Deja-vu is a phenomenon of synapses mapping familiar-looking places in your brain, researchers from MIT have discovered. And it really makes sense. When you go somewhere for the first time, a group of synapses in your brain fire, so that you can remember the place if ever you go back. So, when your brain recognizes a familiar place, something with similar construction or a similar vibe to what you've seen before, it feels as if you've been there, because similar synapses fire to map the new place.
We know. It's a lot less sexy than some sort of pre-ordained fatalistic view of the world that dictates that you've been somewhere before. But, at least it proves the phenomenon once and for all. Plus, once people thought that the best way to treat cancer was to suck out your blood with live leeches, and they were wrong, too.
MIT News Office: Research deciphers 'déjà-vu' brain mechanics