David G. Myers
AP Psychology
Unit 8:
Motivation and Emotion: 8A—Motivation
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Figure 8A.1 Drive-reduction theory Drive-reduction motivation arises from homeostasis—an
organism’s natural tendency to maintain a steady internal state. Thus, if we are water deprived, our
thirst drives us to drink and to restore the body’s normal state.
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Figure 8A.2 Maslow’s hierarchy of needs Once our lower-level needs are met, we are prompted to
satisfy our higher-level needs. (From Maslow, 1970.) For survivors of the disastrous 2007
Bangladeshi flood, such as this man carefully carrying his precious load of clean water, satisfying
very basic needs for water, food, and safety become top priority. Higher-level needs on Maslow’s
hierarchy, such as respect, self-actualization, and meaning, tend to become far less important during
such times.
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Figure 8A.3 Monitoring stomach contractions Using this procedure, Washburn showed that
stomach contractions (transmitted by the stomach balloon) accompany our feelings of hunger
(indicated by a key press).
From Cannon, 1929
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Figure 8A.4 The hypothalamus As we saw in Unit 3B, the hypothalamus (colored red) performs
various body maintenance functions, including control of hunger. Blood vessels supply the
hypothalamus, enabling it to respond to our current blood chemistry as well as to incoming neural
information about the body’s state.
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Figure 8A.5 The appetite hormones
Insulin: Secreted by pancreas; controls blood glucose.
Leptin: Secreted by fat cells; when abundant, causes brain to increase metabolism and decrease
hunger.
Orexin: Hunger-triggering hormone secreted by hypothalamus.
Ghrelin: Secreted by empty stomach; sends “I’m hungry” signals to the brain.
Obestatin: Secreted by stomach; sends out “I’m full” signals to the brain.
PYY: Digestive tract hormone; sends “I’m not hungry” signals to the brain.
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Figure 8A.6 Hot cultures like hot spices Countries with hot climates, in which food historically
spoiled more quickly, feature recipes with more bacteria-inhibiting spices (Sherman & Flaxman,
2001). India averages nearly 10 spices per meat recipe; Finland, 2 spices.
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Figure 8A.7 Levels of analysis for our hunger motivation Clearly, we are biologically driven to
eat, yet psychological and social-cultural factors strongly influence what, when, and how much we
eat.
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Figure 8A.8 Obesity measured as body mass index (BMI) U.S. government guidelines encourage
a BMI under 25. The World Health Organiza-tion and many countries define obesity as a BMI of 30
or more (although muscular bodies may also have a high BMI). The shading in this graph is based on
BMI measurements for these heights and weights. BMI is calculated by using the following formula:
Weight in kg (pounds × .45)
Squared height in meters (inches ÷ 39.4)2
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= BMI.
Figure 8A.9 Obesity and mortality Relative risk of death among healthy nonsmokers rises with
extremely high or low body mass index.
Data from 14-year study of 1.05 million Americans, Calle et al., 1999
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Figure 8A.10 Gender and weight discrimination When women applicants were made to look
overweight, university students were less willing to think they would hire them. Among men
applicants, weight mattered less.
Data from Pingitore et al., 1994
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Figure 8A.11 Fat cells We store energy in fat cells, which become larger and more numerous if we
are obese, and smaller (but still more numerous) if we then lose weight.
Adapted from Jules Hirsch, 2003
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Figure 8A.12 The effects of a severe diet on obese patients’ body weight and metabolism After
seven days on a 3500-calorie diet, six obese patients were given only 450 calories a day for the next
24 days. Body weight declined only 6 percent and then leveled off, because metabolism dropped
about 15 percent.
From Bray, 1969
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Figure 8A.13 American idle: Couch potatoes beware—TV watching correlates with obesity As
life-styles have become more sedentary and TV watching has increased, so has the percentage of
overweight people in Britain, North America, and elsewhere. When California children were placed in
a TV-reduction educational program, they watched less—and lost weight.
Robinson, 1999
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Figure 8A.14 Levels of analysis for sexual motivation Compared with our motivation for eating,
our sexual motivation is less influenced by biological factors. Psychological and social-cultural factors
play a bigger role.
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Figure 8A.15 The fraternal birth-order effect Researcher Ray Blanchard (2008) offers these
approximate curves depicting a man’s likelihood of homosexuality as a function of his number of
older brothers. This correlation has been found in several studies, but only among right-handed men.
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Figure 8A.16 Spatial abilities and sexual orientation Which of the four figures can be rotated to
match the target figure at the top? Straight males tend to find this an easier task than do straight
females, with gays and lesbians intermediate.
From Rahman et al., 2003, with 60 people tested in each group
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