Boing Boing: Deja Vu in Scientific American Mind Deja Vu in Scientific American Mind

"The term "déjà vu"--French for "seen already"--may have first been used in 1876 by French physician Émile Boirac. For much of the 20th century, psychiatrists espoused a Freudian-based explanation of déjà vu--that it is an attempt to recall suppressed memories. This "paramnesia" theory suggests that the original event was somehow linked to distress and was being suppressed from conscious recognition, no longer accessible to memory. Therefore, a similar occurrence later could not elicit clear recall yet would somehow "remind" the ego of the original event, creating an uneasy familiarity...

A survey we conducted several years ago with more than 220 students at the Martin Luther University of Halle-Wittenberg in Germany showed that after they had experienced déjà vu, 80 percent of the respondents were able to recall a past event that was indeed similar in nature--an event they had forgotten. In line with this study, cognitive psychologists have shifted their attention to another unconscious process, that which is responsible for so-called implicit, or nondeclarative, memories. These are artifacts that we have long forgotten and do not retrieve consciously, although they have not been erased from our neural networks. Consider seeing an old cupboard at a flea market, and suddenly it seems strangely familiar, as does the act of viewing it. What you may have forgotten--or, rather, cannot retrieve--is that when you were a young child, your grandparents had a cupboard just like this one in their home.

A related theory implies that we may perceive a person, place or event as familiar if at some earlier time in our lives we were exposed to just a partial aspect of the experience, even if it was within a different context. Perhaps, when you were young, your parents stopped at a flea market while on vacation and one vendor was selling old kitchen cupboards. Or perhaps you smell an odor that was also present at that flea market you attended as a child. A single element, only partially registered consciously, can trigger a feeling of familiarity by erroneously transferring itself to the present setting."

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I love it when deja vu hits, sometimes it flits by quickly, sometimes settles in for tens of seconds. I always try to keep it rolling, it's sort of like a weird inner trip to my own holodeck.
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