Dream Déjà Vu

You're dreaming of a beautiful multicolor forest, floating through the scenery and admiring the flora, when a small cottage appears in a clearing ahead. You recognize something in the light reflecting off the window; a sense that you've been here before, in a distant dream.

Many of us have had the impression of revisiting specific places in our dreams; there may be a clear feeling of familiarity or a vague memory of the dreamscape, a sort of dream déjà vu. It's especially interesting when these places are novel creations of the dreamworld, existing only in the dreamer's mind.

How is it possible for the mind to re-create an imaginary cottage that was dreamed up from the unconscious?

In dream research, we find that even real places such as your home or office are very rarely accurately portrayed within the dream. Often when reporting dreams subjects describe the following curious experience: "I was at my mother's house, but it didn't look anything like her house, I just knew where I was..." or "I was talking to my brother, then he turned into a large orange cat but I still knew it was him." In these examples, there is a feeling of familiarity (my house, my brother), which lends a stable character to a fluid dream image. This feeling of familiarity is a common culprit in the phenomenon of déjà vu (Cleary, 2008).

Déjà vu can be defined as a novel situation that is perceived to be familiar, without any clear memory of having experienced it before. This combination, recognizing a situation without any clear memory why, is perhaps particularly likely to occur during dreaming, where the entirety of our experience is created from a network of memory traces. In other words, everything is familiar because its created from our memories. In support of this idea, people with higher dream recall frequency also report more déjà vu experiences (Brown, 2003).

Recently in sleep research, one study of memory consolidation explored how sleep may promote the creation of false memories through feelings of familiarity. Payne et al. (2009) asked subjects to study a list of words that are conceptually related [glass, pane, shade, sill, curtain, etc] prior to sleep. The word lists are conceptually organized around a "critical" word that is purposely absent from the list [in this case, window].

The authors found that after a daytime nap, subjects reported nearly 50% greater false recognition of unstudied critical words compared to wake controls, ie, subjects claimed to recognize the word "window" despite never having studied it. Thus, sleep led to a false feeling of familiarity (false memory) for the critical concept, the "gist" of the information. This is, in essence, a déjà vu experience: a feeling of familiarity in the absence of a true memory.

Just as the word list leads to the consolidation of the "critical" word during sleep, dream images may utilize multiple memory traces centered around a particular, "critical" feeling. Dreaming of home may involve a composite of memory traces around the core feeling associated with being home; thus, the details are not necessarily important, because the feeling of familiarity is constant. Perhaps at the heart of the imaginary cottage in the woods is a unique feeling of peace, an experience you can only truly visit in your dreams. It's easy to see how such places hold a certain mystical charm and personal significance for the dreamer.

Good news for dream travel: Just as studying the word list prior to sleep led to its activation during sleep, dream incubation, a method of focusing on the intent to dream of a certain place prior to falling asleep, may activate critical memory traces and increase your odds of arriving at the desired dream destination.