Transcript Women’s Long Term Mating Strategies
Women’s Long Term Mating Strategies
chapter 4
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Non-human Species
Weaverbird
Evolutionary History
Problem of selecting a man who would be willing to commit long-term Over thousands of generations, preference for men who showed signs of being willing and able to commit evolved in women This preference solved key reproductive problems
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3 Important issues that are key to understanding the evolution of mate preferences:
1- Why has sexual reproduction evolved?
2- the definition of the 2 distinct types that exist in sexually reproducing species-males and females and the related issue of influence of parental investment on the nature of mating 3- mate preferences as evolved psychological mechanisms
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1- Why has sexual reproduction evolved?
Asexual vs. Sexual Reproduction
Asexual
Advantages Avoid problem of selecting a mate All genes are passed on: offspring are parents identical copies of These advantages of asexual reproduction are the precise disadvantages of sexual reproduction
Big ??:
What advantages could sexual reproduction provide that would be so large that it would outweigh all the costs?
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Sexual Reproduction - Consequences
Problems in mate selection and courting (can be costly in time and resources) *
Genetically Diverse Offspring
different from parents and each other (siblings genetically related by only 50%) – offspring are genetically Diff individuals have different survival requirements, which allows them to inhabit a broader array of niches and cuts down on competition Parasite Theory of the origins of sex – genetically different offspring provide a different host environment for parasites compared w/original host – parasites are thus thwarted Sexual reproduction may have helped host organisms and their offspring combat parasites- providing such a benefit that it outweighs the costs
**Serious adaptive problem posed by sexual reproduction** = finding a mate
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Parental Investment and sexual selection
•
Gametes
– mature reproductive cells
Males
- Small gametes - Greater mobility - Produce millions of sperm (replenished at a rate of 12 million per hour) - Sexual intercourse requires minimal male investment •
Zygote
– a fertilized gamete -
Females
Large gametes - Stationary - Loaded with nutrients - Produce a fixed and unreplenishable lifetime supply of about 400 ova * Women have a greater initial investment *
• This investment continues into the nine-month pregnancy term and breastfeeding
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Parental Investment and sexual selection
* The large initial parental investment of women makes them a valuable reproductive resource * Women in evolutionary past risked investing enormously as a consequence of sex, evolution favored women who were highly selective about their mates ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - Birth Control – suggestion that women can now have short-term sexual encounters with less fear of pregnancy discussion ?? – do you think birth control has had an effect on the way women view casual sex? (are women less selective?) - Do you think this possible change is a good or bad thing? (for women? for men? for reproduction in general?) 7
Trivers’s Theory of Parental Investment and Sexual Selection
Two profound predictions: (1) The sex that invests more in offspring (typically) women) will be more discriminating or selective about mating (2) The sex that invests less will be more competitive for sexual access to the high investing sex 8
Mate Preferences as Evolved Psychological Mechanisms
From among the thousands of ways in which men differ, selection over hundreds of thousands of years focused women’s preferences on the most adaptively valuable characteristics Gauging a man’s mating value requires looking beyond his current situation and evaluating his potential (medical student) Evolution has favored women who prefer men possessing attributes that confer benefits Selecting a mate: Women must identify and correctly evaluate the cues that signal whether a man indeed possesses a particular resource (deceive women about status, etc…) Women must integrate their knowledge about a prospective mate * Selecting a mate requires psychological mechanisms that make it possible to add up the relevant attributes and give each its appropriate weight in the whole * 9
The Content of Women’s Mate Preferences
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Women’s mate preferences are played out in our popular culture…
Older men: “Something’s Gotta Give”
High social status, attractive men: Sex and the City
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Discussion of the characteristics scale
•
What characteristics did you rate as indispensable?
• What is it about those characteristics that makes them so important to you?
• Do you think your preference for these characteristics is an innate preference, or a preference you learned from somewhere else (possibly experience)?
•
What characteristics did you rate as not important or irrelevant?
• Why are these characteristics less important to you in a mate?
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Women’s and Men’s Mate Preferences Category
Income in $ Financial Prospect Scale (0 – 3) Social Status Scale (0 – 3) Age Difference in Years Dependability Scale (0 – 3) Stability Scale (0 – 3) Love/Commitment Scale (0 – 3) Athletic Scale (0 – 3)
Women’s
65,000 1.9
2.6
2.5 years older 2.69
2.68
Most 1.5
Ranking
Not part of ranking 6 th 4 th Not part of ranking 2 nd 3 rd 1 st 7 th
Men’s
40,000 1.2
1.2
1.8 years younger 2.5
2.47
Most .87
Ranking
Not part of ranking 5 th 6 th Not part of ranking 2 nd 3 rd 1 st 7 th Health & Appearance Scale (0 – 3) 2.28
5 th 2.31
4 th Link: http://faculty.oxy.edu/clint/evolution/notes/12/matepreferenceranking.htm
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Preference for Economic Resources
Gray Shrike bird Wherever females show a mating preference, the male’s resources are often the key criterion
The evolution of this preference requires 3
preconditions: 1- resources must be accruable, defensible, and controllable by men throughout history 2- men must differ in their holdings and willingness to invest them in a woman 3- advantages of being w/1 man must outweigh those of being with several these are easily met in humans: Tools, Territory Primates Women needed cues to signal a man’s possession of resources (personality, physical ability, reputation): economic resources is the most obvious cue 14
Preference for Good Financial Prospects
Study in 1939, 1956, 1967, and mid-1980’s (Hill; Hudson & Henze; McGinnis) Women valued good financial prospects in a mate twice as much as did men In personal ads and magazines, female advertisers seek financial resources 11 times as often as men Cross-Cultural Study (Buss, Abbott, Angleitner, et al., 1990) monogamous and polygamous, various religious groups, political systems : 37 cultures, Women from all of the cultures placed more value than men on good financial prospects Women valued financial resources twice as much These findings provided the first cross-cultural evidence supporting the evolutionary basis for the psychology of human mating Link to figure on financial preference: http://faculty.oxy.edu/clint/evolution/notes/12/fig4_3.html
Clip: Sex and the City ?? – What about poor men? Do they have any hope of marrying up in society? What is society’s reaction when a woman marries below her “class”?
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Preference for High Social Status
Proof that historical cultures had words/phrases to describe men who were in high social status Social status is a universal cue to the possession of resources* Study by Buss and Schmitt (1993), examining short- and long-term mating: test which characteristics people valued in potential spouses vs potential sex partners Likelihood of success in a profession and Possession of a promising career were both highly desirable (higher in a spouse than sex partner) Status implies better food, abundant territory, health care More social opportunities for children For the majority of the 37 cultures in the study, it was found that women valued social status in a possible mate more than men (both in Communist and Socialist countries
- Ancestral Women
appear to have solved the adaptive problem of acquiring resources in part by preferring men who are high in status
Link to the table of results from study:
http://faculty.oxy.edu/clint/evolution/notes/12/fig4_4.html
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Preference for Older Men
Age is a clue to resources (they command respect, status, position) In all 37 cultures in study, women preferred older men ( 3 1/2 yrs older ) Actual average age difference b/w brides and grooms Older age, resources, and status are coupled across cultures Tiwi people Traditional societies – age may be related to physical strength and hunting prowess (strength increases with age, peaking in early 30’s) After 30’s, decline is compensated for by increased knowledge, skill, wisdom Much older men – higher risk of dying, less likely to be around to continue providing for and protecting children Link to table of results: http://faculty.oxy.edu/clint/evolution/notes/12/fig4_5.html
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- Economic Resources - Financial Prospects - Social Status - Older men -
These preferences add up to the ability of a man to acquire and control resources that ancestral women could use for themselves and children Women also need men who posses traits that are likely to lead to the sustained acquisition of resources over time… 18
Preference for Ambition and Industriousness
Industrious and ambitious men secure a higher occupational status In a study, women regard men who lack ambition as extremely undesirable, whereas men view lack of ambition as neither desirable nor undesirable Rated b/w important and indispensable Excellent signal of the continuation of present resources
Ancestral Women
-- helped solve the critical adaptive problem of securing resources -- helped them gauge the likelihood of future resources when direct and easily observable signs of resources were absent 19
Preference for Dependability and Stability
Second and third most highly valued characteristics (after love) are a dependable character and emotional stability* These characteristics possess great value to women: 1- they are reliable signals that resources will be provided consistently over time 2- men who lack these provide erratically and inflict heavy emotional and other costs on their mate These are qualities that signal increased likelihood that a woman’s resources will not be drained by the man Ancestral Women: erratic supply of resources could wreak havoc with accomplishing the goals required for survival and reproduction 20
Preference for Athletic Prowess
A cue for physical protection Barbara Smuts - during evolutionary history, physical protection was one of the most important things a man could offer a woman Aggressive men wishing to physically dominate and circumvent women’s sexual choices may have exerted a selection pressure on ancestral women Current number of rape incidences today help support this preference A preference for men 5’11” is ideal for a marriage partner In personal ads where women mentioned height, 80% wanted a man taller than 6’
Seeking:
I am seeking a man with above average height (5'11"" and above). I WILL NOT date anyone less than that. I'm not superficial -- just honest and I know what I like and want and will settle for nothing less. ( www.singlesonline.com
)
Height:
I am extremely attracted to but not limited to tall men (6'2 and up). ( www.yahoopersonals.com
) Tall men received more responses to their personal ads than did short men “traits of male body structure such as height, shoulder width, and upper-body musculature are sexually attractive to women and intimidating to other men” (Barber, 1995, p. 406) 21
Preference for Good Health and Physical Appearance
Unhealthy Mates -- Higher risk of becoming debilitated (fail to provide resources) -- Increased risk of dying (cut off resources, must find a new mate) -- Transfer diseases or viruses to the woman (impair her survival) -- Risk passing on unhealthy genes or poor health to children Men and Women both place a high value on health in a mate Peacocks Their bright plumage serves as a signal of a low load of parasites One cue for the health of a mate is Symmetry (Thornhill, Gangestad, Grammer, Schackelford, Larsen, and others) The degree to which the face and the body are symmetrical Various events and genetic stressors produced deviations from bilateral symm.
Symmetry reflects the ability to withstand environmental and genetic stressors 22
Symmetry in the Human Face
Marquardt Beauty Analysis (MBA) www.beautyanalysis.com
“the form of beauty is composed of 2 things: symmetry, harmony”
1 Symmetry
: the mirror image of parts or components about an axis. By all accounts a beautiful face is symmetric along the y-axis.
2-
Harmony
: a recurring theme With the use of mathematics, computers, and databases full of “attractive” faces, MBA has been able to quantify facial attractiveness in a consistent computer model The “Golden Facial Mask” – based on a series of ratios and geometric shapes -- From this mask comes the “archetypal human face” Link to MBA: http://www.beautyanalysis.com/index2_mba.htm
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As you can see, these “archetypal” faces are symmetrical and made up of a series of recurrent geometric shapes and patterns. 24
An example of how a (beautiful) person’s face fits this “Golden Facial Mask” 25
The “average” face deviates from the “Archetypal Human Face” 26
The “ugly” face does not fit into the mask at all – the nose is too wide, eyes are too far apart, cheekbones too rounded, etc… 27
Preference for Good Health and Physical Appearance
Another cue stems from Masculine Features
Men have longer and broader lower jaws, stronger brow ridges, and more pronounced cheekbones – (consequence of testosterone) Women preferred men’s faces that were more masculine-looking than avg.
Masculine features are a sign of good health (Johnston) Production of high levels of testosterone compromises the immune system Only men who are healthy can “afford” to produce high levels QuickTime movie study supports this The benefits of a healthy mate: longer life More reliable provisioning Lower likelihood of communicable diseases Better genes that can be passed on to children 28
Love
and
Commitment
Gauging commitment requires looking for cues that signal the likelihood of future fidelity in channeling resources
LOVE may be one of the key cues to commitment
Found the presence of romantic love in 88.5% of cultures
Study examined acts of love
(Buss, 1988a) Acts of commitment were viewed as most central to love Giving up romantic relations with others, talking of marriage, expressing a desire to have children When performed by a man, these acts signal intent to commit resources 29
Commitment
Fidelity – remaining faithful Channeling of resources to the loved one – giving expensive gifts Emotional support – being available, listening to problems Channeling of time, energy, and effort to the partner’s needs at the expense of fulfilling one’s own needs Acts of reproduction All of these signal the commitment of sexual, economic, emotional, and genetic resources to one person “Sex and the City” – Why do some women want men who refuse to commit? Why do some women only like to “chase” men?
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Love
Seen as indispensable for marriage 89% of American women, 82% of Japanese women, and 59% of Russian women said that they require love for marriage, even if all other important qualities were met (Sprecher et al., 1994) In the international study (rating the 18 characteristics), LOVE WAS GIVEN THE TOP RATING (most highly valued in a potential mate) 31
Preference for Willingness to Invest in Children
This adaptive problem is important for 2 reasons: 1 - Men sometimes seek sexual variety and so may channel their efforts toward other women (mating) rather than toward children 2 - Men evaluate the likelihood that they are the actual genetic father of a child and tend to withhold investment from the child when they know or think the child is not theirs Study by La Cerra Slide images of men in 5 different contexts
--
women rated each image on how attractive they found the man in each slide as a date, sexual partner, marriage partner, friend, and neighbor Results: women’s ratings of the attractiveness of men as potential mates are increased by cues of their affection toward a child and decreased by cues of their indifference toward a child in distress Replicated same study with images of women for men to rate Results: Men’s attractiveness judgments were the same across all contexts 32
Recap from Tuesday
3 Issues that are key to the evolution of mate preferences: 1- Evolution of Sexual Reproduction – 2- Parental investment – genetically diverse offspring help combat parasites females have greater investment, choosier about mates 3- Mate preferences as evolved psychological mechanisms The Content of Women’s Mate Preferences Economic Resources Good Financial Prospects High social status – Older men – cue to the possession of resources coupled with resources and status Ambition and Industriousness – Dependability and Stability – likelihood of future resources (rated 2 nd and 3 rd ) Athletic Prowess – physical protection Good Health and Physical Appearance – live longer, continuation of resources Love and Commitment – ranked first of all the characteristics desired in a mate Willingness to Invest in Children reproduction 33
Context Effects on Women’s Mate Preferences
Women’s preferences in a mate should depend in part on relevant contexts
Women’s personal resources Temporal context
(committed vs casual mating)
Menstrual cycle Women’s mate value Geographical Location
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Effects of Women’s Personal Resources
Structural Powerlessness Hypothesis
(Buss & Barnes, 1986; Eagly & Wood, 1999) Because women are typically excluded from power and access to resources, women seek mates who have power, status, and earning capacity Men do not value economic resources in a mate because they already have control over these resources Problems with this hypothesis Bakweri women – despite their access to money and mates, they still prefer mates with resources College women – prefer intelligent men with signs of ambition *Successful women with resources - place an even greater value on mates who have professional degrees, high status, and greater intelligence, and who are tall, independent, and self-confident These directly contradict the Structural Powerlessness hypothesis ??
– Why do you think successful women place an even greater value on successful men with resources than less successful women? 35
Effects of Temporal Context
Study by Buss and Schmitt (1993) Women’s preferences shift depending on whether a marriage partner or casual sex partner is sought Study by Scheib (1997) In long-term marital context, women chose character over looks Women emphasize character traits over attractiveness when evaluating a potential husband 36
Effects of Menstrual Cycle
Chance of becoming pregnant increases in late follicular phase as women approach ovulation and is lowest in the postovulation phase Preferences that occur in late follicular phase could reflect mate choice for “good genes” “Good genes” hypothesis seems to find support in research findings Sense of smell increases at or just before ovulation Study on smelly T-shirts (Thornhill & Gangestead, 1999) Link to study: (Blackboard – External Links) http://courses.creighton.edu/webapps/portal/frameset.jsp?tab=courses&url=/bin/common/course.
pl?course_id=_50199_1 Ovulatory-Shift Hypothesis : When women are likely to conceive, their preference shifts toward more masculine-looking male faces and the scents from men who are more symmetrical The attractiveness of traits that are supposed to make good life partners kindness, intelligence, potential for wealth-are unchanged across the monthly cycle (Gangestead, 2006) These might reflect adaptations in women to become fertilized by the healthiest men 37
Ovulatory-Shift Hypothesis
Adaptations to ovulation: Implications for sexual and social behavior Gangestead, S. W., Thornhill, R., & Garver-Apgar, C.E
when fertile, women prefer…
The scent of a symmetrical man: women preferred the scent of symmetrical men Masculine features: women prefer more masculine faces, particularly when they rate men’s sexiness, not attractiveness, as long-term mates Behavioral displays of social presence and intrasexual competitiveness: women found men who were confident and who acted condescending toward their male competitors (in a video tape interview) as more sexy Vocal masculinity: when rating men’s short-term attractiveness, women find masculine (deep) voices more attractive Talent versus wealth: when faced with trade-offs between talent (creativity) and wealth, women choose talent more often, but only when evaluating men’s short-term mating attractiveness Men judged to be faithful were rated as less sexy mid-cycle than at other times women’s preference for men other than their current partners also rises 38
Male Counterstrategies to the Ovulatory-Shift Hypothesis
If women’s interest in their current partners is lowered during fertility, men should have been under selection to take additional steps to prevent them from seeking extra-pair sex at this time… Cues of women’s fertility status: Men find the scent of ovulating women particularly attractive Men also judge women’s faces as more attractive mid-cycle Women’s behavior may also change too Gangestead et al. (2002) found that male vigilance of partners mid-cycle was predicted by enhanced female interest in extra-pair men and not their partners Men may be particularly vigilant of their partners mid-cycle, when their partners least want them to be 39
Effects of Women’s Mate Value
Mate value = one’s overall desirability to men physical attractiveness and youth Women’s self-rated attractiveness was significantly linked to attraction to masculine faces Personal Ads (Canada, America, and Poland) Women with higher mate value specified a longer list of traits that they sought or required in a potential mate They also tended to impose higher minimum standards in their mate requirements– specifically on social status, intelligence, and family orientation Women who are higher in mate value prefer and seek men who are higher in mate value: masculinity, symmetry, and the number of qualities that contribute to men’s desirability 40
Geographical Location
In personal ads, women who live in more densely populated cities or cities where there is a higher cost of living make greater demands for resources in a mate 41
How Women’s Mate Preferences Affect Actual Mating Behavior
• For preferences to evolve, they must affect actual mating decisions at least some of the time • Sources of evidence that preferences do affect mating decision: • Women’s responses to men’s personal ads • • Women’s marriages to men high in occupational status Women’s marriages to older men 42
Women’s Responses to Men’s Personal Ads
Study by Baize and Schroeder (1995), found several variables that significantly predicted the number of responses men received
1 – Age: women responded more often to older men 2 – Income and Education: responded more to men with ads indicating higher income and more years of education Study in Poland received similar results: men with higher levels of education, men who were somewhat older, men who were taller, and men who offered more resources all received a larger number of responses from women 43
i i i i I .
.
.
t t t t t e m a t t m a n w h o s h a n d s o i i t t l t t , , l l i l f i i , , i , , i i , , , , t t t t t m e a n d s u c c e s s u a n d n k e s o d Seeking : I want honesty. I want a man who is handsome and successful and knows how to treat a lady.
sweetsteph72
I am looking for friendship and love on this journey we call life! Orientation: Straight Gentleman who posses Virtues, Moral, Respect, Sincerity, Honesty
mayagirl622
Orientation: Straight Age: 34
Personal Ads “Women Seeking:”
sassysmile
A Sense of humor, a dab of old fashioned charm, a splash of confidence, and a pinch of wit.... makes for a man to turn this girl's head! Orientation: Straight Age: 39 I am seeking a handsome 6'3"" or taller, toned, mature man, 38 46. You must be strong, passionate, romantic, secure, open minded, kind, caring, fatherly role model, a good listener, and very loving. I am NOT looking for a fling or one night stand. I would like to meet a guy who has a great personality and a good sense of humor. He would need to be open, honest and trustworthy, sincere, dependable, genuine and just an all-around likeable guy. Age: 32 44
Women’s Marriages to Men High in Occupational Status
Physically attractive women marry men who are higher in social status and financial holdings Women’s physical attractiveness correlated more strongly with her husband’s status than did other women’s variables such as class of origin Attractive women are in a position to get what they want They appear to select the qualities that most women desire—men with status and resources
Women’s Marriages to Men Are Older
In every country from the international study, grooms were older on average than brides Men’s preferences for younger women may also affect the actual age differences b/w brides and grooms 45
Lesbian Sexual Orientation
Occurs in 1-2% of women (Bailey et al., 1997) Female sexuality appears to be far more flexible over the lifespan than male sexual orientation (Baumeister, 2000) Variability within those classified as “lesbian” or “gay” mate preferences vary across lesbians who describe themselves as “butch” as opposed to “femme”
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Butch lesbians are more masculine, dominant, assertive
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have higher levels of testosterone, more permissive attitudes towards casual sex, more masculine waist-to-hip ratios, less desire for kids
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place less value on financial resources when seeking partners but experience more jealousy over rivals who are more financially successful Femme lesbians are more sensitive, cheerful, and feminine
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place greater importance on financial resources when seeking partners and experience sexual jealousy over more attractive rivals These imply that “butch” and “femme” are not simply labels, but rather reflect genuine differences Their origins still remain a mystery 46
Discussion Questions
Not very many individuals meet all the criteria set by mate preferences. They may have the physical characteristics (healthy, attractive) but lack in resources or financial prospects… so which of the preferences are most important: For a typical relationship to survive (love vs. resources?) For successful reproduction and offspring What about romance? Does anyone have a list of things (mental or on paper) that they “must have” in a mate? (things like must be romantic, must be willing to dance with me, etc…) What OTHER qualities do you look for in a partner?
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Polygamy
“The Masai of Kenya” video The women view multiple wives as a good thing Women have many jobs – more co-wives means a greater divide of the work “Polygamy: A True Story of 1 Husband and 8 Wives” Link to video: Polygamy 1- A True Story of 1 Husband and 8 Wives
Questions for discussion
In the search for a mate who is willing to commit, why would a woman choose a partner that she has to share with other women?
Although these women say they like their polygamist lifestyle, do you think they would choose a monogamous relationship if given the option?
What do you think about polygamy in today’s society? What might be the advantages of being in a polygamist relationship?
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The Evolution of Human Mate Choice
Mate Choice in Non-Human Species OSR (operational sex ratio) – the ratio of sexually active males to sexually active females in a given breeding population; related to rate of reproduction One result of female mate choice is the evolution of exaggerated male traits Related to immunocompetence – the ability to resist infection by parasites Mate Choice in Humans Reproductive potential – the individual’s ability invest in the growth, development, and later social and reproductive competencies of offspring Reproductive investment – the expenditure of this potential offspring Divorce – a woman’s decision to stay married or not is influenced by the quality and quantity of resources provided by her husband Cross-cultural study, “inadequate support is reported as the cause for divorce in 21 societies and ascribed exclusively to the husband in all but 1 case (Betzing, as cited in Geary D.C., Vigil, J., Byrd-Craven, J., 2004) Across age, ethnic status, and socioeconomic status, women preferred husbands who were better educated than they were and who earned more money than they did Found this pattern for women ranging in age fro 20s to 60s When women are forced to make trade-offs b/w a marriage partner’s cultural success and other important traits such as physical attractiveness, a prospective marriage partner’s cultural success is rated as a necessity and other characteristics as a luxury 49
Cont…
Preference for culturally successful men is found in studies of singles ads and fiction novels 1,000 “lonely hearts” ads, found that British women were 3x more likely than British men to seek financial security in prospective partner (McGrew, 1994) Japanese women were 31x more likely than Japanese men to seek financial security and social status (9.4% of women sought, .3% of men) (Oda, 2001) Same themes were found across 25 contemporary romance novels and 6 classic novels that have appealed to women more than men (2 stories from Old T.) In these stories, the male protagonist is almost always an older, socially dominant, and wealthy man Study of more than 1,800 Hungarian men and women (35 yrs or older) found that women who had married older and better educated men on avg. had more children, were less likely to get divorced, and reported higher levels of marital satisfaction Many women prefer men with whom they can develop an intimate and emotionally satisfying relationship with More common in middle- and upper-class Western cultures than in any other cultures In many non-Western contexts, women are more focused on keeping their children alive than on developing intimacy with their husbands (Masai women)
Cont…
Physical Attractiveness and Good Genes Indicators of man’s physical and genetic health Women prefer a taller than avg. man with an athletic and symmetric body shape, including a .9 waist-to-hip ratio, and shoulders that are somewhat wider than their hips Facial features: larger eyes, large smile area, prominent cheek bones and chin Shackelford and Larson (1997) found that men with less symmetric facial features were less physically active, manifested more symptoms of depression or anxiety, and reported more minor physical problems than their peers with more symmetric faces Also have higher basal metabolic rates, lower IQ’s, and fewer sexual partners Physically smaller and less robust men are less likely to be chosen as marriage partners (Phillips et al., 2001) (Nettle, 2002) 51
Cont…
Women’s mate/marriage choices are also influenced by men’s immune system genes Women are not directly aware of this, but immune-system genes are signaled thru pheromones and women respond to these scents (especially when fertile) In terms of disease-resistance, the best outcome for offspring occurs when there is high variability in immune-system genes A study found that women rated the scents of men with dissimilar immune system genes as more pleasant and sexy than the scents of men with similar immune-system genes (Wedekind et al., 1995) Ober found that couples with dissimilar immune-system genes conceived more quickly (2 vs 5 months) and had fewer spontaneous abortions than did couples with more similar genes (1997) Physically attractive women rated masculine-looking men as more attractive long-term partners than did other women, presumably b/c attractive women are better able to divert (thru threats of abandonment) the activities of those attractive men from mating effort to parental effort (Little et al., 2001) 52
Alternative Mating Strategies
Women can sometimes benefit from engaging in short-term sexual relationships or with someone other than her partner (or polyandry) Allow women to secure additional material resources for themselves and children or allow women to mate with physically attractive men and thus secure better genes for their children Short-Term Mates Men’s preference for short-term mates and sexual variety creates a demand that some women use for financial gains Some women appear to engage in short-term sexual relationships when they see the potential for future development of a long-term relationship Extra-Pair Sex 20% of American women reported engaging in at least 1 extra-marital affair, some resulting in pregnancy When women initiated an infidelity, occurred around time of ovulation Cuckoldry is common (male partner parenting another male’s offspring) Dynamics of women’s EPC’s appear to be influenced by hormonal fluctuations 53
Cont…
Serial Monogamy and Polyandry For many women, marriage to a socially dominant, wealthy, and physically attractive man who is devoted to her and her children is not achievable To adjust, some women develop a successive series of relationships with a number of men or several simultaneously, each of whom provides some investment during the course of the relationship South American Indian societies – women engage in sexual relations with men who are not their social partners, especially after becoming pregnant. These secondary fathers are obligated to provide material resources and protection to the woman’s child. The confusion of paternity is such that both the primary and secondary fathers invest in the child 54