Déjà vu is a French phrase meaning “already seen”. It’s a feeling of familiarity that you get when you’re in a new situation despite knowing that you’re experiencing the situation for the first time.
People who experience deja vu usually say something like this…
“Although this is the first time I’ve visited this place, I feel like I’ve been here before.”
No, they’re not just trying to sound cool. Deja vu is a fairly common experience. According to one survey, about two-thirds of the population have had deja vu experiences.
To understand what causes deja vu, we need to observe the psychological state of deja vu a tad more closely.
Firstly, we notice that deja vu is almost always triggered by locations and places rather than people or objects. So locations and places have some kind of an important role to play in triggering deja vu.
Second, we look at what the mind tries to do while being in the state of deja vu.
After the initial feeling of familiarity, we notice that people desperately try to recall why the place looks so familiar. They scan their past intensely hoping to find a clue, usually in vain.
This suggests that deja vu has something to do with memory recall, otherwise this cognitive function (memory recall) wouldn’t be activated in the first place.
Now with these two variables at hand (location and memory recall), we can arrive at a theory as to what triggers deja vu…
Deja vu is triggered when a new situation unconsciously triggers the memory of a past similar situation but we fail to consciously recall the precise memory of the latter.
This is why our mind searches and searches, trying to find out the past situation that is similar to the new situation that we’re currently experiencing.
So deja vu is basically an aberration in the normal way with which memory is recalled. Deja vu may well be defined as ‘an incomplete recollection of a memory’. We have a slight feeling of knowing that we’ve been here before but we can’t exactly recall when.
It’s unclear why some memories are incompletely recalled. A most likely explanation is that such memories were vaguely registered in the first place, hence aren’t properly recalled.
Another explanation is that they were registered in distant past and are buried deep in the unconscious.
Our conscious mind may tug at them a little but is unable to fully pull them out of the subconscious, therefore causing us to experience deja vu.
Similar arrangement of different objects
An experiment revealed that similar spatial arrangement of different objects in different scenes can trigger deja vu.
Participants were first shown images of objects arranged in a particular fashion. Later, when they were shown images of different objects arranged in the same fashion, they reported experiencing deja vu.
Say you visit a picnic spot that is a large field with a sole farmhouse on the horizon. Years later, while looking for a good place to camp, say you find yourself in a large field with a sole hut on the horizon at the far end.
“I think I’ve been here before”, you utter with a weird, other-worldly expression on your face.
The thing is, our memory for the arrangement of objects is not so good as that of the objects themselves. If, for example, you notice a new plant in your dad’s garden that he calls his favourite you may immediately recognize it when you see it next.
But you may not have a good memory of how your dad arranges that plant in his garden i.e. where he sows it and next to what other plants. So if you visit a friend who grows a different plant but arranges it in the same fashion as your dad arranges his favourite plant, you might experience deja vu.
Ever had that experience where you look at a word that you’ve looked at a thousand times before, but suddenly it seems like you’re looking at it for the first time?
Well, this feeling that a familiar thing is new or strange is Jamais vu and it’s the opposite of deja vu. In Jamais vu you know what you’re seeing is familiar, but somehow it seems unfamiliar.
An experimenter once made his participants write the word “door” again and again. Soon, more than half of the participants reported experiencing Jamais vu.
Try it out. Write any word or phrase over and over again like Jack Nicholson in The Shining and see what happens. Please don’t lose your mind though.