‘This has happened before’: How science explains Déjà Vu and the eerie feeling of life on replay

An uncanny feeling of having lived a moment before, known as déjà vu, is explored by scientists. This sensation, often dismissed as a trick of the mind, is now understood as a healthy brain’s ‘fact-checking’ mechanism detecting a mismatch between familiarity and reality. Researchers suggest it reveals much about memory and perception.