Our brains are responsible for the way we process the world. This includes the variety of phenomena we experience throughout our lives. Two of the most mind boggling are déjà vu and lesser known déjà rêvé. Both rely on our brain’s responsibility for memories and its tendency to misfire.

   What exactly is the difference between the two? According to Healthline, “Déjà vu describes that uncanny sensation you’ve already experienced something, even when you know you never have” (healthline.com). Déjà rêvé, while having a similar feeling, instead convinces those experiencing it that they’ve seen the scenario they’re living through in a past premonition. As Exploring Your Mind explained, “…with déjà vu, you think that ‘I’ve already experienced this,’ with déjà rêvé you believe ‘I’ve already dreamed this’” (exploringyourmind.com).

   These experiences are far from uncommon. According to WebMD, “Around 60 percent to 70 percent of people in good health experience some form of déjà vu during their lifetime….  Déjà vu happens most often to people between 15 and 25 years of age. We tend to experience the feeling less as we age” (webmd.com). The article included that those most likely to have this sensation include those who regularly remember their dreams, who are tired or stressed, and those who travel often.

   To explain the mystery of déjà vu, one must look to the human mind. As Scientific American described, “At times, the part of the brain responsible for detecting familiarity — the medial temporal lobe, which is located just behind the temple and plays a large role in encoding and retrieving memories — may fire off overenthusiastically for no particular reason. [University of St. Andrews Cognitive Psychologist Akira Robert] O’Connor says,… Younger brains are a little more excitable, prone to fire more quickly rather than holding back” (scientificamerican.com).

   Déjà rêvé affects one specific population more than others. According to Exploring Your Mind, a study conducted by the University of Nancy, the University Hospital of Toulouse, and the Brain and Cognition Research Center (CNRS) back in 2018 was, “…the first to demonstrate the existence of déjà-rêvé as a habitual experiential phenomenon in patients with epilepsy. It’s a neurological peculiarity that often occurs during seizures” (exploringyourmind.com).

   Although few haven’t experienced these uncanny sensations, the research to understand their mechanisms does not satisfy. As we move into the future, we can hope that improved technology can unravel this mystery.