Everyone must of had that feeling of Deja Vu before?

  • Thread starter richnfg
  • Start date
  • #26
-Job-
Science Advisor
1,151
2
That's not true. You're making the assumption that, as with a Grand Mal seizure, this "small seizure" activity correlated with Deja Vu is random and caused by abnormal functioning of the brain. Should we make that assumption for every "small seizure"? Where does normal activity end and a "small seizure" begin? What brain process can't be correlated to a "small seizure"? Does sex generate a small seizure in certain areas of the brain? Is this brain activity abnormal and uncaused or at least with a cause not identifiable by the subject?
 
  • #27
6,362
1,281
-Job- said:
That's not true. You're making the assumption that, as with a Grand Mal seizure, this "small seizure" activity correlated with Deja Vu is random and caused by abnormal functioning of the brain. Should we make that assumption for every "small seizure"?
Yes, this kind of hypersynchronous firing is not normal and the result is a distorted experience just like muscular seizures represent distorted, abnormal muscular activity.

http://www.emedicine.com/neuro/topic415.htm
Seizures are the manifestation of abnormal hypersynchronous discharges of cortical neurons.
and:
Seizures are paroxysmal manifestations of the electrical properties of the cerebral cortex. A seizure results when a sudden imbalance occurs between the excitatory and inhibitory forces within the network of cortical neurons in favor of a sudden-onset net excitation.

Where does normal activity end and a "small seizure" begin?
First off: a "small" seizure, that is: a simple partial seizure, is small only in that it is limited to a small part of the brain. The actual activity of the smaller number of neurons involved during a simple partial is just as pathological as during a full brain seizure. They aren't seizing more gently or anything like that. There is a definite threshold that is crossed when the neurons begin to fire both more strongly than normal and provoke nearby neurons to do the same. The paper I linked to above goes into the technical details of this if you want to slog through it with a medical dictionary.
What brain process can't be correlated to a "small seizure"?
You don't seem to understand that the firing of neurons is not a seizure. A seizure is a particular kind of abnormal, exaggerated and uncontrolled firing of neurons. This can happen anywhere in a persons brain, or to just about the whole brain at once. It is always disruptive and causes malfunctioning of the brain processes affected.

We percieve everything around and in us by virtue of the smooth, proper functioning of our brains. We percieve, think and feel and plan with our brains. When some small or large population of neurons begins to malfunction for any reason, be it seizure, stroke, Multiple Sclerosis, Parkinson's, Alzheimer's, or any brain disease, a person's perceptions, thought processes, emotions, and body functions can be grossly distorted, exaggerated, or stop functioning altogether.

Does sex generate a small seizure in certain areas of the brain?
Good question. This came up in a thread on an Epilepsy forum once. Is the activity of the parts of the brain responsible for things like orgasms and sneezes anything like seizure activity? Everyone's intuition about it was that things like this seemed to have the same kind of intensity. No one bothered to research it, though, and we left it at wondering.

I'd say there are some obvious important differences. Sneezes and orgasms are provokable in perfectly healthy people by stimulating the right sensory organs. There is no built in, natural way to provoke a seizure in a healthy person (memories don't cause deja vu's, moving the muscles doesn't cause convulsions). Sneezes and orgasms serve a purpose and they are self limiting.

The other thing that came up is hiccups. These are more suspect. They are often not self limiting, seem to go out of control, and they don't seem to serve a purpose.
Is this brain activity abnormal and uncaused or at least with a cause not identifiable by the subject?
Seizure activity is always abnormal and there's always a cause: it's always a symptom that something else is wrong. (Seizures are not a disease unto themselves.) There is always some lesion or chemical problem or oxygen starvation or something that causes it. The paper I linked to in my post to Ivan about simple partials has a list of some common causes:

Causes: Any localized structural lesion of the brain can result in SPS, including the following:

* Developmental abnormalities

* Vascular lesions

* Meningitis/focal encephalitis

* Trauma

* Tumors

* Hypoxic insults

* Postsurgical changes

* Metabolic and electrolyte shifts

* Endocrine disorders

* Medications and toxins

Note especially, "Metabolic and electrolyte shifts". This sort of thing can happen to anyone as a result of being overstressed, overtired, poorly nourished, dehydrated, etc. Notice also "Endocrine disorders". Your endocrine system is quite complex and anything that throws it out of whack might predispose you to a temporary bout with simple partials. Anyone might have a simple partial, or a few of them, without there being anything permanently or seriously wrong with them.
 
  • #28
6,362
1,281
-Job- said:
If in the future without noticing i'm in a place with blue walls, hearing any beatles song, and for some reason, any at all, i start to think about my dog, and that funny thing she once did, then these things can trigger that weak memory. But i won't be aware of the memory because it's not the same place, it only has blue walls, it's not the same beatles song, it's just a beatles song, and it's not the same thought process, it just begins and ends the same. All of this can trigger a memory and yet it maybe impossible for me to identify why the situation seems familiar. Why would it be the blue walls and not ceiling fan? There are many details, how can i identify the ones that triggered the memory? Many times we can't, and we're just left with the feeling of familiarity, Deja Vu. Whether or not neuronal activity is triggered by this is open for debate, but if i have experienced deja vu i'm confient that it is, although i admit the possibility that i never experienced proper deja vu (even though i have no reason to believe that)
I see you added to this post after I responded so I'll address your addition.

What you're describing with the memory that you can't place is not a deja vu. It's just a memory you can't place. Everyone has had this experience: you are unconsciously reminded of something by some subliminal trigger you're not aware of.

I have had this problem before: if someone hasn't actually had a deja vu they assume I'm talking about this sort of vague memory. I find it's impossible to communicate what they're really like to someone who's never had one and the people who've never had one sometimes think they have because of the kind of thing you're talking about. Sometimes I'll be watching a movie on TV and I'll suddenly be struck by the strange feeling that it seems familiar even though I'm not aware of having seen it before. Then later I'll suddenly remember that I did see part of it once several years before but changed the channel out of boredom. This is not a deja vu. Likewise I once was overwhelmed by an amazingly pleasant sense of familiarity when I was in a friend's garage and bent down to pick a wrench up off the floor. For some reason some rusty old cans on the floor smelled exactly like the old tools in my grandmother's tool shed and it reminded me of a whole period in my childhood I hadn't thought about in a long time. It took me a while to place the smell, though. I couldn't remember at first where I'd smelled it before. This was a powerful experience, yes, but it was nothing like a deja vu. And, of course, it wasn't a seizure, just a memory.

A deja vu is quite different. You have the distinct feeling your life is a recording that is being played over again. Everything around you down to the smallest detail seems superfamiliar. You don't feel merely reminded of something you can't put your finger on. You know what is familiar: everything! All the things around you and every thought in your head. Your life seems like a recording that has been rewound a moment and is being replayed with your memory of the previous playing intact.

Still, even that doesn't do the experience justice because if you repeat a song on a CD, for instance, the second playing doesn't amaze you for being familiar. A deja vu does: everything seems superfamiliar, and that fact amazes you. If you happen to speculate about what might happen next, that speculation seems amazingly familiar, and you suddenly believe this is because you know what is going to happen next. If it doesn't happen, the fact it didn't happen seems amazingly familiar, and you say to yourself: "Oh yeah! I made that same mistake about what was going to happen next the last time I lived through this time loop!" No matter what happens it all gets dosed with the same superfamiliarity.

I have talked to many people who've had the same experience of a deja vu that I'm describing, and it was clear from everything they said that we were talking about the same thing. There is generally a ramping up of emotion when they talk about it, an increase in exitement, because it is such a mind-blowing, unforgettable experience. However, you can't gage this sort of thing over the internet and I'm starting to wonder if everyone who reports they've had a deja vu has actually had one.
 
  • #29
-Job-
Science Advisor
1,151
2
I know what you're saying Zoob, but the way you're putting is not the way it's interpreted. It doesn't feel like a memory, like as what you described with the movie and the smell. It's not about something concrete seeming familiar, it's the impression that the situation has happened before. When i mention familiarity, i'm just suggesting that it's unconsciously triggered by some familiarity with the situation, that it's caused by this familiarity, even though you're not aware of anything concrete seeming familiar.
For example, recently before i went to bed there was a mosquito in my room, i can't sleep if there is a mosquito in the room. I had seen it but i didn't know where it was so in my attempt to move it from its hiding place i started to move things. I eventually came to my bed and shook the bed sheets, then looked at the floor in front of the bed and while doing this i had the feeling of Deja Vu, namely that this exact same thing had happened before, namely me being there doing the exact same thing for exactly the same reason. It's a familiarity with the sequence of input-thought-reaction, i.e. the situation, not with anything concrete.
I think this is what the majority of the people, who claim to have experienced Deja Vu, experience, which is possibly not the "clinical Deja Vu" that you mentioned and that is associated with a small seizure.
I think i'll leave it at that.
 
Last edited:
  • #30
Math Is Hard
Staff Emeritus
Science Advisor
Gold Member
4,566
30
Can the deja vu experience vary in intensity or how long it lasts? I think there were a couple of times I had deja vu and it was just a vague feeling of familiarity lasting for a split second. I have also had a longer deja vu feeling that I've had during a conversation with someone. I know it lasted longer because I was analyzing the experience while I was talking, and I was telling the person I was having deja vu and felt I had had that conversation with her before.
 
  • #31
-Job-
Science Advisor
1,151
2
I think if you were to analyze the conversation, possibly, you'd find that the familiarity you experienced was triggered by some aspects of the conversation (i.e. the line of reasoning, not necessarily the wording).
When a situation causes a subject to consider A and B, and conclude A + B => C, it's not a wild assumption that the brain will associate A and B with C. If a situation comes up that leads a subject to consider A + B = C again, it's not unreasonable that the subject might feel that the situation has occured in the past, because the association is already there, independently of how the association was brought by, both times.
This might be testable.
 
Last edited:
  • #32
6,362
1,281
-Job- said:
I know what you're saying Zoob, but the way you're putting is not the way it's interpreted. It doesn't feel like a memory, like as what you described with the movie and the smell. It's not about something concrete seeming familiar, it's the impression that the situation has happened before. When i mention familiarity, i'm just suggesting that it's unconsciously triggered by some familiarity with the situation, that it's caused by this familiarity, even though you're not aware of anything concrete seeming familiar.
For example, recently before i went to bed there was a mosquito in my room, i can't sleep if there is a mosquito in the room. I had seen it but i didn't know where it was so in my attempt to move it from its hiding place i started to move things. I eventually came to my bed and shook the bed sheets, then looked at the floor in front of the bed and while doing this i had the feeling of Deja Vu, namely that this exact same thing had happened before, namely me being there doing the exact same thing for exactly the same reason. It's a familiarity with the sequence of input-thought-reaction, i.e. the situation, not with anything concrete.
I think this is what the majority of the people, who claim to have experienced Deja Vu, experience, which is possibly not the "clinical Deja Vu" that you mentioned and that is associated with a small seizure.
I think i'll leave it at that.

I can't sort out if what you're experiencing should really be called a deja vu. The explanation that satisfied you, that you had simply triggered a similar train of thought, just wouldn't work to explain the intensity of the superfamiliarity.

For clarity's sake and precision the term should only be used in conjunction with the very extreme and unmistakable experience caused by a simple partial. Neurology got dibs on it long ago. It shouldn't be used to refer to authentic memories a person can't quite place, or to situations where the dynamics of a previous situation are authentically repeated. If people are thinking of these two latter things it is no wonder they would object to the notion it's a seizure.
 
  • #33
-Job-
Science Advisor
1,151
2
I think the question can be reduced to whether it is possible to build two scenarios such that a subject, made to experience both scenarios in succession (not necessarily immediate succession), can be made to feel Deja Vu.
 
  • #34
6,362
1,281
Math Is Hard said:
Can the deja vu experience vary in intensity or how long it lasts? I think there were a couple of times I had deja vu and it was just a vague feeling of familiarity lasting for a split second. I have also had a longer deja vu feeling that I've had during a conversation with someone. I know it lasted longer because I was analyzing the experience while I was talking, and I was telling the person I was having deja vu and felt I had had that conversation with her before.
All mine were all superintense and unmistakable untill after a couple years I learned a trick to stop them from escalating to full intensity. Now I can say I've had some "mild" ones, refering to one's I have defused.

The length of mine is always about the same: two or three seconds of very strong familiarity that then attenuates to normal over the next few seconds. I've always assumed most people's were about the same duration and have never thought to ask people about this.

The ones I've read about that last for any appreciable length of time lead to spreading of the seizure activity to include all kinds of other symptoms. Some people have deja vu's that become compounded by extreme feelings of fear, dread, or embarrassment, for example. In others they lead to a chaotic collage of memories with strong but hard to describe emotions attached to them. In others it leads into a complex (as opposed to simple) partial seizure where there is a gross defect of consciousness.

So, I can't really say if there are people out there having mild deja vu's that are seizures because if there are they've never been given any clinical attention. The people I've talked to who clearly understand what I mean when I raise the subject all descibe experiences as intense as mine. They become visibly exited relating their story: it's clearly a remarkable, unforgettable thing for them. These are just normal people who've had one once, twice, or a few times, not people diagnosed with seizure disorders.
 
  • #35
Math Is Hard
Staff Emeritus
Science Advisor
Gold Member
4,566
30
-Job- said:
I think the question can be reduced to whether it is possible to build two scenarios such that a subject, made to experience both scenarios in succession (not necessarily immediate succession), can be made to feel Deja Vu.
This got me thinking how hard it would be to try to reproduce deja vu or a deja vu-like experience in a lab with means other than direct brain stimulation. It seems that this actually has been attempted, though:
In the final box are "double perception" theories of déjà vu, which descend from Allin's 1896 suggestion that a brief interruption in our normal process of perception might make something appear falsely familiar. In 1989, in one of the first laboratory studies that tried to induce something like déjà vu, the cognitive psychologists Larry L. Jacoby and Kevin Whitehouse, of Washington University in St. Louis, showed their subjects a long list of words on a screen. The subjects then returned a day or a week later and were shown another long list of words, half of which had also been on the first list. They were asked to identify which words they had seen during the first round.

The experimenters found that if they flashed a word at extremely quick, subliminal speeds (20 milliseconds) shortly before its "official" appearance on the screen during the second round, their subjects were very likely to incorrectly say that it had appeared on the first list. Those results lent at least indirect support to the notion that if we attend to something half-consciously and then give it our full attention, it can appear falsely familiar.
http://chronicle.com/free/v50/i46/46a01201.htm [Broken]
I thought this entire article was a good read. It discusses alternative theories of deja vu and historical perspectives on the phenomenon.

There's a great quote from Nathaniel Hawthorne describing it as "that odd state of mind wherein we fitfully and teasingly remember some previous scene or incident, of which the one now passing appears to be but the echo and reduplication."
 
Last edited by a moderator:
  • #36
6,362
1,281
We don't normally think of familiarity as an emotion, but if you examine the whole issue in context it's clear that it is, and that a deja vu is the erroneous triggering of an emotional reaction.

Notice that the deja vu has it's opposite, the jamais vu. This is a simple partial during which the sence of familiarity shuts off altogether. The result is that things and situations the person intellectually knows to be familiar feel completely foreign, alien, and strange. The person is confronted by something that looks exactly as they remember it, but fails to elicit any feeling that it's familiar. It seems "wrong" somehow, not the same, as if it's essence had been removed. The same goes for people and places, not just objects, a person might encounter during a jamais vu. They seem like souless copies of the originals.

Familiarity therefore, has to be understood, not as a quality inherent in what we percieve, but as an internally generated reaction to what we percieve. Normally the brain generates a realistic level of this feeling, probably by comparing the current situation to memory. We perceve something, and in a split second the brain has determined the level of our familiarity with it and generated a physiological reation, a "feeling" appropriate to that level. If it fails to do so, as when the hippocampal/amygdala activity is inhibited during a jamais vu things that should feel perfectly familiar won't. If the opposite happens, if the hippocampal/amydala activity is sent into a paroxysmal overreaction the thing will seem falsly superfamiliar.

Repeated exposure to something doesn't produce a feeling of superfamiliarity. In fact, the more we're exposed to something the less we tend to notice it. I'm very familiar with the sight of the laptop in front of me, for example. I see it several hours a day. All this exposure to it doesn't accumulate into a feeling of superfamiliarity, though. I never look at it and become amazed at how familiar it seems.

All emotions are generated in the limbic system of the brain. Normally they are more or less appropriate to the situation and serve some purpose. Fear makes us run from a burning building, amusement relieves stress, etc. But because of the way the brain works any of these emotions can be inappropriately triggered, or, fail to arise when they should.

Deja vu's aren't authentic recognition of things we are familiar with. They are the erroneously amplified activity of a part of the brain that governs the feeling of familiarity, which then becomes falsly associated with our surroundings. (Remember: we think the familiarity is a quality of what we're looking at instead of realizing it's actually a reaction we have to it.) You can't reproduce this experience by repeated exposure to the surroundings because they never actually have anything to do with it in the first place. On the other hand, if you were to electrically stimulate someone's hippocampus where feelings of familiarity are generated you could make anything and everything seem superfamiliar to them.
 
Last edited:
  • #38
618
0
Is a sign of frequent deja vu indicative of any possible neurological damage or problems? Is it "normal" to have it? How often is "normal"?

I get Deja-vu probably once or twice a month. The most frequent style I get is walking into a room in which I have never been and saying to myself "Ive been here before..." and then going "Yea, i knew she was going to say that, and I knew that waitress was going to drop that" though I obviously didnt think about it prior. Its about 5 seconds of complete familiarity.
One thing I've noticed is that my brain instantly recognizes it for what it is. The voice in my head says "this seems really familiar, as if it has happened before, BUT IT HASNT"
It doesn't feel as if its an actual memory that you SHOULD have recollected, but rather some dreamt-up creative storyline that you know never existed, but followed the same plot. As if you were remembering a dream as it happened before you. Or that life was following the same lines as a book you had read 10 years ago. You get the feeling of "oh yea i remember that part"
Once again though, the logical part of my mind tells me instantly that the feelings I have of familiarity are not founded and that I haven't been there/seen that before.
 
  • #39
6,362
1,281
Pythagorean said:
interesting. I didn't think it had been pinpointed that well.
There seems to be some inexplicable gap between neurologists and everyone else. Neurologists have known the deja vu is a simple partial for decades. I think they keep this to themselves because the word seizure is so alarming to most people. The result, though, is that there always seems to be a research team somewhere barking up the wrong tree trying to figure out what deja vu's are from scratch.

The article linked to by Math Is Hard reminds me of an old joke: A guy sees a woman searching the ground in a parking lot at night. "Did you lose something?" he asks? "Yes" she says, I lost a hundred dollar bill." He walks over to where she's searching and offers to help. "Oh", she says, "I'm pretty sure I didn't lose it here. I think I must have dropped it over there." and she points to a spot a hundred yards away. "I'm only looking here because the light's so much better."

Even though the guy in MIH's link knows about simple partials he still keeps searching for a different explanation of deja vu's in all the wrong places because, I think, he wants an explanation he likes better.
 
  • #40
6,362
1,281
Healey01 said:
Is a sign of frequent deja vu indicative of any possible neurological damage or problems? Is it "normal" to have it? How often is "normal"?

I get Deja-vu probably once or twice a month. The most frequent style I get is walking into a room in which I have never been and saying to myself "Ive been here before..." and then going "Yea, i knew she was going to say that, and I knew that waitress was going to drop that" though I obviously didnt think about it prior. Its about 5 seconds of complete familiarity.
One thing I've noticed is that my brain instantly recognizes it for what it is. The voice in my head says "this seems really familiar, as if it has happened before, BUT IT HASNT"
It doesn't feel as if its an actual memory that you SHOULD have recollected, but rather some dreamt-up creative storyline that you know never existed, but followed the same plot. As if you were remembering a dream as it happened before you. Or that life was following the same lines as a book you had read 10 years ago. You get the feeling of "oh yea i remember that part"
Once again though, the logical part of my mind tells me instantly that the feelings I have of familiarity are not founded and that I haven't been there/seen that before.

Once or twice a month is pretty much harmless and no neurologists would bother treating anyone for that.

You could probably get rid of them altogether by eating a consistant, balanced diet, sleeping well every night, completely avoiding alcohol, and getting light, moderate excercise everyday.

I met a woman a few months ago who had a few simple partials every day. I advised her to see a neurologist. He confirmed they were simple partials, but, since she had just quit drinking and joined AA, he wasn't going to treat her at all. He wanted to wait and see how much they subsided after she stopped triggering them by drinking so much.

edit: if you are also having any other weird experiences you can't explain, especially anything you might call "missing time" or "amnesia" then it would indicate that you should be concerned. It could mean you're having the much more serious complex partial seizures.
 
Last edited:
  • #41
618
0
zoobyshoe said:
Once or twice a month is pretty much harmless and no neurologists would bother treating anyone for that.

You could probably get rid of them altogether by eating a consistant, balanced diet, sleeping well every night, completely avoiding alcohol, and getting light, moderate excercise everyday.

I met a woman a few months ago who had a few simple partials every day. I advised her to see a neurologist. He confirmed they were simple partials, but, since she had just quit drinking and joined AA, he wasn't going to treat her at all. He wanted to wait and see how much they subsided after she stopped triggering them by drinking so much.

edit: if you are also having any other weird experiences you can't explain, especially anything you might call "missing time" or "amnesia" then it would indicate that you should be concerned. It could mean you're having the much more serious complex partial seizures.

No, no missing time. But though I'm still fairly young (23), does anyone else get the distinct feeling that as we get older and older the passing of time speeds up more and more and more? I don't mean immediate local passing of time, but more like weeks, months and years pass faster and faster. I thought at first it was a memory issue where the less immediate things I'm remembering leads to a feeling of less things to recall, therefor a feeling of less time passed than actual. Fortunately though, it still seems my memory is more accurate and deep than 90% of the people around me (both from observation and from them telling me so).

Anyone else get that feeling of time getting shorter and shorter?
 
  • #42
selfAdjoint
Staff Emeritus
Gold Member
Dearly Missed
6,852
10
Healey01 said:
No, no missing time. But though I'm still fairly young (23), does anyone else get the distinct feeling that as we get older and older the passing of time speeds up more and more and more? I don't mean immediate local passing of time, but more like weeks, months and years pass faster and faster. I thought at first it was a memory issue where the less immediate things I'm remembering leads to a feeling of less things to recall, therefor a feeling of less time passed than actual. Fortunately though, it still seems my memory is more accurate and deep than 90% of the people around me (both from observation and from them telling me so).

Anyone else get that feeling of time getting shorter and shorter?


Well that's partly true of everyone. Consider that when you were 5 the time between your birthdays was a fifth of your life and now it's one-twenty-ninth, almost six times "shorter" in terms of experienced history. But the other part is that if your mind is active and happily occupied, and your life has a little variety in it, time doesn't flit quite so fast. The space between my birthdays (I am 73) doesn't seem half as long as when I was 36.
 
  • #43
Math Is Hard
Staff Emeritus
Science Advisor
Gold Member
4,566
30
Another attempt at producing a deja vu-like experience -- using hypnosis:
http://news.bbc.co.uk/2/hi/health/5194382.stm
The Leeds team set out to create a sense of deja vu among volunteers in a lab.

They used hypnosis to trigger only the second part of the recognition process - hoping to create a sense of familiarity about something a person had not seen before.

The researchers showed volunteers 24 common words, then hypnotised them and told them that when they were next presented with a word in a red frame, they would feel that the word was familiar, although they would not know when they last saw it.

Green frames would make them think that the word belonged to the original list of 24.

...

After being taken out of hypnosis, the volunteers were presented with a series of words in frames of various colours, including some that were not in the original 24 and which were framed in red or green.

Of the 18 people studied so far, 10 reported a peculiar sensation when they saw new words in red frames and five said it definitely felt like deja vu.
 
  • #44
6,362
1,281
It is estimated that as many as 97% of people have experienced deja vu.
I have heard this figure before but I now don't trust it since it's not clear to me that everyone who says they've had one is actually having the "authentic" deja vu experience. In my own experience I would estimate that only a third of all the people I've met seemed to have experienced the same thing I have.
Two key processes are thought to occur when someone recognises a familiar object or scene.

First, the brain searches through memory traces to see if the contents of that scene have been observed before.

If they have, a separate part of the brain then identifies the scene or object as being familiar.

In deja vu, this second process may occur by mistake, so that a feeling of familiarity is triggered by a novel object or scene.
This is a misunderstanding of a deja vu. The feeling isn't triggered by the novel object or scene. It happens when it happens, but invariably gets falsly ascribed to the external surroundings. It's rather like the old story of the love potion that makes you fall in love with the first person you meet. The feelings of love come from the potion but are falsly assumed to have been triggered by the first person who show up. What it says later is more like it:
And previous work in France has found that electrically stimulating parts of the temporal lobe can trigger a sensation of familiarity with everything a person encounters.

I find this claim to be problematic:
Of the 18 people studied so far, 10 reported a peculiar sensation when they saw new words in red frames and five said it definitely felt like deja vu.
They were instructed under hypnosis to experience the words as familiar and so it isn't of any particular interest that they reported that they did. It doesn't mean they experienced any authentic deja vu feeling, just that they were faithfully presenting the behavior of someone who had. This is how hypnosis works: the hypnotist elicits a loyalty from the subject to stick with the suggestion. You may recall Feynman's story of being hypnotized, and how he felt an inexplicable obligation to behave in accordance with the post hypnotic suggestion. He didn't authentically feel unable to return to his seat by a certain route. Instead, what he felt was a strong, urgent need to act as if he felt unable to do it, a kind of loyalty to the hypnotist to play the game.

I doubt if anything like a real deja vu was created here.
 
  • #45
-Job-
Science Advisor
1,151
2
Zoob, maybe the Deja Vu you describe as having experienced isn't the classical Deja Vu, but something of a bigger scale, or something different altogether.
I've always thought of Deja Vu as a common, low intensity experience.
 
  • #46
Math Is Hard
Staff Emeritus
Science Advisor
Gold Member
4,566
30
My thinking is that maybe the Deja Vu phenomenon needs a clearer taxonomy. There could be different causal bases, and there could also be different effects that would influence how each is categorized. I am not by any any means dismissing temporal lobe simple partial seizures as the basis for the majority of them, but maybe they only create one or two types of experience which are causally and qualitatively unique.

Outside of that, there could be other types of reported Deja Vu experience which might be worth exploring. Some may be hypnotically induced, dream memory induced, or chemically induced, (or other) and they could certainly vary in intensity or length of the sensation.
 
  • #47
83
1
i have this problem, that a short after a certain expirience i get the feeling that i already had a similiar expirience a long long ago, but i always find it a false feeling, since i could not retrieve such memory after long scanning... it happens only after the expirience, so im pretty much sure i cant predict the future =)...

so if it would happen to a man a milisecond after the expirience, it would realy seem as deja vu...

but thats all on assuming that the man is ****ed up as the i.
 
Last edited:
  • #48
6,362
1,281
-Job- said:
Zoob, maybe the Deja Vu you describe as having experienced isn't the classical Deja Vu, but something of a bigger scale, or something different altogether.
I've always thought of Deja Vu as a common, low intensity experience.
The deja vu as I experience it is described over and over in neurological studies and, as I mentioned earlier, at least a third of the people I know seem to have had the same experience as me, with the same intensity. I can't even begin to entertain the notion mine aren't classic when I've read and heard mine described in so many sources and by so many people. These milder, iffy-er reports like yours are really the more unusual.
 
  • #49
6,362
1,281
Math Is Hard said:
My thinking is that maybe the Deja Vu phenomenon needs a clearer taxonomy. There could be different causal bases, and there could also be different effects that would influence how each is categorized. I am not by any any means dismissing temporal lobe simple partial seizures as the basis for the majority of them, but maybe they only create one or two types of experience which are causally and qualitatively unique.
I'd rather that the terminology be more precise. Instead of labeling several essentially different things as different classifications of the same thing it would be much clearer and more accurate to have a separate name for each.
Outside of that, there could be other types of reported Deja Vu experience which might be worth exploring. Some may be hypnotically induced, dream memory induced, or chemically induced, (or other) and they could certainly vary in intensity or length of the sensation.
If there are milder experiences of the kind of hippocampal centered seizures that I have then they are simply milder seizures, milder deja vus. I can't, and didn't, say these don't exist. I don't know if they do. No one could say for sure. The reason being that someone like you who may have had one of these, would never be tested with depth electrodes to see if the feeling corresponds to seizure activity. Such an invasive proceedure would never be allowed just for curiosity's sake.

The people whose deja vus have been recorded by EEG were being prepped for brain surgery because of much more serious seizures that weren't responding to medication. The depth implanted electrodes were for the purpose of locating the seizure focus. The deja vus, (and many other simple partials that have been recorded this way) were not the main point of the procedure at all, and I don't think any neurosurgeon in the world would implant electrodes just to study simple partials. They pick these up, incidently, in the process of looking for the more serious seizures.

So there may be mild deja vus that are simple partials, but I can't assert that for certain. I have no EEG recording to show you.

As for experiences that are apparently the result of precognitive dreams, we should call them "Apparent Dream Precognition", not deja vus, and other non-disprovable incidents of precognition we can call "Apparent Precognition," and not deja vus.

I have had experiences different from my deja vus which I would call "Apparent Dream Precognition" and also "Apparent Precognition". I can't lump these together with the deja vus because they are distinctly different in quality, they just weren't the same thing.

The other problem that may be in play here is descriptive ability of the people reporting the experience. If you've only had a genuine one a few times they can come and go before you can overcome your surprise enough to pay attention to them. It is possible Job has had the same thing as me, but couldn't pay close enough attention to it to see that his explanation doesn't actually fit the experience at all. It was actually a long time before I started realizing certain things about them, especially that they were internally generated "feelings" that only seemed attached to the external situation. Likewise it took probably thousands of them before I sorted out why they were creating the illusion of precogition.

Terminology is important. There was a woman posting on the Epilepsy Forum once about her son's "deja vus". I had to explain to her that what she was describing wasn't deja vu's at all, but flashbacks, another fairly common but distinctly different simple partial. The term "deja vu" seemed to her to fit what he was experiencing because he had fast-changing visual hallucinations of scenes from his past: things he'd already seen, hence, she thought, "deja vu". The term sort of fits but has already been dedicated to a specific kind of experience and it's just going to prevent people from understanding one another if we apply it to anything that roughly feels like "already seen". We don't want to create a "taxonomy" where mice are a kind of subset of cats because they both have fur, four feet, tails, and sleep alot.
 
Last edited:
  • #50
223
0
A deja vu is an extremely mysterious and powerful experience where your current situation suddenly seems remarkably familiar when you concurrently know it cannot be familiar. Not everyone has had a deja vu and I think that people who haven't are somewhat confused about what it's like, and maybe think they have had one. It isn't a matter of something seeming vaguely familiar, it's an overwhelming, stop-you-in-your-tracks, flood of familiarity attached to a situation you intellectually know is not one you've ever been in before. The strength of this feeling is unbelievable. It seems 20 times more familiar than anything that actually is familiar. It's distinctly unnatural feeling: the present seems like an exact repeat of itself down to the smallest detail, as if your mind had skipped back in time and was reliving a moment all over again.
I have this sort of experience happen to me a few times a year. I dont really count them, and actually rather enjoy the experience, it makes me feel 'Human'. It reminds me of some LSD experiances I have had when i was younger, except that was more the feeling of everything taking on a new meaning, rather than everything being familiar, but knowing they are not.
 
Last edited:

Related Threads on Everyone must of had that feeling of Deja Vu before?

  • Last Post
Replies
12
Views
3K
  • Last Post
Replies
3
Views
4K
  • Last Post
Replies
5
Views
1K
  • Last Post
Replies
2
Views
3K
  • Last Post
Replies
1
Views
2K
Replies
1
Views
2K
Replies
19
Views
3K
Replies
5
Views
2K
Replies
27
Views
2K
Top