Transcript Sexual orientation

Psychology in Everyday
Life
David Myers
PowerPoint Slides
Aneeq Ahmad
Henderson State University
Worth Publishers, © 2011
Gender and Sexuality
Chapter 4
Gender and Sexuality
Gender Development
 How are We Alike? How Do We
Differ?
 The Nature of Gender: Our Biology
 The Nurture of Gender: Our Culture
Gender and Sexuality:
Overview of Topics
Human Sexuality
 The Physiology of Sex
 The Psychology of Sex
Sexual Orientation
 Environment and Sexual
Orientation
 Biology and Sexual Orientation
Gender and Sexuality: Overview
of Topics
An Evolutionary Explanation of
Human Sexuality
 Gender Differences in Sexuality
 Natural Selection and Mating Preferences
 Critiquing the Evolutionary Perspective
Thinking About Gender, Sexuality,
and Nature-Nurture Interaction
Defining Gender
• Your biological sex is the basis for defining
your gender, the characteristics our
society defines as male or female
• How are the two genders alike?
• How are they different?
• How much does biology play a role in
gender characteristics?
Gender Similarities and
Differences
• Men and women are alike:
– No differences in intelligence or senses. Of the 46
chromosomes, 45 are unisex
• There are also many differences. Examples:
– Age of puberty, lifespan, body fat, muscle mass,
height.
– Women are more emotional, more altruistic, more
prone to depression and anxiety
– Men are more prone to suicide, alcoholism, colorblindness, autism, and ADHD
Gender Differences in Aggression
Men express themselves and behave in more
aggressive ways than do women. This gender
gap in (physical) aggression appears in many
cultures and at various ages.
• Men are arrested for murder 10 times more
than women in the US
• Fighting, warring, and hunting are primarily
male activities throughout the world
Gender and Social Power
• In most societies, men are socially
dominant and are perceived as such.
• In 2009, men accounted for 82% of the
seats in the world’s governing parliaments.
• Men tend to be more directive and
authoritarian, women more democratic
• With age, these gender differences tend to
decrease
Gender Differences and Social
Connectedness
• Young and old, women are more concerned with
social connections (friendships) with people than
do men.
• Men enjoy doing activities side-by-side and talk
to others to communicate solutions
• Women enjoy talking face-to-face, and often
talk to explore relationships. As friends, women
talk more often and more openly
The Nature of Gender: Our Biology
• Biology influences gender in two ways:
1. Genetically, through differing sex chromosomes
2. Physiologically, from different concentrations of sex
hormones
• Evolutionary psychology: the study of how our
behavior and mind have changed in adaptive
ways over time through the process of natural
selection
Biological Influence on Gender:
Genes
• Your sex was determined by your father’s
contribution the the 23rd pair of
chromosomes – the sex chromosomes
– X chromosomes are found in both men and
women. Females have two, men have an X
and a Y.
– Y chromosomes are found only in males
Biological Influence on Gender:
Prenatal Development
• At about the 7th week after conception, the
Y chromosome causes the testes to
develop and to produce testosterone, the
most important male sex hormone.
• Key period: fourth and fifth prenatal
months
– Sex hormones bathe the fetal brain and influence its
wiring
– High fetal testosterone can produce females with
more masculine muscular and skeletal features
Biological Influence on Gender:
Brain Differences
• Part of frontal lobe, used for verbal
fluency, is thicker in females
• Part of parietal cortex, used for space
perception, is thicker in males
Sexual Differentiation
Sexual differentiation is not only biological, but
also psychological and social.
However, genes and hormones play a very
important role in defining gender, especially in
altering the brain and influencing gender
differences as a result.
The Nature of Gender: Our Culture
• Our culture shapes our gender roles —
expectations of how men and women are
supposed to behave.
• Gender roles can smooth social relationships,
and vary from culture to culture
Gender Identity — one’s sense of being male
or female.
Transgendered Individuals
• Some individuals are
transgendered – their
gender identity feels
mismatched with their
biological sex
• Stu Rassmussen, the
mayor of Silverton,
Oregon, is openly
transgendered
How do we learn to be male or
female?
•
•
•
Social Learning Theory proposes that we
learn gender behavior like any other
behavior—reinforcement, punishment, and
observation.
However, social learning may not fully
explain gender typing – some children are
more attuned than others to traditional
gender roles
Children form gender schemas at an early
age – frameworks for understanding malefemale characteristics
Theories of Gender Typing
Human Sexuality
Sexual Motivation
 The Physiology of Sex
 The Psychology of Sex
Hormones and Sexual Behavior
• Testosterone: main male sex hormone
• Estrogens: main female sex hormones
• Sex hormones are important at several stages:
– During prenatal period, they direct development as
males or females
– During puberty, a surge in sex hormones ushers us
into adolescence
– As adults, sex hormones help activate sexual
behavior
Hormones and Sexual Behavior
• High estrogen levels (injected or with ovulation)
go with increased sexual receptivity
• Human females with partners have increased
sexual initiative behavior around ovulation
• Men’s testosterone levels increased when
exposed to the scent of an ovulating woman or
during social encounters with females
• Restoring testosterone levels in women (after
removal of ovaries) can restore sexual desire
The Sexual Response Cycle
• Masters and Johnson (1960s) identified a
four-stage sexual response cycle:
1.Excitement
2.Plateau
3.Orgasm
4.Resolution
Men then enter a refractory period, a resting
period during which they cannot achieve
another orgasm
Sexually Transmitted Infections
• Rates of STIs (aka STDs) are rising
• Two-thirds of infections occur in people
under 25
Partners
“Phantom” partners
Less Sex, More Pregnancy
• Compared with Europe, US teens have lower
rate of intercourse but higher rates of pregnancy
and abortion which denotes lower rates of
contraceptive use in the US.
• Why?
– Guilt about sex may prevent planned sex but do not
prevent impulsive (unprotected) sex
– Discomfort about discussing birth control prevents
education
– Alcohol use goes with lack of sexual restraint
– Peers and media model unprotected sex
The Psychology of Sex
• Hormones like testosterone are like fuel in
a car –without the right levels of
hormones, there is no drive (sexual
interest and sexual response).
• However, our sexual motivation requires
more than hormones, it requires stimuli:
– External Stimuli
– Imagined Stimuli
– Both involve images and stories
External Stimuli
Studies confirm that men,
and to a lesser extent,
women become sexually
aroused when exposed to
erotic material.
Repeated exposure to
sexual images can reduce
the erotic response and the
attraction to one’s partner.
Imagined Stimuli
Our imagination can influence sexual
arousal and desire. People with spinal cord
injuries and no genital sensation can still
feel sexual desire.
95% of men and women report having
sexual fantasies. Men fantasize about sex
more often, more physically, and less
romantically.
Sexual Orientation
Sexual Orientation
 Environment and Sexual
Orientation
 Biology and Sexual Orientation
Sexual Orientation
Sexual orientation refers to a person’s enduring
pattern of sexual attraction toward with members
of either their own sex or the other sex.
Homosexual
Heterosexual
Bisexual
Sexual Orientation
According to one survey (Mosher, 2005), 3 or
4% of men and 1 or 2% of women reporting
being exclusively homosexual.
Fewer than 1% reported being actively bisexual.
Many people surveyed said they have had an
occasional homosexual fantasy.
As members of a minority who face isolation,
discrimination, and ridicule, homosexuals often
struggle with how to address their sexual
orientation.
Sexual Orientation
• Most psychologists today view
homosexuality as neither willfully chosen,
nor willfully changed
• Homosexuality is not, in and of itself,
associated with mental disorders or
emotional or social problems
• Homosexuality met with bullying, and
harassment, however, can lead to
depression and risk of suicide (Sandfort,
2001, Warner, 2004)
Environment and Sexual Orientation
• Homosexuality is NOT linked with problems in a child’s
relationships with parents
• Homosexuality does NOT involve a fear or hatred of
people of the other gender
• Sexual orientation is NOT linked with current levels of
sex hormones in the blood
• As children, most homosexuals were NOT molested or
otherwise sexually victimized by an adult homosexuality
• The bottom line: if there are environmental factors that
influence sexual orientation, we do not yet know what
they are.
Same-Sex Attraction in Other Species
A number of animal
species are devoted to
same-sex partners,
suggesting that
homosexuality exists in
the animal world.
Biology and Sexual Orientation
Homosexuality is more likely based on biological
factors like differing brain centers, genetics, and
parental hormone exposure rather than
environmental factors.
Gay-Straight Brain Differences
• A cluster of cells in the hypothalamus is
reliably larger in heterosexual men than in
women and homosexual men (Levay,
1991)
• Not an “on-off button” for sexual
orientation, but an important part of the
brain pathway for sexual behavior
• Other studies have since reported
additional gay-straight brain differences
Genetic Influence on Sexual
Orientation
1. Family: Homosexuality seems to run in
families.
2. Twin studies: Identical twins are more likely
than fraternal twins to share a homosexual
orientation. However, they don’t always do so,
suggesting other factors than just genes
alone.
3. Fruit flies: Researchers altered a single gene,
leading females to act like males during
courtship and males to act like females.
Biology of Sexual Orientation:
Prenatal Environment
• Exposure to hormones in months 1 ½ -4 ½ for
fetuses of either sex:
– Female hormones may increase attraction to males
– Testosterone may increase homosexuality.
• Mother’s possible immune defense against
males:
– The more male fetuses that have been in a womb
previously (older brothers), the more likely the next
male fetus will be homosexual.
– Not true for adopted brothers; only true for righthanded men.
Gay-Straight
Differences
• Homosexual individuals
of both sexes fall
halfway between
heterosexual men and
women on several traits,
including spatial
problem-solving abilities,
as shown in this chart.
An Evolutionary Explanation of
Human Sexuality
Evolutionary Psychology and
Human Sexuality
 Gender Differences in Sexuality
 Natural Selection and Mating
Preferences
 Critiquing the Evolutionary
Perspective
Evolutionary Psychology
• Throughout human history, those with trait
characteristics that helped them to survive and
reproduce better were more likely to pass on
those traits
This adaptive process is called natural
selection
• Men who were attracted to young, healthy
women produced more offspring, which may
explain why men today have eyes for women
whose age and features imply fertility
Mating Preferences
Males look for youthful appearing females in order
to pass their genes into the future. Females, on
the other hand, look for maturity, dominance,
affluence, and boldness in males.
Data based on 37 cultures.
Gender Differences in Sexuality
• Men have higher sex drive and are more
interested in casual sex
• Men have a more recreational approach
to sex, women have a more relational
approach
• Thus, gay men have more sex than
lesbians, but lesbians have married more
than gay men (where legal)
Natural Selection & Mating
Preferences
Natural selection has caused males to send their
genes into the future by attempting to mate with
multiple females since males have lower costs
involved with rearing offspring.
However, females tend to prefer a mature and
caring male because of the higher costs involved
with pregnancy and nursing – long-term mates
contribute caring and support, giving their
offspring greater chances.
Critiquing the Evolutionary Perspective
Evolutionary psychologists take an effect and work
backward to explain it in terms of natural selection.
Some worry about the social consequences of the
evolutionary view. Are genes our destiny? Are efforts to
remake society useless?
Culture matters. Socialization can instill values such as
monogamy in men or promiscuity in women. Cultural
expectations influence mate preferences.
Evolutionary Psychologists Reply
Evolutionary psychology is not just retrospective; it
leads to predictions that can be tested.
Evolutionary psychologists remind us how we have
adapted, but do not dictate how we ought to be.
Humans behavior is less hardwired by our genes than
in other species. Rather, we have a tremendous
capacity for learning which has helped us survive.