1 Dec 2006
Déjà Vu Research Is Outta Sight
The first case study of a blind man suffering déjà vu has overturned
traditional theories about how the effect occurs. It was previously
thought that déjà vu was triggered when images from one eye arrived
in the brain a few microseconds after images from the other eye -
causing a feeling that something was being seen for the second time. But
University of Leeds researchers have just reported about a blind person
experiencing déjà vu through smell, hearing and touch.
Researchers Akira O'Connor and Chris Moulin, from the university's
Institute of Psychological Sciences have just had their paper on
non-visual déjà vu published in the journal Brain and Cognition. In
the article, they discuss how mundane experiences - undoing a jacket zip
while hearing a particular piece of music; hearing a snatch of
conversation while holding a plate in the school dining hall - triggered
déjà experiences in the blind subject.
"Optical pathway delay is a quite antiquated theory, but still widely
believed - and was the basis for the déjà vu sequences in Joseph
Heller's novel Catch-22. But this provides strong evidence that optical
pathway delay is not the explanation for déjà vu. The findings are
so obvious, so intuitive, that it's remarkable this research has never
been done before," said O'Connor.
The researchers hope to work with other visually impaired people, to
assess how common the effect is. They'd also like to take the research
further: "It would be really neat to do some neuro-imaging on people
during genuine spontaneous déjà vu experiences - but it's very
difficult to get them to have them on demand," mused O'Connor.
O'Connor is also experimenting with the induction of déjà vu through
hypnosis. "We now believe that déjà experiences are caused when an
area of the brain that deals with familiarity gets disrupted," he said.
In one experiment, subjects were asked to remember words, then
hypnotized to make them forget the words - and then shown the same word
again to induce a feeling that they have seen it before. Around half
said this brought on a sensation similar to déjà vu.