When we dream, the body is out for the count, but the mind is still a stew of thoughts and interpretations. But in this seemingly random stew, some dreams bubble up to the top again and again. And science fiction and fantasy might be the reason why.
When I was a very young child I had a dream about running away from a boarding school, getting shrunk down, and adventuring with the cast of Chip 'n Dale's Rescue Rangers. Boarding schools and talking rodents were never an important facet of my childhood, but I had this dream regularly, once a year for years during my youth. But why? Why do we have these exactly recurring dreams at all, and what singles them out from regular dreams?
Since scientists are split on why we have dreams at all, with theories ranging from dreams being a screen-saver for our conscious brain to dreams helping us to work out problems in everyday life. Recurring dreams have never been entirely pinned down. There are strange little quirks. For example, people with narcolepsy seem to have recurring dreams more commonly than others. Recurring dreams however tend to be associated with unresolved problems or sources of stress in real life. This supports the idea that dreams are ways to sort through problems, or at least examine them, during sleep. But what kind of problems are they?
A dream study in 2000 noted that out of 592 everyday home dreams (i.e. housecleaning dreams), about two-thirds of the dreams contained a threat to the dreamer or someone close to them. Only four percent of the threats were pure fantasy like evil dragons. Just under sixty percent of the threats were likely to happen in real life. And in most cases, the dreamer "fought" the threat and won. The person got to "test-drive" an emergency situation and came up with a way to act appropriately.
So are recurrent dreams practice for dangerous real-life situations? A study in 2006 showed that recurrent dreams followed the patterns of regular dreams, with about 65.6 percent having a threat in them. As before, the subject generally fought back successfully against the threat, and the dream resolved itself. So far, recurrent dreams are exactly like regular dreams. The only thing that's flipped is the content.
While regular dreams in the 2000 survey involved real threats the majority of the time, the 2006 study showed that recurrent dreams dealt in fantasy. About eighty percent of the threats in recurrent dreams were stuff from "fairy tales, comics, or science fiction" — the remaining twenty percent were about real threats. In other words, my Rescue Rangers dream was very much the norm for recurring dreams.
Perhaps science fiction, fantasy, comics, or fairy tales introduce problems the mind can't solve because they don't actually exist, and so get stuck in our heads to be dreamed of over and over. Perhaps they are our dream retreat into a fictional world when we're stressed by real factors in our life. Or perhaps they're just odd enough that we can remember them, while we don't tend to remember stuff like, "And then for the tenth time this year, I dreamed about narrowly avoiding stubbing my toe." Whatever the case may be, if io9 has contributed to your dreams, do let us know.