The Tidal Wave Dream

Of the 880 dreams my colleagues and I have studied from the weeks right after 9/11, not a single one featured planes hitting tall towers, or anything even close to that. This finding may seem curious. After all, the participants, like the rest of us, saw the images of planes hitting the World Trade Center many, many times. But if there’s one thing I have learned in my decades of discussing, analyzing, and researching dreams, it is that dreams are not simply a replay of waking experience, and that was true for the post-9/11 dreamers.

What did they dream of? All kinds of things, but most of the dreams did have one trait in common: they contained a powerful central image. For some people, that image was a tidal wave. It’s a familiar dream. This is how one woman experienced it: I’m walking along the beach with another woman, I think—I don’t see her too clearly—when all of a sudden a huge tidal wave, 30 feet tall, comes and sweeps us away. I struggle to breathe, try to get to the surface. It’s all swirling white and blue water with debris—pieces of wood mostly—floating by. I’m not sure I make it to the surface. Then I wake up.

The tidal wave dream is especially apt to occur in people who have recently experienced a trauma, such as a fire, a rape, or an attack. It is hardly surprising, then, that it showed up in profusion after 9/11, a day that was traumatic, or at least highly stressful, for everyone in the United States.

Dreams after trauma are not always about tidal waves, of course. Some involve earthquakes or storms, for instance: I was on a hilltop watching a whirlwind or tornado in the distance. Suddenly it was right on top of me. I found myself lifted up and carried away. I was terrified.

Here is a dream that occurred soon after the dreamer’s mother died: I was in a large empty house—not sure where. The windows were open and a cold wind was blowing right through the house. No furniture at all. A desolate empty house.

In each case, the central image—the tidal wave, the tornado, the windblown house—seems to embody a powerful emotion such as terror or grief. All of our most memorable dreams are like this. Dreams that stay with us for the rest of our lives—what Jung called “big” dreams—are almost invariably characterized by a single striking image. We seldom consider a dream “big” because of a detailed plot structure, interesting characters, or specific words that are spoken in it.

When you compare the dreams people had in the weeks and months before and after 9/11, the only thing that distinguishes them is the intensity of that central image. The two sets of dreams differ not at all in length, vividness, strangeness, or the presence of towers, airplanes, or attacks.

A phenomenon as universal as the central image must be important. But in what way? What is this thing we call dreaming, and why do we dream? After many years of study, I have developed a theory that offers some tentative answers to such questions. It tries to explain how those powerful central images form and how—if they can be said to have any purpose at all—the images and the dreams that give rise to them might actually promote a form of emotional healing. I call it the Contemporary Theory of Dreaming.

Dreams and Daydreams Let me begin, as the theory does, with a bold pronouncement: dreaming is not a unique state but one of several forms of mental functioning that can be seen as a continuum, with focused waking thought on one end and dreams on the other. Dreams are so vivid, so bizarre, so out of our control that we often consider them totally different from the rest of our mental life. But the distance between thinking and dreaming may not be so great.

Most of us will concede that we slide easily from focused waking thought to looser, unfocused waking thought, since these states are only slightly different. We’ll acknowledge as well that this unfocused waking thought can readily become more unfocused still, until we’re daydreaming.

Studies have shown that daydreaming is often surprisingly dreamlike. Even the “out of our control” features of dreaming can occur in waking life. In my research on people with frequent nightmares, I found that several of them also had “daymares”—a word some made up to describe daydreams that start out pleasantly enough but then become scary. Other daydreams, though less disturbing, may be just as strange, like this one:

I am seeing outlines of things. Then I see what appears as an eye. The eye winks and the surroundings jumble around and turn to mist. There seems to be a pit with levels of ledges. That is the only way to go, but I don’t go down there. I stay my ground and wait and wait, but nothing happens till I look up and try to reach a light and then turn around and get comforted by the warm darkness that surrounds this place.

People susceptible to such daydreams usually have what my collaborators and I call “thin boundaries.” That is, they are open in many respects, accepting ambiguities and thinking in shades of gray rather than black and white. They are the sorts of people who “see” music and “hear” color, since they don’t make rigid distinctions between information from different senses. When my group conducted a study comparing students’ recent dreams and recent daydreams, we observed that the daydreams of students with thin boundaries (as measured by personality tests) were just as dreamlike and bizarre as the night dreams of others. These findings strengthened our conviction that dreaming is part of a continuum of mental functioning, rather than an alien state, disconnected from everything else. Biological research lends further support to this idea (see “The Brain’s Continuum”).

Of course, the mind operates a bit differently in dreams. Ideas and objects are brought together and connected more readily in dreaming than in focused waking thought. My own dreams, for example, often take place in a city that is partly Boston and partly New York, two cities I know well. But dreaming is not a state in which “anything goes.” We’ve discovered that the mental connections made in dreaming bypass regions of memory needed for logical “A leads to B leads to C” thinking.

Dreamers rarely engage in the orderly testing of hypotheses. Let’s say that, while awake, we see an unusual light on the horizon. We think, “Hmm, it could be a plane’s landing lights, though there is no airport nearby. Perhaps a car is lost in an unusual location. Or could someone have built a campfire over there? Or maybe an alien spaceship has landed.” We next try to deduce the likelihood of each possibility. Such reasoning is notably absent in dreams.

Nor do dreamers tend to engage in routine but complex tasks like typing that are performed almost automatically. In one study, 400 people who recorded their dreams were asked to rate how often they dreamed about reading, writing, typing, and calculating. Some 90 percent said they “never” or “almost never” did.

In the absence of logic or routine, the guiding force that connects ideas to create images in dreams appears to be, as I noted earlier, the dreamer’s emotions. The intensity of the dream’s central image seems to correspond with the intensity of the underlying emotion.

The Function of Dreams When it comes to establishing why we dream, my theory becomes far more conjectural. There is little agreement on whether dreaming has any function at all. There is not even agreement on the functions of sleep itself.

But this is what might be going on, according to my clinical and experimental observations: the mental connections made in dreaming may help us adapt to the conditions under which we must live, and may do so by integrating new experiences, new material, into existing memory stores.

One can envision the entire mental process after trauma as a series of questions and answers generated by emotion. First comes absolute terror: “The world is ending! This is the most horrible thing that has ever happened to anyone! How can I or anyone survive this?”

The typical tidal wave dream attempts an answer along the lines of an internal dialogue: “Let’s take a look at what happened. It is a terrible event, yes, but is it unique? Allow the emotion to flood your mind, and see what images it calls up. Other terrifying situations, other catastrophes . . . Awful, yes, but part of a whole catalogue of human disasters. All are horrible, but sometimes people seem to survive. In fact, you seem to be surviving this time.”

Eventually, terror lessens. A sense of annihilation, separation, or loss may emerge. And we often see vulnerability, a feeling that is closely allied with fear but less intense.

The dreams, which may portray someone or something other than the dreamer as victim, are not always described as nightmares, and do not culminate with the dreamer awakening in fright:

• I dreamt of a small, hurt animal just lying in the road bleeding.
• There were these shellfish creatures, like lobsters or crayfish maybe, with their shells torn off. They were just lying there, white and pink and very exposed.
• There was this light yellow-white membrane, sort of like a skin, stretched taut. I could feel it, and these huge birds and things were diving down and pecking at it. It felt very painful.

Then, after days, weeks, months, or years—depending on the dreamer—survivor guilt may come to the fore: “Yes, I seem to have survived, but he was blown up. I’m a worse person than he was. I deserve to have died.” Survivor guilt is clear in this dream of a young man who escaped from a fire in which his brother was killed: I dreamt of a fire somewhat like the one we were really in, only the house was different, and in the dream my brother and everyone else escaped. I think I was still in the house getting burned.

And soon enough, the guilt begins to lessen: “Let’s see what happened before. Weren’t there other times like this? Let’s look at those, even situations in your childhood, or maybe a similar event involving someone else.” The same young man reported: I dreamt that my brother and I got into a bad fight and my brother was beating me up.

Gradually, dreams return to more or less the pattern they had before the trauma, and I speculate—but certainly cannot prove—that this is because the powerful new experience has been incorporated into the dreamer’s general emotional knowledge. The value of such incorporation would be that if we ever had to face the same kind of experience again, we would find it easier to handle. From an evolutionary standpoint, the ability to deal with trauma would have been advantageous for survival.

According to my theory, this adaptive function should occur regardless of whether dreams are remembered. My reasoning here is that the mental connections are probably what matter most, not the dreams themselves. The connections would remain even if the dreams that made them were forgotten.

But when you do remember a dream, it can be extremely useful. Research bears this out. In one study, students identified a problem that was emotionally important to them and then tried to work on it in their dreams. Judges evaluated the dreams and determined that 51 percent were indeed about the identified problem. Moreover, 25 percent contained a solution.

One student who had applied to graduate programs in both clinical psychology and industrial psychology and couldn’t decide which to pursue had this dream: A map of the United States. I am in a plane flying over this map. The pilot says we are having engine trouble and need to land, and we look for a safe place on the map indicated by a light. I ask about “MA,” which we seem to be over right then, and he says all of MA is very dangerous. The lights seem farther west.

The student continued: “I wake up and realize that my two clinical schools are both in Massachusetts (MA), where I have spent my whole life and where my parents live. Both industrial programs are far away, in Texas and California. That was because I was originally looking to stay close to home, and there were no good industrial programs nearby. I realize that there is a lot wrong with staying at home and that, funny as it sounds, getting away is probably more important than which kind of program I go to.”

And don’t forget that numerous artists —among them Mozart, Wagner, Coleridge, and Robert Louis Stevenson—have found creative inspiration in their dreams. Some have even insisted that an entire work of art came to them during a dream. The eighteenth-century composer Giuseppe Tartini was one of these. He reported that he dreamed the devil came to him with a violin and played a difficult piece of music that contained a prolonged trill. Upon waking, Tartini wrote down the piece, which became his well-known “Devil’s Trill” Sonata.

Scientists have benefited from dreams, too. Here’s how the German chemist August Kekulé figured out the structure of the benzene molecule, which he had been puzzling over for some time: I turned my chair to the fire and dozed. Again the atoms were gamboling before my eyes. This time the smaller groups kept modestly in the background. My mental eye, rendered more acute by repeated visions of the kind, could now distinguish larger structures of manifold conformation: long rows, sometimes more closely fitted together, all twining and twisting in snakelike motion. But look! What was that? One of the snakes had seized hold of its own tail, and the form whirled mockingly before my eyes. Kekulé said he awoke and “spent the rest of the night in working out the consequences of the hypothesis.”

Based on this image, he realized that the molecule’s six carbon atoms must have a ring structure.

The final point of the Contemporary Theory of Dreaming is that the whole mental continuum from focused waking thought through unfocused waking thought to dreaming has an adaptive function—a conclusion that seems obvious once one has accepted the idea of the continuum itself. Isn’t it clearly worthwhile to operate at the focused end, thinking logically and in straight lines? And haven’t we just demonstrated the advantages of operating at the unfocused end, having even the most bizarre dreams?

It stands to reason, then, that the continuum’s in-between points would have their uses as well, and we see ample evidence that this is the case. For instance, my patients often make useful but not especially predictable mental connections while wide awake in my office. They’ve simply allowed their thoughts to loosen up. Life presents us with a huge range of situations, and laser-like concentration is not always the best approach. At times, it’s better to associate more broadly, to be more creative, to try out new possibilities—in other words, to daydream and to dream.

ERNEST HARTMANN is a professor of psychiatry at Tufts University School of Medicine. A former president of the International Association for the Study of Dreams, he is the author of nine books. His latest research findings on post-9/11 dreams were published in the journal Sleep (February 1, 2008).