1. Human Mating Strategies

2. Some relevant facts: 1. Female investment in offspring – very high Male investment in offspring – variable 2. Reproductive life 1020304050607080 Female Male

3. 1. Can humans be shown to mate in a manner consistent with the hypotheses surrounding mate choice by either perception of genetic quality or of ability to provide resources? Central Question

4. What should males look for in a mate? Indicators of fertility (age [youth], health) What should females look for in a mate? Indicators of ability to provide resources (age, wealth)

5. Hypothesis Women value earning potential more than men Women value ambition and industriousness more than men Men value physical attributes more than women Men value chastity more than women Men prefer women younger than themselves Proportion of cultures supporting hypothesis 0255075100

6. Question: If you could mate with a member of the opposite sex who was no more or less attractive than your permanent mate and there was no risk of disease, discovery or forming a permanent liaison, would you do it? 100 80 60 40 20 0 Certainly would Probably would Probably notCertainly not Probably/certainly not- Females - 91% - Males - 50% - Males - Females

7. Most primates Males  concentration on mating effort Females  concentration on parental effort

8. Dominance in a Social Group Environmental constraints Group structure Male strategiesFemale strategies

9. Dominance in a Social Group Underlying principle: Higher status males  more copulations & more offspring

10. Dominance in a Social Group Kipsigis Acres owned # wives

11. Dominance in Social Group 12 - 14 15 - 16 17 - 19 Age at puberty Bride price 52-61 62-71 72-81 82-91 Decade

12. Ecology of human mating systems Protein deficiency Starvation Subsistence Female contribution Marriage system Population density Mobility Group size Pathogens Rain predictibility Rainfall extremes Temperature extremes Food storage/trade

13. Ecology of human mating systems Protein deficiency Starvation Subsistence Female contribution Marriage system Population density Mobility Group size Pathogens Rain predictibility Rainfall extremes Temperature extremes Food storage/trade

14. Ecology of human mating systems Protein deficiency Starvation Subsistence Female contribution Marriage system Population density Mobility Group size Pathogens Rain predictibility Rainfall extremes Temperature extremes Food storage/trade

15. Ecology of human mating systems If there are no resources??? Wives Children UnokaiNon-Unokai Age 20-2425-3031-40>40 Wives More wives earlier in life Unokai – Yanomami warriors (involved in a killing)

16. Human mating systems Sperm competition How monogamous is monogamy? Indigo bunting Days before egglaying 12 0 Extra-pair Within pair

17. Human mating systems Sperm competition When does it occur? 1. Adolescent courtship Triobrand Islands

18. Human mating systems Sperm competition When does it occur? 2. Facultative polyandry polygyny monogamy polyandry Polyandry

19. Human mating systems Sperm competition When does it occur? 2. Facultative polyandry polygyny monogamy polyandry Polyandry Facultative Polyandry universalmoderateoccasionaluncommon

20. Human mating systems Sperm competition Why should females be polyandrous? 1. Good genes 2. Genetic Diversity 3. Fertility Backup - 25% of couples - sterility (35% -male) 4. Material Resources -females mate extramaritally more often with men of higher socioeconomic status -females mate extramaritally more often with men older than their primary mate

21. Human mating systems Sperm competition What attributes of humans may have evolved in context of sperm competition? Males 1. Mating patterns - most common -monogamy (with extramarital mating?) -only if cost of any extramarital tactic is free or < cost of supporting second mate

22. Human mating systems Sperm competition What attributes of humans may have evolved in context of sperm competition? Males 2. Sexual Jealousy and Paternity Assurance Spousal homocide related to sexual jealousy USA - 33% Africa (several studies) - 45%

23. Human mating systems Sperm competition What attributes of humans may have evolved in context of sperm competition? Females 1. Cryptic ovulation and continuous sexual receptivity Most primates Humans

24. Human mating systems Sperm competition What attributes of humans may have evolved in context of sperm competition? Females 2. Perennially obvious breasts