Cause of Déjá vu

[Dean Mullen]

If moving faster through space also makes you travel faster through time then maybe when observing the world if my left eye moves slightly faster than the right eye it would move slightly faster through time hence would receive information from the outside world faster than the right eye, so this could be the cause of déjá vu because you observe the same event twice in a row within a split second.

Edited February 19, 2011 by Dean Mullen

[Blahah]

Just my initial thought, but wouldn't your eyes have to be quite far apart for light to hit them a significant time apart? I mean, for there to be a second difference between when they saw things, your face would have to be 299,792,458 metres wide. Obviously the time difference between the eyes could be smaller, but it would still be a huge distance.

 

Also, wouldn't that then cause you to have déjá vu every time you saw something which required you to turn your head? I think I've only had it about 10 times in my life.

[Mr Skeptic]

Not even close to fast enough for the nerve signals to even leave the eye, much less register in the brain.

[lemur]

Maybe sometimes sensory input signals get routed through memory lobes or something like that. It would be interesting to find out what brain process is responsible for creating a sense of recognition. If you could control that, it would really streamline arranged marriages, I think. Or maybe you could use it as a marital aid, i.e. if you could temporarily suspend familiarity with your partner for the sake of having an exciting 'first-date' experience.

[hypervalent_iodine]

Or maybe you could use it as a marital aid, i.e. if you could temporarily suspend familiarity with your partner for the sake of having an exciting 'first-date' experience.

 

I can see that ending in arrests and sexual offence charges; depending of course on if only one of both of them are deprived of the ability to recognise the other. Having said that, the latter case is nothing more than a tool for a wonderfully simple and clean cut divorce/break up.

Edited February 20, 2011 by hypervalent_iodine

[lemur]

I can see that ending in arrests and sexual offence charges; depending of course on if only one of both of them are deprived of the ability to recognise the other.

You're assuming that one would behave that aggressively toward the other if they recognized their spouse as an unknown stranger. Picture this: you find a note to yourself one day in bed while waking up as a single person and in the note, in your own handwriting, it says that you have a blind date with a person who is actually your spouse but that you've taken a drug that blocks your memories and familiarity with that person. So you show up at the prescribed meeting place and experience a strange sense of familiarity (deja vu) yet you don't feel like you know this person. Then you spend the rest of the evening getting to know each other with the comfort of test-driving a car that you don't have to worry about deciding whether to buy or not because it already belongs to you. (Sorry if the "car test-drive" analogy sounds like a cheap reference to sex - I'm not actually even alluding that sex has to happen or not; just that the people have a comfortable blind-date without pressure of acceptance/rejection - I think this would be good for a relationship).

 

 

Having said that, the latter case is nothing more than a tool for a wonderfully simple and clean cut divorce/break up.

Interesting. I wonder if you would still experience symptoms of emotional/sexual withdrawal without consciously remembering what your forgotten life was like to cause you to feel something missing. I think relationship-withdrawal is a gradual process of becoming emotionally self-contained. If you couldn't remember your ex, you might not have anyone to blame the withdrawal symptoms on, but you'd probably still feel the pain of loneliness and rejection/failure. Without the negative feelings toward the ex, you might end up putting all that energy into seeking a new partner right away to end your discomfort and that could make you that much more vulnerable to a subsequent break-up, no?

 

 

[PhDwannabe]

Let me tell you the very (very) general and simplified cognitive science view of deja vu.

 

Typically important to explanations of deja vu is the concept of "inattentional blindness." Normally, we're reasonably attentive to our major sensory inputs (vision, particularly), but sometimes, we get distracted and end up profoundly unaware of our own processing. So, you process the red van as you speak to your friend in the parking lot, and a moment later, as your conversation winds down, you look again at the red van and have a memory of seeing it without a memory of encoding that memory. Very creepy, and unsurprisingly the cause of much superstition and magical thinking.

 

In general, the principle of most importance here is the simple fact that the brain shares a lot of pathways between memory (which is mostly "created" on-demand, not "stored"), imagination, and perception (of the present). So much so that some throw up their hands and suggest that all of these things are almost entirely the same process.

 

Once you get away from a homoncular view of the mind as a little guy up there looking at video screens and pulling up files on a big cognitive computer, it makes a little more sense.

[Dean Mullen]

Just my initial thought, but wouldn't your eyes have to be quite far apart for light to hit them a significant time apart? I mean, for there to be a second difference between when they saw things, your face would have to be 299,792,458 metres wide. Obviously the time difference between the eyes could be smaller, but it would still be a huge distance.

 

Also, wouldn't that then cause you to have déjá vu every time you saw something which required you to turn your head? I think I've only had it about 10 times in my life.

 

It doesn't need to be significant, any time at all would still exist I guess. But although the time difference is like about 10^-100 Seconds or even less it would matter and also I do believe you’ve had déjà vu more than 10 times a life time because I performed a one month long test and took a record of déjà vu every time I had it and realized it happened once every 26 hours when I thought it occurred much more rarer than that so I guess you need to keep a note of it to remember it just like dreams.

[John Cuthber]

The speed at which nerve impulses travel through the nerves will be affected slightly by things like temperature gradients across the head.

That would swamp any effect due to the finite speed of light.

Your two eyes would never be well enough synchronised to tell the difference.

[Blahah]

It doesn't need to be significant, any time at all would still exist I guess. But although the time difference is like about 10^-100 Seconds or even less it would matter and also I do believe you've had déjà vu more than 10 times a life time because I performed a one month long test and took a record of déjà vu every time I had it and realized it happened once every 26 hours when I thought it occurred much more rarer than that so I guess you need to keep a note of it to remember it just like dreams.

 

I admit it's certainly possible I've experienced it more times than I can readily remember. However, as others have pointed out your optic nerve has a greater potential lag difference than the possible difference between the time of light reception. Cool idea though! Keep coming up with them, they are interesting to think about.

[lemur]

Typically important to explanations of deja vu is the concept of "inattentional blindness." Normally, we're reasonably attentive to our major sensory inputs (vision, particularly), but sometimes, we get distracted and end up profoundly unaware of our own processing. So, you process the red van as you speak to your friend in the parking lot, and a moment later, as your conversation winds down, you look again at the red van and have a memory of seeing it without a memory of encoding that memory. Very creepy, and unsurprisingly the cause of much superstition and magical thinking.

But that doesn't explain how you can experience a whole conversation or situation as having occurred before, e.g. in a dream. It's a sense that the present in all its complexity is occurring exactly as it was perceived at some time long ago (such as a dream). So that can't be the result of some actual earlier perception, unless your brain is able to mistake entire situations for entire dreams or previous situations. Maybe since dreams are remembered vaguely or not at all, this level of vagueness would lend itself to easy association with actual situations that bore little resemblance to the original dream, but it seems more likely to me that it would be a coding-glitch in which the present moment makes a neural connection with the part of the brain that codes something as a dream or memory. I don't know if cognition actually works this way, but it seems logical. How else could people distinguish between dreams, memories, and present occurrences?

[guitarborist]

About 20 years ago I was doing some geology sampling on the side of a mountain and then....oops....never did know what happened. Probably slipped and hit my head or conked by a falling rock. Next thing I know there was a a guy unstrapping me from a rescue gurney at a hospital in Yellowknife/ NWT

 

For the next couple of hours everything was deja vu. The weirdest few hours of my life...I'd have sworn I was watching a rerun of a some reality I had experienced. I saw a local neurologist and then sent south to Calgary to see another. Everything turned out A-OK....nothing beyond some temporary trauma. Not a smidgen of lasting effect (and no more deja vu).

 

The neurologists was not at all surprised by my vivid deja vu experiences. He said it is not uncommon in brain damage either temporary or long lasting. Everyone has a bit of it but frequent deja vu is not a healthy symptom. If I had more episodes I was to contact him (which was never a necessity).

 

Bottom line...he said deja vu was a physical phenomenon or short circuit between various parts of the brain. You are temporarily nuts with a false perception of your physical presence.

Edited February 22, 2011 by guitarborist

[PhDwannabe]

So that can't be the result of some actual earlier perception, unless your brain is able to mistake entire situations for entire dreams or previous situations.

It is.

 

it seems more likely to me that it would be a coding-glitch in which the present moment makes a neural connection with the part of the brain that codes something as a dream or memory. I don't know if cognition actually works this way

It doesn't.

[Charlie22]

I once asked somebody why deja vu happened and i was told that its caused when our brain registers something wrong, our brain stores it in a part that controls memory and instead of it being instand memory so telling us its happening right now, its been stored as something older, which makes us think we have seen it before or maybe dreamed it. I dont no if this is right i cant remeber who told me either. It sounds possible though.

 

What i find strange though are the different levels of deja vu because what ive been told and just explained as a possible explanation only covers short instants of deja vu, but i have and i no of others who claim that once or twice in their life they have had deja vu for 30 seconds to a couple minutes, and can somewhat predict whats going to happen in that time, i dont personally believe its psychic or anything like that but its interesting non the less. I remember once when i was a young kid, i was in the car with my mum and sister and for about 15 seconds i pritty much new exactly what they were gonna say and stuff like that, i put it down to predicting because they are my family and im used to what they say but at the time it fealt like the event had taken place before and i was re-doing it. so that kind of deja vu is interesting and ide love feedback and comments on things like this.

 

please excuse poor grammer and spelling mistakes im not very good at either.

[Edtharan]

There are two main processing paths in the brain: There is a quick and a slow path.

 

The quick path allows us to react quickly to a situation. It strips out a lot of information that is not necessary for us to be able to react to a situation. If we need to react quickly the slow path is discarded and the information in the quick path reaches our consciousness.

 

If we don't need to react quickly to a situation, it is better for us to have more information, and so the slow path, which contains all this information is allowed to reach our consciousness.

 

However, glitches can occur (like from a head injury - as guitarborist story shows, or they can just occur for no obvious reason). When you get such glitches, both information paths reach our consciousness.

 

However, the fast, information poor path doesn't contain any information to enable us to link it to time. Thus memories associated with it can be scrambled (and either be non existent or filled in at the time of the deja vu).

 

Because we become conscious of one then the other, we get a feeling that we have experienced the situation before, because as far as our conciousness is concerned, we have just experienced it twice (and because of the lack of time detail in the fast path we can't quite remember when or we get a false memory of when we think we experienced it).

 

This was discovered, by chance, when someone undergoing functional magnetic resonance imaging of their brain experienced a deja vu episode (I can't remember the details of it, but a bit of research should bring it up).