The movie "In
ception" is based upon the premise that there exists a technology which allows people to enter into and share the dreams of others, manipulate them in ways which suit their purposes and plans, and even to create dreams within the dreams.
When one of the partners of the main character of the film (played by Leonardo DiCaprio) explains how this works to a young student he has recruited to help him in his next, most difficult task, he describes how time itself slows down while dreaming. Seconds turn to minutes, minutes to hours and days, even longer if one enters a dream within a dream. This becomes critical to the plot in the second half of the film.
This concept of the relativity or elasticity of time during dreaming is intriguing, and familiar to most of us. Many have had the experience of almost ignoring their alarm clock as it goes off, incorporating its ringing into a dream in which, for example, a fire truck, sirens blaring and bells ringing races by, and only after several seconds realizing that the ringing was in fact the alarm which they had set to awaken them. The realization that while the alarm may only have been ringing for a number of seconds, a whole dream has been constructed around it can be very disorienting, especially if the dream was detailed and had other components that can be easily recalled.
There are a number of possible explanations for this phenomenon. One is that the dream, already underway, is able to "explain" the external disturbance by adapting to and incorporating it into its own internal narrative, thus allowing sleep to continue. This is an example of the "dream as the guardian of sleep" hypothesis. In this case, the duration of the dream is, in fact, much longer than the few seconds during which the alarm is ringing, and so the apparent disconnect between the richness of the dream, particularly that which preceded the appearance of the fire engine (in this case) is not as difficult to reconcile.
Another possibility is more in line with the premise of the movie, which is that the brain does indeed work at different speeds than that which we are aware that it does during conscious wakefulness. This is not to say that warping through time as we know it does not occur while awake. The utilization of subliminal advertising is a classic example of taking advantage of the brain's ability to process and integrate information at speeds much greater than what our conscious selves are able to follow. However, our sense of time while awake is pegged to our consciousness' ability to keep track of our surroundings. When sleeping, and mostly disconnected from our surroundings, we enter into a different state of consciousness. Theories abound as to what happens during sleep, but it is clear that the brain is much freer to work at its own pace, unencumbered for the most part by external stimuli that would otherwise force it to slow down and take notice.
Many, such as Freud, hold that dreams represent the emergence of subconscious conflicts. Others, such as Cartwright, feel that dreams are a mechanism through which negative emotional experiences encountered during wakefulness are down regulated, matched with other similar ones and then melded into the larger sense of self, thus blunting their impact. However, some, Hobson and McCarley for example, explain via their activation synthesis theory that dreams are simply the cortical response to spontaneous neuronal activity during sleep. If that is correct, then perhaps the pace at which the brain processes information is indeed much faster than that during wakefulness, and elaborate dreams rich in content may indeed only "play out" on the screen of our minds for seconds or less.
Dennis Rosen, M.D.
Learn how to help your child get a great night’s sleep with:
Successful Sleep Strategies for Kids (a Harvard Medical School Guide)