We ask a lot of weird questions here at The Body Odd. But so do you! Here's our answer to one of your latest queries. Got an inquiring mind? Head over to our Facebook page and ask us your oddest health, medical or human behavior question. We may answer it in an upcoming post.
Becky Coombs asks: Why/how does deja vu happen?
Maybe it's a short circuit in the brain. Or bit of far-off memory slipping into the present. Or perhaps it's both those things and something more.
Whatever the case, deja vu isn't just a strange but irrelevant fact of life (like, say, Snooki). Better understanding of deja vu will almost certainly lead to better understanding of how our brains work.
So what is deja vu in the first place? "It's the feeling that you have done this exact same thing before -- been to this place or performed this particular activity -- when you know that you haven't," says Colorado State University's Anne M. Cleary, a leading deja vu specialist. "Not everybody experiences it, but the majority of people do."
Young people, from the teenage years through the mid-20s, experience deja vu the most, says Akira O'Connor, who studies deja vu at the University of St. Andrews in Scotland. Tired people also get it more often, as do those who travel a lot. Even though they have many more years stored in their memory banks, older people aren't as prone to deja vu.
When most of us feel deja vu, we think it's a little odd or even meaningful -- maybe a past life is coming through! -- and go on with our day. Others aren't so fortunate. Some people suffer from deja vecu, a feeling of having already lived.
"It sounds kooky and fun, like a 'Groundhog Day'-type experience, but in reality it's extremely unsettling and drastically changes people's behavior," O'Connor says. "People find that they experience it most strongly for novel experiences. As they find the experience unsettling, they tend to avoid novelty altogether, with the sad consequence that they can withdraw into a world of true familiarity, watching reruns of movies and TV shows over and over again because that brings them the least distress."
There's no good treatment for people with this condition, which is often related to the memory problems of aging. No wonder: there's no clear understanding of what causes deja vu and related feelings in the first place.
Colorado State University's Cleary said some possible causes of deja vu include errors in the way the brain processes the world around us or "a brief neurological dysfunction, such as spontaneous brain activity that triggers an inappropriate sense of familiarity, or a brief minor seizure." It's possible that multiple causes are at work.
For now, researchers are finding new ways to analyze deja vu. Cleary is using virtual reality to see if they can trigger it in people and figure out exactly what in a "scene" makes it happen. (Vision isn't necessary, though. Blind people have deja vu too.)
"Researchers need to figure out what causes the disconnect between feeling that something is familiar, and knowing that it can't be," Scotland's O'Connor says. "I hope that in my lifetime we figure what parts of the brain are associated with 'feeling' familiarity and what parts are associated with 'knowing' that something should or should not evoke memories."
Just remember this: Maybe it's a short circuit in the brain. Or bit of memory slipping into the present. Or perhaps it's both those things and something more. (No, you're not having deja vu. You already read that. Or did you?)
Leave a comment telling us about the weirdest or most memorable time you experienced deja vu. We may use your answer in an upcoming post.