MOTIVATION
DEF: GOAL-DIRECTED BEHAVIOR
HUNGER---BRAIN REGULATION
 Hypothalamus
 Lateral hypothalamus (LH) triggers when to start
eating
 Ventromedial nucleus of the hypothalamus (VMH)
triggers when to stop
 Paraventricular nucleus (PVN) uses
neurotransmitters to regulate hunger
GLUCOSE REGULATION
 Glucose is a simple sugar; an important source of
energy
 Glucostatic theory: fluctuations in blood glucose
level are monitored by glucostats: neurons sensitive
to glucose in the surrounding fluid
 Glucostats in the liver signal hypothalamus through
the vagus nerve
DIGESTIVE REGULATION
 The stomach has 2 types of signal to inhibit further
eating:
 1) vagus nerve monitors stretching of stomach wall
 2) other nerves monitor nutrients in the contents of
the stomach
HORMONAL REGULATION
 Insulin: secreted by the pancreas; must be present
for cells to extract glucose from the blood
 Leptin: produced by fat cells; provide hypothalamus
w/info about body’s fat stores
ENVIRONMENTAL FACTORS IN
REGULATION OF HUNGER
 Learned preferences and habits
 Food related cues
 Stress, arousal
EATING AND WEIGHT: ROOTS OF OBESITY
 Obesity: the condition of being overweight
(exceeding ideal weight by 20%)
 Health risks: cardiovascular diseases, diabetes,
hypertension, stroke, arthritis, and back problems
GENETIC PREDISPOSITION TO OBESITY
 Adoption studies
 Body mass index (BMI): weight (kg) divided by
height (m) squared
 kg/m2
 Genetic factors account for 61% of variation in
weight for men and 73% for women
CONCEPT OF A SET POINT
 Set point: natural point of stability in body weight
 Set point theory: body monitors fat-cell levels to
keep them fairly stable
SEX
SEXUAL MOTIVATION AND BEHAVIOR
HORMONAL REGULATION
 Estrogens: principal gonadal hormones in females
 Androgens: principal gonadal hormones in males
 Increased levels of testosterone correlate w/higher
rates of sexual activity
PHEROMONES
 DEF: a chemical secreted by one animal that affects
the behavior of another
 Aphrodisiacs: substances thought to increase sexual
desire
 There is no “Spanish Fly”
EROTIC MATERIALS
 Pornography does not appear to incite overpowering
sexual urges
 May alter attitudes toward sexual behavior
 May create unrealistic expectations
ATTRACTION TO A PARTNER
 Coolidge Effect: the preference for variety in sexual
partners seen in males of many species
 Most species are selective
EVOLUTIONARY ANALYSES OF HUMAN
SEXUAL BEHAVIOR
 Parental investment theory: the sex that makes the
smaller investment will compete for mating
opportunities with the sex that makes the larger
investment, and the sex with the larger investment
will tend to be more discriminating in selecting its
partners
EVOLUTIONARY ANALYSES
 Human males are required to invest little
 Females invest 9 months
 Therefore females are selective with mates
GENDER DIFFERENCES IN PATTERNS OF
SEXUAL BEHAVIOR
 Men think about sex more often
 Men more motivated to have sex w/a variety
 Men more likely to have sex w/someone they have
known for a short period of time
GENDER DIFFERENCES IN MATE
PREFERENCES
 Males place more emphasis on youthfulness and
attractiveness
 Females place more emphasis on intelligence,
ambition, income, and social status
GENDER DIFFERENCES IN RELATIONSHIP
JEALOUSY
 Males of many species worry about paternity
uncertainty
 Males will guard the female from other males
 Sexual infidelity is threatening
 Male emotional infidelity is threatening to females
MYSTERY OF SEXUAL ORIENTATION
 DEF: a person’s preference for emotional and sexual
relationships with individuals of the same sex, the
opposite sex, or both
 Heterosexual
 Homosexual
 Bisexual
SEXUAL ORIENTATION CONTINUED
 Alfred Kinsey (1948, 1953) described sexuality as a
continuum---heterosexuality on one end,
homosexuality on the other
 10% of the population could be characterized as
homosexual
ENVIRONMENTAL THEORIES
 Freudian: homosexuality stems from being raised by
an ineffectual father and overprotective mother
 Behaviorist: acquired through experience
 Feminine boys and masculine girls tend to grow up
homosexual
BIOLOGICAL THEORIES
 Research in the last 15 years has shown a biological
basis for homosexuality
 Possible brain structure
INTERACTIONIST VIEW AND
SOCIOPOLITICAL IMPLICATIONS
 Genes and hormones shape temperament that
ultimately shapes sexual orientation
 Interactions w/peers solidifies arousal for same sex
 Gays are still discriminated against
HUMAN SEXUAL RESPONSE
THE BIRDS AND THE BEES
EXCITEMENT PHASE
 Muscle tension, respiration rate, heart rate, and
blood pressure increase rapidly
 Vasocongestion: engorgement of the blood vessels
PLATEAU PHASE
 Physiological arousal continues to grow, but at a
slower pace
 Further vasocongestion
ORGASM PHASE
 Orgasm: when sexual arousal reaches its peak
intensity and is discharged in a series of muscular
contractions that pulsate through the pelvic area
 There are gender differences but they are extremely
similar in both sexes
RESOLUTION PHASE
 Refractory period: a time following orgasm during
which males are largely unresponsive to further
stimulation
 From a few minutes to hours---increases w/age