For example, the threat simulation hypothesis suggests that dreams may provide a sort of virtual reality simulation in which we can rehearse threatening situations, even if we don’t remember the dreams. Sigmund Freud’s suggestion that dreams express forbidden desires is of course the most famous of these, but there are lots of other theories about what dreams might do, many with more empirical support than the Freudian view. As usual in psychology, there are lots of different ideas about what this function could be. In contrast to an activation-synthesis model, which views dreams as epiphenomena-a simple by-product of neural processes in sleep-other scientists have suggested that dreams serve an important function.
It is easy to imagine that the random imagery and sensations created in this way could be woven together to create a complex, multisensory hallucination which we might call a dream. If that firing occurs at random, these perceptions can feel like crazy, randomly fragmented hallucinations. This means that neurons firing in the primary visual cortex create the illusion of seeing things, neurons firing in the primary auditory area create the illusion of hearing things, and so forth. Neural activity in the primary sensory areas of the neocortex produces the impression of sensory perception. Everything we see, imagine, or think about is linked to neural responses somewhere in the brain. One aim of neuroscience is to map the brain loci of thoughts and mental experiences. For example, one uses an eight-point rating system from 0 (no dream) to 7 (“an extremely long sequence of 5 or more stages”).īut let me backtrack. One fairly safe catch-all is “all perceptions, thoughts, or emotions experienced during sleep.” Because this is very broad, there are also several different ways of rating, ranking, and scoring dreams. We all intuitively know what a dream is, but you’ll be surprised to learn there’s no universally accepted definition of dreaming. It just means the experience was never really carved into your memory, has decayed in storage, or isn’t accessible for easy call back. Failing to remember a dream later on when you’re awake doesn’t mean you weren’t aware of it when it occurred. Many people will protest, “I never remember my dreams!,” but that is a different matter entirely. It may be fragmentary, disconnected, and illogical, but if you aren’t aware of it during sleep then it isn’t a dream.
The pursuer is gaining, but when it finally catches you, the whole scene vanishes.and you wake up.Īlmost by definition, a dream is something you are aware of at some level. Your fear is compounded by the fact that your feet won’t do what you want-it feels like they are moving through molasses. Something very evil and scary is chasing you, but you’re not sure why.
You are terrified and running along a dark, narrow corridor. (Scientific American and Palgrave Macmillan are part of the Holtzbrinck Publishing Group.) Excerpted with permission from The Secret World of Sleep: The Surprising Science of the Mind at Rest, by Penelope A.
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