So now we know what causes déjà vu — though, of course, we always did.
According to researchers at the University of St. Andrews, déjà vu — that feeling that you’ve experienced something before — isn’t some psychic connection to a dream or vision. It’s simply the brain checking its memories, a report in New Scientist says.
The team’s technique uses a standard method to trigger false memories. It involves telling a person a list of related words – such as bed, pillow, night, dream – but not the key word linking them together, in this case, sleep. When the person is later quizzed on the words they’ve heard, they tend to believe they have also heard “sleep” – a false memory.
To create the feeling of déjà vu, O’Connor’s team first asked people if they had heard any words beginning with the letter “s”. The volunteers replied that they hadn’t. This meant that when they were later asked if they had heard the word sleep, they were able to remember that they couldn’t have, but at the same time, the word felt familiar. “They report having this strange experience of déjà vu,” says O’Connor.
It’s an intriguing hypothesis. Another scientist notes that people who have déjà vu likely have better-functioning memory circuitry than those who don’t.
“Without being unkind, they don’t reflect on their memory systems,” Christopher Moulin told New Scientist.
And yet, I wonder. Maybe it’s based on the aforementioned memory checking, but I could swear I’ve had experiences that I’ve dreamed or envisioned months before. Of course, when I was actually having the experience, all I had was that feeling of déjà vu — it’s not like I could suddenly predict a sports score or even the next words out of a companion’s mouth. Which is what makes déjà vu so damned eerie.
I hope I remember this when I have it again.