“Wait a minute, this has happened before!”
Ever walked into some place or heard someone say something that made you stop dead in your tracks because you had experienced the exact same situation before?
Let’s define both of these terms first. Precognition is the ‘foreknowledge of an event’, while Deja Vu is the feeling of already having experienced something. The literal meaning of precognition is previous awareness (pre – previous, cognition – awareness).
The mind as we know it is made of deep layers, most unfathomable to us even now. And whereas the two terms defined above are (wrongly) used interchangeably, they refer to different phenomena experienced.
For example, if I bang my toes on a table corner, I expect to undergo pain. This is based on facts and previous experiences. On the other hand, if one night I dream of reconnecting with an old friend and the next day it actually happens – that’s precognition. Such events are not based on any logical or rational deductions. People who experience this are sometimes referred to as psychic. Precognition isn’t something that occurs on a daily or regular basis, and can seldom be predicted.
Precognition can happen via flashing thoughts, hallucinations or other means, but 60 – 70% of it occurs in dreams. It has also been recorded that precognition happens 24 – 48 hours prior to the event’s occurrence. In fact, there is a theory in quantum physics based on this phenomena, stating that the future can cause the past – backward/retro causality – depending on present conditions and information, the tiniest stimuli, which can be altered by free will.
Deja Vu is a French term, meaning already seen. Ever walked into a cafe and felt an overwhelming sense of familiarity wash over you? That vague, uneasy feeling you experience is Deja Vu. Unlike precognition, this has nothing to do with future events.
There have been lots of theories by scientists around the world, attempting to explain what causes Deja Vu, and some of them include reproducing the feeling of having seen something or someone once, as opposed to seeing a different thing of the same type multiple times, in a laboratory.
Other theorists believe that Deja Vu is caused by neurons in the temperol lobe of the brain, which is responsible for memory. In people who undergo epileptic seizures, deja vu is said to be a warning sign.
However, for perfectly healthy people, one of the most prominent explanations is described as a ‘glitch’ in the brain – when the neurons for recognition and familiarity both fire electrical impulses, allowing us to mistake the present for the past, or when an electrical impulse takes a short cut. For instance, it takes a small amount of sensory information (like a familiar smell or sight) for the brain to create a detailed recollection.
Déjà vu could be linked to discrepancies in the memory systems of the brain, leading the sensory information to by-pass short-term memory and reach long-term memory instead. This may produce the unsettling feeling that we’ve experienced a new moment before.
Michelle Hook, Ph.D., assistant professor in the Department of Neuroscience and Experimental Therapeutics, at the Texas A&M Health Science Center College of Medicine says, “Some suggest that when a difference in processing occurs along these pathways, the perception is disrupted and is experienced as two separate messages. The brain interprets the second version, through the slowed secondary pathway — as a separate perceptual experience — and thus the inappropriate feeling of familiarity (déjà vu) occurs.”
There is still much to learn about this enigmatic, gray matter. But we’re getting there.