Yes, I think we did discuss deja vu a while ago. One way to demonstrate deja
vu is to read a list of words all having to do with a topic, such as sleep:
tired, bed, rest... but leave out sleep. Later students will recall having
heard sleep. I forget the reference off hand. I will include something I
wrote on this.
don
Donald McBurney
Following is quoted from McBurney, _How to think like a psychologist_, Prentice
Hall, 1996.
But, let's step back, and do something that scientists find basic to studying
a new problem: Let's ask whether this experience can be explained by something
we know already.
A little reflection will reveal that, whatever d�j� vu is, it is an error of
memory. And one thing we know about memory is that it isn't perfect -- we all
have wished our memories were perfect when we were taking a test, or trying to
remember someone's name.
First, we should note that we have so many experiences in a lifetime that it
is rare when we see something totally new to us. Most rooms have four walls, a
floor, and a ceiling. Even social situations tend to be stereotyped. Suppose
you are in the middle of an argument with someone. Under the emotional stress
of the moment, we tend to engage in exchanges of the "so's your old
man"--"you're one, too" type; not exactly creative. These are the sorts of
situations in which we tend to have the strong feeling that we have been there
before--we have.
And even if we haven't experienced a situation directly, consider the amount
of vicarious experiences we obtain from reading, television, and the like. You
have probably had the experience of watching a TV show for a few minutes and
then realizing that you have seen it many years before. Considering the amount
of reading and television we engage in, it would be hard to imagine an
experience that is totally new to us. Thus many situations could seem to be
old and new at the same time because they are very similar to an old
experience.
So, realizing that new situations may be similar to old ones, let's consider
some of the difficulties we face every day. Suppose you are at a party, and an
attractive person comes up and says, "Hi, remember me? We met last year at
Craig's party!" You scratch your head and try to decide if you really did meet
her, or if this is a pickup line. Let's analyze the possibilities.
Now, either you did meet her before, or you didn't. And you either remember
her or you don't. This provides us with a two-by-two matrix of possibilities,
as we see in Table 27-1. ----------------------
Table 27-1
----------------------
Have you met before?
---------------------------------------------------
Do you remember? Yes No
----------------------------------------------------------------
Yes you remember her | you think you remember
(ordinary memory) | her (d�j� vu)
-----------------------------------------------------
no you don't remember her | you don't remember her
(ordinary forgetting) | (ordinary memory)
-----------------------------------------------------------------
You are not surprised when you remember someone you have met before (upper left
cell of the matrix). Nor are you surprised when you realize you haven't met
someone before (lower right cell). Alas, you are all too familiar with the
case where you can't remember someone you met last year at a party. You chalk
it up to forgetting, and realize it is a failure of memory.
Why, then, should we be surprised when we see a new face, and think it is an
old one? If we realize that our memory can fail by not recognizing something
that is actually old, why can't our memory fail in the opposite way? In other
words, if we accept false negatives (forgetting an old face), why can't we
accept false positives (thinking we remember a new face)?
But d�j� vu bothers us because the knowledge that we couldn't possibly have
experienced this before comes along with a strong feeling that we did. Here we
must introduce another idea: Our degree of certainty about a memory is not a
perfect measure of its truth. Usually, we are reasonably sure that we know or
don't know something. But there are times when we are positive we know
something we don't. Many experiments could be cited that demonstrate this
point.
A theory known as Signal Detection Theory demonstrates that, although there is
a correlation between our certainty that we remember (or don't remember)
something, the correlation is far from perfect. Sometimes when we are positive
that we remember something, we don't, and vice versa.
But let's take an everyday example. Suppose you have lost your keys, and you
ask you roommate if she has seen them. You may say that you are positive you
put them in your purse. She may be equally positive that she saw you putting
them on the desk. You may each suspect the other of taking them. (This is a
familiar scene in nursing homes, sadly.) Eventually, after much searching, and
perhaps some unpleasantness, you find the keys in the pocket of your jeans,
where you no doubt left them.
To repeat, our certainty about the truth of some memory (and lots of other
things as well) is not infallible proof of the facts of the matter.
These two notions, that d�j� vu is an error of memory, and that we can be
wrong about things we believe, take the mystery out of d�j� vu. We have taken
something that we didn't understand and found a way of understanding it in
terms of something else that we do understand. This is a fundamental
characteristic of the way scientists work. (But it still seems spooky when it
happens! although, we hope, less so than before.)
David Bennett wrote:
> Hi TIPSters,
>
> I took a lengthy leave from the list, I hope there are still a few familiar
> faces around.
>
> I have a question. Years ago I remember reading an account of "deja vu"
> being able to be explained (in theory anyway) biologically. It had
> something to do with mismatches between sensory experience and
> interpretation (or something like that). I wonder if any of you can point
> me to original sources to explanations of this phenomenon.
>
> Thanks much (in advance)
> Dave
>
> ===================================================
> David J. Bennett Ph.D. Voice: 617/521-2603
> Department of Psychology Email:[EMAIL PROTECTED]
> Simmons College
> 300 The Fenway ObQuote:
> Boston, MA 02115 "Life does not cease to be funny when people
> FAX: 617-521-3086 die any more than it ceases to be serious when
> people laugh."
> -George Bernard
> Shaw
> ===================================================
