Deja Vu refers to those odd and usually rare moments when the present feels like the past. Its a hard experience to interpret. Some people search their memories for dreams that might have been like the present. Others think that the experience is what happens when things from past lives emerge in this one. Both notions are impossible to prove, disprove, or (until recently), investigate. The belief that its about past lives is a matter of faith. The idea that it has to do with dreams is less a matter of faith - only a few people claim to recall past lives, but almost everybody remembers some of their dreams. Some recall a lot of them. The theory of reincarnation that is most consistent with modern brain science (Algorithmic Reincarnation) predicts that no memories are passed from one life to the next. What is transferred is a set of signals that reflect states of consciousness. Memories don't need to go along.

Memories are state-specific. We can have experiences in one state of consciousness (like when we are drunk, for example) that we cannot remember at all when we are in another. States of consciousness provide a much more direct way for someone to select how they will behave than remembering past behaviors and comparing them to present possibilities.

There is a fly in the ointment with dreams as well. Both dreams and deja vu experiences happen in non-normal states of consciousness. Most altered states are are a fertile ground for confabulations. This means that in the moment when someone is experiencing deja vu, its easier for them to create a false memory than it would be normally. In fact, during moments of deja vu , one's consciousness has unusually direct access to long-term memories, and the brain processes that allow us to retrieve them.

I'm not going to write it here that deja vu doesn't come from past lives or dreams, and that that's just how it is. But we want to understand what deja vu is, and how we can respond to it when it happens. If we explain it in terms of past lives and dreams, we are giving ourselves explanations that can't be proven. Or proved to be false. It will boil down to a matter of faith.

There are some people who experience precognitive dreams, but most episodes of deja vu happen without the person having any sense of it relating to a dream. Precognitive dreams are a different matter altogether. Having the present moment feel like a repeat of something from the past is not the same as having the present validate a previous precognition. I have spoken to some professional psychics about this, and one of them said that he could tell the two apart, but that it took him some time to learn the difference. I asked him what the difference was, and he said that it was an 'energy.' That's not really enough to help understand what the difference was, but enough for us to know that there might be one.


How does deja vu happen?


The scientific explanation is that it has to do with memory processes. I'll make it as simple as I can here. The basic idea is that there are portions of the brain that are specialized for the past, the present and the future. In general, the frontal lobes are concerned with the future, the temporal lobes are concerned with the past, and the underlying, intermediate portions (the limbic system) are concerned with the present. When these are all doing their normal thing, in normal states of consciousness, the feeling that 'something is going to happen will only come up when we are thinking about the future, worrying about it, anticipating it or making plans for it. The sense of the past will only come up when our memories have been triggered in some way.

The structure that overwhelms our consciousness when we are 'in the present are 'being here now' is the amygdala. It assigns an emotional 'tone' to our perceptions. When you step into the street and see a car speeding towards you, and you instantly freeze in terror and jump out of the way, that terror is the amygdala at work. Present. Here and now. The amygdala also recognizes expressions the expressions on people's faces. When we are talking to someone, we can recognize their expressions and change the way we are talking to them just as quickly as we recognize danger. Words can often seem dangerous to the one hearing them. "we're thinking of letting you go." "I've been thinking that our relationship is holding me back." "You are under arrest."

Phrases like these need instant, appropriate responses, and the amygdala is specialized to provide them. For example, one function it participates in, the maintenance of the sense of self, is repeated 40 times per second. Each instance of the self is able to manifest a new emotional response, but only if circumstances have changed. Every 25 milliseconds. In fact, the duration of the 'present' in neurological terms is so brief that we don't experience it so much as remember it.

The next level could be called 'being around here-just about now.'


Short term-memory deals in periods of a few minutes. Its mostly based in the hippocampus. We know this because problems with the hippocampus. often lead to severe short-term memory problems. It helps us to stay oriented in time. There have been a few people who have lost all hippocampal functions, and they are unable to remember anything that happened after their brain problems began. Humans are a linguistic species, and an intensely social one. We relate to each other through words. We have conversations. In order to do this, we have to be able to remember what people say to us. We also have to be to think about it long enough to be able to respond to it. We have to remember what we have just finished doing in order not to have to do it again.

There is a joke I heard while working in a nursing home: Happiness is finding your glasses before you forget what you need them for.


Then there is long-term memory. Its 'seated' in the surface of the brain, along the bottom of the temporal lobes. The area has been called the parahippocampal cortex, and its very closely connected to the hippocampus.

Ordinarily, there is a fairly seamless integration of the past, present and the future. In simple terms, we experience something in the present, compare it to similar experiences in the past, and decide how we will respond. The time frame can be very brief; even a few seconds. Once in a while, though, there can be too much communication between short-term and long-term memories. When this happens, then the present can feel like the past.

If perceptions from the present are shunted through the parts of the brain that process memories from the past, those perceptions will feel like they are memories, and the person will feel that they are re-living a moment stored in long-term memory.

There is another experience worth mentioning; Jamais Vu. Its the opposite of deja vu. Instead of feeling extra familiar, thing seem totally unfamiliar. In this case there is too little connection between long-term memory and perceptions from the present. When a person is in this state, nothing they experience seems to have anything to do with the past. They might be talking to a person they know well and suddenly they person seems totally unfamiliar. Their sense of knowing the person, and knowing how to relate to them simply vanishes. A room in which they spend a lot of time suddenly becomes totally novel; everything seems new. Details they will have seen a thousand times suddenly become engaging.

Jamais Vu is not so common as deja vu, but it can be just as compelling.

How do I respond to Deja Vu?

That depends on whether you enjoy it or not. Some people are just terrified when it happens. Others find it mildly euphoric.

As with all other altered state experiences, most people who enjoy it think of the experience in spiritual terms, and those who don't, think about it in psychological terms. I have talked to people who had it often, and found the experience to be terrifying. There is nothing frightening about deja vu in itself, but it can happen that activity from the hippocampus. can spill over into the neighboring structure, the amygdala, which is a highly emotional structure. If it gets into the one on the right, the emotion is going to be unpleasant, most likely fearful.