Gateway THEME Our behavior is energized and directed by motives and emotions.
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Russian novelist Leo Tolstoy once commented, “Music is the shorthand of emotion.” So true, as any American-born, Grammy Award–winning glam rocker with a wicked fashion sense could tell you. But there is more to motivation and emotion than getting you all gaga about an upcoming concert. The words motivation and emotion both derive from the Latin word movere (to move). Even getting out of bed in the morning can be difficult if you are unmotivated. And if you are unaware of your emotions, you will be vulnerable to health problems, such as depression or addiction.
In this chapter, you will learn how motives provide the drumbeat of human behavior and emo- tions color its rhythms. As we will see, both play complex roles in our daily lives. Even “simple” motivated activities, such as eating, are not solely under the control of the body. In many instances, external cues, expectations, learning, cultural values, and other factors influence our motives and emotions.
Let’s begin with basic motives, such as hunger and thirst, and then explore how emotions affect us. Although emotions can be the music of life, they are sometimes the music of death as well. Read on to find out why.
Gateway QUESTIONS 10.1 What is motivation and are there different types
of motives? 10.2 What causes hunger, overeating, and eating
disorders? 10.3 What kinds of biological motives are thirst, pain
avoidance, and the sex drive? 10.4 How does arousal relate to motivation? 10.5 What are learned and social motives and why are
they important?
10.6 Are some motives more basic than others? 10.7 What happens during emotion? 10.8 What physiological changes underlie emotion,
and can “lie detectors” really detect lies? 10.9 How accurately are emotions expressed by the
face and “body language”? 10.10 How do psychologists explain emotions? 10.11 What does it mean to have “emotional
intelligence”?
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Motivation and Emotion
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Chapter 10332
Motivation—Forces That Push and Pull
Gateway Question 10.1: What is motivation and are there different types of motives? What are your goals? Why do you pursue them? When are you satisfied? When do you give up? These are all questions about motivation, or why we act as we do. Let’s begin with a basic model of motivation and an overview of types of motives. Motivation refers to the dynamics of behavior—the ways in which our actions are initiated, sustained, directed, and terminated (Deckers, 2010; Franken, 2007).
Can you clarify that? Yes. Imagine that Stefani Joanne is study- ing biology in the library. Her stomach begins to growl and she can’t concentrate. She grows restless and decides to buy a snack from a vending machine. The machine is empty, so she goes to the cafeteria. Closed. Stefani Joanne drives to a nearby fast food outlet, where she finally eats. Her hunger satisfied, she resumes studying. Notice how Stefani Joanne’s food seeking was initiated by a bodily need. Her search was sustained because her need was not immedi- ately met, and her actions were directed by possible sources of food. Finally, achieving her goal terminated her food seeking.
A Model of Motivation Many motivated activities begin with a need, or internal defi- ciency. The need that initiated Stefani Joanne’s search was a short- age of key substances in her body. Needs cause a drive (an ener- gized motivational state) to develop. The drive was hunger, in Stefani Joanne’s case. Drives activate a response (an action or series of actions) designed to push us toward a goal (the “target” of moti- vated behavior). Reaching a goal that satisfies the need will end the chain of events. Thus, a simple model of motivation can be shown in this way:
NEED DRIVE RESPONSE GOAL (NEED REDUCTION)
Aren’t needs and drives the same thing? No, because the strength of needs and drives can differ (Deckers, 2010). For example, it is not uncommon for older people to suffer from dehydration (a bodily need for water) despite experiencing a lack of thirst (the drive to drink) (Farrell et al., 2008).
Now, let’s observe Stefani Joanne again. It’s a holiday weekend and she’s home from school. For dinner, Stefani Joanne has soup, salad, a large steak, a baked potato, two pieces of cheesecake, and three cups of coffee. After dinner, she complains that she is “too full to move.” Soon after, Stefani Joanne’s aunt arrives with a straw- berry pie. Stefani Joanne exclaims that strawberry pie is her favorite and eats three large pieces! Is this hunger? Certainly, Stefani Joanne’s dinner already satisfied her biological needs for food.
How does that change the model of motivation? Stefani Joanne’s “pie lust” illustrates that motivated behavior can be energized by the “pull” of external stimuli, as well as by the “push” of internal needs.
Incentives The “pull” of a goal is called its incentive value (the goal’s appeal beyond its ability to fill a need). Some goals are so desirable (straw- berry pie, for example) that they can motivate behavior in the absence of an internal need. Other goals are so low in incentive value that they may be rejected even if they meet the internal need. Fresh silkworms, for instance, are highly nutritious. However, it is doubtful that you would eat one no matter how hungry you might be. Regardless, because they are also easy to grow and produce few waste products, silkworms may become the preferred food on long space voyages (Yang et al., 2009). (Attention, aspiring astronauts: Are you ready for silkworms and motion sickness?)
Usually, our actions are energized by a mixture of internal needs and external incentives. That’s why a strong need may change an unpleasant incentive into a desired goal. Perhaps you’ve never eaten a silkworm, but we’ll bet you’ve eaten some pretty horrible leftovers when the refrigerator was bare. The incentive value of goals also helps explain motives that don’t seem to come from internal needs, such as drives for success, status, or approval (• Figure 10.1).
(b) Low-incentive value goal
Need Drive Response
(a) High-incentive value goal
Need Drive Response
• Figure 10.1 Needs and incentives interact to determine drive strength (above). (a) Moderate need combined with a high-incentive goal produces a strong drive. (b) Even when a strong need exists, drive strength may be moderate if a goal’s incentive value is low. It is important to remember, however, that incentive value lies “in the eye of the beholder.” No matter how hungry, few people would be able to eat the pictured silkworms.
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Motivation and Emotion 333
Motivation Internal processes that initiate, sustain, direct, and terminate activities.
Need An internal deficiency that may energize behavior. Drive The psychological expression of internal needs or valued goals. For
example, hunger, thirst, or a drive for success. Response Any action, glandular activity, or other identifiable behavior. Goal The target or objective of motivated behavior. Incentive value The value of a goal above and beyond its ability to fill
a need. Biological motives Innate motives based on biological needs. Stimulus motives Innate needs for stimulation and information. Learned motives Motives based on learned needs, drives, and goals. Homeostasis A steady state of body equilibrium. Circadian rhythms Cyclical changes in body functions and arousal levels
that vary on a schedule approximating a 24-hour day.
Types of Motives For our purposes, motives can be divided into three major categories:
1. Biological motives are based on biological needs that must be met for survival. The most important biological motives are hunger, thirst, pain avoidance, and needs for air, sleep, elimination of wastes, and regulation of body temperature. Biological motives are innate.
2. Stimulus motives express our needs for stimulation and information. Examples include activity, curiosity, exploration, manipulation, and physical contact. Although such motives also appear to be innate, they are not strictly necessary for survival.
3. Learned motives are based on learned needs, drives, and goals. Learned motives, which are often social in nature, help explain many human activities, such as standing for election or auditioning for America’s Got Talent. Many learned motives are related to learned needs for power, affiliation (the need to be with others), approval, status, security, and achievement.
Biological Motives and Homeostasis How important is air in your life? Water? Sleep? Food? Tempera- ture regulation? Finding a public restroom? For most of us, satisfy- ing biological needs is so routine that we tend to overlook how much of our behavior they direct. But exaggerate any of these needs through famine, shipwreck, poverty, near drowning, bitter cold, or drinking ten cups of coffee, and their powerful grip on behavior becomes evident.
Biological drives are essential because they maintain homeostasis (HOE-me-oh-STAY-sis), or bodily equilibrium (Cooper, 2008). The term homeostasis means “standing steady” or “steady state.” Optimal levels exist for body temperature, for chemicals in the blood, for blood pressure, and so forth (Franken & Dijk, 2009; Levin, 2006). When the body deviates from these “ideal” levels, automatic reactions begin to restore equilibrium (Deckers, 2010). Thus, it might help to think of homeostasis as similar to a thermo- stat set at a particular temperature.
A (Very) Short Course on Thermostats The thermostat in your house constantly compares the actual room tem- perature to a set point, or ideal temperature, which you can control. When room temperature falls below the set point, the heat is automatically turned on to warm the room. When the heat equals or slightly exceeds the set point, it is automatically turned off or the air conditioning is turned on. In this way, room temperature is kept in a state of equilibrium hovering around the set point.
The first reactions to disequilibrium in the human body are also automatic. For example, if you become too hot, more blood will flow through your skin and you will begin to perspire, thus lower- ing body temperature. We are often unaware of such changes, unless continued disequilibrium drives us to seek shade, warmth, food, or water.
Circadian Rhythms Our needs and drives can change from moment to moment. After eating, our motivation to eat more food tends to diminish, and a few minutes in the hot sun can leave us feeling thirsty. But our motivation can also vary over longer cycles. Scientists have long known that body activity is guided by internal “biological clocks.” Every 24 hours, your body undergoes a cycle of changes called circadian (SUR-kay-dee-AN) rhythms (circa: about; diem: a day) (Beersma & Gordijn, 2007; Franken & Dijk, 2009). Throughout the day, activities in the liver, kidneys, and endocrine glands undergo large changes. Body temperature, blood pressure, and amino acid levels also shift from hour to hour. These activities, and many others, peak once a day (• Figure 10.2). People are usually more motivated and alert at the high point of their circadian rhythms (Bass & Takahashi, 2010; Chipman & Jin, 2009).
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12:00 Midnight
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12:00 Midnight
12:00 Noon
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• Figure 10.2 Core body temperature is a good indicator of a person’s circa- dian rhythm. Rapid travel to a different time zone, shift work, depression, and illness can throw sleep and waking patterns out of synchronization with the body’s core rhythm. Mismatches of this kind are very disruptive (Reinberg & Ashkenazi, 2008). Most people reach a low point 2 to 3 hours before their normal waking time. It’s no wonder that both the Chernobyl and Three-Mile Island nuclear power plant acci- dents occurred around 4 A.M. Copyright © 2012 Wadsworth, Cengage Learning, Inc.
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Chapter 10334
People with early peaks in their circadian rhythms are “day people,” who wake up alert, are energetic early in the day, and fall asleep early in the evening. People with later peaks are “night peo- ple,” who wake up groggy, are lively in the afternoon or early eve- ning, and stay up late (Martynhak et al., 2010). Such differences are so basic that when a day person rooms with a night person, both are more likely to give their relationship a negative rating (Carey, Stanley, & Biggers, 1988). This is easy to understand: What could be worse than having someone bounding around cheerily when you’re half asleep, or the reverse?
Jet Lag and Shift Work Circadian rhythms are most noticeable after a major change in time schedules. Businesspeople, athletes, and other time zone trav- elers tend to perform poorly when their body rhythms are dis- turbed. If you travel great distances east or west, the peaks and valleys of your circadian rhythms will be out of phase with the sun and clocks. For example, you might be wide awake at midnight and feel like you’re sleepwalking during the day (return to • Figure 10.2). Shift work has the same effect, causing fatigue, irritability, upset stomach, and depression (Shen et al., 2006; Smith et al., 2011).
How fast do people adapt to rhythm changes? For major time zone shifts (5 hours or more), it can take up to 2 weeks to resynchronize. The direction of travel also affects adaptation (Herxheimer & Waterhouse, 2003). If you fly west, adapting is relatively easy; if you fly east, adapting takes much longer. When you fly east, the sun comes up earlier relative to your “home” time. Let’s say that you live in San Diego and fly to Philadelphia. If you get up at 7 a.m. in Philadelphia, it’s 4 a.m. back in San Diego—and your body knows it. If you fly west, the sun comes up later. In this case, it is easier for people to “advance” (stay up later and sleep in) than it is to shift backward.
Adjusting to jet lag is slowest when you stay indoors, where you can sleep and eat on “home time.” Getting outdoors speeds adapta- tion. A few intermittent 5-minute periods of exposure to bright light early in the morning are also helpful for resetting your circa- dian rhythm (Dodson & Zee, 2010; Duffy & Wright, 2005). Bright light affects the timing of body rhythms by reducing the amount of melatonin produced by the pineal gland. When melato- nin levels rise late in the evening, it’s bedtime as far as the brain is concerned.
Changes in melatonin levels are thought to partly explain winter depressions that occur when people endure several months of long dark days. See Chapter 14, pages 494–495.
BRIDGES
How does this affect those of us who are not world travelers? There are few college students who have not at one time or another “burned the midnight oil,” especially for final exams. At such times, it is wise to remember that departing from your regular schedule usually costs more than it’s worth. You may be motivated to do as much during 1 hour in the morning as you could have done in 3 hours of work after midnight. You might just as well go to sleep
2 hours earlier. In general, if you can anticipate an upcoming body rhythm change, it is best to preadapt to your new schedule. Pread- aptation refers to gradually matching your sleep–waking cycle to a new time schedule. Before traveling, for instance, you should go to sleep 1 hour later (or earlier) each day until your sleep cycle matches the time at your destination.
Knowledge Builder Overview of Motivation
RECITE 1. Motives __________________, sustain, _________________, and
terminate activities. 2. Needs provide the _______________________ of motivation,
whereas incentives provide the ______________________. Classify the following needs or motives by placing the correct letter in the blank. A. Biological motive B. Stimulus motive C. Learned motive
3. _____ curiosity 6. _____ thirst 4. _____ status 7. _____ achievement 5. _____ sleep 8. _____ physical contact
9. The maintenance of bodily equilibrium is called thermostasis. T or F? 10. Desirable goals are motivating because they are high in
a. secondary value b. stimulus value c. homeostatic value d. incentive value
1 1. The term jet lag is commonly used to refer to disruptions of a. the inverted U function b. circadian rhythms c. any of the
episodic drives d. the body’s set point
REFLECT Think Critically
1 2. Many people mistakenly believe that they suffer from “hypoglycemia” (low blood sugar), which is often blamed for fatigue, difficulty concentrating, irritability, and other symptoms. Why is it unlikely that many people actually have hypoglycemia?
Self-Reflect
Motives help explain why we do what we do. See if you can think of something you do that illustrates the concepts of need, drive, response, and goal. Does the goal in your example vary in incentive value? What effects do high and low incentive-value goals have on your behavior?
Mentally list some biological motives you have satisfied today. Then list some stimulus motives and learned motives. How did each influence your behavior?
Answers: 1. initiate, direct 2. push, pull 3. B 4. C 5. A 6. A 7. C 8. B 9. F 10. d 11. b 12. Because of homeostasis: Blood sugar is normally maintained within narrow bounds. Although blood sugar levels fluctuate enough to affect hunger, true hypoglycemia is an infrequent medical problem.
Hunger—Pardon Me, My Hypothalamus Is Growling
Gateway Question 10.2: What causes hunger, overeating, and eating disorders? You get hungry, you find food, and you eat: Hunger might seem like a “simple” motive, but we have only recently begun to under- stand it. Hunger provides a good example of how internal and external factors direct our behavior. And, as we will see later, many
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Motivation and Emotion 335
Hypothalamus A small area at the base of the brain that regulates many aspects of motivation and emotion, especially hunger, thirst, and sexual behavior.
Gastric balloon
Record of breathing
Record of hunger pangs
Time record in minutes
Record of stomach contractions
For more information about the role of the hypothalamus in controlling behavior, see Chapter 2, pages 71–72.
BRIDGES
The hypothalamus is sensitive to levels of sugar in the blood (and other substances described in a moment). It also receives neu- ral messages from the liver and stomach. When combined, these signals determine whether you are hungry (Freberg, 2010; Woods et al., 2000).
One part of the hypothalamus acts as a feeding system that initi- ates eating. If the lateral hypothalamus is “turned on” with an elec- trified probe, even a well-fed animal will immediately begin eating. (The term lateral simply refers to the sides of the hypothalamus. See • Figure 10.5.) If the same area is destroyed, the animal may never eat again.
The lateral hypothalamus is normally activated in a variety of ways. For example, when you are hungry, your stomach lining pro- duces ghrelin (GREL-in), a hormone that activates your lateral hypothalamus (Castañeda et al., 2010; Olszewski et al., 2003). (If your stomach is growlin’, it’s probably releasing ghrelin.) Ghrelin also activates parts of your brain involved in learning. This means you should consider studying before you eat, not immediately afterward (Diano et al., 2006).
How do we know when to stop eating? A second area in the hypo- thalamus is part of a satiety system, or “stop mechanism” for eating. If the ventromedial (VENT-ro-MEE-dee-al) hypothalamus is destroyed, dramatic overeating results. (Ventromedial refers to the bottom middle of the hypothalamus.) Rats with such damage will eat until they balloon up to weights of 1,000 grams or more (• Figure 10.6). A normal rat weighs about 180 grams. To put this weight gain in human terms, picture someone you know who weighs 180 pounds growing to a weight of 1,000 pounds.
Hypothalamus
• Figure 10.3 In Walter Cannon’s early study of hunger, a simple apparatus was used to simultaneously record hunger pangs and stomach contractions. (Adapted from Cannon, 1934.)
• Figure 10.4 Location of the hypothalamus in the human brain. Copyright © 2012 Wadsworth,
Cengage Learning, Inc.
of the principles that explain hunger also apply to thirst. Like almost every other human motive, our hunger levels are affected by both internal bodily factors and external environmental and social ones. To understand how this works, let’s begin with a survey of some of the internal fac- tors controlling our hunger.
Internal Factors in Hunger Don’t feelings of hunger originate in the stomach? To find out, Walter Cannon and A. L. Washburn (1912) decided to see whether stom- ach contractions cause hunger. In an early study, Washburn trained himself to swallow a balloon, which could be inflated through an attached tube. (You, too, will do anything for science, right?) This allowed Cannon to record the movements of Washburn’s stomach (• Figure 10.3). When Washburn’s stomach contracted, he reported that he felt “hunger pangs.” In view of this, the two scien- tists concluded that hunger is nothing more than the contractions of an empty stomach. (This, however, proved to be an inflated conclusion.)
For many people, hunger produces an overall feeling of weak- ness or shakiness rather than a “growling” stomach. Of course, eating does slow when the stomach is stretched or distended (full). (Remember last Thanksgiving?) However, we now know that the stomach is not essential for feeling hunger. Even people who have had their stomachs removed for medical reasons continue to feel hungry and eat regularly (Woods et al., 2000).
Then what does cause hunger? Many different factors combine to promote and suppress hunger (Ribeiro et al., 2009). The brain receives many signals from parts of the digestive system, ranging from the tongue and stomach to the intestines and the liver.
Brain Mechanisms What part of the brain controls hunger? Although no single “hunger thermostat” exists, a small area called the hypothalamus (HI-po- THAL-ah-mus) is especially important because it regulates many motives, including hunger, thirst, and the sex drive (• Figure 10.4).
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Chapter 10336
A chemical called glucagon-like peptide 1 (GLP-1) is also involved in causing eating to cease. After you eat a meal, GLP-1 is released by the intestines. From there, it travels in the bloodstream to the brain. When enough GLP-1 arrives, your desire to eat ends (Hayes, De Jonghe, & Kanoski, 2010). As you might imagine, GLP-1 pills show promise in the treatment of obesity (Raun et al., 2007). By the way, it takes at least 10 minutes for the hypothalamus to respond after you begin eating. That’s why you are less likely to
overeat if you eat slowly, which gives your brain time to get the message that you’ve had enough (Liu et al., 2000).
The paraventricular (PAIR-uh-ven-TRICK-you-ler) nucleus of the hypothalamus also affects hunger (• Figure 10.5). This area helps keep blood sugar levels steady by both starting and stopping eating. The paraventricular nucleus is sensitive to a
Corpus callosum
Lateral hypothalamus
Paraventricular nucleus
Ventromedial hypothalamus
• Figure 10.5 This is a cross-section through the middle of the brain (viewed from the front of the brain). Indicated areas of the hypothalamus are associated with hunger and the regulation of body weight. Copyright © 2012 Wadsworth, Cengage Learning, Inc.
Your Brain’s “Fat Point”Brainwaves
Like a thermostat, your brain maintains a set point in order to control your weight over the long term. It does this by monitor- ing the amount of fat stored in your body in specialized fat cells (Ahima & Osei, 2004; Gloria-Bottini, Magrini, & Bottini, 2009).
Your set point is the weight you maintain when you are making no effort to gain or lose weight. When your body weight goes below its set point, you will feel hungry most of the time. On the other hand, fat cells release a substance called leptin when your “spare tire” is well inflated. Leptin is carried in the blood- stream to the hypothalamus, where it tells us to eat less (Williams et al., 2004).
Can you change your fat set point? Good question. Your leptin levels are partly under genetic control. In rare cases, mice (and
we humans) inherit a genetic defect that reduces leptin levels in the body, leading to obesity. In such cases, taking leptin can help (Williamson et al., 2005).
For the rest of us, the news is not so encouraging because there is currently no known way to lower your set point for fat, since the number of fat cells remains unchanged throughout adult life (Spalding et al., 2008). To make matters worse, radical diets do not help (but you knew that already, didn’t you?). They may even raise the set point for fat, resulting in diet-induced obesity (Ahima & Osei, 2004). You may not be able to lose weight by resetting your hypothala- mus, but psychologists have studied more effective approaches to weight loss. We will examine some later in this chapter.
• Figure 10.6 Damage to the hunger satiety system in the hypothalamus can produce a very fat rat, a condition called hypothalamic hyperphagia (Hi-per-FAGE- yah: overeating). This rat weighs 1,080 grams. (The pointer has gone completely around the dial and beyond.) (Courtesy of Neal E. Miller, Rockefeller University.)
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The mouse on the left has a genetic defect that prevents its fat cells from producing normal amounts of leptin. Without this chemical signal, the mouse’s body acts as if its set point for fat storage is, shall we say, rather high.
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Motivation and Emotion 337
Set point The proportion of body fat that tends to be maintained by changes in hunger and eating.
substance called neuropeptide Y (NPY). If NPY is present in large amounts, an animal will eat until it cannot hold another bite (Williams et al., 2004). Incidentally, the hypothalamus also responds to a chemical in marijuana, which can produce intense hunger (the “munchies”) (Di Marzo et al., 2001).
In addition to knowing when to start eat- ing, and when meals are over, your brain also controls your weight over long periods of time (see “Your Brain’s ‘Fat Point’”).
The substances we have reviewed are only some of the chemical signals that start and stop eating (Geary, 2004; Turenius et al., 2009). Others continue to be discovered. In time, they may make it possible to artificially control hunger. If so, better treatments for extreme obesity and self-starvation could follow (Bat- terham et al., 2003).
External Factors in Hunger and Obesity As we have seen, “hunger” is affected by more than just the “push” of our biological needs for food. In fact, if internal needs alone controlled eating, many fewer people would overeat (Stroebe, Papies, & Aarts, 2008). Nevertheless, in 2006, roughly 65 percent of adults in the United States were overweight and more than one third were obese (extremely overweight) (Centers for Disease Control, 2008; Flegal et al., 2010; • Figure 10.7). (See “What’s Your BMI?”) Childhood obesity has also shown a dramatic rise. As
a result, obesity is overtaking smoking as a cause of needless deaths (Freedman, 2011). Let’s consider some external influences on hun- ger and their role in obesity, a major health risk and, for many, a source of social stigma and low self-esteem.
What’s Your BMI? (We’ve Got Your Number.)Discovering Psychology
From the standpoint of fashion, you may already have an opinion about whether you are overweight. But how do you rate from a medical perspective? Obesity is di- rectly linked to heart disease, high blood pressure, stroke, type 2 diabetes, and prema- ture death. But how heavy do you have to be to endanger your health? A measure called the body mass index (BMI) can be used to as- sess where you stand on the weight scale (so to speak). You can calculate your BMI by using the following formula:
BMI �
1your weight in pounds2
1height in inches2 1height in inches2 � 703
To use the formula, take your height in inches and multiply that number by itself (square the number). Then divide the result into your weight in pounds. Multiply the re- sulting number by 703 to obtain your BMI. Fo r e x a m p l e, a p e r s o n w h o we i g h s 220 pounds and is 6 feet 3 inches tall has a BMI of 27.5.
1220 pounds2 175 inches2 175 inches2
� 703 � 27.5
Now, compare your BMI to the following scale:
Underweight less than 18.5 Normal weight 18.5 to 24.9 Overweight 25 to 29.9 Obesity 30 or greater
If your BMI is greater than 25, you should be concerned. If it is greater than 30, your weight may be a serious health risk. (There are two exceptions: The BMI may overesti- mate body fat if you have a muscular build, and it may underestimate body fat in older persons who have lost muscle mass.) Losing weight and keeping it off can be very chal- lenging. However, if you’re overweight, low- ering your BMI is well worth the effort. In the long run, it could save your life.
Obese
Overweight
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Overweight and Obese in America: An Epidemic
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• Figure 10.7 A near epidemic of obesity has occurred in the United States during the last 20 years, with over 65 percent of all Americans now classified as overweight or obese. (Adapted from Centers for Disease Control, 2008; Flegal et al., 2010.)
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Chapter 10338
External Eating Cues Most of us are sensitive to the “pull” of external eating cues, signs and signals linked with food. For example, do you tend to eat more when food is highly visible and easy to get? In cultures like ours, in which food is plentiful, eating cues add greatly to the risk of over- eating (Casey et al., 2008). Many college freshmen gain weight rapidly during their first 3 months on campus (the famous “Frosh 15”). All-you-can-eat dining halls in the dorms and nighttime snacking appear to be the culprits (Kapinos & Yakusheva, 2011). The presence of others can also affect whether people overeat (or undereat), depending on how much everyone else is eating and how important it is to impress them (Pliner & Mann, 2004).
Taste The availability of a variety of tasty foods can also lead to overeat- ing and obesity in societies in which such foods are plentiful. Nor- mally, tastes for foods vary considerably. For example, if you are well fed, leptin dulls the tongue’s sensitivity to sweet tastes (Kawai et al., 2000). If you have noticed that you lose your “sweet tooth” when you are full, you may have observed this effect. Actually, if you eat too much of any particular food, it will become less appeal- ing. This probably helps us maintain variety in our diets. However, it also encourages obesity. If you overdose on hamburgers or French fries, moving on to some cookies or chocolate cheesecake certainly won’t do your body much good (Pinel, Assanand, & Lehman, 2000).
It is easy to acquire a taste aversion, or active dislike, for a par- ticular food. This can happen if a food causes sickness or if it is merely associated with nausea (Chance, 2009). A friend of one of your authors once became ill after eating a cheese Danish (well, actually, several) and has never again been able to come face to face with this delightful pastry.
If you like animals, you will be interested in an imaginative approach to an age-old problem. In many rural areas, predators are poisoned, trapped, or shot by ranchers. These practices have nearly wiped out the timber wolf, and in some areas the coyote faces a
similar end. How might the coyote be saved without a costly loss of livestock?
In a classic experiment, coyotes were given lamb tainted with lithium chloride. Coyotes who took the bait became nauseated and vomited. After one or two such treatments, they developed bait shyness—a lasting distaste for the tainted food (Gustavson & Gar- cia, 1974; Nakajima & Nagaishi, 2005). If applied consistently, taste aversion conditioning might solve many predator–livestock problems.
Bait shyness is similar to human aversion conditioning, which is used to help people control bad habits, such as smoking, drinking, or nail biting. See Chapter 15, pages 521–522, to explore this connection.
BRIDGES
If getting sick occurs long after eating, how does it become associ- ated with a particular food? A good question. Taste aversions are a type of classical conditioning. As stated in Chapter 6, a long delay between the conditioned stimulus (CS) and the unconditioned stimulus (US) usually prevents conditioning. However, psycholo- gists theorize that we have a biological preparedness to associate an upset stomach with foods eaten earlier. Such learning usually protects us from eating unhealthy foods.
Taste aversions may also help people avoid severe nutritional imbalances. For example, if you go on a fad diet and eat only grape- fruit, you will eventually begin to feel ill. In time, associating your discomfort with grapefruit may create an aversion to it and restore some balance to your diet.
Emotional Eating Is it true that people also overeat when they are emotionally upset? Yes. People with weight problems are prone to overeat when they are anxious, angry, or sad (Macht & Simons, 2011). Furthermore, obese individuals are often unhappy in our fat-conscious culture. The result is overeating that leads to emotional distress and still more overeating (Davis & Carter, 2009).
Cultural Factors Learning to think of some foods as desirable and others as revolt- ing also has a large impact on what we eat. In North America, we would never consider eating the eyes out of the steamed head of a monkey, but in some parts of the world they are considered a deli- cacy. By the same token, vegans and vegetarians think it is barbaric to eat any kind of meat. In short, cultural values greatly affect the incentive value of foods.
Dieting A diet is not just a way to lose weight. Your current diet is defined by the types and amounts of food you regularly eat. Some diets actually encourage overeating. For instance, placing animals on a “supermarket” diet leads to gross obesity. In one classic experi- ment, rats were given meals of chocolate chip cookies, salami, cheese, bananas, marshmallows, milk chocolate, peanut butter,
Childhood obesity has reached epidemic proportions in the United States, having tripled in prevalence since 1980 (Ogden et al., 2010). In 2010, First Lady Michelle Obama launched “Let’s Move,” her national program to confront this problem head on.
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Motivation and Emotion 339
Taste aversion An active dislike for a particular food. Bait shyness An unwillingness or hesitation on the part of animals to eat a
particular food. Biological preparedness (to learn) Organisms are more easily able to
learn some associations (e.g., food and illness) than others (e.g., flashing light and illness). Evolution then places biological limits on what an animal or person can easily learn.
Anorexia nervosa Active self-starvation or a sustained loss of appetite that has psychological origins.
and fat. These pampered rodents overate, gaining almost three times as much weight as rats that ate only laboratory chow (Scla- fani & Springer, 1976). (Rat chow is a dry mixture of several bland grains. If you were a rat, you’d probably eat more cookies than rat chow, too.)
People are also sensitive to dietary content. In general, sweetness, high fat content, and variety tend to encourage overeating (Lucas & Sclafani, 1990). Unfortunately, North American culture provides the worst kinds of foods for people who suffer from obesity. For example, restaurant and fast food tends to be higher in fat and calo- ries than meals made at home (Kessler, 2009). “Supersized” meals are another problem. Food portions at restaurants in the United States are 25 percent larger, or more, than they are in France. Far fewer people are obese in France, most likely because they simply eat less. The French also take longer to eat a meal, which discour- ages overeating (Rozin et al., 2003).
An added problem faced by people who want to control their weight concerns “yo-yo” dieting.
The Paradox of Yo-Yo Dieting If dieting works, why are hundreds of “new” diets published each year? The answer is that although dieters do lose weight, most regain it soon after they stop dieting. In fact, many people end up weighing even more than before (Freedman, 2011). Why should this be so? Dieting (starving) slows the body’s rate of metabolism (the rate at which energy is used up). In effect, a dieter’s body becomes highly efficient at conserving calories and storing them as fat (Pinel, Assanand, & Lehman, 2000).
Apparently, evolution prepared us to save energy when food is scarce and to stock up on fat when food is plentiful. Briefly starving yourself, therefore, may have little lasting effect on weight. “Yo-yo dieting,” or repeatedly losing and gaining weight, is especially dan- gerous. Frequent changes in weight can dramatically slow the
body’s metabolic rate. As noted earlier, this may raise the body’s set point for fat and makes it harder to lose weight each time a person diets and easier to regain weight when the diet ends. Frequent weight changes also increase the risk for heart disease and prema- ture death (Wang & Brownell, 2005). To avoid bouncing between feast and famine requires a permanent change in eating habits and exercise.
To summarize, eating and overeating are related to internal and external influences, diet, emotions, genetics, exercise, and many other factors. People become obese in different ways and for differ- ent reasons. We live in a culture that provides inexpensive, good- tasting food everywhere, and have a brain that evolved to say “Eat whenever food is available.” Nevertheless, many people have learned to take control of eating by applying psychological princi- ples (see “Behavioral Dieting”).
Eating Disorders Under the sheets of her hospital bed, Krystal looks like a skele- ton. Victims of anorexia, who are mostly adolescent females, suf- fer devastating weight losses from severe, self-inflicted dieting (Cooper, 2005). If she cannot overcome her anorexia nervosa (AN-uh-REK-see-yah ner-VOH-sah: self-starvation), Krystal may die of malnutrition.
Singer Jennifer Hudson has been a life-long dieter who tried many different diets and experienced weight swings. As a spokeswoman for a national weight- loss program, Jennifer lost about 80 pounds. Will she maintain her weight loss over time?
Anorexia nervosa is far more dangerous than many people realize. This haunting Italian anti-anorexia poster shows 68-pound model Isabelle Caro, who suffered from anorexia for years up until her death in 2010 at age 28. Many celebrities have struggled with eating disorders, including Karen Carpenter (who died of starvation- induced heart failure), Paula Abdul, Kirstie Alley, Fiona Apple, Victoria Beckham (Posh Spice), Princess Diana, Tracey Gold, Janet Jackson, and Mary-Kate Olsen.
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Chapter 10340
Do anorexics lose their appetite? Although a compulsive attempt to lose weight causes them to not seek or desire food, they usually still feel physical hunger. Often, anorexia starts with “normal” dieting that slowly begins to dominate the person’s life. In time, anorexics suffer debilitating health problems. From 5 to 8 percent (more than 1 in 20) die of malnutrition (Polivy &
Herman, 2002). ■ Table 10.1 lists the symptoms of anorexia nervosa.
Bulimia nervosa (bue-LIHM-ee-yah) is a second major eating disorder (Bardone-Cone et al., 2008; Koda & Sugawara, 2009). Bulimic persons gorge on food, then vomit or take laxatives to avoid gaining weight (see ■ Table 10.1). As with anorexia, most victims of
Behavioral DietingDiscovering Psychology
As we have noted, dieting is usually fol- lowed by rapid weight gain. If you really want to lose weight, you must overhaul your eating and exercise habits, an approach called behavioral dieting (Freedman, 2011; Roizen & Oz, 2006). Here are some helpful behavioral techniques:
1. Get yourself committed to weight loss. Involve other people in your ef- forts. Programs such as Overeaters Anonymous or Take Off Pounds Sensi- bly can be a good source of social sup- port (Mitchell et al., 2010).
2. Exercise. No diet can succeed for long without an increase in exercise. To lose weight, you must use more calories than you take in. Burning just 200 extra calories a day can help prevent rebound weight gains. Add activity to your rou- tine in every way you can think of. Stop saving steps and riding elevators. Buy a step counter to track the number of steps you take every day. Walking 10,000 steps per day will burn between 2,000 and 3,500 calories a week (de- pending on your weight). The more fre- quently and vigorously you exercise, the more weight you will lose (Jeffery & Wing, 2001).
3. Learn your eating habits by observ- ing yourself and keeping a “diet diary.” Begin by making a complete, 2-week record of when and where you eat, what you eat, and the feelings and events that occur just before and after eating. Is a roommate, relative, or spouse encouraging you to overeat? What are your most “dangerous” times and places for overeating?
4. Learn to weaken your personal eat- ing cues. When you have learned when and where you do most of your eating, avoid these situations. Try to restrict
your eating to one room, and do not read, watch TV, study, or talk on the phone while eating. Require yourself to interrupt what you are doing in order to eat.
5. Count calories, but don’t starve your- self. To lose weight, you must eat less, and calories allow you to keep a record of your food intake. If you have trouble eating less every day, try dieting 4 days a week. People who diet intensely every other day lose as much as those who diet moderately every day (Viegener et al., 1990).
6. Develop techniques to control the act of eating. Whenever you can, check for nutritional information and buy grocer- ies and meals lower in calories and fats. Begin to take smaller portions. Carry to the table only what you plan to eat. Put all other food away before leaving the kitchen. Eat slowly, sip water between bites of food, leave food on your plate, and stop eating before you are com- pletely full. Be especially wary of the extra large servings at fast-food restau- rants. Saying “supersize me” too often can, indeed, leave you supersized (Mur- ray, 2001).
7. Avoid snacks. It is generally better to eat more small meals a day than fewer large ones because more calories are burned (Roizen & Oz, 2006). (No, we
don’t mean high-calorie snacks in addi- tion to meals.) If you have an impulse to snack, set a timer for 20 minutes and see if you are still hungry then. Delay the impulse to snack several times if possible. Dull your appetite by filling up on raw carrots, bouillon, water, coffee, or tea.
8. Chart your daily progress. Record your weight, the number of calories eaten, and whether you met your daily goal. Set realistic goals by cutting down calo- ries gradually. Losing about a pound per week is realistic, but remember, you are changing habits, not just dieting. Diets don’t work!
9. Set a “threshold” for weight control. Maintaining weight loss can be even more challenging than losing weight. It is easier to maintain weight losses if you set a regain limit of 3 pounds or less. In other words, if you gain more than 2 or 3 pounds, you immediately begin to make corrections in your eating habits and amount of exercise (Kessler, 2009).
Be patient. It takes years to develop eat- ing habits. You can expect it to take at least several months to change them. If you are unsuccessful at losing weight with these techniques, you might find it helpful to seek the aid of a psychologist familiar with behav- ioral weight-loss techniques.
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Motivation and Emotion 341
Behavioral dieting Weight reduction based on changing exercise and eating habits, rather than temporary self-starvation.
Bulimia nervosa Excessive eating (gorging) usually followed by self- induced vomiting and/or taking laxatives.
bulimia are girls or women. Approximately 5 percent of college women are bulimic, and as many as 60 percent have milder eating problems. Bingeing and purging can seriously damage health. Typi- cal risks include sore throat, hair loss, muscle spasms, kidney dam- age, dehydration, tooth erosion, swollen salivary glands, menstrual irregularities, loss of sex drive, and even heart attack.
Men and Eating Disorders Eating disorders are on the rise among men. More and more men are experiencing muscle dysmorphia, excessive worry about not being muscular enough (Mosley, 2009). Currently, one third of men say they want less body fat and another third want more muscles (McCabe & Ricciardelli, 2004). As a result, many men are altering what they eat and exercising excessively. Some are going too far: About 10 percent of anorexics and 25 percent of bulimics are now males (Weltzin et al., 2005).
Causes What causes anorexia and bulimia? People who suffer from eating disorders are extremely dissatisfied with their bodies (Crisp et al., 2006). Usually, they have distorted views of themselves, exagger- ated fears of becoming fat, and low self-esteem. Many overestimate their body size by 25 percent or more. As a result, they think they are disgustingly “fat” when they are actually wasting away (• Figure 10.8) (Polivy & Herman, 2002).
Many of these problems are related to the idealized body images presented in the media (Levine & Harrison, 2004). Some websites even go so far as to celebrate anorexia and bulimia (referred to by
“fans” as “Ana” and “Mia”) (Borzekowski et al., 2010; Tierney, 2008). Girls who spend a lot of time reading fashion magazines or visiting these websites are more likely to have distorted body images and unrealistic ideas about how they compare with others (Martinez-Gonzalez et al., 2003).
The popularity of fitness, exercise, and sports has also contrib- uted to eating disorders. Today, more people are changing their diets in search of a lean, muscular look. People engaged in sports that require low body fat or extreme weight loss (such as wrestling, gym- nastics, pole vaulting, high jumping, and even cycling) are particu- larly likely to develop eating disorders (Weltzin et al., 2005).
People with eating disorders appear to be trying to gain some measure of control. Anorexic teen girls are usually described as “perfect” daughters—helpful, considerate, conforming, and obedi- ent. They seem to be rewarded by seeking perfect control in their lives by being perfectly slim (Castro et al., 2004; Keating, 2010). People suffering from bulimia are also concerned with control (Bardone-Cone et al., 2008). Typically, they are obsessed with thoughts of weight, food, eating, and ridding themselves of food. As a result, they feel guilt, shame, self-contempt, and anxiety. Vom- iting reduces their anxiety, which makes purging highly reinforcing (Powell & Thelen, 1996).
Treatment Most people suffering from eating disorders will not seek help on their own. This is especially true for men, because eating disorders are still widely perceived to be a female problem (Weltzin et al.,
Recognizing Eating Disorders
Anorexia Nervosa
• Refusal to maintain body weight in normal range. Body weight below 85 percent of normal for one’s height and age.
• Intense fear of becoming fat or gaining weight, even though underweight.
• Disturbance in one’s body image or perceived weight. Self-evaluation is unduly influenced by body weight. Denial of seriousness of abnormally low body weight.
• Absence of menstrual periods (may be removed from DSM-5).
• Purging behavior (vomiting or misuse of laxatives or diuretics).
Bulimia Nervosa
• Recurring binge eating. Eating within an hour or two an amount of food that is much larger than most people would consume. Feeling a lack of control over eating.
• Purging behavior (vomiting or misuse of laxatives or diuretics). Excessive exercise to prevent weight gain. Fasting to prevent weight gain.
• Self-evaluation is unduly influenced by body weight.
■ TABLE 10.1
Adapted from American Psychiatric Association, 2000, 2010.
Actually most attractive to men
Perceived current weight
Perceived ideal weight
Perceived as most attractive to men
2 3 4 5
• Figure 10.8 Women with abnormal eating habits were asked to rate their body shape on a scale similar to the one you see here. As a group, they chose ideal figures much thinner than what they thought their current weights were. (Most women say they want to be thinner than they cur- rently are, but to a lesser degree than women with eating problems.) Notice that the women with eating problems chose an ideal weight that was even thinner than what they thought men prefer. This is not typical of most women. In this classic study, only women with eating problems wanted to be thinner than what they thought men find attractive (Zellner, Harner, & Adler, 1989).
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Chapter 10342
2005). Typically, it takes strong urging by family or friends to get victims into treatment.
Treatment for anorexia usually begins with giving drugs to relieve obsessive fears of gaining weight. Then, a medical diet is used to restore weight and health. Next, a counselor may help patients work on the emotional conflicts that led to weight loss. For bulimia, behavioral counseling may include self-monitoring of food intake. A related cognitive-behavioral approach focuses on changing the thinking patterns and beliefs about weight and body shape that perpetuate eating disorders (Byrne & McLean, 2002; Cooper, 2005; Goldstein et al., 2011).
Culture, Ethnicity, and Dieting Women with eating disorders are not alone in having body image problems. In Western cultures, many women learn to see them- selves as “objects” that are evaluated by others. As a result, they try to shape their bodies to the cultural ideal of slimness through diet- ing (Fredrickson et al., 1998).
Just looking at a fashion magazine tends to leave women less satisfied with their weight and anxious to be thinner (Simpson, 2002). However, women from some cultural backgrounds appear to be less susceptible to the glorification of slimness. For example, Asian American college students are only half as likely to diet as other college women are (Tsai, Hoerr, & Song, 1998). Within the African American and Pacific-Islander communities, there is a general preference for a fuller and shapelier figure. In these groups, a larger body size is associated with high social status, health, and beauty (Flynn & Fitzgibbon, 1998; Ofosu, Lafreniere, & Senn, 1998). Clearly, what constitutes an attractive body style is a matter of opinion.
Biological Motives Revisited— Thirst, Sex, and Pain
Gateway Question 10.3: What kinds of biological motives are thirst, pain avoidance, and the sex drive? Most biological motives work in ways that are similar to hunger. For example, thirst is only partially controlled by dryness of the mouth. If you were to take a drug that made your mouth constantly wet, or dry, your water intake would remain normal. Like hunger, thirst is regulated by separate thirst and thirst satiety systems in the hypothalamus. Also like hunger, thirst is strongly affected by learn- ing and cultural values.
Thirst You may not have noticed, but there are actually two kinds of thirst (Thornton, 2010). Extracellular thirst occurs when water is lost from the fluids surrounding the cells of your body. Bleeding, vom- iting, diarrhea, sweating, and drinking alcohol cause this type of thirst (Franken, 2007). When a person loses both water and miner- als in any of these ways—especially by perspiration—a slightly salty liquid may be more satisfying than plain water.
Why would a thirsty person want to drink salty water? The rea- son is that before the body can retain water, minerals lost through perspiration (mainly salt) must be replaced. In lab tests, animals greatly prefer saltwater after salt levels in their bodies are lowered (Strickler & Verbalis, 1988). Similarly, some nomadic peoples of the Sahara Desert prize blood as a beverage, probably because of its saltiness. (Maybe they should try Gatorade?)
A second type of thirst occurs when you eat a salty meal. In this instance, your body does not lose fluid. Instead, excess salt causes fluid to be drawn out of cells. As the cells “shrink,” intracellular thirst is triggered. Thirst of this type is best quenched by plain water (Thornton, 2010).
The drives for food, water, air, sleep, and elimination are all similar in that they are generated by a combination of activities in the body and the brain, and they are influenced by various external factors. However, the drive to avoid pain and the sex drive are more unusual.
Pain How is the drive to avoid pain different? Hunger, thirst, and sleepi- ness come and go in a fairly regular cycle each day. Pain avoidance, by contrast, is an episodic (ep-ih-SOD-ik) drive. That is, it occurs in distinct episodes when bodily damage takes place or is about to occur. Most drives prompt us to actively seek a desired goal (food, drink, warmth, and so forth). Pain prompts us to avoid or eliminate sources of discomfort.
Some people feel they must be “tough” and not show any dis- tress. Others complain loudly at the smallest ache or pain. The first attitude raises pain tolerance, and the second lowers it. As this sug- gests, the drive to avoid pain is partly learned. That’s why members of some societies endure cutting, burning, whipping, tattooing, and piercing of the skin that would agonize most people (Chang, 2009) (but apparently not devotees of piercing and “body art”). In general, we learn how to react to pain by observing family members, friends, and other role models (McMahon & Koltzenburg, 2005).
Tolerance for pain and the strength of a person’s motivation to avoid discomfort are greatly affected by cultural practices and beliefs, such as this penitent at a Hindu ceremony.
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Motivation and Emotion 343
Extracellular thirst Thirst caused by a reduction in the volume of fluids found between body cells.
Intracellular thirst Thirst triggered when fluid is drawn out of cells due to an increased concentration of salts and minerals outside the cell.
Episodic drive A drive that occurs in distinct episodes. Sex drive The strength of one’s motivation to engage in sexual behavior. Estrus Changes in the sexual drives of animals that create a desire for
mating; particularly used to refer to females in heat. Estrogen Any of a number of female sex hormones. Androgen Any of a number of male sex hormones, especially testosterone. Non-homeostatic drive A drive that is relatively independent of physical
deprivation cycles or bodily need states.
The Sex Drive Sex is unlike other biological motives because sex (contrary to any- thing your personal experience might suggest) is not necessary for individual survival. It is necessary, of course, for group survival.
The term sex drive refers to the strength of one’s motivation to engage in sexual behavior. In lower animals, the sex drive is directly related to hormones. Female mammals (other than humans) are interested in mating only when their fertility cycles are in the stage of estrus, or “heat.” Estrus is caused by a release of estrogen (a female sex hormone) into the bloodstream. Hormones are impor- tant in males as well. In most animals, castration will abolish the sex drive. But, in contrast to females, the normal male animal is almost always ready to mate. His sex drive is aroused primarily by the behavior and scent of a receptive female. Therefore, in many species, mating is closely tied to female fertility cycles.
How much do hormones affect human sex drives? Hormones affect the human sex drive, but not as directly as in animals (Crooks & Baur, 2011). The sex drive in men is related to the amount of androgens (male hormones such as testosterone) pro- vided by the testes. When the supply of androgens dramatically increases at puberty, so does the male sex drive. Likewise, the sex drive in women is related to their estrogen levels (Hyde & DeLama- ter, 2011). However, “male” hormones also affect the female sex drive. In addition to estrogen, a woman’s body produces small amounts of androgens. When their androgen levels increase, many women experience a corresponding increase in sex drive (Van Goozen et al., 1995). Testosterone levels decline with age, and vari- ous medical problems can lower sexual desire. In some instances, taking testosterone supplements can restore the sex drive in both men and women (Crooks & Baur, 2011).
Human sexual behavior and attitudes are discussed in detail in Chapter 11. For now it is enough to note that the sex drive is largely non-homeostatic (relatively independent of bodily need states). In humans, the sex drive can be aroused at virtually any time by almost anything. Therefore, it shows no clear relationship to deprivation (the amount of time since the drive was last satisfied). Certainly, an increase in desire may occur as time passes. But recent sexual activity does not prevent sexual desire from occurring again. Notice, too, that people may seek to arouse the sex drive as well as to reduce it. This unusual quality makes the sex drive capable of motivating a wide range of behaviors. It also explains why sex is used to sell almost everything imaginable.
The non-homeostatic quality of the sex drive can be shown in this way: A male animal is allowed to copulate until it seems to have no further interest in sexual behavior. Then, a new sexual partner is provided. Immediately, the animal resumes sexual activ- ity. This pattern is called the Coolidge effect after former U.S. Presi- dent Calvin Coolidge. What, you might ask, does Calvin Coolidge have to do with the sex drive? The answer is found in the following story.
While touring an experimental farm, Coolidge’s wife reportedly asked if a rooster mated just once a day. “No ma’am,” she was told, “he mates dozens of times each day.” “Tell that to the president,” she said, with a faraway look in her eyes. When President Coolidge
reached the same part of the tour, his wife’s message was given to him. His reaction was to ask if the dozens of matings were with the same hen. No, he was told, different hens were involved. “Tell that to Mrs. Coolidge,” the president is said to have replied.
Knowledge Builder Hunger, Thirst, Pain, and Sex
RECITE 1. The hunger satiety system in the hypothalamus signals the body
to start eating when it receives signals from the liver or detects changes in blood sugar. T or F?
2. Maintaining your body’s set point for fat is closely linked with the amount of __________ in the bloodstream. a. hypothalamic factor-1 b. ventromedial
peptide-1 c. NPY d. leptin 3. A cancer patient has little appetite for food several weeks after the
nausea caused by chemotherapy has ended. Her loss of appetite is probably best explained by a. increased NPY in the brain b. a conditioned taste
aversion c. the aftereffects of yo-yo dieting d. a loss of extracellular hunger
4. People who diet frequently tend to benefit from practice: They lose weight more quickly each time they diet. T or F?
5. In addition to changing eating habits, a key element of behavioral dieting is a. exercise b. well-timed snacking c. better eating
cues d. commitment to “starving” every day 6. Bingeing and purging are most characteristic of people who have
a. taste aversions b. anorexia c. bulimia d. strong sensitivity to external eating cues
7. Thirst may be either intracellular or ___________________________ _______.
8. Pain avoidance is a(n) _________________________ drive. 9. Sexual behavior in animals is largely controlled by estrogen levels in
the female and the occurrence of estrus in the male. T or F?
REFLECT Think Critically
1 0. Kim, who is overweight, is highly sensitive to external eating cues. How might her wristwatch contribute to her overeating?
Self-Reflect
Think of the last meal you ate. What caused you to feel hungry? What internal signals told your body to stop eating? How sensitive are you to external eating cues? How were you influenced by portion size? Have you developed any taste aversions?
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Chapter 10344
Stimulus Motives—Skydiving, Horror Movies, and the Fun Zone
Gateway Question 10.4: How does arousal relate to motivation? Are you full of energy right now? Or are you tired? Clearly, the level of arousal you are experiencing is closely linked with your motivation. Are there ideal levels of arousal for different people and different activities? Let’s find out.
Most people enjoy a steady “diet” of new movies, novels, music, fashions, games, news, websites, and adventures. Yet stimulus motives, as we noted earlier, which reflect needs for information, exploration, manipulation, and sensory input, go beyond mere entertainment. Stimulus motives also help us survive. As we scan our surroundings, we constantly identify sources of food, danger, shelter, and other key details. The drive for stimulation is already present during infancy. By the time a child can walk, there are few things in the home that have not been tasted, touched, viewed, handled, or, in the case of toys, destroyed!
Stimulus motives are readily apparent in animals as well as humans. For example, monkeys will quickly learn to solve a mechan- ical puzzle made up of interlocking metal pins, hooks, and latches (Butler, 1954) (• Figure 10.9). No food treats or other external
rewards are needed to get them to explore and manipulate their sur- roundings. The monkeys seem to work for the sheer fun of it.
Arousal Theory Are stimulus motives homeostatic? Yes. According to arousal theory, we try to keep arousal at an optimal level (Franken, 2007; Hancock & Ganey, 2003). In other words, when your level of arousal is too low or too high, you will seek ways to raise or lower it.
What do you mean by arousal? Arousal refers to activation of the body and nervous system. Arousal is zero at death, low during sleep, moderate during normal daily activities, and high at times of excitement, emotion, or panic. Arousal theory assumes that we become uncomfortable when arousal is too low (“I’m bored”) or when it is too high, as in fear, anxiety, or panic (“The dentist will see you now”). Most adults vary music, parties, sports, conversa- tion, sleep, surfing the Web, and the like, to keep arousal at moder- ate levels. The right mix of activities prevents boredom and over- stimulation (Csikszentmihalyi, Abuhamdeh, & Nakamura, 2005).
Sensation Seekers Do people vary in their needs for stimulation? Arousal theory also suggests that people learn to seek particular levels of arousal (Lynne-Landsman et al., 2011). Where would you prefer to go on your next summer vacation? Your back yard? How about a week with your best friends at a cottage on a nearby lake? Or a shopping and museum trip to New York City? Better yet, how about cage diving with great white sharks in South Africa? If the shark adven- ture attracts you, you are probably high in sensation seeking and would be interested in a vacation that includes activities like bungee-jumping, scuba diving, skiing, skydiving, and white water rafting (Pizam et al., 2004).
Sensation seeking is a trait of people who prefer high levels of stimulation (Gray & Wilson, 2007). Whether you are high or low in sensation seeking is probably based on how your body responds to new, unusual, or intense stimulation (Zuckerman, 2002). People
A friend of yours seems to be engaging in yo-yo dieting. Can you explain to her or him why such dieting is ineffective? Can you summarize how behavioral dieting is done?
If you wanted to provoke extracellular thirst in yourself, what would you do? How could you make intracellular thirst occur?
Answers: 1. F 2. d 3. b 4. F 5. a 6. c 7. extracellular 8. episodic 9. F 10. The time of day can influence eating, especially for externally cued eaters, who tend to get hungry at mealtimes, irrespective of their internal needs for food.
• Figure 10.9 Monkeys happily open locks that are placed in their cage. Because no reward is given for this activity, it provides evidence for the existence of stimulus needs.
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Sensation seeking is a trait of people who prefer high levels of stimulation.
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Motivation and Emotion 345
Arousal theory Assumes that people prefer to maintain ideal, or comfortable, levels of arousal.
Yerkes-Dodson law A summary of the relationships among arousal, task complexity, and performance.
Test anxiety High levels of arousal and worry that seriously impair test performance.
high in sensation seeking tend to be bold and independent, and value change. They also report more sexual partners, are more likely to smoke, and prefer spicy, sour, and crunchy foods over bland foods. Low sensation seekers are orderly, nurturant, and giv- ing, and enjoy the company of others.
Exciting lives aside, there is a dark side to sensation seeking (Dunlop & Romer, 2010). High sensation seekers are more likely to engage in high-risk behaviors such as substance abuse and casual unprotected sex (Gullette & Lyons, 2005; Horvath et al., 2004).
Levels of Arousal Is there an ideal level of arousal for peak performance? If we set aside individual differences, most people perform best when their arousal level is moderate. Let’s say that you have to take an essay exam. If you are feeling sleepy or lazy (arousal level too low), your performance will suffer. If you are in a state of anxiety or panic about the test (arousal level too high), you will also perform below par. Thus, the relationship between arousal and performance forms an inverted U function (a curve in the shape of an upside-down U) (• Figure 10.10) (Hancock & Ganey, 2003).
The inverted U tells us that at very low levels of arousal, you’re not sufficiently energized to perform well. Performance will improve as your arousal level increases, up to the middle of the curve. Then, it begins to drop off as you become emotional, fren- zied, or disorganized. For example, imagine trying to start a car stalled on a railroad track, with a speeding train bearing down on you. That’s what the high-arousal end of the curve feels like.
Is performance always best at moderate levels of arousal? No, the ideal level of arousal depends on the complexity of a task. If a task is relatively simple, it is best for arousal to be high. When a task is more complex, your best performance will occur at lower levels of arousal. This relationship is called the Yerkes-Dodson law (see • Figure 10.10). It applies to a wide variety of tasks and to mea- sures of motivation other than arousal.
For example, at a track meet, it is almost impossible for sprinters to get too aroused for a race. The task is direct and simple: Run as fast as you can for a short distance. On the other hand, a golfer making a tournament-deciding putt faces a more sensitive and complex task. Excessive arousal is almost certain to hurt his or her
performance. In school, most students have had experience with “test anxiety,” a familiar example of how too much arousal can lower performance.
Coping with Test Anxiety Then is it true that by learning to calm down, a person would do bet- ter on tests? Usually, but not always. To begin with, some arousal is healthy; it focuses us on the task at hand. It is only when arousal interferes with performance that we refer to anxiety. Test anxiety is a mixture of heightened physiological arousal (nervousness, sweat- ing, pounding heart) and excessive worry. This combination— arousal plus worry—tends to distract students with a rush of upset- ting thoughts and feelings (Eysenck et al., 2007; Stipek, 2002).
Also, studies show that students are typically most anxious when they don’t know the material (Cassady, 2004). Not studying while remaining calm simply means you will calmly fail the test. Here are some suggestions for coping with test anxiety.
Preparation Hard work is the most direct antidote for test anxiety. Many test- anxious students simply study too little, too late. That’s why improving your study skills is a good way to reduce test anxiety (Cassady, 2004).
One of the best ways to avoid test anxiety is to improve your study skills. If test anxiety is a problem for you, it would be wise to return to the Introduction in this book and review the learning and test-taking skills described there.
BRIDGES
The best solution is to overprepare by studying long before the “big day.” Well-prepared students score higher, worry less, and are less likely to panic (Kaplan, 2008; Santrock & Halonen, 2010).
(c) Complex task
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ess • Figure 10.10 (a) The general relationship between arousal and effi- ciency can be described by an inverted U curve. The optimal level of arousal or motivation is higher for a simple task (b) than for a complex task (c). Copyright © 2012 Wadsworth, Cengage
Learning, Inc.
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Chapter 10346
Relaxation Learning to relax is another way to lower test anxiety (Bradley et al., 2010; Powell, 2004). You can learn self-relaxation skills by look- ing at Chapter 13, where a relaxation technique is described. Emo- tional support also helps (Stöber, 2004). If you are test anxious, discuss the problem with your professors or study for tests with a supportive classmate.
Rehearsal To reduce nervousness, rehearse how you will cope with upsetting events. Before taking a test, imagine yourself going blank, running out of time, or feeling panicked. Then, calmly plan how you will handle each situation—by keeping your attention on the task, by focusing on one question at a time, and so forth (Watson & Tharp, 2007).
Restructuring Thoughts Another helpful strategy involves listing the upsetting thoughts you have during exams. Then you can learn to combat these wor- ries with calming, rational replies ( Jones & Petruzzi, 1995; Olpin & Hesson, 2010). (These are called coping statements; see Chap- ter 13 for more information.) Let’s say you think, “I’m going to fail this test and everybody will think I’m stupid.” A good reply to this upsetting thought would be to say, “If I prepare well and control my worries, I will probably pass the test. Even if I don’t, it won’t be the end of the world. My friends will still like me, and I can try to improve on the next test.”
Students who cope well with exams usually try to do the best they can, even under difficult circumstances. Becoming a more confident test taker can actually increase your scores because it helps you remain calm. With practice, most people can learn to be less testy at test-taking time.
Learned Motives—The Pursuit of Excellence
Gateway Questions 10.5: What are learned and social motives and why are they important? Many motives are acquired directly. It is easy enough to see that praise, money, success, pleasure, and similar reinforcers affect our goals and desires. But how do people learn to enjoy activities that are at first painful or frightening? Why do people climb rocks, jump out of airplanes, run marathons, take saunas, or swim in fro- zen lakes? For an answer, let’s examine a related situation.
When a person first tries a drug such as heroin, he or she feels a “rush” of pleasure. However, as the drug wears off, discomfort and craving occurs. The easiest way to end the discomfort is to take another dose—as most drug users quickly learn. But in time, habitu- ation takes place; the drug stops producing pleasure, although it will end discomfort. At the same time, the after effects of the drug grow more painful. At this point, the drug user has acquired a powerful new motive. In a vicious cycle, heroin relieves discomfort, but it guarantees that withdrawal will occur again in a few hours.
Opponent-Process Theory Psychologist Richard L. Solomon (1980) offers an intriguing expla- nation for drug addiction and other learned motives. According to his opponent-process theory, if a stimulus causes a strong emotion, such as fear or pleasure, an opposite emotion tends to occur when the stimulus ends. For example, if you are in pain and the pain ends, you will feel a pleasant sense of relief. If a person feels pleasure, as in the case of drug use, and the pleasure ends, it will be followed by craving or discomfort (Vargas-Perez, Ting-A-Kee, & van der Kooy, 2009). If you are in love and feel good when you are with your lover, you will be uncomfortable when she or he is absent.
What happens if the stimulus is repeated? Solomon assumes that when a stimulus is repeated, our response to it habituates, or gets weaker. Like almost every first-timer, our intrepid extreme skydiver Henry (who we met in Chapter 1) was terrified during his first jump. But with repeated jumps, fear decreases, until finally the sky- diver feels a “thrill” instead of terror (Roth et al., 1996). In contrast, emotional after effects get stronger with repetition. After a first jump, beginners feel a brief but exhilarating sense of relief. After many such experiences, seasoned skydivers, like Henry, can get a “rush” of euphoria that lasts for hours after a jump. With repetition, the pleasurable after effect gets stronger and the initial “cost” (pain or fear) gets weaker. The opponent-process theory thus explains how skydiving, rock climbing, ski jumping, and other hazardous pursuits become reinforcing. If you are a fan of horror movies, car- nival rides, or bungee jumping, your motives may be based on the same effect. (Notice, too, the strong link between motivation and emotion in such examples. We will return to this idea later.)
Social Motives Some of your friends are more interested than others in success, achievement, competition, money, possessions, status, love, approval, grades, dominance, power, or belonging to groups—all of which are social motives or goals. We acquire social motives in complex ways, through socialization and cultural conditioning (Deckers, 2010). The behavior of outstanding artists, scientists, athletes, educators, and leaders is best understood in terms of such learned needs, particularly the need for achievement.
The Need for Achievement To many people, being “motivated” means, like Lady Gaga, being interested in achievement (Wigfield & Eccles, 2002). In a later chapter, we will investigate aggression, helping, affiliation, seeking approval, and other social motives. For now, let’s focus on the need for achievement (nAch), which is a desire to meet an internal standard of excellence (McClelland, 1961). People with a high need for achievement strive to do well any time they are evaluated (Steinmayr & Spinath, 2009).
Is that like the aggressive businessperson who strives for success? Not necessarily. Needs for achievement may lead to wealth and prestige, but people who are high achievers in art, music, sci- ence, or amateur sports may excel without seeking riches. Such people typically enjoy challenges and relish a chance to test their
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Motivation and Emotion 347
Opponent-process theory States that strong emotions tend to be followed by an opposite emotional state; also the strength of both emotional states changes over time.
Social motives Learned motives acquired as part of growing up in a particular society or culture.
Need for achievement (nAch) The desire to excel or meet some internalized standard of excellence.
Need for power The desire to have social impact and control over others.
abilities (Puca & Schmalt, 1999). (See “True Grit” for more information about the characteristics of people high in achieve- ment motivation.)
Power The need for achievement differs from the need for power, which is a desire to have impact or control over others (McClel- land, 1975; Wirth, Welsh, & Schultheiss, 2006). People with strong needs for power want their importance to be visible: They buy expensive possessions, wear prestigious clothes, and exploit relationships. In some ways the pursuit of power and financial success is the dark side of the American dream. People whose main goal in life is to make lots of money tend to be poorly adjusted and unhappy (Kasser & Ryan, 1993).
The Key to Success? Psychologist Benjamin Bloom (1985) found that the first steps toward high achievement begin when parents expose their children to music, swimming, scientific ideas, and so forth, “just for fun.” At first, many of the children had very ordinary skills. One Olympic
True GritDiscovering Psychology
So you want to be a success. To best achieve your goals, would it be better to be naturally talented or determined? (Yes, we know you would definitely prefer to have it both ways. So would we.) It probably will not surprise you to learn that, in general, drive and determination, not great natural talent, lead to exceptional success (Bloom, 1985; Duckworth et al., 2007).
How can this be? When people high in need for achievement (nAch) tackle a task, they do so with perseverance, passion, and self-confidence (Duckworth et al., 2007; Munroe-Chandler, Hall, & Fishburne, 2008).
They tend to complete difficult tasks, they earn better grades, and they tend to excel in their occupations. College students high in nAch attribute success to their own ability, and failure to insufficient effort. Thus, high nAch students are more likely to renew their efforts when they perform poorly. When the going gets tough, high achievers get going.
How self-confident are you? Achieving elite performance may be reserved for the dedicated few. Nevertheless, like elite ath- letes, you may be able to improve your moti- vation by increasing your self-confidence (Hanton, Mellalieu, & Hall, 2004). It is easier to
perform an activity or reach a goal with per- severance and passion when you believe you can be successful.
When you tackle an important task, how many of the items on the following list can you check off? To enhance self-confidence, you would be wise to do as many as possible (Druckman & Bjork, 1994; Munroe-Chandler, Hall, & Fishburne, 2008):
• Set goals that are specific and challeng- ing but attainable.
• Visualize the steps you need to take to reach your goal.
• Advance in small steps. • When you first acquire a skill, your goal
should be to make progress in learning. Later, you can concentrate on improving your performance compared with other people.
• Get expert instruction that helps you master the skill.
• Find a skilled model (someone good at the skill) to emulate.
• Get support and encouragement from an observer.
• If you fail, regard it as a sign that you need to try harder, not that you lack ability.
Self-confidence affects motivation by in- fluencing the challenges you will undertake, the effort you will make, and how long you will persist when things don’t go well. You can be confident that self-confidence is worth cultivating.
The Williams sisters possess high achievement motivation. They have become professional tennis champions by playing with perseverance, passion, and self-confidence.
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