We’ve all heard of déjá vu and I have already written here about that strange feeling of having “already seen” something or experienced it before without really having a memory of it. It is a fairly common experience.
And the less often heard jamais vu (from French, meaning “never seen”) is a real term in psychology which is used to describe any familiar situation which is not recognized by the observer. Sometimes it is seen as the opposite of déjà vu.
Jamais vu can evoke a strange and perhaps frightening feeling. I imagine if you are older this experience might make you think you are suffering from memory loss. It’s more than just not recognizing a word, or a person, or place that you should know. An example given is not having a memory of a place you lived in for several years and also have the feeling that you should know this place.
Although this can be associated with serious pathological reasons (aphasia, amnesia, epilepsy, Alzheimer’s disease), it can also occur because of stress and fatigue.
Since I last wrote about those two phenomena, I also discovered other related terms for odd feelings.
Presque vu (“almost seen”) is supposed to describe that moment when you are on the edge of almost remembering a word, name or memory. It’s on the “tip of your tongue.”
Déjà entendu (“already heard”) is the auditory version of feeling that you have already heard something, even though the exact details are uncertain or were perhaps imagined.
But the one that interested me much more is déjá rêvè. It means “already dreamed.” This is when you believe that you have already dreamed about a real-life situation or via a dream you knew that you were going to be in that situation.
The dream may have been last night or years ago, but if it is déjá rêvè you think you have somehow prophesized an event.
Déjá rêvè is similar to déjá vu in that in both cases you seem to know something before you really encounter it, but in déjá rêvè it is linked to dreams. With déjá vu you feel like you have already lived that experience and are now reliving it again.
Déjá rêvè is like a dream-based premonition. I have read that there appear to be three variations of déjá rêvè.
The episodic version is when you can pinpoint the exact moment you had the dream and so it feels like you could “see into the future.”
The second version is when it is a more hazy dream memory that echoes a current circumstance. This would seem very close to déjá vu.
The third kind is quite odd. This is when the experience itself seems dream-like, sort of like lucid dreaming except the subject knows they are awake.
Déjá vu is said to occur in 60-80% of all people. It has been well-researched and it seems to be a memory-based experience where what we experience at the moment echoes what we have experienced in the past. Some researchers believe there is a split-second delay between the transfer of information from one side of the brain to the other and so that is processed twice causing the feeling that it was experienced twice.
The random nature of all these experiences makes it hard to study since it relies on individual testimony. You can’t induce the experiences for experimental purposes.
Although dreams have certainly been studied for many years and quite seriously, déjá rêvè has not been studied as deeply.