One obstacle to research is that déjà vu is difficult to produce in a lab setting, says Moulin. Déjà vu is transitory. There is no method for evoking it consistently and reliably. And self-reports are subjective. “When different people say they have déjà vu, it is difficult to know if they are describing the same experience,” says Moulin.
A number of memory illusions may be related to déjà vu. Jamais vu, to start off, is the feeling of looking at something for the first time when in fact it is familiar. Déjà entendu refers to the distinct familiar sense of having heard something already, such as a piece of music or a new voice. Déjà su means something already known (intellectually). Déjà pensee means having thought something. Déjà senti refers to having felt something previously.
Given that there is no simple explanation for déjà vu, and other memory phenomena, some people believe in mystical or spiritual causes, such as evidence of past lives or predictions about the future. Scientists generally reject such notions, but that does not mean that déjà vu itself should be dismissed. Déjà vu is often accompanied by a sharpening of the senses and increased awareness. As such, it could be a chance to take note of a situation or place. There could be opportunities for discovery. Or maybe the brain is signaling that there is something worth revisiting. Déjà vu can also be triggered by a dream or imaginary experience.
Feelings of intuition can be useful in creativity and problem-solving, too. Finally, déjà vu might serve as a reminder of the human ability to imagine oneself in past or future situations, refine memories, and reconstruct one’s experience of the world.
New Understanding?
It’s been more than a decade since Moulin first encountered a patient with chronic déjà vu. That patient also had dementia. However, Moulin believes that various sources for the occurrences — not only anxiety — may still be identified.
The recent report of persistent déjà vu may have been rare, but it was followed by a flurry of responses. “People from around the world have contacted us,” says Moulin. “Many say they had the same experience during their 20s and that it resolved spontaneously.”
Scientists hope that studying déjà vu will further the understanding of memory and consciousness in general. Knowing how memory is organized and stored in the brain could be useful for retrieval purposes, for instance. Research on the brain and cognitive processes may also yield clues that could be used in treating neurological dysfunctions.
“Déjà vu is so complex,” says Moulin. “If we could uncover the difference between déjà vu and other memory experiences, we could gain a better understanding of many other problems along the way.”
This article was first published in Brain World Magazine’s Winter 2016 issue.
More From Brain World
- Daniel Kahneman on the Marvels and Flaws of Our Human Intuition
- Ghosts in the Machine: Why Moaning Spirits Are Probably Just in Our Heads
- God Is In The Details
- I Always Knew You Were Telepathic: Investigating the Brain’s “Supernatural” Communication
- Not-So-Total Recall: The Elusive Story Behind What We Remember and Forget
- “Predicting” the Future: A Look Into Psi Phenomena
