Dreams
Soon playing at your inner theater: the premiere of a vivid dream. This never-before-seen mental movie features captivating characters wrapped in a plot so original and unlikely, yet so intricate and so seemingly real, that you’ll later marvel at its creation.
“ I do not believe that I am now dreaming, but I cannot prove that I am not.”
Philosopher Bertrand Russell (1872–1970)
Daydreams tend to involve the familiar details of our life — perhaps picturing ourselves explaining to a teacher why an assignment will be late, or replaying in our minds personal encounters we relish or regret. Unlike daydreams, REM dreams are vivid, emotional, and often bizarre (Loftus & Ketcham, 1994). Waking from one, we may wonder how our brain can so creatively, colorfully, and completely construct this alternative world. In the shadowland between our dreaming and waking consciousness, we may even wonder for a moment which is real. Awakening from a nightmare, a 4-year-old may be sure there is a bear in the house.
A dreamy take on dreamland The 2010 movie Inception creatively played off our interest in finding meaning in our dreams, and in understanding the layers of our consciousness. It further explored the idea of creating false memories through the power of suggestion — an idea we will discuss in Module 33.
Discovering the link between REM sleep and dreaming began a new era in dream research. Instead of relying on someone’s hazy recall hours after having a dream, researchers could catch dreams as they happened. They could awaken people during or within 3 minutes after a REM sleep period and hear a vivid account.
What We Dream
We spend six years of our life in dreams, many of which are anything but sweet. For both women and men, 8 in 10 dreams are marked by at least one negative event or emotion (Domhoff, 2007). Common themes include repeatedly failing in an attempt to do something; being attacked, pursued, or rejected; or experiencing misfortune (Hall et al., 1982). Dreams with sexual imagery occur less often than you might think. In one study, only 1 in 10 dreams among young men and 1 in 30 among young women had sexual content (Domhoff, 1996).
More commonly, a dream’s story line incorporates traces of previous days’ experiences and preoccupations (De Koninck, 2000):
- Trauma and dreams. After suffering a trauma, people commonly report nightmares, which help extinguish daytime fears (Levin & Nielsen, 2007, 2009). One sample of Americans recording their dreams during September 2001 reported an increase in threatening dreams following the 9/11 terrorist attacks (Propper et al., 2007). Compared with Palestinian children living in a peaceful town in Galilee, those living in the conflict-ridden Gaza Strip more often dream of aggression (Punamäki & Joustie, 1998).
“ For what one has dwelt on by day, these things are seen in visions of the night.”
Menander of Athens (342–292 B.C.E.), Fragments
- Musicians’ dreams. Compared with nonmusicians, musicians report twice as many dreams of music (Uga et al., 2006).
- Blind people’s dreams. Studies in four countries have found blind people mostly dreaming of using their nonvisual senses (Buquet, 1988; Taha, 1972; Vekassy, 1977). But even natively blind people sometimes “see” in their dreams (Bértolo, 2005). Likewise, people born paralyzed below the waist sometimes dream of walking, standing, running, or cycling (Saurat et al., 2011; Voss et al., 2011).
- Media experiences and dreams. In a study of 1287 Turkish people, “participants who consumed violent media tended to have violent dreams, and participants who consumed sexual media tended to have sexual dreams” (Van den Buick et al., 2016).
Our two-track mind continues to monitor our environment while we sleep. Sensory stimuli — a particular odor or a phone’s ringing — may be instantly and ingeniously woven into the dream story. In a classic experiment, researchers lightly sprayed cold water on dreamers’ faces (Dement & Wolpert, 1958). Compared with sleepers who did not get the cold-water treatment, these people were more likely to dream about a waterfall, a leaky roof, or even about being sprayed by someone.
“Uh-oh. I think I’m having one of those dreams again.”
So, could we learn a foreign language by hearing it played while we sleep? If only. While sleeping we can learn to associate a sound with a mild electric shock (and to react to the sound accordingly). We can also learn to associate a particular sound with a pleasant or unpleasant odor (Arzi et al., 2012). But we do not remember recorded information played while we are soundly asleep (Eich, 1990; Wyatt & Bootzin, 1994). In fact, anything that happens during the 5 minutes just before we fall asleep is typically lost from memory (Roth et al., 1988). This explains why sleep apnea patients, who repeatedly awaken with a gasp and then immediately fall back to sleep, do not recall the episodes. Ditto someone who awakens momentarily, sends a text message, and the next day can’t remember doing so. It also explains why dreams that momentarily awaken us are mostly forgotten by morning. To remember a dream, get up and stay awake for a few minutes.
“ Follow your dreams, except for that one where you’re naked at work.”
Attributed to comedian Henny Youngman
Why We Dream
Flip It Video: Why Do We Dream?
Dream theorists have proposed several explanations of why we dream, including these:
To satisfy our own wishes. In 1900, in his landmark book The Interpretation of Dreams, Sigmund Freud offered what he thought was “the most valuable of all the discoveries it has been my good fortune to make.” He proposed that dreams provide a psychic safety valve that discharges otherwise unacceptable feelings. He viewed a dream’s manifest content (the apparent and remembered story line) as a censored, symbolic version of its latent content, the unconscious drives and wishes (often erotic) that would be threatening if expressed directly. Thus, a gun might be a disguised representation of a penis.
Freud considered dreams the key to understanding our inner conflicts. However, his critics say it is time to wake up from Freud’s dream theory, which they regard as a scientific nightmare. “There is no reason to believe any of Freud’s specific claims about dreams and their purposes,” observed dream researcher William Domhoff (2003). Some contend that even if dreams are symbolic, they could be interpreted any way one wished. Others maintain that dreams hide nothing: A dream about a gun is a dream about a gun. Legend has it that even Freud, who loved to smoke cigars, acknowledged that “sometimes, a cigar is just a cigar.” Freud’s wish-fulfillment theory of dreams has in large part given way to other theories.
To file away memories. The information-processing perspective proposes that dreams may help sift, sort, and fix the day’s experiences in our memory. Some studies support this view. When tested the day after learning a task, those who had been deprived of both slow-wave and REM sleep did not do as well as those who had slept undisturbed (Stickgold, 2012). Other studies showed similar memory lapses for new material among people who were awakened every time they began REM sleep (Empson & Clarke, 1970; Karni & Sagi, 1994).
“ When people interpret [a dream] as if it were meaningful and then sell those interpretations, it’s quackery.”
Sleep researcher J. Allan Hobson (1995)
Brain scans confirm the link between REM sleep and memory. The brain regions that were active as rats learned to navigate a maze, or as people learned to perform a visual-discrimination task, became active again later during REM sleep (Louie & Wilson, 2001; Maquet, 2001). So precise were these activity patterns that scientists could tell where in the maze the rat would be if awake. To sleep, perchance to remember.
This is important news for students, many of whom, observed researcher Robert Stickgold (2000), suffer from a kind of sleep bulimia — sleep deprived on weekdays and binge sleeping on the weekend. “If you don’t get good sleep and enough sleep after you learn new stuff, you won’t integrate it effectively into your memories,” he warned. That helps explain why high school students with high grades slept about 25 minutes longer each night than their lower-achieving classmates (Wolfson & Carskadon, 1998; see Figure 24.3). Sacrificing sleep time to study actually worsens academic performance by making it harder the next day to understand class material or do well on a test (Gillen-O’Neel et al., 2013).
Figure 24.3 A sleeping brain is a working brain
To develop and preserve neural pathways. Perhaps dreams, or the brain activity associated with REM sleep, serve a physiological function, providing the sleeping brain with periodic stimulation. This theory makes developmental sense. As you will see in Unit IX, stimulating experiences preserve and expand the brain’s neural pathways. Infants, whose neural networks are fast developing, spend much of their abundant sleep time in REM sleep (Figure 24.4).
Figure 24.4 Sleep across the life span
As we age, our sleep patterns change. During our first few months, we spend progressively less time in REM sleep. During our first 20 years, we spend progressively less time asleep.
To make sense of neural static. Other theories propose that dreams erupt from neural activation spreading upward from the brainstem (Antrobus, 1991; Hobson, 2003, 2004, 2009). According to activation-synthesis theory, dreams are the brain’s attempt to synthesize random neural activity. Much as a neurosurgeon can produce hallucinations by stimulating different parts of a patient’s cortex, so can stimulation originating within the brain. As Freud might have expected, PET scans of sleeping people also reveal increased activity in the emotion-related limbic system (in the amygdala) during emotional dreams (Schwartz, 2012). In contrast, frontal lobe regions responsible for inhibition and logical thinking seem to idle, which may explain why our dreams are less inhibited than we are when awake (Maquet et al., 1996). Add the limbic system’s emotional tone to the brain’s visual bursts and — Voilà! — we dream. Damage either the limbic system or the visual centers active during dreaming, and dreaming itself may be impaired (Domhoff, 2003).
To reflect cognitive development. Some dream researchers prefer to see dreams as part of brain maturation and cognitive development (Domhoff, 2010, 2011; Foulkes, 1999). For example, prior to age 9, children’s dreams seem more like a slide show and less like an active story in which the dreamer is an actor. Dreams overlap with waking cognition and feature coherent speech. They simulate reality by drawing on our concepts and knowledge. They engage brain networks that also are active during daydreaming — and so may be viewed as intensified mind wandering, enhanced by visual imagery (Fox et al., 2013). Unlike the idea that dreams arise from bottom-up brain activation, the cognitive perspective emphasizes our mind’s top-down control of our dream content (Nir & Tononi, 2010). Dreams, says G. William Domhoff (2014), “dramatize our wishes, fears, concerns, and interests in striking scenarios that we experience as real events.”
Table 24.4 compares these major dream theories. Although today’s sleep researchers debate dreams’ function — and some are skeptical that dreams serve any function — there is one thing they agree on: We need REM sleep. Deprived of it by repeated awakenings, people return more and more quickly to the REM stage after falling back to sleep. When finally allowed to sleep undisturbed, they literally sleep like babies — with increased REM sleep, a phenomenon called REM rebound. Most other mammals also experience REM rebound, suggesting that the causes and functions of REM sleep are deeply biological. (That REM sleep occurs in mammals — and not in animals such as fish, whose behavior is less influenced by learning — fits the information-processing theory of dreams.)
| Theory | Explanation | Critical Considerations |
|---|---|---|
| Freud’s wish-fulfillment | Dreams preserve sleep and provide a “psychic safety valve” — expressing otherwise unacceptable feelings; contain manifest (remembered) content and a deeper layer of latent content (a hidden meaning). | Lacks any scientific support; dreams may be interpreted in many different ways. |
| Information-processing | Dreams help us sort out the day’s events and consolidate our memories. | But why do we sometimes dream about things we have not experienced and about past events? |
| Physiological function | Regular brain stimulation from REM sleep may help develop and preserve neural pathways. | This does not explain why we experience meaningful dreams. |
| Activation-synthesis | REM sleep triggers neural activity that evokes random visual memories, which our sleeping brain weaves into stories. | But it’s our brain weaving the stories, so this still tells us something about ourselves. |
| Cognitive development | Dream content reflects dreamers’ level of cognitive development — their knowledge and understanding. Dreams simulate our lives, including worst-case scenarios. | Does not propose an adaptive function of dreams. |
So does this mean that because dreams serve physiological functions and extend normal cognition, they are psychologically meaningless? Not necessarily. Every psychologically meaningful experience involves an active brain. We are once again reminded of a basic principle: Biological and psychological explanations of behavior are partners, not competitors.
Dreams are a fascinating altered state of consciousness. But they are not the only altered states. As we will see next, psychoactive drugs also alter conscious awareness.