This idea of misplaced familiarity not only helps provide an explanation for déjà vu other than superstition but also could help treat patients with memory problems.

"Our findings suggest that when people fail to retrieve something from memory, they can often still have a sense about their memories despite the failure to access the memory that is responsible for that sense," Cleary says. "People who are impaired at memory retrieval may benefit from training in how to rely on familiarity or intuition."

Even in people without memory afflictions, a better understanding of the feelings of familiarity and intuition may help solve problems. "In his book The Girl with The Dragon Tattoo, Stieg Larsson wrote about a gut feeling that the main character keeps having upon studying a picture album," Cleary observes, noting that the character Blomkvist cannot identify what in the set of pictures is causing the feeling that there is something of interest there, something that may help him to solve the case he's working on. "This illustrates how it might be beneficial for everyone, whether memory-impaired or not, to understand how such feelings of familiarity operate," Cleary asserts.

Virtual reality may also help scientists investigate other strange illusions that appear related to déjà vu. For déjà entendu, the feeling of having heard something before, one could incorporate sounds in virtual-reality scenarios. In the case of jamais vu—the feeling of novelty in response to something that should be familiar—some experts have speculated that this perception results from "oversaturation" of a memory, "such as when you stare at a word for too long and it starts to seem like it is not a word," Cleary says. "Perhaps there might be a way to investigate that idea in virtual reality by having people repeatedly experience the same scene."

6 Comments

1. 1. promytius 08:33 AM 6/6/12

   Mildly tangential idea, but since déjà vu is a non-predictable event, how can you possibly reproduce it in a prepared environment? This is more money-sci than actual investigation. The "jarring" experience is the leading indicator - the mind is so upset or interrupted by the experience that it is usually unprepared to "take good notes" during the feeling, and yet,after there is often a great deal of matching "experiences" - my strongest déjà vu was when I was eight years old in the playground, on a new teacher's first day - the bell rang to go in, and from that moment, through lining up, going upthe ramp and passing back into the school through the double doors, I KNEW everything that was going to happen, speech, order, position, everything was a repeat performance in front of me, led by a person I had never seen before that day; it was intensely marvelous and led to years and years of reality-confusion,and hope for another déjà vu.
   Any constructs designed to somehow "capture" déjà vu will only succeed in a placebo effect for results, it cannot be a valid test or production or reproduction of déjà vu; have I said that before???

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2. 2. Shortie 11:36 AM 6/6/12

   I am severely geographucally challenged and can only drive to known locations through habit or on-board GPS. Occasionally, I will drive through a place - location, city, street, town -- and think I have been here before, it looks so familiar...
   But this is NOT what dejavu feels like. When I experience dejavu, it is like my mind is falling into a vortex, the air is sucked out of my lungs and I am drawn forward to some place that I know I have been to before, yet, know that I haven't.
   Familiarity - being reminded of something/someplace -- is qualitatively different from dejavu. It would appear that the VR testing matched the former, but not the latter.

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3. 3. Lurker 04:31 PM 6/6/12

   I'm convinced earlier comments were made by people who have true deja vu experiences, because they each have stated an important difference between the hazy feeling described in the article and the actual deja vu. In a deja vu experience, every detail of the scene, including people, words, clothes, scenery, etc. is exactly the same as the, "memory." The memory is extremely sharp; it is not just, "similar."
   
   I've had deja vu experiences all my life, and there is absolutely no hazy memory at all.
   
   I have read a lot of articles about deja vu experiments, but none have discussed what actually seems to be happening to me. In short, my brain seems to be confusing short term memory with long term memory. Rather than consciously experiencing an event in real time, my brain seems to push the event into a long-term memory pattern before actually allowing me to consciously realize the event. Therefore, when I consciously experience the event, I also remember this new long-term memory pattern. It seems like I have had the experience at some time in the long-ago past, although I didn't.
   
   In fact, there have been times that I would remember that I remembered the event before. The whole process goes into a loop, so that I will, "remember," it previously happening multiple times.
   
   I first thought of this possible explanation while I was studying BASIC programming in the 1970's. Just as programming code can include a loop back to a previous line in the code, my brain seems to do the same thing during a deja vu. That would explain why every detail of the memory is exceptionally clear and identical to the actual event. The event only just happened, so it would obviously be easy to remember. It would also explain why I often, "know," what is about to happen. Obviously, I had the experience first; but, my brain quickly exchanges the order of the real-time memory and the long-term pattern, making it seem like I knew what was going to happen before it actually happened. Of course, this happens so quickly (and in the wrong order), that I can't tell anyone else that I know what is about to happen.
   
   This is certainly not some kind of supernatural event. There is no such thing. This is something that is happening in my brain that cannot be explained by a hazy memory of being in a similar scene at some time in the past.
   
   I do not have the expertise or equipment needed to test my hypothesis. However, I believe that approaching the subject from this angle would be more productive than the many studies I have read which assumed that deja vu is a memory of a similar scene and designed experiments based on that assumption. (Hint: scientific experiments should not automatically assume the truth of the thing being tested.)
   
   I will agree with the author about this: if my hypotheses turns out to be correct, the study of true deja vu could open a lot of avenues for the study of memory.

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4. 4. mggordon 07:28 PM 6/6/12

   Three comments all agree about this -- Deja vu is very sharp. The times I have experienced it have been so abrupt that I nearly stumble at a bad time upon realizing that I have done it before but I couldn't have.
   
   I disagree with Lurker's assertion "This is certainly not some kind of supernatural event. There is no such thing."
   
   That's not for him to say or to know. No one can know with certainty the non-existence of a thing, especially if you don't bother to define the thing you believe does not exist. He can only say that for HIM there is no supernatural. For me, there is, but like this deja vu thing, isn't really amenable to testing.
   
   However I think Lurker is more likely correct that the visual cortex has already processed the image and placed it in storage before conscious perception takes place, such that when conscious perception DOES take place it feels like you have done this exact same thing before and yet not really *before*, it is more like a peek into an alternate universe in real time.
   
   

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5. 5. mggordon 07:37 PM 6/6/12

   I am surprised not more association is made between deja vu and supernatural, other than Lurker's assertion there is no such thing.
   
   When I was stationed in Iceland about to go on an adventure to Gulfoss, I had a vision of my roommate suddenly turning and walking toward the waterfall, but slipping on ice and falling in. On a grey day the slope of the ice is impossible to discern. I insisted as a condition of him going, that when the time came that I told him to stop, that he would instantly and unquestioningly obey for his life would depend on it.
   
   Sure enough, after some time at the waterfall, on the flat area on the west side of the river, out of the corner of my eye I saw him suddenly turn like a robot and start to walk closer to the edge. Now to explain; this is in winter, water spray freezes to the lava cliffs and wet ice is incredibly slippery and being also very smooth and featureless, impossible to discern slope. I said "stop", he did, and I walked in front of him. I was wearing crampons so it was relatively safer for me. I turned around from about ten feet in front of him and was looking at about his kneecaps. Then another 30 feet or so of level ice, then it drops down into the mid-atlantic rift which is what Gulfoss actually falls into. One more step and he would have started sliding toward his death with no way to stop it.
   
   This is a fact, not deja vu, he knows it and I know it and maybe so do some others because I didn't care what people thought of me then and not a lot right now. It is arrogant for the blind to assert that others cannot see.

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6. 6. jtdwyer 08:08 PM 6/6/12

   I generally agree with the earlier commentators - that the sensations were very clear. I've not had any such experiences in many years, but those I most clearly recall from my teenage years had no visual or even audible component (in terms of specific frequencies or patterns, etc.): it was solely the sensation of having a premonition of a dialog among several people; the feeling that I knew in advance exactly what would be said next by whom (deja entendu?).

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