Human Mating Systems Anthropology 201 Fall 2024 PDF

12. Human Mating Systems Anthropology 201 Fall 2024  Objectives Take what we learned about primate mating strategies and apply it to humans Understand basic challenges in studying human mating patterns from a biological perspective Understand human mating pre...

12. Human Mating Systems Anthropology 201 Fall 2024  Objectives Take what we learned about primate mating strategies and apply it to humans Understand basic challenges in studying human mating patterns from a biological perspective Understand human mating preferences Know the different mating systems found in humans and examples of these Explore human perspectives on paternal investment, infanticide and adoption Reading: Chapter 15 2  Human Mating Patterns Challenging to Study Strongly culturally mediated – Culture is a better predictor but we CAN learn from evolutionary theory – Likely to be changing rapidly (globalization, availability of birth control, etc.) People LIE when asked – Under/over-report sexual activity/partners – Paternity Human sexuality and romantic relationships are complicated! – Focus here is on mating patterns (i.e. child-bearing) 3 Male and Female Fertility Differs with Age 4  Males Paternal investment can be highly variable Expect differences in behaviour based on paternal investment Should prefer female mates that have higher potential fertility – Correlates with female AGE – Prefer indicators of high fertility that can be judged – physical appearance Sexual fidelity should be very important 5  Females Maternal investment in offspring is always high Should be very selective in choosing mates Select mates who can provide resources for them and their offspring Minimal concern about age – show preferences for older males – more resources available Fidelity is important, but less so than for males Conservative in initiating sexual relationships 6  Both Sexes Value physical attraction and love Value stability, pleasantness, sociability and overall compatibility Why? 7 Some Preferences are Culturally Mediated Traits; Others More Universal 8 Preference for number of sexual partners (per month) 9  Human Mating Systems Humans form unions to mate and rear offspring: “Marriage” – usually incorporate exclusive sexual access (but practice often departs from principle) – investment by male and female in offspring – defines social status of offspring Functions: – minimize male-male competition (as does concealed ovulation?) – protect females from mating aggression – maximize paternity certainty (not absolutely though!) Variable in : – number of mates and children – how marriages are regulated (official?, arranged, termination) – relationships between individuals 10 – where they live Are Humans Monogamous? 11  Polygyny Men have multiple wives Varies between men – hunting ability, wealth (land, other resources), political rank all correlated with RS – Wealth and power enable some men to attract more mates and to provide them with resources – in post-agricultural societies, potential for extreme polygyny Recall this means some men have no wife 12  Even with polygyny: – actual rates of polygyny vary widely – often tolerated, but not the norm – men have fewer wives than they aspire to Even with monogamy: – extramarital sex is not infrequent biological father is not the mother’s husband non-paternity highly variable - ~10%? – serial monogamy and frequent divorce 13  Infidelity Major cause of marriage termination across cultures Rates vary greatly between cultures, as does social acceptance Does appear to be more common in males than females Female infidelity ‘matters more’ from a biological standpoint – More restrictions placed on women – Social punishments more severe for women Very challenging to study! 14  Financial Considerations Bridewealth/ Bride Price – Paid TO the family of the bride by the groom/his family – Compensation to the bride’s family for loss of her labour – More common in polygynous societies because man may marry other wives and divert resources to other offspring Dowry – Paid BY the family of the bride to the groom/his family – Rare but more common in highly stratified societies and in monogamous societies – Strategy to marry females to higher status males whose status will be passed on to the offspring 15 Example of Polygyny: Kipsigis Kenya Females marry in late teens Males marry in their 20s Many marriages are arranged Bridewealth is paid in livestock and cash Competition for females is strong (normally receive several offers) 16 Kipsigis Females 17 Polygynous Females – Competition among wives for their mate’s resources – Prefer males who can offer the largest amount of land per wife, regardless of number of wives AND – Males whose co-wives have produced the fewest children – Those women who balance these two considerations have the highest RS. 18 Kipsigis Males 19  Polyandry One woman married to several men Rare (0.5% of human societies) Men in polyandrous marriages have lower RS Fraternal polyandry is most common form in humans – woman marries brothers – reduces the impact on fitness because children he is helping to raise are his brother’s children Share some genetic material 20  Example of Polyandry: Nyinba Nepal Fraternal polyandry where brothers set up a communal household with one woman Mixed industries – agriculture, herding, long- distance trade Paternity is tracked and considered important 21  Paternity Uncertainty Women KNOW who their children are Men don’t necessarily know Degree of paternity uncertainty varies by individuals, cultures, and circumstances Paternity uncertainty is predicted to influence paternal investment and investment of paternal family 22  Paternal Investment Male investment in offspring will vary – are they his biological children? – is their mother his current mate? Balancing current and potential future offspring (old version of textbook) 23 Paternal Investment: New Mexico, US 24 Paternal Investment: South Africa 25 Grandparent Care 26  Human Infanticide Different from non-human primates because can be carried out by the mother Infanticide happens when: – Child is unlikely to survive (birth defects, illness) – Parents cannot care for child (multiple births, lack of resources, mother dies in childbirth) related to social/mating systems rarely give up 1st born children – Child not sired by the husband (similar to primates) Recall limited options in many societies… 27  Human Adoption Offspring raised by someone other than biological parents Seen in other animals, but extremely rare – More common in non-mammals than mammals? Variable rates in humans, but very common in some societies Normally adopted by kin – grandparents, aunts, etc. Idea of adopting non-kin considered odd in many societies 28  Adoption and Relatedness 29 0.25 is the same amount of relatedness as grandparents, aunts/uncles  Adoption When parents are alive, give up children: – reluctantly – because of lack of resources – prefer wealthy relatives with no other children – maintain access to children and can reclaim them Asymmetries exist between resources given to biological and adopted children Why do people adopt non-related children? 30