PSYC205 Evolutionary Psychology Short-Term Sexual Strategies PDF

PSYC205 Evolutionary Psychology Short-Term Sexual Strategies Edison Tan Evolutionary Psychology Singapore Management University “Hi, I’ve been noticing you around town lately, and I find you very attractive. Would you _____________?” 1. "Would you go out with me to...

PSYC205 Evolutionary Psychology Short-Term Sexual Strategies Edison Tan Evolutionary Psychology Singapore Management University “Hi, I’ve been noticing you around town lately, and I find you very attractive. Would you _____________?” 1. "Would you go out with me tonight?“ 2. "Would you come over to my apartment tonight?“ 3. "Would you go to bed with me tonight?" Edison Tan Evolutionary Psychology Singapore Management University  01 Men’s Short-Term Mate Preference Edison Tan Evolutionary Psychology Singapore Management University Cost and Benefit of Short-Term Mating for Men Benefits Cost The potential adaptive advantage for men engaging Increased number of Sexually Transmitted in short-term mating is direct and large despite the offspring fathered. Disease numerous costs Reputational cost Natural selections will favor adaptations that Lower survival odds of allow men to pursue short-term mating when offsprings due to lack of cost and risk are minimized. paternal investment Aggression from a jealous rival or woman’s long- term mate Aggression from woman’s male kin Retaliatory affairs Edison Tan Evolutionary Psychology Singapore Management University Evidence for Men’s Short-Term Mating Preferences Sexual Fantasies and Extramarital Testicle Size Sex Drive Affairs Intense sperm competition during short-term mating involving multiple males with a female imposes selective pressure to Men are more likely to dream Men are more likely produce a higher volume of ejaculate. of sexual events to be involved in Human testes size relative to body size is greater than some Men fantasies more about extramarital affairs primates. having sex with strangers, switching and having multiple partners Prostitution & Variation in Sperm Insemination Women’s fantasies are Hookup Men’s sperm count increases with an increasing amount of time much more romantic, since the last sexual intercourse with a long-term mate emotional, and Occurs practically in Despite having casual sex and masturbation in between every human society monogamous in content intercourse. Men universally have a higher Crowding out and displacing potential interlopers’ sperm sex drive Edison Tan Evolutionary Psychology Singapore Management University Adaptive Problems Associated with Men’s Short-Term Mating Adaptive Problems Solution Problem of Partner Desire for a variety of women Number/Variety Relaxation of standards Minimize time lapse before seeking sex. Preferring promiscuous women with higher sex drive Signal a higher likelihood of success in gaining sexual access Sensitivity to cues of sexual exploitation Preferring seemingly immature, intoxicated, reckless, flirtatious, young, sleepy, wearing skimpy clothing, and showing an open body posture. Men found women displaying these cues to be sexually attractive for short-term mates but unattractive for long- term mates. Sexual regret Negative affect in response to missed opportunities to motivate future attempts Edison Tan Evolutionary Psychology Singapore Management University The Closing Time Phenomenon Edison Tan Evolutionary Psychology Singapore Management University Adaptive Problems Associated with Men’s Short-Term Mating Adaptive Problems Solution Problem of Preferring fertile women over women with high reproductive value? Identifying which ?Testable prediction derived from sexual selection theory Women are Fertile Preferring promiscuous women with higher sex drive Signal a higher likelihood of success in gaining sexual access Problem of Avoiding Loss of interest in sexual partner following intercourse Commitment Sexual regret Negative affect in response to costly sexual contact to motivate future avoidance Edison Tan Evolutionary Psychology Singapore Management University  02 Women’s Short-Term Mate Preference Edison Tan Evolutionary Psychology Singapore Management University Evidence for Women’s Short-Term Mating Preferences Male’s Short-Term Female Orgasm Mating Preferences Women who experience orgasm experience less sperm ejection following sexual intercourse – which aids sperm retention Men’s short-term mating Women engaging in affairs are more likely to experience preferences could not have orgasm evolved without a female participant from the majority of the short-term mating Timing of Affairs episodes Women who have affairs are more likely to time their affairs to Complete lack of access means a coincide with the time she is ovulating. lack of fitness enhancement opportunities for men Extramarital Affairs Prostitution Hookups Edison Tan Evolutionary Psychology Singapore Management University Benefit of Short-Term Mating for Women Hypothesis Benefits Resource Immediate Economic Resource Hypothesis Investment via Paternal Confusion Men might be willing to offer SOME investment in the woman’s children on the chance that they are genetically his own. Protection received from “friends with benefits” Men tend towards providing physical protection of mates and offspring from predators and other men “Friends with benefits” is an alternate source seeking protection Status Elevation Elevated social standing by offering sexual favors to high-status man Genetic Benefits Superior offspring genetics Hypotheses Enhance Fertility Compensate for infertile long-term mate Sexy-Son” Hypothesis - Affairs with attractive men may produce a son who is able to attract other highly attractive, fertile women to compensate for a less fertile father. Genetic Diversity in Offsprings Genetic hedging Edison Tan Evolutionary Psychology Singapore Management University Benefit of Short-Term Mating for Women Hypothesis Benefits Mate Switching Mate expulsion strategy “Trading up” Opportunity to find a man of more desirable characteristics than their long-term mate Mate Insurance Cultivating potential replacement mates “just in case” Mate replacement – replacing debilitated or dead long-term mate Short-term Sex to evaluate long-term potential. Sexual compatibility mating for long- Uncover hidden cost (e.g., existing long-term mates) term goals Clarifying mate preference Honing mate attraction skills Mate Increasing long-term mate’s commitment Inducing mate defense via introduction of potential mate rival Manipulation Revenge as deterrence Edison Tan Evolutionary Psychology Singapore Management University  Cost of Short-Term Mating for Women Reputational Cost Reputation as a promiscuousness and infidelity. Unwanted, unaffordable Pregnancies Related to the phenomenon of maternal infanticide Sexually-Transmitted Disease Resource withdrawal from long-term mate Higher odds of sibling conflict due to lower genetic relatedness Short-term mating strategy is favored as long as the benefits outweigh the cost. Edison Tan Evolutionary Psychology Singapore Management University  03 Contextual Effects Edison Tan Evolutionary Psychology Singapore Management University  Context Effects Affecting Short-Term Mating Parental Individual Life Transition Sex Ratio Influence Differences The absence of a father while Casual sex is related to people’s The shift in sex ratio within local A number of individual differences growing up is reliably linked to a developmental stages in life, possibly ecology changes the magnitude of influence short-mating tendencies preference for short-term mating in indicative of stage-specific demands. inter- and intra-sexual competition and success. both sexes. for both sexes Other family factors include E.g., functions of teenage Surplus of men is linked to longer- Male’s own mate value (e.g., status, Harsh family environment experimentation term mating resource, physical strength, and Harsh parenting Accessing own mate value on the market Surplus of women is linked to attractiveness) History of sexual abuse Honing attraction skills more short-term mating High extraversion, low agreeableness, Clarifying preferences and low conscientiousness predicted an Potential explanations: interest in short-term mating Daughter-guarding Other transition points include High dark triad personality predicts Life History Theory divorce, change in social status with exploitative short-term mating career progression, etc. strategies Edison Tan Evolutionary Psychology Singapore Management University  Discussion Edison Tan Evolutionary Psychology Singapore Management University (Digitalized) Sexual Selection Theory How would the modern commodity of dating apps interact with our evolved mate preferences? Consider: Individual differences (including sex differences and preferences for long vs short-term mating strategy) in determining who uses dating apps. Given the changes in contextual inputs (please identify), how would dating and sexual behavior (the outputs) change in the context of online dating? Edison Tan Evolutionary Psychology Singapore Management University  (Digitalized) Sexual Selection Theory Predictions From Sexual Selection Existing Empirical Findings Theory Women will be choosier than men in According to commercial data from Tinder, men selecting potential mates, whereas men approximately outnumber women 4 to 1. seek to increase mate number and Men are more likely to report dating app use (Barrada et al., 2021) variety Men use dating platforms, hoping to extend the number of sex Men are more likely to use dating partners, more than women do; however, they do not succeed apps, particularly for short-term in this as much as they expected (Harris & Aboujaoude, 2016) mating. Men more than women use online dating platforms for Women will receive more requests extradyadic sex (Martins et al., 2016) than men do. Highly desirable women are more 80% of first messages were sent from men (Bruch & Newman, 2018). selective than less desirable women Highly attractive women give fewer responses to messages than less attractive women do (Bruch & Newman, 2018) Women prefer good financial prospects On dating apps, a high level of education is demanded more in to men. men than it is in women (Bruch & Newman, 2018) Because older women has lower Messaging patterns revealed being older is less favorable for reproductive value and fertility, older women than for men (Bruch & Newman, 2018) women are disadvantaged in mate competition. Edison Tan Evolutionary Psychology Singapore Management University A New Arena for Short-Term Mating… (?) Edison Tan Evolutionary Psychology Singapore Management University …Or a landmine of Evolutionary Mismatches Conditions of the EEA Modern Dating Conditions Effect on Dating Psychology Ancestral humans residing in small groups Dating apps expose modern humans to visual Perceived availability of options causes with limited geographic mobility would have images of hundreds of potential mates within inflated self-perceived mate value and a shift encountered, perhaps, a few dozen potential a few days and many thousands over time. of preferences towards short-term mating and mates in their lifetime. making both men and women even more choosy. In men, self-perceived mate value scores higher on measures of sociosexuality, indicating that they are more inclined toward casual sex. (Clark, 2006) Self-perceived mate value is also associated with mate preferences- both men and women who are higher in self-perceived mate value place greater importance on desirable traits in potential mates, presumably because they are in a position to attract high quality partners (e.g., Buss and Shackelford, 2008; Burriss et al., 2011) Edison Tan Evolutionary Psychology Singapore Management University PSYC205 Evolutionary Psychology Problems of Parenting Edison Tan Evolutionary Psychology Singapore Management University  Why do Women Invest More than Men? For most organism, female tend to invest more than men in the care of their off-springs. WHY? Paternal Uncertainty Mating Opportunity Cost When a male mate with a female, the following Men can enhance their reproductive success by mating as circumstance may occur that increase paternal doubt: much as possible. Resources devoted to parenting are resources not available for mating. Female may have already mated with another male, and her ovum have already been fertilised The Mating Opportunity Cost Hypothesis outlines that Female may have additional mate, perhaps in secret paternal parenting efforts would be high when males are Resources devoted to a rival’s children are resources taken less likely to incur mating opportunity costs. away from one’s own. E.g., male fish that guard eggs in their territory do not suffer mating opportunity costs. Parenting behaviors can often be observed (e.g., feeding the egg). In humans, parental care may be a tactic to attract women The ability of human males to obtain mates predicts parenting effort. Factors include: Higher personal mate value Sex Ratio Population Density Edison Tan Evolutionary Psychology Singapore Management University  Sex Differences in Parenting Adaptations As women are always certain about maternity, and fathers are generally not, natural selection should favor parental adaptations that differ from men. Primary Caretaker Hypothesis (Babchuk, Hames, & Thompson, 1985). Women have evolved adaptations that increase the odds that their children will survive. Women (vs. men) show a preference for photos with infants and viewed photos with infants longer Women are better than men at recognizing infant facial expressions of emotion Women should be better than men at decoding all facial expressions of emotion—responsiveness to infants likely to produce securely attached children (Attachment Promotion Hypothesis) Women should be particularly sensitive to dangers that might be conveyed by negative emotions (Fitness Threat Hypothesis) Edison Tan Evolutionary Psychology Singapore Management University  Sex Differences in Parenting Adaptations “Tend-and-Befriend” Hypothesis (Taylor et al., 2000). Women are said to have adopted a two-pronged approach to promote offspring survival. “Tending” involves protecting children from dangerous predators and other threats and calming and quieting them down to avoid detection “Befriending” involves creating and maintaining social networks that offer a social cocoon of protection. Women (vs. men) are more likely to seek friendship under stress “The Baby Effect” (Fischer & Hills, 2000). Women take less risk in the presence of an infant. Key Note: Sex-differentiated differences in parenting adaptations do not imply that men do not take care of and protect their offsprings Edison Tan Evolutionary Psychology Singapore Management University  01 Evolved Psychological Mechanism for Parental Care Edison Tan Evolutionary Psychology Singapore Management University  Evolved Psychological Mechanisms for Parental Care Decision Algorithm Input: IF → THEN Output: e.g., Child look like me IF (Child mine) Parental Care THEN (Invest in child) The evolved psychological mechanism for parents Parental care refers to the preferential allocation should be sensitive to the following inputs: of parental investment to one or more offspring. Genetic relatedness of offspring to self Investments allocated to offspring are investments Ability for offspring to convert investments into not available for other offspring or to enhance the reproductive success fitness of the parents. Inputs suggestive of an alternative use for investment instead of investment in offspring. Natural selection would shape the parents to E.g., Self invest in offspring more likely to provide a Mating opportunities reproductive return on investment. Kin-investment Reciprocal Altruism Edison Tan Evolutionary Psychology Singapore Management University  Genetic relatedness of offspring Mothers are more likely to insist on infant’s resemblance to father to assuage paternal uncertainty. Cross-culturally, mothers and relatives of mothers tend to attribute resemblance of the infant to the father. Men are much more receptive to baby faces that resemble them Men found the faces into which their photo had been morphed to be the most attractive and indicated that they would (Platek et al., 2000): Spend more time with this child Invest more money in this child Least resentful of paying child support to this child Men show greater cortical activity – brain area associated Men who judged their children to look like them reported with inhibition – than do women when shown images of more positive relationships with their children. (Burch & Gallup, 2000) children’s faces that resemble their own. (Platek et al., 2005) Edison Tan Evolutionary Psychology Singapore Management University Genetic relatedness of offspring “Parental investment is a precious resource, and selection must favour those parental psyches that do not squander it on nonrelatives” (Daly & Wilson, 1988) Men will allocate more resources to their genetic children than to their stepchildren Men who are uncertain about whether children are genetically their own will invest less than men who are certain the children are their own Men will invest more in children when the child’s mother is their current mate than they will in children from former mate ships. Edison Tan Evolutionary Psychology Singapore Management University  Genetic relatedness of offspring The “Cinderella Effect” Compared to actual parents, step-parents are substantially less likely to report having Child Abuse parental feelings for stepchildren. Cross-cultural phenomenon “Evil stepparent” narratives exist across folk literature. Child Homicide Parental discrimination of genetically unrelated children is a by-product of parental care (Daly & Wilson, 2008) All else equal, parents will provide parental care for their own children more than other people's children. Substitute parents (e.g., step-parents, foster parents) tend to care less profoundly for their own child. Cross-culturally, child abuse, child homicide, and infanticide risks are far higher when the caregivers are not genetically related to the child. Daly & Wilson (1988). Edison Tan Evolutionary Psychology Singapore Management University Offspring’ s Ability to Convert Parental Care Into Reproductive Success Parental investment to a child unable to utilize the investment are Offspring’s Health/Age investment lost Selection should favor adaptations that cause parents to invest heavily when the children are most able to convert the parental care into fitness by an Parental Investment Offspring’s Reproductive increase in the children’s chances for Fitness survival or reproduction. Edison Tan Evolutionary Psychology Singapore Management University  Offspring’ s Ability to Convert Parental Care Into Reproductive Success Healthy Baby Hypothesis (Mann, 1992) The level of investment mothers The health status of the child would affect the devote is based on the health degree of positive maternal behavior the mother would show after birth. status of the child functionally, Children’s health with poor health and depending on her own level of developmental abnormalities have low resources. (Beaulieu & Bugental, 2008) reproductive odds of success, and parents are likely to treat them differently. Mothers lacking resources invest less in high-risk At 8 months old, every mother in the study infants (vs. low-risk) conducted by Mann (1992) directed more Mothers who have a lot of positive maternal behavior toward the resources actually invest healthier infant. more in high-risk than in Children who have a congenital disease are at risk of complete or partial abandonment low-risk infants during institutionalization Edison Tan Evolutionary Psychology Singapore Management University Offspring’ s Ability to Convert Parental Care Into Reproductive Success Age of the child Reproductive value increases from birth to pubescence as children survive till reproductive viability. If parental care positively correlates with the reproductive success of offspring, parents are most likely to withhold or terminate parental care when the offspring’s reproductive value is low, i.e., at a young age. Results from Daly & Wilson (1988) cannot be explained by the development of Available existing data support this self-defense availability with age as the risk of homicides by non-kin increases with age. prediction. Edison Tan Evolutionary Psychology Singapore Management University  Offspring’ s Ability to Convert Parental Care Into Reproductive Success Trivers-Willard Hypothesis (1973) Sons and daughters should have equal reproductive success, assuming an equal sex ratio in the population. The condition by which the son or daughter are produced might make it more likely that one or the other would be better able to utilize parental care. For example, parents in good conditions are likely to produce more sons who will be successful at the mating game – producing more grandchildren “嫁出去的女儿, 泼出去的水” “A daughter married away is like water cast away”- Chinese saying from multiple works of literature Parents in poor conditions or with few resources to invest would invest more in their daughters Empirical findings are mixed – boundary conditions are yet to be found. Edison Tan Evolutionary Psychology Singapore Management University  Alternative use for investment available for parental investment Time and energy are finite; time and energy spent on parental investment are Daly and Wilson (1988) time and energy not available elsewhere. Natural selection would favor high parental investment when the fitness benefits of parental care (e.g., offspring reproductive success) outweigh the opportunity cost (e.g., mating opportunity cost). Men are less likely than women to provide parental care Through mating opportunity cost and parental uncertainty, men are less likely to benefit from the same unit of parental investment than women Effect is cross-culturally observed Men who are unlikely to benefit from increased mating efforts (e.g., lower mate value) tend towards parental care. (Apicella & Marlowe, 2007) Women’s age is related to infanticide Higher incidence of infanticide in younger women, whose reproductive value is higher than older women, who may not have a second chance at reproducing (Bugos & McCarthy, 1984; Daly & Wilson, 1988) Edison Tan Evolutionary Psychology Singapore Management University  Alternative use for investment available for parental investment Women’s marital status is related to infanticide Daly and Wilson (1988) Daly and Wilson (1988) hypothesize that a woman’s marital status will affect the likelihood that she will commit infanticide. An unmated woman who gives birth has three unsettling choices: She can try to raise the child without the help of an investing father. She can abandon the child or give it up for adoption She can kill the child and devote her efforts to trying to attract a husband and then have children with him. Both age and marital status are correlated with rates of infanticide. At every age except the very oldest age bracket, unwed mothers are more likely than married mothers to commit infanticide. Edison Tan Evolutionary Psychology Singapore Management University  02 Parent-Child Conflict Theory Edison Tan Evolutionary Psychology Singapore Management University Evolutionary Conflict of Interest Parent’s Perspective Premise of Conflict Available Food Parents share at most 50% of the genes with their offspring, while Resource offspring have 100% of their own genes. Resources tend to have diminishing returns with increasing allocation E.g., eating food when hungry vs. eating food while being full. Offspring A (50% Full) Offspring B (50% Full) Suppose a parent has two offspring. Available food resources are fairly allocated between the offsprings. 100% Yield From the parent’s perspective, a fair allocation of food yields maximum efficiency in fitness benefits Offspring A’s Perspective From the offspring's perspective, they are not extracting maximum fitness benefits from available food resources. Available Food Resource Imperfect genetic relatedness results in an evolutionary conflict of interest, fertile grounds for an evolutionary arms race. Offspring A Offspring B Cycle of evolution and counter-evolution of adaptations due to (90% Full, >50%) (0% Full) organisms being each other’s adaptive problem 90% Yield Edison Tan Evolutionary Psychology Singapore Management University  The Arenas of Parent-Child Conflict In Utero Siblings Relations Mothers should evolve adaptations Parents are more likely to channel to spontaneously abort risky resources to offspring with the pregnancies that risk their lives. highest reproductive success odds, ensuring the persistence of at least E.g., miscarriages are more likely 50% of their genes, assuming when mothers are facing life- limited resources. threatening circumstances or bear fetuses with genetic defects. Offspring’s persistence of 100% of The fetus should also evolve their genes may be affected by the adaptations that ensure the asymmetrical allocation of persistence of pregnancy. resources among siblings. Human chorionic gonadotropin Having a younger sibling tends to increase mother-child conflict, hormone prevents menstruation to further accentuated if the sibling is a ensure foetus implantation half-sibling (Schlomer et al. 2010) Edison Tan Evolutionary Psychology Singapore Management University  The Arenas of Parent-Child Conflict Offspring’s Mating Decision Parents might disapprove of the offspring’s mate choice and may even attempt to control their mating decision (e.g., arranged marriage). A mate choice might be highly beneficial to offspring but less for the parents. Having that said…. Offsprings may stand to benefit more from choosing a physically attractive mate to provide superior genes It is not always about parents’ conflicting interests with their offspring Parents may prioritize the formation of alliances and – offspring share 50% of their parent’s genes. cooperations, favoring the mate’s status and family background. Daughter guarding may be in the daughter’s best interest—for example, to prevent them from being sexually exploited or to Parents find short-term mating to be significantly preserve their long-term mate value (Perilloux et al., 2008). more acceptable for themselves than for their sons and daughters (Apostolou, 2010). Edison Tan Evolutionary Psychology Singapore Management University NEXT WEEK: Problems of Kinship Additional Readings: Buss, D. M. (2019). Problems of Parenting. In Evolutionary Psychology: The New Science of the Mind (6th ed.). Edison Tan Evolutionary Psychology Singapore Management University