Have I seen this before? Have I been here already? If you have experienced something like this, it may be a déjà vu. Plato believed it was evidence of past lives. Sigmund Freud described it as ‘the memory of an unconscious fantasy along with a desire to improve the current situation,’ but what really happens?
This intriguing phenomenon occurs when something that is very familiar to us suddenly feels strange or new. Déjà vu is an experience that has happened to almost all of us at some point in our lives. It’s that strange feeling of experiencing something we have already experienced before, but according to science, it is messages in our brain that can reach directly into long-term memory.
The science behind déjà vu, the story behind the mystery
Although it may seem like a rarity, a presence of parallel worlds or astral travels, for science, experiencing déjà vu is quite common. Most people have experienced it, probably more than once. That’s why this phenomenon—also called paramnesia in Spanish—is being widely investigated and debated in serious scientific fields such as neuroscience and psychology.
These sciences suggest that it is due to fragmented memory. Here, it is proposed that sometimes a present experience fits perfectly with a piece of our puzzle of past memories, making us feel like we have already lived something similar. Additionally, there is the theory of recognition errors, which suggests that our brain can get confused and think it recognizes something new as familiar, even when it is not and never has been so.
This is because neural connections between different brain regions can be activated unusually, generating the feeling of familiarity with a new experience. Now, three different types of déjà vu have been described: déjà visité, or “already visited”; déjà vécu, or “already lived”, and déjà senti, or “already felt”.
- Déjà visité, “already visited”, corresponds to the example we started this article with: when you feel like you already know the place even though it’s your first time visiting.
- Déjà vécu, “already lived”, happens when we perceive that we haven’t just seen something before, but we have lived it. For example, you’re telling a story about your vacations and suddenly feel like you’ve already narrated that same story, with the same details and your friends’ reactions, even though it’s the first time you’re doing it.
- An example of déjà senti, “already felt”, could be when you hear someone say something for the first time and have the sensation that you’ve heard it before. It’s like in a dream someone told you exactly the same thing, leaving you wondering “where have I heard that before?”
Despite all this, given that the brain is like a supercomputer that processes all the information it receives, sometimes this powerful computer does some quirky things, and that’s what generates the strange feeling of “I’ve already lived this.”
