Déjà vu in hindsight
Why we believe in false premonitions
Written by Maria Cohut,
Ph.D.
Fact checked by Isabel Godfrey
But is it also
linked with a sense of postdiction — the feeling that our false premonition
was, in fact, correct?
New research
shows how déjà vu influences aspects of our recollection.
Have you ever
turned a corner into a street that you had never been on before and had a
nagging feeling that some time, perhaps in a different life, you had turned
that same corner into that same street?
If so, you have
experienced what is known as “déjà vu.”
If, following
such an experience, you have also thought that you knew what would come next —
say, that a black cat was about to cross your path in a hurry — then you have
experienced a false premonition, which is often associated with déjà vu.
Déjà vu and its
associated phenomena have interested cognitive scientist Anne Cleary, from
Colorado State University in Fort Collins, for many years.
In a previous study that Medical
News Today covered, Cleary and a fellow researcher, Alexander Claxton,
focused on the sense of false premonition that tends to accompany déjà vu and
concluded that this likely happens because of the programming of our brains.
Humans, Cleary
and Claxton explained, amass and store memories for predictive purposes — when
we face a situation, we access previous similar experiences so that we can
predict the likely outcomes automatically and thus make the best choices.
With a phenomenon
such as déjà vu, our brains become “tricked” into thinking that they can rely
on previous experience to predict what will come up next.
However, this
is merely a false impression.
Now, Cleary and
colleagues from Colorado State University are reporting their findings
regarding another phenomenon relating to déjà vu: postdiction.
False familiarity tricks the
brain
When a person
experiences postdiction, they are “filling in” memory gaps with newer
information, but they remain under the mistaken impression that this
information was already part of the original memory.
So far, it has
been unclear whether déjà vu has as strong an association with postdiction as
it does with false premonitions.
However, in the
new study paper that they published in the Psychonomic Bulletin & Review, Cleary and colleagues
now report that it is and explain why this may be so.
“If this is an illusion — just a feeling — why do people so
strongly believe they actually predicted what unfolded next? I wondered if
there was an explanation in some sort of cognitive illusion,” says Cleary.
To find out,
the researchers tasked study participants with the exploration of a virtual
reality scene and then asked them whether they were experiencing déjà vu.
After this, the
participants returned to the virtual scene, which randomly turned to the left
or right.
Finally, in
another experiment, a second cohort of participants went through the same
series of actions, with the additional task of rating how familiar the scene
was to them both before and after the turn took place.
The researchers
found that when participants experienced déjà vu and also reported a strong
sense that they could predict what would happen next, this situation was
strongly associated with the phenomenon of postdiction.
These
participants were convinced, in hindsight, that they had correctly predicted
the direction of the turn in the scene.
However, as the
turns occurred at random, the researchers explain, they would have been pretty
much impossible to foresee.
Cleary and
colleagues argue that this mistaken belief in the accuracy of a false
prediction is likely to be due to the intense sense of familiarity that the
déjà vu sensation provides.
“If the entire scene feels familiar as it unfolds, that might
trick our brains into thinking we got it right after all. Because it felt so
familiar as you were going through it, it felt like you knew all along how it
was going to go, even if that could not have been the case.” Anne Cleary
In the future,
Cleary is planning to put her findings to good use in a clinical context.
She says that
she will be joining forces with neuroscientists from Emory University in
Atlanta, GA, to conduct a study focusing on individuals who have injuries of
the medial temporal lobe of the brain.
The researcher
explains that people with such injuries often experience seizures that
recurring experiences of déjà vu accompany.
The forthcoming study may offer a glimpse into the underlying biological mechanisms at play in this phenomenon.
Maria
Cohut,
Ph.D.
Maria is
an insatiably curious soul, particularly fascinated by the mysterious workings
of the human brain, medical history, and our relationship with our own bodies,
both during and after life. Before joining Medical News Today, Maria worked as
a teacher, academic ambassador, and a freelance writer and copy editor.
Recently, she finished a Ph.D. in English at the University of Warwick in the
U.K. In her spare time, she learns Japanese, occasionally practices taxidermy,
and spreads her infectious love of invertebrates.
Medical
News Today,
part of Healthline Media UK, is one of the fastest growing health information
sites in the United States. Every month, more than 70 million people come to
Medical News Today for our in-depth health content and the latest news in
medical research. Consider us your intellectual peer. We unravel the
complexities of health information and make it easy to understand.
We take
a deep dive into medical research of the past and present, and we break it down
to give you the clear-cut facts. Ultimately, we want you to be confident in
making informed health decisions for yourself and your loved ones. Using peer
reviewed studies and reputable sources, our knowledgeable and curious editors
and writers create more than 250 pieces of content every month.
