Lecture 18: Sexual Dimorphism Flashcards
Love and Sex Views
Simple view: Natural, positive, mutually beneficial
In reality: Biologically very complicated process
Psychologically: Source of misery conflict, jealousy, exploitation coercion, loss
3 Psychological Mechanisms
- Lust
- Romantic Passions
- Long Term Companionate Love
Studying Human Sexuality
- General theory of how species sexual physiology and ecology relates to its sexual motives and behaviors
- Characterization of the physiology and ecology of Homo sapiens
- Experiments on human sexual motives to see whether predictions are verified or falsified
Darwin: Two phenomena of Sexual Selection
- Male on Male Competition
- Female Choice
- Darwin didn’t understand why
Physical Differences in Males and Females that Affects Investment
- Eggs take many resources while sperm are small and cheap
- Females invest egg, gestation and lactation while males only give sperm and copulation
-Females are rate limiting step of reproduction - Single male can fertilize many females while other goes mateless
-Male reproductive success depends on how many mates he has
Female reproductive success depends on choosing a mate that has good genes and is willing to invest in child
Jicanas
- See that males have to invest more than females, females can easily abandon the offspring
- Females tend to be more promiscuous
- Males tend to be more choosy
Psychological and Ecological Properties of Sexual Reproduction
- Minimal Parent Investment
Mother- 9 months of pregnancy, 2 years of lactation
Father-Sex
-Signs of sexual dimorphism in male size, age of puberty - Typical Investment
Men feed, protect, teach offspring
-Humans have long dependent childhood- evolutionary beneficial to be monogamous
-Increased survival of children with invested father - Concealed fertilization and gregariousness- Always paternal uncertain
Cuckoldry is the worst for the man
Cuckoldry
- Bad for men because he has fertilized no female and has invested in another child
- Good for female because she mated with male with best fitness and partnered with male who is willing to invest
- Sexual Jealousy evolutionary advantage to prevent this
Factors in Modern Society that Affect this
- Contraception
- Artificial Insemination
- Substitutes for Lactation
- Females and males are able to put in more equal investment
Prediction from Human Analysis
Males are more promiscuous, look for more sexual partners
Females are more choosy
David Buss Survey
-Showed males look for more sexual partners
- Males more willing to have sex earlier
Women Goal- Find a relationship partner that is committed
Male Goal- Find a way to sleep with a woman
Complex Female Sexuality
- Find more variability in women
- Change more through different points at their
- Greater complexity in her choice to have sex, choice of partner, criteria of attractiveness
Crosscultural Actions
Men more than women on average: woo seduce hire prostitutes rape
What does a man what?
- Reduce sexual drive (drive reduction theory)
Hyperpromiscuity - Hyper-polygyny- Ancient rulers surrounded by multiple wives and thousands of prostitutes
Importance of Interaction
-Behavior doesn’t only depend on on desires but on context: opportunity and cost
-Emotions typical to each sex are masked by need to compromise with other sex
-Homosexual Men-(unhindered by compromise with women) More sexual partners, more value on beauty, youth, porn
Lesbian- Reduced sexual partners
