Lecture Notes
Chapter 1 Introduction to Human Sexuality
Updated:
2007-05-30
Please complete the Questionnaire for Student Evaluation of Normal
Sexual Behavior in class. Now see:
- Biological Issues in Sex and Sexuality
- Why Sex? Or, Why Did Sex Evolve?
- Costs of sex (Daly and Wilson, 1978)
- Recombination (breaking up of successful
combinations)
- Meiosis (discarding 1/2 of one's genes)
- Mating (many costs!)
- Benefits of sex
- Increased variability (both short-term and
long-term)
- Hedge against uncertain future
- Watch out for human asexuality!
- Why Male and Female? Why Not More Sexes?
- Size?
- No predictable pattern of male--larger,
female--smaller
- Mechanism for sexual selection
- Search and find strategy from game theory
- Number?
- In most cases the number of males is equal to the
number of females (see Hamilton, 1996 for
exceptions)
- Sociobiology of sex
- Large eggs and small sperm
- Natural Selection
- Definition
- Compared to artificial selection
- Role of reproduction in natural selection
- Natural selection compared to cultural selection (genes
versus memes)
- Importance of cultural evolution to human
behavior
- Sex versus Sexuality
- Sex is simpler--male and female (although that
difference is not always obvious, as we will see later),
reproduction too
- Sexuality is more complex and includes:
- Relationship of gender and sexuality?
- Cross-Cultural Issues
- What is culture? What is a subculture?
- Macroenvironmental differences
- So pervasive, it is hard to notice
- Sexual behavior and culture
- You can find just about any imaginable sexual practice
in some culture
- Know American sub-cultural patterns.
- Three Cultures and Sex
- Inis Beag--island off of the coast of Ireland
- Late marriage--men 36, women 25
- Women less sexual, orgasm rare
- Men believe intercourse wears them down
- Nudity is shameful
- Men indulge in sexual humor
- Mangaia--Polynesia
- Uncircumcised boys go naked
- Masturbation begins around 7 years of age
- Superincision and sexual training (age 13)
- Teenagers engage in sex every night
- Girls have three to four boyfriends before marriage
- Boys have 10 or more girlfriends before marriage
- Sex continues at high but declining rate after
marriage
- Mehinaku--Brazil
- High levels of sexual behavior and high levels of
anxiety about sex
- Gender segregated culture
- Children know who their parent's lovers are
- Sexual violence against women (gang rape) for
territorial transgressions
- Sex--Summary
- Where and when
- night, day, during menses, not during menses, in
private, in public, lights on, lights off, during pregnancy
or not, after pregnancy, before work, after work, during
work, some people not allowed to have sex
- Who
- spouse, unmarried men and women, other married persons,
children, strangers, friends
- How often
- once every 4-6 years (Dani), 3 times a night, 3-5 times
a week, varies with age
- Duration
- Position
- missionary, woman above, side by side are most common
positions
Bibliography
Daly, Martin & Wilson, Margo, (1978). Sex, evolution, and
behavior : Adaptations for reproduction . Boston : Willard Grant
Press.
Gregor, Thomas. (1985). Anxious pleasures: the sexual lives of
an Amazonian people. Chicago: University of Chicago Press.
Hamilton, W. D. ( 1996). Narrow roads of gene land : The
collected papers of W. D. Hamilton. Oxford : W.H.
Freeman/Spektrum.
Messenger, John (1983, [1969]). Inis Beag, isle of
Ireland. Prospects Heights, Ill.: Waveland Press.
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