【科学】Can Science Explain Deja Vu?

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科学能解释似曾相识这种现象吗？

科学美国人

Wait, have I been here before? Sometimes, as we experience a new event or place, we get that creepy feeling that it's not the first time. We call that sensation déjà vu, a French phrase that means "already seen." But what is déjà vu, and can science explain why it happens?

We associate the feeling of déjà vu with mystery and even the paranormal because it is fleeting and usually unexpected. The very things that intrigue us about déjà vu are the same things that make it hard to study. But scientists have tried using tricks like hypnosis and virtual reality. One study found that participants reported experiencing déjà vu when moving through the virtual reality Sims video game when one scene was purposefully created to spatially map to another.

These experiments have led scientists to suspect that déjà vu is a memory phenomenon. We encounter a situation that is similar to an actual memory but we can’t fully recall that memory. So our brain recognizes the similarities between our current experience and one in the past. We're left with a feeling of familiarity that we can’t quite place.

Beyond this general explanation, there are dozens of theories that attempt to explain why our memories might malfunction in this way. Some say it’s like a short in the circuits in our brain leading to long- versus short-term memory so that new incoming information goes straight to long term memory instead of making a stop in the short term memory bank.

Another theory is that déjà vu is associated with false memories—memories that feel real but aren’t. This form of déjà vu would be similar to the feeling when you can’t differentiate between something that really happened versus a dream. However, researchers have begun to push back on this idea.

Interestingly, one study shows the areas of the brain involved in memory, like the hippocampus, were not triggered as we would suspect if the feeling was linked to a false memory. Instead, the active areas of the brain were those involved in decision making. They interpret this result to mean that déjà vu could instead be a result of our brains conducting some form of conflict resolution.