The term déjà vu is French and means, literally, "already seen." Those who have experienced the feeling describe it as an overwhelming sense of familiarity with something that shouldn't be familiar at all. Say, for example, you are traveling to England for the first time. You are touring a cathedral, and suddenly it seems as if you have been in that very spot before. Or maybe you are having dinner with a group of friends, discussing some current political topic, and you have the feeling that you've already experienced this very thing -- same friends, same dinner, same topic. Mismatches and Short Circuits Déjà vu in healthy participants is reported as a memory error which may expose the nature of the memory system. Some researchers speculate that déjà vu occurs due to a discrepancy in memory systems leading to the inappropriate generation of a detailed memory from a new sensory experience. This feeling of familiarity is, of course, known as déjà