Deja Vu, a French term meaning "already seen," is a psychological phenomenon where an individual feels they have experienced a situation before, despite knowing it is happening for the first time. This eerie sensation is common, affecting nearly two-thirds of people at some point in their lives. Scientists believe Deja Vu occurs due to a temporary glitch in the brain's memory processing system. One theory suggests it results from the brain mistakenly processing new experiences in long-term memory instead of short-term memory, creating a false sense of familiarity. Another theory links it to the brain detecting similarities between the present moment and past memories, even if the prior event isn’t consciously remembered. Neurologists have studied Deja Vu in relation to temporal lobe activity, particularly in individuals with epilepsy. Seizures in the temporal lobe, which is responsible for memory and recognition, can trigger intense Deja Vu experiences. However, for most people, Deja Vu is harmless and lasts only a few seconds. Psychologists also associate Deja Vu with stress, fatigue, and cognitive processing speed. It occurs more frequently in younger adults and may decrease with age. Some researchers propose that Deja Vu is linked to the brain’s way of detecting inconsistencies or minor memory errors, helping it maintain an accurate perception of reality. While Deja Vu remains a fascinating mystery, it underscores the complexity of human memory and perception. Although its exact cause is still debated, it offers valuable insights into how our brains process and store experiences.