Déjà vu is a phenomenon where a person feels that they have experienced a situation before, even when it is happening for the first time. This sensation can be brief and often leaves individuals feeling confused or disoriented. It is thought to occur when the brain processes information in a way that creates a false sense of familiarity. Researchers believe that déjà vu may be linked to memory and perception. Some theories suggest it arises from a glitch in the brain's memory systems, while others propose it could be related to the temporal lobe or hippocampus, areas involved in memory formation.