There is this feeling that I believe everyone has experienced one way or the other before. It strikes a chord within. Have you ever had a conversation with someone in a particular place and you felt like what is happening at that very moment is something you have already seen before? Or an event or a program is taking place and you just have a sudden flashback as you have already seen yourself in that program way before it even happened?
To some people, it is a very awkward and creepy feeling but I remember when I had that experience for the first time, I was so much in awe and I was wondering what it could be. It was so shocking for me because what I thought I had already seen was happening for the very first time, so clearly it wasn’t an old happening.
Well, this very creepy feeling to quite many people is known as déjà vu which is French for “already seen”. As the name spells out clearly, it is a very short moment of confusion where an individual feels like they have already experienced a current happening or circumstance. It usually lasts only a couple of seconds and it’s almost as if there is no explanation for it.
Can neuroscience try to explain this phenomenon that others interpret as a glitch in the matrix, a paranormal occurrence, or even a prophetic vision?
HOW DOES IT HAPPEN?
Déjà vu, along with insight and intuition, is one of the more enigmatic things our brains are capable of. It is quite a complex and unclear topic from the neuroscience point of view although scientists have tried to use tricks like hypnosis and virtual reality to explain it. This is because it’s impossible to research and experiment déjà vu in the lab. Alas, practical scientific evidence cannot be used to “prove” the phenomenon except theoretical explanation based on subjective experiences.
According to these theoretical explanations, déjà vu is linked to memory health. The phenomenon occurs when someone lives through an experience similar to their actual memory but unfortunately, the person fails to remember it. As a result, the brain notices the similarities between the present experience and that of the past, thereby leaving you with a feeling of familiarity that you can’t quite place.
Also, according to other studies, 80% of people have had the experience of déjà vu at least once and it is more common in children and young adults than it is in older people or the aged because as some scientists say, older people have a less active imagination, and their brains are more capable of distinguishing between what is real and what is linked to memory. Howbeit, older people who travel and watch movies a lot have déjà vu more often.
Déjà vu is also more likely to happen with people who suffer from temporal lobe epilepsy, anxiety, or dissociative personality disorders.
IS MY BRAIN UNHEALTHY?
If you are scared that your brain is unhealthy as a result of experiencing déjà vu maybe not just once like others but probably a lot of times like me, please relax!
Even though déjà vu is a complex topic from the neuroscience point of view, Neuroscientists, after several types of research have discovered that this memory illusion is no indication of a malfunctioning brain, neither is it a memory error and that, it occurs when the frontal regions of the brain attempt to correct an inaccurate memory.
According to experts like Dr. Akira O’Connor, Senior Psychology lecturer at the University of St. Andrews, experiencing déjà vu is beneficial for a great number of people as it is a sign that the fact-checking brain regions are working well by preventing you from misremembering events. “In a healthy person, such misremembering is going to happen every day. This is to be expected because your memory involves millions and billions of neurons. It’s very messy’’ he says.
WHAT ARE SOME THEORIES?
1. Déjà vu as a glitch or perception
The temporal lobes are the parts of the brain that store long-term memories, experiences, and facts. Déjà vu per all we have read so far certainly has something to do with these things so it isn’t out of place to look at this part of the brain. As has already been mentioned, déjà vu is frequently experienced by people with temporal lobe epilepsy. In an actual sense, a series of déjà vu usually precedes the seizures these patients experience and can even be treated as a warning sign. So, what does this theory mean? It simply states that the ‘glitch’ happens when the part of the brain that is responsible for monitoring present events and the one that is responsible for remembering events or memories are both active simultaneously. In short, it occurs when the brain perceives a present event as a memory by mistake.
2. Déjà vu as a memory mistake
This theory states that déjà vu occurs as a result of a mismatch of neural pathways (a neural pathway is a series of connected neurons that send signals from one part of the brain to another). In brief, the usual pathways follow a particular order and route and that is Perception to Short-term memory and then finally to long-term memory. So, déjà vu occurs when the short-term memory is skipped and whatever information is being processed goes directly into the long-term memory. In short, it occurs when the brain makes new memories but mistakenly treats them as old memories. The theory also suggests that déjà vu occurs when the brain remembers some details of a past event but doesn’t remember all happenings fully.
For example, you might experience déjà vu when you enter a hospital you have never been to but the bedsheet pattern seems vaguely familiar.
1. Déjà vu as a delay in processing
This theory says that the brain sends the information we perceive by two or more pathways and sometimes, one of the pathways can deliver the information a little faster than the others but when it so happens that the delay is very significant, a single event can be perceived as two different experiences. In short, déjà vu occurs when some parts of what we perceive arrive at memory centers earlier than others. Also, déjà vu can occur when the focus is placed on a particular object as the brain unconsciously takes in the environment where that object is. Then we stop focusing and start looking around, we get the feeling as if we have been there before.
For example, you enter an eatery for the first time and you immediately notice a wall clock hanging at the reception and you pay no attention to the environment or what the restaurant looks like, i.e, the tables, the chairs, the flowers, etc. but the brain still takes note of them unconsciously through peripheral vision (all that is visible outside the central area of focus; side vision). So when you pull yourself away from the wall clock, you think you have been there before- because you have, you were just not paying attention.
There are so many more scientific theories that explain the phenomenon, déjà vu. What is important is that it is not an unhealthy happening. The experience is very subjective- so if you think about the times you have gotten it, you might have an insight into how your brain is working.
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