Deja vu, a French phrase meaning "already seen," is a feeling of familiarity when experiencing new events or places. Scientists have attempted to recreate deja vu in the lab using hypnosis and virtual reality, leading them to suspect that it's a memory phenomenon. When we encounter a situation similar to an actual memory, our brain recognizes the similarities but can't fully recall the memory, leaving us with a feeling of familiarity. Various theories attempt to explain why our memories might malfunction in this way, including short circuits in the brain, false memories, and conflict resolution. Research using fMRI suggests that deja vu could be a result of our brain conducting conflict resolution, checking through memories for any discrepancies between what we think we've experienced and what actually happened.