Invitation to Psychology - Chapter 5 - Body Rhythms and Mental States PDF

Psychology in the News Measure to Legalize Marijuana since 1996, and in January, a new law will change pos- session of less than an ounce from a criminal misde- Fails in California...

Psychology in the News Measure to Legalize Marijuana since 1996, and in January, a new law will change pos- session of less than an ounce from a criminal misde- Fails in California meanor to a civil infraction. But California law conflicts LOS ANGELES, November 3, 2010. An initiative to with federal law, and within the state, attitudes and poli- make California the first state to legalize small amounts cies often clash. Some cities permit pot clubs, some cur- of marijuana for recreational use failed yesterday at the rently have moratoriums in effect until they can come up polls. The vote was 54 percent opposed to legalization with regulations, and some prohibit them outright. versus 46 percent in favor. In San Diego, the District Attorney’s office consid- The initiative, Proposition 19, would have allowed ers marijuana for any use to be illegal, yet a jury there anyone 21 or older to possess up to an ounce of mari- recently acquitted a Navy veteran who was operating a juana and to grow plants in an area up to 25 square medical-marijuana dispensary. In Los Angeles, the law feet, so long as the drug was for personal use. In addi- caps the number of dispensaries at 70 and exempts an- tion, cities and counties would have been able to pass other 100 that were in existence as of 2007, but now laws allowing the production and sale of marijuana and bans the more than 800 dispensaries established after to tax profits on it. Most law enforcement groups, many that. clergy, the California League of Cities, and Mothers Against Drunk Driving opposed the measure. The California Young De- mocrats, the Republican Liberty Caucus, the California Council of Churches, some law enforcement officials, and several large labor unions supported it. Despite the measure’s defeat, Richard Lee, the wheelchair-bound medical-marijuana millionaire who largely bankrolled the measure, called the effort a “tremendous moral victory” because millions of Californians voted for it. Lee, who was paralyzed from the waist down after an accident in 1990, owns sev- eral medicinal- marijuana businesses in Oakland. He says that after his ac- cident, marijuana helped control his severe back spasms. His successful dispensaries have contributed to the revival of part of downtown Oakland. At a cannabis buyers cooperative in Oakland, California, customer Ken Estes chooses a The use of pot for medical pur- marijuana muffin. Estes has been a quadriplegic for 22 years, due to a motorcycle poses has been legal in California accident.  CHAPTER Biological Rhythms: The Tides The Riddle of Hypnosis Taking Psychology with You: of Experience How to Get a Good Night’s Consciousness-Altering Drugs Sleep The Rhythms of Sleep Psychology in the News, Exploring the Dream World Revisited Body Rhythms and Mental States C alifornians, who years ago voted to permit the use of marijuana for med- ical reasons, still prefer to keep its recreational use illegal. Whether the drug is legal or illegal, however, many people will continue to use mari- juana and others will continue to try to prohibit it. Marijuana is just one of many drugs used throughout the world to alter consciousness, our awareness of ourselves and the environment. But conscious- ness also changes in predictable ways without any help from drugs. Each day, we all experience swings in mood, alertness, and efficiency. Each night, we all undergo a dramatic shift in consciousness when the ordinary rules of logic are suspended in the dream world of sleep. And performance and mood may be sub- ject to much longer cycles as well, stretching over a month or even a season. In this chapter, we will see that fluctuations in subjective experience are accompanied by ups and downs in brain activity and hormone levels, and that the mental and physical aspects of consciousness are as intertwined as sunshine and shadow. We will begin with a discussion of the body’s natural rhythms, which ebb and flow over time. Next we will zoom in on one fascinating state of conscious- ness: dreaming. And then we will explore what psychologists have learned about two techniques used to alter consciousness deliberately: hypnosis and the use of recreational drugs. Our goal is to give you a better understanding of the human fascination with altered states of consciousness and why some people use drugs to achieve them. Are all drugs equally dangerous? Should there be different policies for med- ical, recreational, and religious use? Are current drug laws realistic? We will return to these issues at the end of the chapter. 147 148 CHAPTER 5 Body Rhythms and Mental States YOU are about to learn... more frequently than once a day, many of them on about a 90-minute cycle. These include physiologi- how biological rhythms affect our physiology and cal changes during sleep and (unless social customs performance. intervene) stomach contractions, hormone levels, susceptibility to visual illusions, verbal and spatial why you feel out of sync when you fly across time zones or change shifts at work. performance, brain-wave responses during cogni- tive tasks, and daydreaming (Escera, Cilveti, & why some people get the winter blues. Grau, 1992; Klein & Armitage, 1979; Kripke, 1974; how culture and learning affect reports of PMS and Lavie, 1976). estimates of its incidence. With a better understanding of our internal tempos, we may be able to design our days to take better advantage of our bodies’ natural tempos. Biological Rhythms: The Tides of Experience Circadian Rhythms Do an Internet search on “biorhythm charts,” and Circadian rhythms exist in plants, animals, insects, you’ll get hundreds of sites advertising them. Such and human beings. They reflect the adaptation of charts supposedly foretell daily fluctuations in organisms to the many changes associated with the mood, alertness, and physical performance over rotation of the earth on its axis, such as changes in your entire lifetime, solely on the basis of when you light, air pressure, and temperature. were born. They even warn you about days when In most societies, clocks and other external you will be susceptible to accidents, errors, and ill- time cues abound, and people’s circadian rhythms ness. But you can save your money: Whenever re- become tied to them, following a strict 24-hour Listen to searchers have taken the trouble to test such claims schedule. Therefore, to identify endogenous Brain Time on scientifically, they have found biorhythm charts to rhythms, scientists must isolate volunteers from mypsychlab.com be utterly useless (Hines, 1998). sunlight, clocks, environmental sounds, and all It is true, however, that the human body goes other cues to time. Some hardy souls have spent through dozens of ups and downs in physiological weeks isolated in underground caves; usually, how- functioning over the course of a day, a week, a year, ever, researchers have people live in specially de- biological rhythms changes that are known as biological rhythms. A signed rooms equipped with audio systems, Periodic, more or less reg- biological clock in our brains governs the waxing comfortable furniture, and temperature controls. ular fluctuations in a bio- and waning of hormone levels, urine volume, blood logical system; they may When participants in these studies have been pressure, and even the responsiveness of brain cells allowed to sleep, eat, and work whenever they or may not have psycho- to stimulation. Biological rhythms are typically in logical implications. wished, free of the tyranny of the timepiece, a few tune with external time cues, such as changes in have lived a “day” that is much shorter or longer clock time, temperature, and daylight, but many than 24 hours. If allowed to take daytime naps, rhythms continue to occur even in the absence of however, most people soon settle into a day that av- endogenous Generated from within rather than by such cues; they are endogenous, or generated from erages about 24.3 hours (Moore, 1997). And when external cues. within. people are put on an artificial 28-hour day, in an Circadian rhythms are biological rhythms that environment free of all time cues, their body tem- circadian [sur-CAY- occur approximately every 24 hours. The best- perature and hormone levels follow a cycle that is dee-un] rhythms known circadian rhythm is the sleep–wake cycle, very close to 24 hours—24.18 hours, to be precise Biological rhythms with a but hundreds of others affect physiology and per- (Czeisler et al., 1999). These rhythms are remark- period (from peak to peak formance. For example, body temperature fluctu- ably similar in length from one person to the next. or trough to trough) of ates about 1 degree centigrade each day, peaking, about 24 hours; from the For many people, alertness, like temperature, peaks on average, in the late afternoon and hitting a low in the late afternoon and falls to a low point in the Latin circa, “about,” and point, or trough, in the wee hours of the morning. dies, “a day.” very early morning (Lavie, 2001). Listen Other rhythms occur less frequently than once a day—say, once a month, or once a season. In the suprachiasmatic [soo- pruh-kye-az-MAT-ick] animal world, seasonal rhythms are common. Birds The Body’s Clock Circadian rhythms are con- nucleus (SCN) An area migrate south in the fall, bears hibernate in the trolled by a biological clock, or overall coordinator, of the brain containing a winter, and marine animals become active or inac- located in a tiny cluster of cells in the hypothalamus biological clock that tive, depending on bimonthly changes in the tides. called the suprachiasmatic nucleus (SCN). Neural governs circadian In human beings, the female menstrual cycle occurs pathways from special receptors in the back of the rhythms. every 28 days on average. And some rhythms occur eye transmit information to the SCN and allow it  CHAPTER 5 Body Rhythms and Mental States 149 Stefania Follini (left) spent four months in a New Mexico cave (above), 30 feet under- ground, as part of an Italian study on biological rhythms. Her only companions were a computer and two friendly mice. In the absence of clocks, natural light, or changes in temperature, she tended to stay awake for 20 to 25 hours and then sleep for 10. Because her days were longer than usual, when she emerged, she thought she had been in the cave for only two months. to respond to changes in light and dark. The SCN When the Clock Is Out of Sync Under nor- then sends out messages that cause the brain and mal conditions, the rhythms governed by the SCN body to adapt to these changes. Other clocks also are in phase with one another. Their peaks may exist, scattered around the body, but for most circa- occur at different times, but if you know when one dian rhythms, the SCN is regarded as the master rhythm peaks, you can predict fairly well when an- melatonin A hormone pacemaker. secreted by the pineal other will. It is a little like knowing the time in gland; it is involved in the The SCN regulates fluctuating levels of hor- London if you know the time in New York. But regulation of circadian mones and neurotransmitters, and they in turn pro- when your normal routine changes, your circadian rhythms. vide feedback that affects the SCN’s functioning. rhythms may be thrown out of phase. Such internal During the dark hours, one hormone regulated by desynchronization often occurs when people take internal desynchro- the SCN, melatonin, is secreted by the pineal gland, airplane flights across several time zones. Sleep nization A state in which deep within the brain. Melatonin induces sleep. and wake patterns usually adjust quickly, but biological rhythms are not When you go to bed in a darkened room, your temperature and hormone cycles can take several in phase with one another. melatonin level rises; when light fills your room in the morning, it falls. Melatonin, in turn, appears to help keep the biological clock in phase with the light–dark cycle (Haimov & Lavie, 1996; Lewy et al., 1992). Regulates Neurotransmitters, SCN hormones (e.g., melatonin) Feedback Melatonin treatments have been used to regu- late the disturbed sleep–wake cycles of blind people who lack light perception and whose melatonin production does not cycle normally (Sack & Lewy, 1997). Travel can be exhausting, and jet lag makes it worse. 150 CHAPTER 5 Body Rhythms and Mental States melatonin, drugs, or other techniques to “reset the clock” (Revell & Eastman, 2005), but so far these techniques do not seem ready for prime time. A com- prehensive government-sponsored review of mela- tonin research, which took the quality of the research into account, found little or no support for mela- tonin’s effectiveness in treating shift-work desyn- chronization (or for ordinary insomnia and sleep disturbances associated with jet lag) (Buscemi et al., 2004). The best approach at present is to follow cir- cadian principles by switching workers from one shift to another as infrequently as possible. One reason that a simple cure for desynchro- nization has so far eluded scientists is that circadian rhythms are not perfectly regular in daily life. They can be affected by illness, stress, fatigue, excite- ment, exercise, drugs, mealtimes, and ordinary daily experiences. In research with mice, these rhythms have even been influenced by diet. Mice usually sleep during the day, but putting them on a high-fat diet altered the activity of genes involved in appetite and metabolism, and the mice began waking up and eating during the day (Kohsaka et al., 2007). days to return to normal. The resulting jet lag Further, circadian rhythms can differ greatly affects energy level, mental skills, and motor from individual to individual because of genetic dif- coordination. ferences. A variation in a single gene seems to be Internal desynchronization also occurs when the reason that some people are early birds, bounc- workers must adjust to a new shift. Efficiency ing out of bed at the crack of dawn, whereas others drops, the person feels tired and irritable, accidents are night owls who do their best work late at night become more likely, and sleep disturbances and di- and can’t be pried out of bed until noon (Archer gestive disorders may occur. For police officers, et al., 2003). (Schools are not designed to accom- emergency room personnel, airline pilots, truck modate night owls.) You may be able to learn about drivers, and operators of nuclear power plants, the your own personal pulses through careful self- consequences can be a matter of life and death. observation, and you may want to try putting that Night work itself is not necessarily a problem: With information to use when planning your daily a schedule that always stays the same, even on schedule. weekends, people often adapt. However, many swing- and night-shift assignments are made on a rotating basis, so a worker’s circadian rhythms Moods and Long-Term Rhythms never have a chance to resynchronize. According to Ecclesiastes, “To every thing there is a Some scientists hope eventually to help rotating- season, and a time for every purpose under shift workers adjust more quickly by using heaven.” Modern science agrees: Long-term cycles Get Involved! Measuring Your Alertness Cycles For at least three days, except when you are sleeping, keep an hourly record of your mental alertness level, using this five-point scale: 1 ⫽ extremely drowsy or mentally lethargic, 2 ⫽ somewhat drowsy or mentally lethargic, 3 ⫽ moderately alert, 4 ⫽ alert and efficient, 5 ⫽ extremely alert and efficient. Does your alert- ness level appear to follow a circadian rhythm, reaching a high point and a low point once every 24 hours? Or does it follow a shorter rhythm, rising and falling several times during the day? Are your cycles the same on weekends as during the week? Most important, how well does your schedule mesh with your natural fluctuations in alertness?  CHAPTER 5 Body Rhythms and Mental States 151 have been observed in everything from the thresh- old for tooth pain to conception rates. Folklore holds that our moods follow similar rhythms, par- ticularly in response to seasonal changes and, in women, menstrual changes. But do they? Does the Season Affect Moods? Clinicians report that some people become depressed during particular seasons, typically winter, when periods of daylight are short. This pattern of depression has come to be known as seasonal affective disorder (SAD) (Rosenthal, 2006). During the winter months, patients with SAD report feelings of sad- ness, lethargy, drowsiness, and a craving for carbo- These young Norwegian women are receiving light therapy for seasonal affective disorder (SAD). This type of treat- hydrates. To counteract the effects of sunless days, ment has become popular and appears to be effective. physicians and therapists often treat them with But fewer people actually have SAD than is commonly phototherapy, having them sit in front of bright flu- thought, and the causes remain uncertain. orescent lights at specific times of the day, usually early in the morning. Some physicians also pre- scribe antidepressants. quickly as other people’s. However, it is not clear Some therapists, generalizing from clinical why light therapy also appears to help some people cases of patients who report symptoms of SAD, be- with nonseasonal depression. True cases of SAD lieve the disorder may affect as much as 20 percent may have a biological basis, but if so, the mecha- of the population, but this estimate is highly exag- nism remains unclear. Keep in mind, too, that many gerated. A national survey estimated the lifetime people get the winter blues because they hate cold prevalence of major seasonal depression in the weather, are physically inactive, do not get outside United States at only 0.4 percent, and the preva- much, or feel lonely during the winter holidays. lence of major or minor seasonal depression at only 1 percent (Blazer, Kessler, & Swartz, 1998). Other Does the Menstrual Cycle Affect Moods? estimates vary from about 1 to 9 percent, with the Controversy has persisted about another long-term higher estimates usually associated with greater dis- rhythm, the female menstrual cycle, which occurs, tance from the equator. on average, every 28 days. During the first half of As for the effectiveness of light treatments, this cycle, an increase in the hormone estrogen much of the research on this question has been causes the lining of the uterus to thicken in prepa- flawed. A review of 173 light-treatment studies ration for a possible pregnancy. At mid-cycle, the published between 1975 and 2003 found that only ovaries release a mature egg, or ovum. Afterward, 20 studies—12 percent of the total—had used an the ovarian sac that contained the egg begins to acceptable design and suitable controls (Golden produce progesterone, which helps prepare the et al., 2005). But a meta-analysis of the data from uterine lining to receive the egg. Then, if concep- those 20 studies did throw some light on the sub- tion does not occur, estrogen and progesterone lev- ject, so to speak. When people with SAD were ex- els fall, the uterine lining sloughs off as the posed to either a brief period (e.g., 30 minutes) of menstrual flow, and the cycle begins again. The in- bright light after waking or to light that slowly be- teresting question for psychologists is whether came brighter, simulating the dawn, their symp- these physical changes cause emotional or intellec- toms were in fact reduced. Light therapy even tual changes, as folklore and tradition would have helped people with mild to moderate nonseasonal us believe. depression (see also Wirz-Justice et al., 2005). Most people are surprised to learn that it was Many researchers believe that the circadian not until the 1970s that a vague cluster of physical seasonal affective dis- rhythms of patients with SAD are out of sync— and emotional symptoms associated with the days order (SAD) A contro- that, in essence, the individuals have a chronic form preceding menstruation—including fatigue, versial disorder in which of jet lag (Lewy et al., 2006). Others argue that they headache, irritability, and depression—was pack- a person experiences must have some abnormality in the way they pro- aged together and given a label: premenstrual depression during the duce or respond to melatonin (Wehr et al., 2001). syndrome (“PMS”) (Parlee, 1994). Since then, most winter and an improve- They may produce too much daytime melatonin in laypeople, doctors, and psychiatrists have assumed, ment of mood in the the winter, or their morning levels may not fall as uncritically, that many women “suffer” from PMS spring. 152 CHAPTER 5 Body Rhythms and Mental States at other times of the month to a stressful day or a low grade on an English paper (“No wonder I’m ir- ritable and cranky; I worked really hard on that paper and only got a C”). Some studies have en- couraged biases in the reporting of premenstrual and menstrual symptoms by using questionnaires with gloomy titles such as “Menstrual Distress Questionnaire.” To get around these problems, some psycholo- gists have polled women about their psychological and physical well-being without revealing the true purpose of the study (e.g., AuBuchon & Calhoun, Many women say they become more irritable or depressed 1985; Chrisler, 2000; Englander-Golden, Whitmore, premenstrually, and PMS remedies line the shelves of & Dienstbier, 1978; Gallant et al., 1991; Hardie, drugstores. But what does the evidence show about this so-called syndrome? How might attitudes and expecta- 1997; Parlee, 1982; Rapkin, Chang, & Reading, tions affect reports of emotional symptoms? What hap- 1988; Slade, 1984; Vila & Beech, 1980; Walker, pens when women report their daily moods and feelings to 1994). Using double-blind procedures, they have had researchers without knowing that menstruation is being women report symptoms for a single day and have studied? then gone back to see what phase of the menstrual cycle the women were in; or they have had women or from its supposedly more extreme and debilitat- keep daily records over an extended period of time. ing version, “premenstrual dysphoric disorder” Some studies have also included a control (PMDD). What does the evidence actually show? group that is usually excluded from research on “PMS” symptoms have been reported most hormones and moods: men. In one such study, men often in North America, western Europe, and and women filled out a symptom questionnaire that Australia. In most tribal cultures, PMS has been made no mention of menstruation (Callaghan et al., virtually unknown; the concern has been with 2009). The proportion of men who met the criteria menstruation itself, which is often considered “un- for PMDD, the more extreme version of “PMS,” clean.” In other cultures, women report physical did not differ significantly from the proportion of symptoms but not emotional symptoms: For exam- women who did so! ple, during the 1990s, research found that women In another study, researchers examined in China reported fatigue, water retention, pain, changes in the pleasantness, arousal level, and sta- and cold (American women rarely report cold), but bility of moods over time by having 15 women on not depression or irritability (Yu et al., 1996). Many women do have physical symptoms asso- © The New Yorker Collection 1999 William Haefeli from cartoonbank.com. ciated with menstruation, including cramps, breast tenderness, and water retention, although women vary tremendously in this regard. And, of course, these physical symptoms can make some women feel grumpy or unhappy, just as pain can make men feel grumpy or unhappy. But emotional symptoms associated with menstruation—notably, irritability and depression—are pretty rare, which is why we put “PMS” in quotation marks. In reality, fewer than 5 percent of all women have such symptoms predictably over their cycles (Brooks-Gunn, 1986; Reid, 1991; Walker, 1994). All Rights Reserved. Then why do so many women think they have it? One possibility is that they tend to notice feel- ings of depression or irritability when these moods happen to occur premenstrually but overlook times when such moods are absent premenstrually. Or they may label symptoms that occur before a period “You’ve been charged with driving under as PMS (“I am irritable and cranky; I must be get- the influence of testosterone.” ting my period”) and attribute the same symptoms For both sexes, the hormonal excuse rarely applies.  CHAPTER 5 Body Rhythms and Mental States 153 birth control pills, 12 normally cycling women, and 7 15 men rate their moods every day for 70 days (McFarlane, Martin, & Williams, 1988). None of the participants knew that the study had anything to do with menstruation; they thought it was a straightforward study of mood and health. After the 6 positive 70 days were up, the women then recalled their Mood pleasantness ratings average moods for each week and phase of their menstrual cycle. In their daily reports, normally cycling women reported more pleasant moods than the other participants during the menstrual phase neutral and the follicular phase (when an egg is forming). 5 But there were no differences at all during the pre- menstrual phase. In fact, women’s moods fluctuated less over the menstrual cycle than over days of the Women’s negative week. Mondays, it seems, are tough for most of us. daily reports Moreover, women and men did not differ signifi- 4 Women’s cantly in their emotional symptoms or the number retrospective of mood swings they reported at any time of the reports month, as you can see in Figure 5.1. In their retro- Men’s daily spective reports, however, women recalled feeling reports more angry, irritable, and depressed in the premen- Menstrual Ovulatory Premenstrual strual and menstrual phases than they had reported Menstrual phase in their daily journals. Other investigations have confirmed that FIGURE 5.1 most women do not have typical PMS symptoms Mood Changes in Men and Women even when they firmly believe that they do In a study that challenged popular stereotypes about “PMS,” college women and men (Hardie, 1997; McFarlane & Williams, 1994). For recorded their moods daily for 70 days without knowing the purpose of the study. At the example, women often say they cry more premen- end of the study, the women thought their moods had been more negative premenstru- ally than during the rest of the month (green line), but their daily diaries showed other- strually than at other times, but an interesting wise (purple line). Both sexes experienced only moderate mood changes, and there were Dutch study had women keep “crying diaries” and no significant differences between women and men at any time of the month found no association at all between crying and (McFarlane, Martin, & Williams, 1988). phase of the menstrual cycle (van Tilburg, Becht, & Vingerhoets, 2003). The key question in all this is whether premen- them—and it doesn’t matter whether the women strual symptoms of any kind affect women’s ability are premenstrual, menstrual, postmenstrual, or to work, think, study, do brain surgery, run for of- nonmenstrual (Hardie, 1997). fice, or run a business. In the laboratory, some re- With the rise of globalization, the exporting of searchers have found that women tend to be faster American media, and the influence of drug market- on tasks such as reciting words quickly or sorting ing worldwide, PMS symptoms are now increasing objects manually before and after ovulation, when in cultures where previously there were no reports their estrogen is high (e.g., Saucier & Kimura, of them—from Mexico (Marvan et al., 1998) to 1998). But empirical research has failed to establish Saudi Arabia (Rasheed & Al-Sowielem, 2003). The any connection between phase of the menstrual belief that PMS is universal, along with promotion cycle and work efficiency, problem solving, college of products to treat it, makes it more probable that exam scores, creativity, or any other behavior that women will interpret their premenstrual moods matters in real life (Golub, 1992; Richardson, and symptoms as part of a syndrome that requires 1992). In a British study, female college students medicating. said that PMS interfered with their academic work, In sum, the body only provides the clay for our but the researchers could find no association be- symptoms and feelings. Learning and culture mold tween the number of symptoms reported by the that clay by teaching us which symptoms are im- students and their actual grades and test scores portant or worrisome and which are not. Whether (Earl-Novell & Jessop, 2005). In the workplace, we are male or female, the impact of most of the men and women report similar levels of stress, well- changes associated with our biological rhythms de- being, and ability to do the work required of pends on how we interpret and respond to them. 154 CHAPTER 5 Body Rhythms and Mental States Study and Review on mypsychlab.com Quick Quiz There are no hormonal excuses for avoiding this quiz. 1. The functioning of the biological clock governing circadian rhythms is affected by the hormone. 2. Jet lag occurs because of. 3. For most women, the days before menstruation are reliably associated with (a) depression, (b) irritability, (c) elation, (d) creativity, (e) none of these, (f) a and b. 4. A researcher tells male subjects that testosterone usually peaks in the morning and that it probably causes hostility. She then asks them to fill out a “HyperTestosterone Syndrome Hostility Survey” in the morning and again at night. Based on your knowledge of menstrual cycle findings, what do you think her study will reveal? How could she improve her study? Answers: biased. A more neutral title, such as “Health and Mood Checklist,” would be better. could be added to see whether their hostility levels vary in the same way that men’s do. Finally, the title on that questionnaire is pretty actual hormone levels at different points in the day, because individuals vary in their biological rhythms. Also, a control group of women be biased to report more hostility in the morning. It would be better to keep them in the dark about the hypothesis and to measure their 1. melatonin 2. internal desynchronization 3. e 4. Because of the expectations that the men now have about testosterone, they may YOU are about to learn... did occur but they were rapid, not slow (Aserinsky & Kleitman, 1955). Using the electroencephalograph the stages of sleep. (EEG) to measure the brain’s electrical activity (see Chapter 4), these researchers, along with another of what happens when we go too long without enough sleep. Kleitman’s students, William Dement, were able to correlate the rapid eye movements with changes in how sleep disorders disrupt normal sleep. sleepers’ brain-wave patterns (Dement, 1992). Adult the mental benefits of sleep. volunteers were soon spending their nights sleeping in laboratories, while scientists measured changes in The Rhythms of Sleep their brain activity, muscle tension, breathing, and other physiological responses. Perhaps the most perplexing of all our biological As a result of this research, today we know that rhythms is the one governing sleep and wakeful- during sleep, periods of rapid eye movement (REM) ness. Sleep, after all, puts us at risk: Muscles that alternate with periods of fewer eye movements, or are usually ready to respond to danger relax, and non-REM (NREM) sleep, in a cycle that recurs every senses grow dull. As the British psychologist 90 minutes or so. The REM periods last from a few Christopher Evans (1984) once noted, “The behav- minutes to as long as an hour, averaging about 20 ior patterns involved in sleep are glaringly, almost minutes in length. Whenever they begin, the pat- insanely, at odds with common sense.” Then why is tern of electrical activity from the sleeper’s brain sleep such a profound necessity? changes to resemble that of alert wakefulness. Non- Simulate Stages of REM periods are themselves divided into distinct Sleep on The Realms of Sleep stages, each associated with a particular brain-wave mypsychlab.com pattern (see Figure 5.2). Simulate Let’s start with some of the changes that occur in the When you first climb into bed, close your eyes, brain during sleep. Until the early 1950s, little was and relax, your brain emits bursts of alpha waves. known about these changes. Then a breakthrough On an EEG recording, alpha waves have a regular, occurred in the laboratory of physiologist Nathaniel slow rhythm and high amplitude (height). Gradu- Kleitman, who at the time was the only person in ally, these waves slow down even further, and you the world who had spent his entire career studying drift into the Land of Nod, passing through four rapid eye movement sleep. Kleitman had given one of his graduate stu- stages, each deeper than the previous one: (REM) sleep Sleep peri- dents, Eugene Aserinsky, the tedious task of finding ods characterized by eye out whether the slow, rolling eye movements that Stage 1. Your brain waves become small and irreg- movement, loss of muscle characterize the onset of sleep continue throughout ular, and you feel yourself drifting on the edge tone, and vivid dreams. the night. To both men’s surprise, eye movements of consciousness, in a state of light sleep. If  CHAPTER 5 Body Rhythms and Mental States 155 awakened, you may recall fantasies or a few visual images. Awake Small, rapid Stage 2. Your brain emits occasional short bursts of rapid, high-peaking waves called sleep spindles. Minor noises probably won’t disturb you. Stage 1 Small, irregular Stage 3. In addition to the waves that are character- istic of Stage 2, your brain occasionally emits delta waves, very slow waves with very high peaks. Your breathing and pulse have slowed Stage 2 Sleep spindles down, your muscles are relaxed, and you are hard to waken. Stage 4. Delta waves have now largely taken over, and you are in deep sleep. It will probably take Stage 3 Delta waves appear vigorous shaking or a loud noise to awaken you. Oddly, though, if you walk in your sleep, this is when you are likely to do so. No one yet knows what causes sleepwalking, which occurs more often in children than adults, but it seems Stage 4 Mostly delta to involve unusual patterns of delta-wave activity (Bassetti et al., 2000). This sequence of stages takes about 30 to 45 minutes. Then you move back up the ladder from REM Rapid, somewhat irregular Stage 4 to 3 to 2 to 1. At that point, about 70 to 90 minutes after the onset of sleep, something peculiar happens. Stage 1 does not turn into drowsy wakeful- ness, as one might expect. Instead, your brain begins FIGURE 5.2 to emit long bursts of very rapid, somewhat irregular Brain-Wave Patterns During Wakefulness and Sleep waves. Your heart rate increases, your blood pressure Most types of brain waves are present throughout sleep, but different ones predominate at rises, and your breathing gets faster and more irreg- different stages. ular. Small twitches in your face and fingers may occur. In men, the penis may become somewhat the general population has experienced at least erect as vascular tissue relaxes and blood fills the one such episode, and about 5 percent have had genital area faster than it exits. In women, the clitoris a “waking dream” in this state. Their eyes are may enlarge and vaginal lubrication may increase. At open, but what they the same time, most skeletal muscles go limp, pre- “see” are dreamlike hal- Thinking Critically venting your aroused brain from producing physical lucinations, most often about Waking Dream movement. You have entered the realm of REM. Images shadowy figures. They Because the brain is extremely active while the may even “see” a ghost body is entirely inactive, REM sleep has also been or space alien sitting on their bed or hovering in a called “paradoxical sleep.” During these periods, hallway, a scary image that they would regard as per- vivid dreams are most likely to occur. People report fectly normal it if were part of a midnight nightmare. dreams when they are awakened from non-REM sleep, too; in one study, dream reports occurred 82 percent of the time when sleepers were awakened during REM sleep, but they also occurred 51 per- cent of the time when people were awakened during non-REM sleep (Foulkes, 1962). Non-REM dreams, however, tend to be shorter, less vivid, and more realistic than REM dreams, except in the hour or so before a person wakes up in the morning. Occasionally, as the sleeper wakes up, a curious phenomenon occurs. The person emerges from REM sleep before the muscle paralysis characteristic Because cats sleep up to 80 percent of the time, it is easy to catch them in the various of that stage has entirely disappeared, and becomes stages of slumber. A cat in non-REM sleep (left) remains upright, but during the REM aware of an inability to move. About 30 percent of phase (right), its muscles go limp and it flops onto its side. 156 CHAPTER 5 Body Rhythms and Mental States Instead of saying, “Ah! How interesting! I am having a waking dream!” some people interpret this experi- ence literally and come to believe they have been vis- ited by aliens or are being haunted by ghosts (Clancy, 2005; McNally, 2003). REM and non-REM sleep continue to alternate throughout the night. As the hours pass, Stages 3 and 4 tend to become shorter or even disappear and REM periods tend to get longer and closer together. This pattern may explain why you are likely to be dreaming when the alarm clock goes off in the morning. But the cycles are far from regular. An in- dividual may bounce directly from Stage 4 back to Stage 2 or go from REM to Stage 2 and then back to REM. Also, the time between REM and non-REM is highly variable, differing from person to person and also within any given individual. The reasons for REM sleep are still uncertain. If you wake people up every time they lapse into REM sleep, nothing dramatic will happen. When finally allowed to sleep normally, however, they will spend a longer time than usual in the REM phase, and it will be hard to rouse them. Electrical brain activity associated with REM may burst through into non-REM sleep and even into wakefulness, as if the person is making up for something he or she had been deprived of. Some researchers have proposed that this “something” is connected with dreaming, but that idea has problems. For one thing, in rare cases, brain-damaged patients have lost the capacity to dream, yet they continue to show the normal sleep stages, including REM (Bischof & Bassetti, 2004). Moreover, although nearly all mammals experience REM sleep—the only known exceptions are the bottlenose dolphin and the porpoise—it seems un- likely that rats and anteaters have the cognitive abilities required to construct dreams. Moles, which can hardly move their eyes at all, nonetheless show EEG patterns associated with REM sleep. As William Domhoff, a prominent dream researcher, told us, “no one, but no one, has been able to come up with a convincing explanation for REM sleep.” Why We Sleep A leading sleep scientist, Jerome Siegel (2009), observes that sleep falls along a continuum of states that range from one extreme, hibernation (bears, bats, and many rodents), to continuous activity for Whatever your age, sometimes the urge to sleep is irre- significant lengths of time (birds don’t sleep while sistible, especially because in fast-paced modern soci- they are migrating, walruses may stop sleeping for eties, many people do not get as much sleep as they need. days at a time, and whale mothers and their calves Late hours or inadequate sleep won’t do anything for your remain awake for several weeks after birth). The grade point average. Daytime drowsiness can interfere reason for this variation in sleep patterns, he with reaction time, concentration, and the ability to learn.  CHAPTER 5 Body Rhythms and Mental States 157 argues, has to do with which strategy is beneficial times a night, often without the person knowing it. sleep apnea A disorder for the species. Lions sleep long and deeply, Sleep apnea is seen most often in older males and in which breathing briefly whereas their favorite prey, giraffes, have one of the overweight people but also occurs in others. It has stops during sleep, caus- lowest recorded sleep durations—giraffes had bet- several causes, from blockage of air passages to fail- ing the person to choke and gasp and momentarily ter not sleep deeply if they are going to survive! ure of the brain to control respiration correctly. awaken. Among species that do sleep, such as human Over time it can cause high blood pressure and ir- beings, sleep increases efficiency, for example by regular heartbeat; it may gradually erode a person’s narcolepsy A sleep dis- decreasing muscle tone and brain and body metab- health, and is associated with a shortened life ex- order involving sudden olism during periods of inactivity. This process, pectancy (Young et al., 2008). and unpredictable day- says Siegel (2009), is “analogous to turning out the With narcolepsy, an even more serious disorder time attacks of sleepiness lights when you leave a room.” Sleep provides a that often develops in the teenage years, an individual or lapses into REM sleep. time-out period, so that the body can eliminate is subject to irresistible and unpredictable daytime at- waste products from muscles, repair cells, conserve tacks of sleepiness lasting from 5 to 30 minutes. REM behavior disorder or replenish energy stores, strengthen the immune When the person lapses into sleep, he or she is likely A disorder in which the system, and recover abilities lost during the day. to fall immediately into the REM stage. A quarter of muscle paralysis that nor- When we do not get enough sleep, our bodies op- a million people in the United States suffer from this mally occurs during REM sleep is absent or incom- erate abnormally. Although most people can still condition, many, again, without knowing it. Nar- plete, and the sleeper is get along reasonably well after a day or two of colepsy seems to be caused by the degeneration of able to act out his or her sleeplessness, sleep deprivation that lasts for four neurons in the hypothalamus, possibly due to an au- dreams. days or longer becomes uncomfortable and soon toimmune malfunction or genetic abnormalities becomes unbearable. (This is why forced sleepless- (Lin, Hungs, & Mignot, 2001; Mieda et al., 2004). ness is an especially cruel weapon of torturers.) Other disorders also disrupt sleep, including some that cause odd or dangerous behavior. In REM behavior disorder, the muscle paralysis associated The Mental Consequences of Sleepless- with REM sleep does not occur, and the sleeper ness Sleep is also necessary for normal mental (most often an older male) becomes physically ac- functioning. Chronic sleep deprivation increases tive, often acting out a dream without any awareness levels of the stress hormone cortisol, which may of what he is doing (Schenck & Mahowald, 2002). If damage or impair brain cells that are necessary for he is dreaming about football, he may try to “tackle” learning and memory (Leproult, Copinschi et al., a piece of furniture; if he is dreaming about a kitten, 1997). Also, new brain cells may either fail to de- he may try to pet it. Other people may consider this velop or may mature abnormally (Guzman-Marin disorder amusing, but it is no joke. Sufferers may et al., 2005). Perhaps in part because of such dam- hurt themselves or others, and they have an in- age, after the loss of even a single night’s sleep, creased risk of later developing Parkinson’s disease mental flexibility, attention, and creativity all suffer. and dementia (Postuma et al., 2008). After several days of staying awake, people may However, the most common cause of daytime even begin to have hallucinations and delusions sleepiness is the most obvious one—not getting (Dement, 1978). enough sleep. Some people do fine on relatively Of course, sleep deprivation rarely reaches that few hours, but most adults need more than six point, but people do frequently suffer from milder hours and many adolescents need ten hours for sleep problems. According to the National Sleep optimal performance. The National Transporta- Foundation, about 10 percent of adults are plagued tion Safety Board estimates that drowsiness is by difficulty in falling or staying asleep. The causes of their insomnia include worry and anxiety, psy- from cartoonbank.com. All Rights Reserved. © The New Yorker Collection, 1990, Koren, chological problems, physical problems such as arthritis, and irregular or overly demanding work and study schedules. In addition, many drugs inter- fere with the normal progression of sleep stages— not just the ones containing caffeine, but also alcohol and some tranquilizers. The result can be grogginess and lethargy the next day. Another cause of daytime sleepiness is sleep apnea, a disorder in which breathing periodically stops for a few moments, causing the person to choke and gasp. Breathing may cease hundreds of “Judith is someone who needs her sleep.” 158 CHAPTER 5 Body Rhythms and Mental States consolidation The involved in 100,000 vehicle accidents a year, caus- their usual business (Jenkins & Dallenbach, 1924). process by which a ing 1,500 road deaths and 71,000 injuries. Sleep For years, researchers attributed this result to the memory becomes durable deprivation also leads to accidents and errors in the lack of new information coming into the brain dur- and stable. workplace, a concern especially for first-year doc- ing sleep, information that could interfere with al- tors doing their medical residency. In the United ready-established memories. Today, however, many States, federal law limits work hours for airline scientists believe that sleep plays a more active role pilots, truck drivers, and operators of nuclear by contributing to consolidation, in which synaptic plants, but medical residents still often work 24- to changes associated with recently stored memories 30-hour shifts (Landrigan et al., 2008). become durable and stable (Racsmány, Conway, & Don’t doze off as we tell you this, but lack of Demeter, 2010). One theory is that during sleep, sleep has also been linked to lower grades. Re- the neural changes involved in a recent memory are searchers had a group of elementary and middle reactivated, making those changes more permanent school students go to sleep at their normal time for (Rasch et al., 2007). a week, earlier than usual for a week, and much later Improvements in memory have been associated than usual for a week. Their teachers, who were most closely with REM sleep and slow-wave sleep blind to which condition a child was in during any (Stages 3 and 4), and with memory for specific given week, reported more academic and attention motor and perceptual skills. In one study, when Watch How to Get a Good problems when the children stayed up late (Fallone people or animals learned a perceptual task and Night’s Sleep on et al., 2005). These results probably apply to high were allowed to get normal REM sleep, their mem- mypsychlab.com school and college students as well. Watch ory for the task was better the next day, even when they had been awakened during non-REM periods. The Mental Benefits of Sleep Just as sleepi- When they were deprived of REM sleep, however, ness can interfere with good mental functioning, a their memories were impaired (Karni et al., 1994). good night’s sleep can promote it, and not just But sleep also seems to strengthen other kinds of because you are well rested. In a classic study con- memories, including the recollection of events, ducted nearly a century ago, students who slept for locations, and facts (Rasch & Born, 2008). Emotional eight hours after learning lists of nonsense syllables memories, especially, are improved with sleep. retained them better than students who went about When people look at emotionally arousing scenes in the morning or evening and are then tested for 70 their memory of the materials after 12 hours of daytime wakefulness or normal nighttime sleep, those tested after sleeping rather than wakefulness recall the emotional scenes more reliably than the 60 neutral ones (Hu, Stylos-Allan, & Walker, 2006). Recognition score (%) They also do better at remembering negative emo- tional scenes than other participants do (Payne 50 et al., 2008). (See Figure 5.3.) If sleep enhances memory, perhaps it also en- hances problem solving, which relies on informa- tion stored in memory. To find out, German 40 researchers gave volunteers a math test that re- quired them to use two mathematical rules to gen- erate one string of numbers from another and to 30 deduce the final digit in the new sequence as quickly Wake Sleep Wake Sleep as possible. The volunteers were not told about a Negative scenes Neutral scenes hidden shortcut that would enable them to calculate the final digit almost immediately. One group was FIGURE 5.3 trained in the evening and then got to snooze for Sleep and Consolidation in Memory eight hours before returning to the problem. An- When college students studied neutral scenes (e.g., an ordinary car) other group was also trained in the evening but then and emotionally negative scenes (e.g., a car totaled in an accident), sleep affected how well they later recognized the objects in the scenes. stayed awake for eight hours before coming back to Students who studied the scenes in the evening and then got a night’s the problem. A third group was trained in the morn- sleep before being tested did better at recognizing emotional objects ing and stayed awake all day, as they normally than did those who studied the scenes in the morning and were tested would, before taking the test. Those people who got after 12 hours of daytime wakefulness (Payne et al., 2008). the nighttime sleep were nearly three times likelier  CHAPTER 5 Body Rhythms and Mental States 159 to discover the hidden shortcut as those in the other mounting (Cai et al., 2009). The underlying biol- two groups (Wagner et al., 2004). ogy may involve the formation of new synaptic Researchers are not unanimous on the role of connections in the brain and also the weakening of sleep in learning; some studies have failed to find connections that are no longer needed (Donlea, that sleep improves memory (Vertes & Siegel, Ramanan, & Shaw, 2009; Gilestro, Tononi, & 2005). In one study, researchers who believe that Cirelli, 2009). In other words, we sleep to remem- sleep promotes consolidation found, to their sur- ber, but we also sleep to forget, so that the brain prise, that depriving people of REM sleep actually will have space and energy for new learning. improved memory for motor and perceptual skills Remember that the next time you are tempted to involving finger tapping and mirror tracing (Rasch pull an all-nighter. Even a quick nap may help your et al., 2009). Of course, not many of us have much mental functioning and increase your ability to put occasion to use these particular skills! together separately learned facts in new ways (Lau, Nonetheless, the evidence for the importance Alger, & Fishbein, 2008; Mednick et al., 2002). of sleep in human memory and problem solving is Sleep on it. Study and Quick Quiz Review on mypsychlab.com Now wake up and take this quiz. A. Match each term with the appropriate phrase: 1. REM periods a. delta waves and sleepwalking 2. alpha b. irregular brain waves and light sleep 3. Stage 4 sleep c. relaxed but awake 4. Stage 1 sleep d. active brain but inactive muscles B. Sleep is necessary for normal (a) physical and mental functioning, (b) mental functioning but not physical functioning, (c) physical functioning but not mental functioning. C. True or false: Most people need more than six hours of sleep a night. D. True or false: Only REM sleep has been associated with dreaming and memory consolidation. Answers: C. true D. false B. a 4. b 3. a 2. c A. 1. d YOU are about to learn... awakened during REM sleep. There are rare cases of people who apparently do not dream at all Freud’s theory that dreams are the “royal road to the (Pagel, 2003; Solms, 1997). Most, but not all, of unconscious.” these individuals have suffered some brain injury. In dreaming, the focus of attention is inward, how dreams might be related to your current problems and concerns. though occasionally an external event, such as a wailing siren, can influence the dream’s content. how dreams might be related to ordinary daytime While a dream is in progress, it may be vivid or thoughts. vague, terrifying or peaceful. It may also seem to how dreams could be caused by meaningless brain- make perfect sense—until you wake up and recall it stem signals. as illogical, bizarre, and disjointed. Although most of us are unaware of our bodies or where we are while we are dreaming, some people say that they Exploring the occasionally have lucid dreams, in which they know Dream World they are dreaming and feel as though they are con- scious (LaBerge & Levitan, 1995). A few even claim For years, researchers believed that everyone that they can control the action in these dreams, lucid dreams Dreams in dreams, and indeed most people who claim they much as a scriptwriter decides what will happen in a which the dreamer is never have dreams will report them if they are movie, although this ability is probably uncommon. aware of dreaming. 160 CHAPTER 5 Body Rhythms and Mental States Why do the images in dreams arise at all? Why must become temporarily delusional so that our doesn’t the brain just rest, switching off all thoughts anxiety will be kept at bay and our sleep will not be and images and launching us into a coma? Why, in- disrupted. stead, do we spend our nights taking a chemistry To understand a dream, said Freud, we must dis- exam, reliving an old love affair, flying through the tinguish its manifest content, the aspects of it that we air, or fleeing from dangerous strangers or animals consciously experience during sleep and may re- Watch Lucid in the fantasy world of our dreams? We will con- member upon wakening, from its latent (hidden) Dreaming on sider four leading explanations and then evaluate content, the unconscious wishes and thoughts being mypsychlab.com them. Watch expressed symbolically. Freud warned against the simpleminded translation of symbols (the kind that Dreams as Unconscious Wishes today often turn up in magazines and pop-psych One of the first psychological theorists to take books promising to tell you exactly what your dreams dreams seriously was Sigmund Freud, the founder mean). Each dream, said Freud, should be analyzed of psychoanalysis. After analyzing many of his pa- in the context of the dreamer’s waking life, as well as tients’ dreams and some of his own, Freud the person’s associations to the dream’s contents. (1900/1953) concluded that our nighttime fantasies Not everything in a dream is symbolic. Sometimes, provide insight into desires, motives, and conflicts Freud cautioned, “A cigar is only a cigar.” of which we are unaware. Because dreams allow us to express our unconscious wishes and desires, Dreams as Efforts to Deal which are often sexual or violent in nature, they provide a “royal road to the unconscious.” with Problems According to Freud, every dream is meaning- Another explanation holds that dreams reflect the ful, no matter how absurd the images might seem. ongoing conscious preoccupations of waking life, But if a dream’s message arouses anxiety, the ra- such as concerns over relationships, work, sex, or tional part of the mind must disguise and distort it. health (Cartwright, 2010; Hall, 1953a, 1953b). In Otherwise, the dream would intrude into con- this problem-focused approach to dreaming, the sym- sciousness and waken the dreamer. In dreams, bols and metaphors in a dream do not disguise its therefore, one person is often disguised as another: true meaning; they convey it. Psychologist Gayle A brother may be disguised as a father or may even Delaney told of a woman who dreamed she was be represented by several different characters. Sim- swimming underwater. The woman’s 8-year-old ilarly, thoughts and objects are translated into sym- son was on her back, his head above the water. Her bolic images. A penis may be disguised as a snake, husband was supposed to take a picture of them, umbrella, or dagger; a vagina as a tunnel or cave; but for some reason he wasn’t doing it, and she was and the human body as a house. Because reality is starting to feel as if she were going to drown. To distorted in such ways, a dream resembles a psy- Delaney, the message was obvious: The woman was chosis, a severe mental disturbance; each night, we “drowning” under the responsibilities of child care and her husband wasn’t “getting the picture” (in Dolnick, 1990). The problem-focused explanation of dreaming is supported by findings that dreams are more likely to contain material related to a person’s current concerns—such as a breakup or exams—than chance would predict (Cartwright et al., 2006; © The New Yorker Collection 1973 Dana Fradon from Domhoff, 1996). Among college students, who are often worried about grades and tests, test-anxiety dreams are common: The dreamer is unprepared for or unable to finish an exam, or shows up for the cartoonbank.com. All Rights Reserved. wrong exam, or can’t find the room where the exam is being given. (Sound familiar?) For their part, in- structors sometimes dream that they have left their lecture notes at home, or that they are expected to give a lecture in a foreign language on a subject they know nothing about. Traumatic experiences can also affect people’s dreams. In a cross-cultural study in which children kept dream diaries for a  CHAPTER 5 Body Rhythms and Mental States 161 These drawings from dream journals show that the images in dreams can be either abstract or literal. In either case, the dream may reflect a person’s concerns, problems, and interests. The two fanciful paintings (left and center) represent the dreams of a person who worked all day long with brain tissue, which the drawings rather resemble. The desk was sketched in 1939 by a scientist to illustrate his dream about a mechanical device for instantly retrieving quotations—a sort of early desktop computer! week, Palestinian children living in neighborhoods thoughts, concepts, and scenarios that may or may under threat of violence reported more themes of not be related to our daily problems. We are most persecution and violence than did Finnish or Pales- likely to dream about our families, friends, studies, tinian children living in peaceful environments jobs, or recreational interests—topics that also (Punamaeki & Joustie, 1998). occupy our waking thoughts. Some psychologists believe that dreams not In the cognitive view, the brain is doing the only reflect our waking concerns but also provide same kind of work during dreams as it does when us with an opportunity to resolve them we are awake; indeed, parts of the cerebral cortex (Cartwright, 2010). In people suffering from the involved in perceptual and cognitive processing grief of divorce, recovery is related to a particular during the waking hours are highly active during pattern of dreaming: The first dream of the night dreaming. The difference is that when we are often comes sooner than it ordinarily would, lasts asleep we are cut off from sensory input and feed- longer, and is more emotional and story-like. De- back from the world and from our bodily move- pressed people’s dreams tend to become less nega- ments; the only input to the brain is its own output. tive and more positive as the night wears on, and That is why our dreaming thoughts tend to be this pattern, too, predicts recovery (Cartwright more unfocused and diffuse than our waking et al., 1998). The researchers concluded that get- ones—unless of course we’re daydreaming! ting through a crisis or a rough period in life takes This view predicts that if a person could be “time, good friends, good genes, good luck, and a totally cut off from all external stimulation while good dream system.” awake, mental activity would be much like that dur- ing dreaming, with the same hallucinatory quality. In Chapter 6, we will see that this is, in fact, the case. Dreams as Thinking The cognitive approach also predicts that as cogni- Like the problem-focused approach, the cognitive tive abilities and brain connections mature during approach to dreaming emphasizes current concerns, childhood, dreams should change in nature, and but it makes no claims about problem solving during they do. Toddlers may not dream at all in the sense sleep. In this view, dreaming is simply a modification that adults do. And although young children may of the cognitive activity that goes on when we are experience visual images during sleep, their cogni- awake. In dreams, we construct reasonable simula- tive limitations keep them from creating true narra- tions of the real world, drawing on the same kinds of tives until age 7 or 8 (Foulkes, 1999). Their dreams memories, knowledge, metaphors, and assumptions are infrequent and tend to be bland and static, often about the world that we do when we are not sleeping about everyday things (“I saw a dog; I was sitting”). (Antrobus, 1991, 2000; Domhoff, 2003; Foulkes, But as they grow up, their dreams gradually become 1999). Thus, the content of our dreams may include more and more intricate and story-like. 162 CHAPTER 5 Body Rhythms and Mental States activation–synthesis Dreams as Interpreted the cortex’s interpretation—the dream—is likely to theory The theory that be incoherent and confusing. And because the cor- dreaming results from the Brain Activity tical neurons that control the initial storage of new cortical synthesis and A fourth approach to dreaming, the memories are turned off during sleep, we typically interpretation of neural activation–synthesis theory, draws heavily on physi- forget our dreams upon waking unless we write signals triggered by ological research. According to this explanation, them down or immediately recount them to some- activity in the lower part first proposed by psychiatrist J. Allan Hobson one else. of the brain. (1988, 1990), dreams are not “children of an idle Since Hobson’s original formulation, he and brain,” as Shakespeare called them. Rather, they are his colleagues have added further details and modi- largely the result of neurons firing spontaneously in fications (Hobson, Pace-Schott, & Stickgold, the pons (in the lower part of the brain) during 2000). The brain stem, they say, sets off responses REM sleep. These neurons control eye movement, in emotional and visual parts of the brain. At the gaze, balance, and posture, and they send messages same time, brain regions that handle logical to sensory and motor areas of the cortex responsi- thought and sensations from the external world ble for visual processing and voluntary action dur- shut down. These changes could account for the ing wakefulness. fact that dreams are often emotionally charged, According to the activation–synthesis theory, hallucinatory, and illogical. the signals originating in the pons have no psycho- In this view, wishes do not cause dreams; brain logical meaning in themselves. But the cortex tries mechanisms do. Dream content, says Hobson to make sense of them by synthesizing, or integrat- (2002), may be “as much dross as gold, as much ing, them with existing knowledge and memories to cognitive trash as treasure, and as much informa- produce some sort of coherent interpretation. This tional noise as a signal of something.” But that does is just what the cortex does when signals come from not mean dreams are always meaningless. Hobson sense organs during ordinary wakefulness. The idea (1988) has argued that the brain “is so inexorably that one part of the brain interprets what has gone bent upon the quest for meaning that it attributes on in other parts, whether you are awake or asleep, and even creates meaning when there is little or is consistent with many modern theories of how the none to be found in the data it is asked to process.” brain works (see Chapter 4). By studying these attributed meanings, you can learn about your unique perceptions, conflicts, and ACTIVATION–SYNTHESIS THEORY OF DREAMS concerns—not by trying to dig below the surface of