Friday, 29 May 2009

Simulating déjà vu in the lab

Déjà vu is that creepy feeling that you're living through a moment for the second time, as if retreading the path of an earlier existence. Now Alan Brown and Elizabeth Marsh believe they've found a way to simulate the déjà vu sensation in the laboratory - a finding that could help us understand why the phenomenon occurs.

Twenty-four participants were presented with dozens of symbols that had been carefully chosen, with the help of a pilot study, to be either entirely novel, rarely encountered, or highly familiar (e.g. the division symbol). The participants' task was simply to state for each symbol whether they'd seen it prior to the experiment.

A vital twist was that some of the symbols were preceded by an exceedingly brief flash - too quick to be detected consciously - of the same or a different symbol.

The take-home finding was that a brief flash of an entirely novel symbol before its subsequent, longer presentation, significantly increased the likelihood that a participant would wrongly claim to have seen that symbol prior to the experiment. Indeed, novel symbols not preceded by a subliminal flash were judged to be familiar just three per cent of the time, compared with 15 per cent of the time when preceded by a subliminal flash of the same symbol.

The relevance of these findings to the déjà vu effect were highlighted by post-test questioning of the participants, in which 50 per cent of them reported having experienced déjà vu during the study and 79 per cent said they'd sometimes been confused about whether or not they'd seen a symbol before.

The researchers said their experimental paradigm was analogous to a person glancing fleetingly at an unfamiliar street scene, being distracted by a poster in a window, before returning their gaze to the street and experiencing a strange sense of having been there before. The experiment provides "a possible mechanism for common illusions of false recognition," they concluded.
_________________________________

ResearchBlogging.orgBrown, A., & Marsh, E. (2009). Creating Illusions of Past Encounter Through Brief Exposure. Psychological Science, 20 (5), 534-538. DOI: 10.1111/j.1467-9280.2009.02337.x

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

10 comments:

  1. Fascinating. I guess the pattern matching process also works metaphorically as well as subliminally as when someone suffering post traumatic stress disorder feels terrible familairity in response to something symbolic of a previous real life horrific experience.

    I worked with someone who had been raped who "felt it was happening again" on seeing a similarly dressed but kindly stranger.

    Interesting post thank you.

    ReplyDelete
  2. My own experience of deja vu doesn't really jibe with the kind this research addresses. While sometimes I'll think to myself, "Haven't I seen this before?" it usually takes the form of, "This situation seems eerily familiar." Like: "Haven't I talked about aardvarks while shooting pool before?" It would seem nearly impossible to study that form of deja vu in the lab though, because it's so context-dependent. Still, the conceptual basis for this more image-based kind of deja vu couldn't apply to the situational form I experience; it's not as if you can experience a situation rapidly and subliminally and then feel like you've been through it before later on.

    ReplyDelete
  3. Anonymous10:47 am

    Yes i agree with lalalala, when deja vu is more in depth, and dependant on more unique factors. It is easy to say we have all seen certain symbol before however this doesn't give us the feeling of deja vu, its the irrational feelings we get with deja vu that make it so hard to explain.

    ReplyDelete
  4. As I understand deja vu it occurs when we believe we remember a place or situation when it is, in fact entirely new to us. That is to say it is a glitch in our memory retrieval system.

    It would appear to me that this experiment has more to do with subliminal image perception than deja vu as I understand it.

    ReplyDelete
  5. interesting stuff. i just wanted to add that when i experience deva vu if is in the for of scenes/conversations, not mearly static images. and furthermore i can often link them to dreams i have had in the past.. ok, i can fully see the irationality of this claim and i only mention it because it has happened since childhood and the experience is so vivid that i cannot ignor it.
    i was just wondering if anybody else has had similar experiences? or any explination, bar coincidence?
    thanks.

    ReplyDelete
  6. Anonymous9:29 pm

    Hmmm, I completely agree with ashreid. I experience deja vu a lot, I definitely think more often than most people. The odd thing about is that many times it feels more like I'm remembering a dream than the way some describe it having been there before and going through that experience twice. I've even felt deja vu was going to happen moments before it actually happened. That is very weird. I'm also an extremely deep sleeper and dream well, however I do not remember the dreams. My grandmother used to claim she had premonitions and we would dismiss it many times until the day she said her sister was going to die tomorrow and she woke up in the middle of the night, called my mom and said I think my sister just died. She did die in her sleep. How do you explain that kind of cosmic connection? I think there are a lot things in the world that cannot be explained in a lab, but we should still keep trying. That is one of the things that makes us human and separates us from the rest of the species on the planet.

    ReplyDelete
  7. Anonymous2:55 pm

    How can I have seen the place where I lay right now before. I remember telling my cousin I had a dream of a girl I have never seen and man united curtains and a blue bunny teddy months ago and yet today I have seen what I dreamt months ago. Is déjà vu something that went wrong at a point months later but then safeguards that point you will go back to. Or is it a place or situation you have dreamt of or seen I believe it to be extremely weird but perhaps mind has done this before. Perhaps u live life over and over till it becomes perfect where you have déjà vu something bad happened someone died even yourself maybe it is a total mystery. I have done some reading but scientists and others believe it is a familiar situation you have been in before and you believe it’s the same thing as you see in front of you. I have never seen anything to resemble anything in that room before so tell me how and why I have seen this.

    ReplyDelete
    Replies
    1. I agree with u but I seen this old guy fall and ive seen him before but not that I can remimber but if I did live and seen him in another life why is he still old?

      Delete
  8. Jez is correct.

    The study is only interesting in that it demonstrates an interaction between subliminal perception and memory processes. This has been demonstrated time and again through a number of studies. In February this year, Duke University replicated James Vicary's study to some degree (this time the results were presumably not manipulated). This study doesn't really add anything into the mix. There was no simulated déjà vu.

    ReplyDelete
  9. Anonymous3:00 am

    ever since i had ect, i get deja vu once in a while - never had it before.....

    ReplyDelete

Note: only a member of this blog may post a comment.

Google+