous

- But also lacking in self-control, dirty, aggressive, and reckless (Reed and Blunk 1990)

• More culturally specific

- Cranial Hair • Muscarella and Cunningham (1996) suggested hart male pattern baldness evolved as a signal of aging and social maturity

- Male with enhanced social status and reduced physical aggression • 6 male models with different levels of facial and cranial hair were rated on 32 social perception adjectives

- Female Facial Structures • Attractive females associated with high levels of estrogen and low levels of testosterone include

- Prominent cheek bones - Full lips - Small nose - Small chin - Large eyes - Skin condition

- Neoteny 2

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• A key feature of female facial attractiveness is the extent of babyish features that the face displays

• Such features are created by a high estrogen/ low testosterone ratio • Any cues of illness or advanced age are universally rated as being unattractive

• Johnson and Franklin (1993) used a computer program which allowed participants to morph the faces of females

- Skin Condition • Skin condition may be a reliable signal of female health and fertility and flawless skin is one of the most universally desired female features

• It reflects the ratio of sex hormones; women with higher than average levels of testosterone have more acne and facial hair

- Pheromones • There is not a lot of evidence for human pheromones • Best examples - Androstadienone alters female limbic system function and causes positive reactions

• Females improve feelings toward males, feel submissive - Menstrual synchronization among female cohabitants

- Male Body Types • Correlations with attractiveness include - Height - Torso dimension

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- Athleticism/ musculature

- Height • Height is associated with power and status and confers economic and social advantages

• Graziano est al. (1978) had women judge pictures of men who they believed to be short, medium, or tall on attractiveness and dating desirability

• In a sample of over 4,000 Polish men, it was found that height was significantly associated with the likelihood of getting married and having children

- Torso • Horvarth (1979) found that shoulder with was a strong positive indicator of attractiveness of male figures

• Waist-chest ratio was the principal determining factor of attractiveness - Inverted triangle was rated as being more attractive • A protruding stomach is seen as a exceptionally unattractive trait in men • More recently, Hughes and Gallup (2003) showed that males with higher shoulder-hip ratio reported having sex at an earlier age

- Body Hair • Rantala et al. (2009) Behavioral Ecology - Females ranked attractiveness of male torso hairlines - Found correlation with females current partner and fathers

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- Preferences also correlated with Western cultural ideals of hairlessness as being more attractive rather than traditional views based on hormone levels

- Athleticism • Physical competition is widespread in human societies • Sporting achievement is an honest signal of physical condition, motivation, and competitiveness

• Faurie et al. (2004)

- Female Body Size and Shape • Standards for body size preferences vary between cultures and individuals

• In Western societies, the general preference is for average-slim body sizes

- Playboy centrefolds have declined in body size from the 1950s - Winners of beauty pageants and competitions are several body sizes smaller than average

- Distribution of Body Fat • Body fat distribution may be an honest signal of reproductive status • At puberty, females deposit tissue on the thighs, breasts, and buttocks • Differences in fat distribution

- WHR, Health and Fertility

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• After puberty, the female’s WHR becomes significantly lower than that of the male due to the presence of estrogens

• The typical healthy female WHR is between .67-.80 - Lower WHR- wider hips relative to waist - Higher WHS- smaller hips relative to waist

- WHR and Attraction • Singh (1993) presented participants with line drawings representing four levels of WHR

- Permanent Breast Enlargement • All female primates have enlarged breasts during pregnancy and lactation

• Only humans have permanently enlarged breasts

- Nubility Hypothesis • Marlowe (1997) - Hominin females evolved protruding breasts because their size and shape function as a signal of reproductive value (age)

- Signal of fat reserves- reflect ability to give birth and invest in offspring - That is why males see breast as erotic • With concealed ovulation males may be selecting females for their ability to make healthy babies

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