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 Sexual Motivation & Behavior

Note that there is an upper division course, PSY 360 Human Sexuality, that covers this material in far greater depth.

A. The Human Sexual Response Cycle

"Masters and Johnson"
William Masters
Virginia E. Johnson
[Masters & Johnson]            Human Sexual Response (1966)

Psychological: Desire (Appetitive)

Physical: (1) Excitement
(2) Plateau
(3) Orgasm
(4) Resolution

[Male Sexual Response

 B. Evolutionary Analyses of Human Sexual Motivation

Consider the danger of pregnancy faced by women historically

Mortality Rates England Wales Historical

What are the differences between the causes of maternal death in the 19th & 20th centuries?
       Note: ("puerperal" means "around the time of birth")

Causes of Maternal Death England Wales Historical

Consider the danger of pregnancy faced by women in low-income nations today

Maternal Mortality Rates 2015

Robert Trivers' Parental Investment Theory

  • Parental Investment = what each sex has to invest (i.e., time, energy, survival risk, and foregoing other opportunities) in order to produce and nurture offspring

Gender Differences: Are there such differences in what people actual do?

          • Sexual Activity
          • Mate Preferences (David Buss)
          • Relationship Jealousy (David Buss)

Critiques of Evolutionary Theory

  • Powerful cultural forces for men and women to learn gender role stereotypical behaviors
  • Preference differences for mates may reflect cultural & economic disadvantages for females
  • As national populations show greater gender equality, sex differences in partner preferences grows smaller

C. The Mystery of Sexual Orientation

Focus here on sexual orientation, not gender identity

Famous     Alfred Kinsey

  Alfred Kinsey (see photo above on right ) 1948 Sexual Behavior in the Human Male

Is sexual orientation a continuum? Or, is there a clear distinction between heterosexual & homosexual?

Kinsey Sexual Orientation Scale

Male genital arousal

Male pupil dilation

Prevalence of homosexuality

LGBT Adult US 2012 estimate

Prevalence of sexual orientation in western culture

1. Environmental Factors do not, of themselves, explain homosexual orientation

  • Gender nonconformity in childhood is predictive of adult homosexual orientation for males and females.
  • Most male homosexuals, though, are not significantly non-conforming ("feminine") in their behavior

2. Biological Factors associated with homosexual orientation

Bottom Line


This page was originally posted on 10/16/03 and last updated on October 15, 2021