Mating preferences

Mating preferences are qualities that one desires in a romantic or sexual partner. Research across many domains, such as evolutionary biology, psychology, and anthropology, shows that humans display both widely shared (consensual) preferences– like preferences for kindness, intelligence, and health– as well as sex-differentiated preferences shaped by ancestral selection pressures. These preferences are understood within the framework of sexual selection (first proposed by Charles Darwin in 1871)^[1] and more contemporary theories that draw on evolutionary explanations, cultural variation, and evidence from actual mating behaviors. These theories account for the variation in desires for certain traits, the divergence of preference between men and women, and the adoption of short-term vs long-term mating strategies. Together, these approaches explain the origins, adaptive functions, and real-word outcomes of human mate preferences.

Historical Background

Darwin's Theory of Sexual Selection

One of the earliest theories posited to explain mate preferences was Darwin's Theory of Sexual Selection.^[1] This theory came about when he noticed that certain characteristics (most famously, the feathers of a male peacock) appeared to have no survival value. Unsatisfied with his theory of natural selection as the primary driver of evolution, he proposed that sexual selection was at play.^[1] Namely, Darwin suggested two mechanisms of this evolutionary process.

The first mechanism, intrasexual selection, describes the competition with same-sex others for access to mates.^[1] This can include directly antagonistic interactions, such as physical contests and fights, or indirect interactions like competition for territory or high status positions.^[2] As a result of success in such competitions, the victors are able to mate, meaning that their heritable traits are passed down to offspring with greater frequency.^[3] Those who lost do not gain access to mates and have less reproductive success. Over many generations, this differential reproductive success causes the qualities that contribute to winning these competitions (like upper body strength, formidability, or intelligence, for example) to become more common in the population. This pattern shapes preferences because individuals who choose mates with successful, competitive traits have a greater chance of producing children who survive and are reproductively successful themselves. As a result, preferences for such advantageous traits are passed down along with the traits themselves.

The second mechanism, intersexual selection (also called epigamic selection), represents one sex's propensity to prefer and, in turn, select specific members of the opposite sex that embody preferred characteristics.^[1] Because desired qualities (like physical attractiveness or intelligence, for instance) are notably heritable, individuals who select mates who display such qualities are more likely to have children who also possess them. Over time, this process increases the frequency of preferred traits in the population and also strengthens the preferences themselves (offspring inherit both the desired traits and the preference for them). Thus, this preferential mate choice directly influences one's reproductive success.

Both processes work together to select for qualities that enhance an individual's reproductive success, favoring characteristics that improve mating opportunities (even if those characteristics do not directly improve survival) and, importantly, shaping what we deem to be preferable in a mate.^[1] These mechanisms have been substantiated across virtually every species that reproduces sexually,^[3] highlighting sexual selection theory as a pervasive evolutionary force.

Consensual Mate Preferences

During human evolution, there was a selection pressure to pursue mates who had traits that could yield reproductive success. Those who successfully mated with reproductively fit individuals passed their genes onto the next generation with greater frequency. This sexual selection strengthened the presence of the reproductively beneficial traits themselves as well as the preference for them. The resulting consensual mate preferences refer to the widely shared, cross-cultural judgments regarding the desirable mate qualities that most people, regardless of sex or culture, tend to value.

Physical Qualities

Physical Attractiveness & Symmetry

Physical attractiveness is highly desired among men and women because it functions as a cue to fertility and health. Moreover, a very attractive mate would likely produce offspring that are also attractive, enhancing their fitness.^[4][5][6][7] Though men tend to prioritize and prefer physical attractiveness more so than women, it is still a quality that is highly desired by both sexes.^[8][9]

Symmetry is one of the many aspects that factors into attractiveness for both men and women.^[10] Both facial and bodily symmetry are considered to be very attractive because they essentially act as a certificate of good health and reproductive potential (developmental stability, genetic diversity, and parasite resistance, for example).^[11][12][13] Fluctuating asymmetry, or deviation from perfect bilateral evenness, can indicate poor genetic quality and is thus deemed undesirable in a mate.^[14] Preference for symmetry in a mate is observed cross-culturally, indicating its robustness as a cue to good health.^[15]

Evidence from Actual Mating Behavior

Research shows that physically attractive individuals have better sex lives.^[16] Symmetry in particular is a good predictor of the number of sex partners one has.^[17] Furthermore, more symmetrical men tend to have their first intercourse at an earlier age than do less symmetrical men.^[17]

Good Health

A healthy appearance is very desirable in a mate because it can indicate a resilient body that is free from chronic illness/disease with a low exposure to pathogens.^[18] Health is an important mate preference, as poor health can be passed onto offspring or to a partner and consequently decrease fitness.^[2] Because aspects of health are genetically influenced, it is imperative that one chooses a healthy mate in order to increase the fitness of progeny, both directly and indirectly.^[2][19]

Visible indicators of health include bilateral symmetry, skin condition, and sexual dimorphism.^{[20][10][21][22][23]} For example, clear skin tone and complexion is broadly considered to be desirable in a mate, functioning as a signal of health and high quality genetics.^[24] The presence of sexually dimorphic traits also indicates health, as both estrogen and testosterone (hormones that produce sexually dimorphic traits) are known immunosuppressants.^[21][22] Because these hormones temporarily reduce immune function, only individuals with robust underlying health can afford to produce and maintain strongly sex-typical traits. Thus, a person with sexually dimorphic traits (like a small chin in females or a large jaw in males) signals good health– only those with high genetic quality would be able to develop such masculine or feminine qualities.^{[21][22][25][26][23]}

Other Qualities

Traits such as kindness, dependability, intelligence, and honesty are highly valued among men and women alike.^[27][9][28] These traits are cues to adaptive behaviors that would highly benefit one's partner and family.

Kindness & Empathy

Kindness, the quality of being nice or friendly, is consistently ranked as one of the top priorities in a mate.^{[29][9][28][8]} Displays of kindness and empathy may indicate a tendency to cooperate with others and place a partner's needs relatively high in processes of decision-making. In addition, kindness can signal greater parenting ability.^[30]

Intelligence

Intelligence is also consistently ranked by men and women as a top priority for a mate.^[29][9][28] Greater cognitive ability can help partners figure out the complex challenges that may arise when making decisions, managing a household, raising children, and solving everyday problems.

Dependability

Dependability is preferred by men and women because it communicates a partner's likelihood of maintaining commitment throughout the relationship as well as remaining steady and reliable during difficult times.^[29][9][28]

Social Status

Many people prefer a mate who maintains a high social status within their community.^[31][32][33] A mate who is highly respected by others in their social network would be able to gain access to resources and, in turn, confer upon their family.^[31][32][33]

Love

Love, the deep emotional bond that underpins long-term romantic relationships, is consistently valued across cultures.^[34] It is a human universal^[35] and has been suggested to act as a commitment device designed to promote stable pair bonding, cooperation in parenting, and reproductive success.^[36][37][38]

Honesty

A mate's honesty is highly valued and preferred by both men and women.^[29][9][28] Honesty, or the tendency to tell the truth, is a trait that can signal loyalty in many important domains. Honest behavior can reflect the general propensity to act transparently instead of manipulating or exploiting others.

Humor

Humor, the quality of being funny or entertaining, is widely desired among men and women.^[8] Research suggests that humor functions as an honest signal of cognitive capacity, creativity, and social intelligence– qualities that reflect fitness.^[39][8]

Explanations for Consensual Preferences

Relationship Satisfaction

One prominent theory as to why these preferences are rated as very desirable and important for many people is their association with relationship satisfaction. This theory posits that some qualities (such as kindness or empathy) greatly contribute happiness within the relationship.^[29] Unkind or unempathetic partners may decrease relationship satisfaction and, as a result, increase the likelihood of relationship dissolution. Other trivial qualities (such as good housekeeping skills) are deemed less important in a relationship simply because they don't have a significant effect on relationship satisfaction or maintenance.^[29]

Evolutionary Biology

Another theory as to why some qualities are consistently desired among men and women is the traits' association with reproductive investment capability.^[29] Essentially, this theory states that mate qualities like physical attractiveness or intelligence are considered important and desirable because they are more greatly correlated with parental investment abilities than are traits like good housekeeping skills.^[29] As a result, minor traits (such as good housekeeping skills) are not widely desired or prioritized. Ancestral humans who prioritized mate preferences that served proximate cues to reproductive investment capabilities were able to have more offspring and thus propagate their genes with a greater frequency.^[29]

Both of these theories are not incompatible. They likely, in fact, work together to strengthen the importance of certain mate preferences from two different angles.

Sex-Differentiated Mate Preferences

In ancestral environments, men and women faced different selection pressures. Women are highly constrained in their reproductive output because they are limited by gestation and lactation, therefore having significant obligatory parental investment.^[40][41] Men do not have such constraints– they are only limited by the number of fertile mates they have access to and are thus able to sire several children in a year.^[40][41] These asymmetries in parental investment led to differing optimal strategies for maximizing fitness and reproductive success.^[40][41] As such, men and women evolved diverging mate preferences which remain prevalent to this day.

Women

Short-Term Mating Preferences

Physical Attractiveness: Masculinity

For women, short-term mating (i.e., engagement in low-commitment sexual acts, such as a one-night stand) could be extremely costly due to obligatory parental investment (e.g., gestation, lactation, etc).^[40][41] Because of this, women who engage in short-term mating are motivated to pursue men who have high genetic quality.^[42][43] One indicator of high genetic quality is physical attractiveness and the presence of sexually dimorphic features.^[25] Indeed, in short-term mating, women have exhibited stronger preferences for male physical attractiveness, such as facial symmetry and masculine features (large jaw, prominent eyebrows).^[42][43]

These sexually dimorphic features are highly desired because they function as an honest immunocompetence handicap signal.^[42][43] Masculinity acts as cue to testosterone exposure, which signals high genetic quality due to testosterone's immunosuppressant effects.^[25] Because testosterone suppresses the immune system, only men with good immune systems would be able to develop these masculine secondary sex characteristics.^[42][43] Therefore, women are attracted to such dimorphic features because they indicate high quality genes that would be passed onto offspring.^[42][43]

It is proposed that this preference for sexually dimorphic features is stronger in short-term mating strategies because the male's high genetic quality is traded off for parental investment. Some evidence backs this up, as researchers have found links between high levels of masculinity and low levels of investment.^[44] For instance, high testosterone men are less likely to get married, and when they do, they tend to have more marital problems and higher rates of divorce than low testosterone men.^[44]

Preference for Masculinity & Local Pathogen Threat

Local pathogen threat is a significant influence in female preference for a masculine partner.^[45][46] Because the presence of masculine features in men is indicative of a good immune system, exposure to pathogen cues is shown to be associated with stronger preferences for male facial masculinity among women.^[47] Across a variety of cultures, it has been found that pathogen load is positively correlated with importance of partner physical attractiveness.^[45] This is further supported by data that reports females more strongly prefer masculinity in places with poorer health statuses, such as high mortality and disease rates.^[46] It has also been found that women with high sensitivity to pathogen disgust exhibit stronger preferences for masculinity.^[46]

Evidence from Actual Mating Behavior

Indeed, it has been found that men who are more masculine tend to have a higher number of sexual partners.^[48] Research shows that men with broad shoulders relative to hips (a highly sexually dimorphic quality correlated with testosterone) tend to lose their virginity at a younger age, have more sex mates, have more affairs, and have more sex with other people's mates as compared to men with lower shoulder-to-hip ratios.^[49]

Functions of a Short-Term Mating Strategy

Women may prefer to acquire a short term mate in some scenarios. There are 4 possible adaptive functions to preference for short-term mating strategies.^[50]

One explanation is that she may need to acquire immediate resources, and mating with a man (with the ability to confer benefits) would secure those resources (for her and her children).

Secondly, she may wish to participate in short-term mating in order to acquire good genes for her future child. This is known as the Good Genes Hypothesis.^[3] Some lines of evidence suggest that women prefer short-term mates when target mates have indicators of high genetic quality, such as facial symmetry, masculine features, and high physical attractiveness.^{[51][52][53][54][55][56]} This is partly explained by the fact that short-term mating is a profitable mating tactic for highly masculine men, and research has found correlations between high levels of masculinity and low levels of romantic/parental investment.^[57][58] Since men who have such cues of high genetic quality may be more inclined to engage in short-term mating, women who want to secure good genes for her offspring must also engage in short-term mating.^[47]

Another explanation is that she may be evaluating a short term mate for a possible long-term relationship.

Lastly, she might engage in short term mating during acts of infidelity. In this case, a short-term mating strategy functions as a means to mate switch, an outcome that may occur following an extrapair copulation. Four variants of mate switching have been identified.^[3]

• First, a woman may engage in short-term mating in order to acquire a backup mate, acting as a sort of mate insurance if something were to happen to her primary mate.
• Next, she may use short-term mating as a means to facilitate disinvestment in an existing mate.
• Thirdly, a woman could engage in short-term mating in order to acquire a mate who offers greater benefits and fewer costs than her current mate.
• Lastly, a woman may mate in the short-term as a means to evaluate her own mate value and determine whether or not more desirable mates exist in the mating market.

Long-Term Mating Preferences

Resources & Financial Prospects

A man's reproductive investment is highly tied to his ability to attain and confer benefits for the family.^[59] Because women pay the enormous cost of pregnancy and child rearing, ancestral women needed to solve the problem of provisioning enough food for herself and her children. Given this, ancestral women would have placed extreme importance on a mate's ability to forage, hunt, and provide meat (i.e., give benefits to her and her offspring).^[60] Today, this translates to a man's ability to bring in economic resources and provide for the family monetarily. Monetary privilege allows access to resources that may provide material and social advantages to offspring.^[59][29] Indeed, many lines of evidence from various cultures suggest that women prefer men who possess economic resources and good financial prospects.^{[61][62][63][64][60][28]}

Evidence from Actual Mating Behavior

Multiple studies have shown that this preference occurs in real mating behavior: women are more likely to select mates who have greater ability to confer economic benefits. For example, speed dating studies have shown that women are more inclined to select mates who grew up in an affluent neighborhood and had higher levels of both education and income.^[65] Another study found that women in Kenya preferentially select mates who have lots of land.^[66] Indeed, married men consistently have higher levels of income than single men of the same age.^[2] In addition, one cross-cultural study found that inadequate economic support was a frequent cause of divorce as reported by females.^[67] Divorce due to a lack of economic support never occurred among males.^[67]

Ambition, Industriousness, & Social Status

In line with female preference for a mate's economic resources and financial prospects, women cross-culturally have shown preference for a mate's ambition, industriousness, and social status.^[61][68] For example, one study found that women rated high-status men as significantly more attractive than lower-status men.^[69] These qualities would have, again, signaled the ability of a mate to provide for a woman and her offspring.

Evidence from Actual Mating Behavior

There is lots of evidence that this preference translates into real life mating behavior. For instance, mail-order brides from a variety of countries were more likely to select men who had higher levels of status and ambition.^[70] Another study found that women were more likely to seek out mates who owned a car and placed importance on their career.^[71]

Protection & Physical Formidability

Because ancestral women were more susceptible to dangerous others, they evolved preferences for mates that signal both the ability and willingness to protect. Qualities such as dominance, a larger body size, physical formidability, athleticism, and bravery are all highly valued among women.^[3] For example, women have shown strong preferences for males who are muscular and lean with a broad chest and V-shaped torso (broad shoulders relative to hips).^[49] Many lines of evidence show that women strongly prefer tall men over short men because they are seen as more dominant and physically formidable.^{[72][73][74][75]}

Evidence from Actual Mating Behavior

Indeed, tall men are more likely to date, get responses on dating ads, and acquire highly attractive partners.^[75][74] Also, men with a high shoulder-to-hip ratio are shown to have more sex partners.^[49] Moreover, men who are perceived as dominant copulate earlier in life than their counterparts.^[76]

Older Partner

Cross-culturally, women have shown a strong preference for men who are older than themselves.^[28][29][77] One prominent reason for this is that older men typically have greater economic security and social status than younger men.^[77] Research has shown that women actually prefer a larger age gap than do men, with an average ideal preference of 3.42 years older.^[27]

Evidence from Actual Mating Behavior

Multiple studies have shown that age preferences are actualized in real-world relationships. For example, many women report having a partner older than themselves.^[27][77] Consistently across cultures and centuries, women date and marry men who are a few years older than themselves.^[77][28][78]

Costs and Benefits of a Long-Term Mating Strategy for Women

Costs

The primary cost of employing a long-term mating strategy among women is having to forgo short-term mating opportunities and the previously described benefits they might bring.^[3]

Benefits

There are many benefits of using a long-term mating strategy for women. Namely, a woman's long-term mate can secure status and resources for herself and her offspring.^[3] Also, having a long-term mate can ensure the physical protection of herself and her family.^[3] Lastly, employing a long-term mating strategy can ensure enhanced mating success of the offspring by means of the material and social benefits acquired from a father.^[3]

Men

Short-Term Mating Preferences

Sexual Variety

Men have evolved stronger preferences for sexual variety than women, mostly due to the fact that parental investment is not nearly as costly for men.^[50] Men, then, should be highly motivated to acquire as many mates as possible– the only constraint to his reproductive success is the number of fertile mates he has access to.^[40][41] As a result, studies show that men, moreso than women, express a strong desire for short-term mates and want a greater number of sexual partners.^[50] Indeed, men in many countries maintain more permissive attitudes towards causal sex than do women.^[79] In comparison to women, men prefer to have sex sooner and are more willing to loosen their preference standards while seeking casual sex.^[50]

Evidence from Actual Mating Behavior

A preference for sexual variety is actualized in men's real mating behavior in several ways. For example, men tend to feel less sexual regret than women– they are less likely to be upset following a causal hookup.^[80][81][82] In addition, men are more likely than women to feel regret regarding missed sexual opportunities.^[83] Substantially more men than women will agree to have sex with a stranger, a finding that has been replicated across many countries.^[84][85][86] Cross-culturally, men solicit prostitutes far more than women do, with 99% of sex worker patrons being male.^[3] Moreover, men often report that their ideal outcome of a short-term mating experience is more sex, while women describe their ideal outcome to be a romantic relationship.^[3] On top of this, men have been shown to employ tactics of deception in order to obtain short-term sex, such as faking interest in a long-term romantic relationship.^[87][88][3] Furthermore, married men are more likely than married women to have affairs (and with a greater number of partners)^[2]. Findings in support of men's engagement in acts involving increased sexual variety have been replicated cross-culturally.^[89][90][91]

Sexual Exploitability

Men who employ a short-term mating strategy are more attracted to women who possess indicators of sexual exploitability.^[92] Appearing to be immature, under the influence, flirtatious, sleepy, and wearing revealing clothing are preferred by men seeking casual sex because they are believed to be cues that a woman can be easily seduced.^[92][3] Men who desire a short-term mate are substantially more attracted to these qualities than men seeking a long-term mate.^[93] In fact, these sexual exploitability indicators are not preferred (and are found to be unattractive) by men employing a long-term mating strategy.^[93]

Long-Term Mating Preferences

High Reproductive Value

Ancestral men who had successfully pursued a fertile mate passed down their genes with a higher frequency. As a result, men evolved preferences for cues that historically correlated with a woman's reproductive value^[3]. Reproductive value is not directly observable in women due to concealed ovulation, so it must be inferred through visible qualities^[94]. In fact, physical appearance contains lots of information about a person, like their age and health status^[18]. Most men today are attracted to women who signal high reproductive value, inferred through her age and physically healthy/attractive appearance^{[59][95][50][96]}.

Cues to Reproductive Value: Physical Attractiveness (Healthy & Youthful Appearance)

Indicators of relative youth and health are substantial predictors of female attractiveness judgments by men.^{[59][97][98][3]} Indeed, men reliably report preferences for a long-term mate who is beautiful and neotonous.^{[59][97][98][3]}

Physical qualities considered attractive by men include traditionally feminine and youthful features, such as full lips, facial adiposity, small chin, thin jaws, high cheekbones, clear/supple skin, facial symmetry, and clear/large eyes.^{[59][95][50][99][49]} These feminine facial features are believed to be associated with high estrogen levels, a hormone that is linked to fertility and tends to decline with age.^[100]

Other physical qualities preferred by men are healthy hair, lively gait, bodily symmetry, and firm/symmetrical breasts.^{[59][95][50][96][49][101]}

One prominent mate preference among men is a low waist-to-hip ratio (hourglass figure).^{[59][95][50][96][49]} A low waist-to-hip ratio is highly important as it is one of the best visible cues to fecundity.^[4][102] In fact, it has been found that congenitally blind men show preference for a low waist-to-hip ratio in a mate, indicating that the hourglass figure is a robust indicator of reproductive value.^[103]

Cues to Reproductive Value: Younger Partner

Numerous studies point to the fact that men prefer a mate who is younger than themselves.^{[27][104][77]} The ideal age for a mate according to one sample of men is approximately 2.66 years younger.^[27]

Evidence from Actual Mating Behavior

Many lines of evidence support the notion that men acquire mates who are physically attractive and youthful. Typically, men who are of high status are able to actualize their preferences and, in turn, secure the most attractive mates. Across different centuries and cultures, it has been found that men with high-income, high status jobs (kings, CEOs, famous actors and musicians, etc.) often acquire spouses and mistresses who are substantially younger and more physically attractive than the average woman.^{[105][106][107][108][104][77][109]}

In addition, cross-cultural marriage statistics throughout time show that women are typically younger than their partners by anywhere from 3 to 10 years.^{[27][77][78][104]} This age gap increases as men get older– the age of their mate becomes increasingly younger.^[110] Furthermore, data from foreign bride purchases showed that men tended to select considerably younger mates for marriage.^[111]

Other behavioral data also points to a preference fulfillment for younger mates among men. For example, in cultures that take part in bridewealth practices, the age of a potential wife impacts the amount of money spent, with younger wives getting higher amounts of money.^[66] It has also been shown that men tend to spend more money on engagement rings for younger brides.^[112] Research also indicates that mate guarding tactics are more strongly employed for younger women.^[113]

Sexual Fidelity

Sexual fidelity, or the propensity to remain sexually devoted to one's partner, is highly valued by men and regularly placed among their top priorities in a mate.^{[50][114][115]} Such loyalty indicates a woman's commitment to the relationship, reducing the likelihood of partner defection.^[3] Remaining sexually faithful is very desirable for men because it protects against the substantial fitness costs associated with betrayal, such as cuckoldry, thereby increasing paternity certainty.^[59]

Costs and Benefits of a Long-Term Mating Strategy for Men

Costs

In line with the costs for women, a long-term mating strategy for men may be costly because he must relinquish other short-term sexual opportunities.^[3]

Benefits

There are many benefits to pursuing a long-term mating strategy for men. One benefit is that he may utilize a woman's lifetime reproductive means.^[3] In doing so, a man may gain paternity certainty.^[3][116] Furthermore, he may enhance the fitness of his offspring via parental investment and strengthen social power via his alliances with his partner's family.^{[117][50][116]} Given the fact that many women require commitment prior to engaging in a sexual relationship, a man may benefit from employing a long-term mating strategy by simply increasing the chance of attaining a mate at all.^[50][116]

Mate Preference Priorities

Mate preference priorities are often measured using budget allocation, a method in which research participants are given a limited number of "dollars" they must distribute to various mate traits, a paradigm which forces them to make decisions about which characteristics are most important to them.^[8] This method generally yields two categories of preferences: necessities and luxuries.

Necessities

One study showed that, when given a small budget, people prioritize mate traits that were ancestrally significant for reproductive success.^[8] These traits are thought to be necessities, meaning they are considered essential in a mate.

Cross-cultural and Sex-Differentiated Necessities

The traits that were viewed as necessities differed among men and women in both Eastern and Western samples.^[8]

• Western women placed a higher priority on a partner having good financial prospects, a sense of humor, and a desire for children.
• Western men viewed humor as a necessity.
• Eastern women and men saw good financial opportunities as a necessity in a partner.
• Eastern men rated a partner's religiosity as a necessity.

Consensual Necessities

Despite the observed differences, men and women from various cultural backgrounds consistently placed a high value on kindness and physical attractiveness (though men did allocate a slightly higher amount toward attractiveness).^[8]

Luxuries

When given a large budget, participants allotted resources to traits considered luxuries– qualities that are desirable but nonessential in a partner.^[8]

Cross-cultural and Sex-Differentiated Luxuries

• Western men tended to rate good financial prospects in a mate as a luxury.
• Eastern men and women viewed humor as a luxury.
• Eastern men and women, as well as Western men saw a partner's desire for children as a luxury.
• Eastern women and Western women and men saw religiosity in a mate as a luxury.

Consensual Luxuries

Regardless of sex or cultural background, the participants in this study frequently rated creativity and chastity as luxuries.^[8]

See also

• Mate choice in humans
• Assortative mating
• Sexual selection
• Sexual strategies theory
• Evolutionary psychology
• Intersexual selection
• Parental investment theory
• Mate value
• Mate guarding
• Life history theory
• Good genes hypothesis
• Sexual dimorphism
• Facial symmetry
• Physical attractiveness
• Cross-cultural psychology