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PSYC 1010 Lecture Notes - Aphrodisiac, Sex Steroid, Paraventricular Nucleus Of Hypothalamus

Course Code
PSYC 1010

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Jan/6/2004 CHANAPS
Notes From Reading
I. The Motivation of Hunger and Eating
A. Introduction
1. Motives are the needs, wants, interests and desires that propel people in
certain directions.
2. Motivation involves goal-directed behavior.
3. There are 2 types of motivation – biological motives that originate in
biological needs (i.e. hunger), and social motives, that originate in social
experiences (i.e. achievement).
4. People share the same biological needs, but their social needs (and their
strengths) may vary.
B. Biological Factors in the Regulation of Hunger
1. Brain Regulation – experience of anger is controlled in the brain, specifically
2 areas in the hypothalamus.
a. Hypothalamus – tiny structure involved in the regulation of a variety of
biological needs related to survival.
b. Lateral hypothalamus (LH) & the ventromedical nucleus of the
hypothalamus (VMH) regulate hunger, but not the key elements.
c. 3rd area of hypothalamus, known as the paraventricular nucleus (PVN)
may play role in hunger regulation.
d. Contemporary theories of hunger focus more on neural circuits rather
than anatomical centers of the brain.
2. Glucose and Digestive Regulation
a. Glucose – a simple sugar that is an important source of energy.
i. Mayer – proposed that hunger is regulated by the rise and fall of
blood glucose levels.
ii. Glucostic Theory – proposed that fluctuations in blood glucose level
are monitored by glucostats – neurons sensitive to glucose in the
surrounding fluid.
b. Digestive system – nerves send signals that inhibit further eating by
monitoring stretching of stomach walls or carry messages that depend on
how rich in nutrients the contents of the stomach are.
3. Hormonal Regulation – appear to contribute to regulation of hunger.
a. Insulin – hormone secreted by the pancreas which much be present for
cells to extract glucose from the blood.
b. Leptin - produced by fat cells throughout the body and released into the
bloodstream. High levels of fat produce high levels of leptin, and
circulates through the bloodstream, providing the hypothalamus with
info about the body’s fat stores.
C. Environmental Factors in the Regulation of Hunger
1. Hunger is a biological need, but eating may in some instances be social, and
influenced by 3 factors – learned prefs/habits, food related cues, and stress.
2. Learned Prefs and Habits – People from different cultures display very
different patterns of food consumption.
a. Prefs for high fat foods.
b. Taste prefs are partly a function of learned associations formed through
classical conditioning.

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Jan/6/2004 CHANAPS
Notes From Reading
c. Eating habits are shaped by observational learning – people prefer
familiar foods, or the reactions of others around them.
d. May also dictate when and how much people eat.
3. Food Related Cues – hunger can be influenced by exposure to environmental
cues that have been associated with eating.
4. Stress, Arousal, and Eating – Stress may lead to increased eating.
D. Eating and Weight: The Roots of Obesity
1. Obesity 0 the condition of being overweight. May occur due to abandonment
of diet followed by early humans.
2. Genetic Predispotion may cause obesity.
a. BMI – body mass index – weight in kilos, divided by height in meters,
squared (kg/m^2).
3. The Concept of a Set Point – body may have a set point, or natural point range
of stability in body weight.
4. Dietary Restraint – chronic dieters are restrained eaters – people who
consciously work overtime to control their eating impulses and who feel
guilty when they fail.
5. When their cognitive control is disrupted, they become disinhibited and eat
II. Sexual Motivation and Behavior
A. Determinants of Sexual Desire
1. Sex is essential for the survival of a species, but not essential to an
individual’s survival.
2. Sexual desire is influenced by a complicated network of biological and social
3. Hormonal Regulation – may have a small impact on sexual desires.
a. Hormones secreted by the gonads can influence sexual motivation.
b. Estrogen – principal class of gonadal hormones in females, and
androgens are the principal class for males. Regulated by the
hypothalamus and the pituitary gland.
4. Pheromes – chemical secreted by one animal that affects the behavior of
another. i.e. usually a scent.
a. No evidence of pheromones exerting and impact on sex drive in humans.
b. Human pheromes may cause synchronization of menstrual cycles, etc.
c. Aphrodisiacs – substances thought to increase sexual desire.
5. Erotic Materials
a. Women are more likely than men to report that they dislike erotic
materials, but physiological responses are similar to males.
b. Evidence may suggest that exposure to erotic material elevates the
likelihood of overt sexual activity for a few hours immediately after
c. More likely to change the attitude towards sex – more exposure = more
d. Aggressive pornography may increase male subjects’ aggressive
behavior toward women.
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