This episode explores the psychological phenomena of déjà vu and jamais vu, delving into their causes, triggers, and what they reveal about memory. Dr. Chris Moulin defines déjà vu as the unsettling feeling of familiarity in a novel situation and jamais vu as the strange feeling when a known thing seems unfamiliar. Triggers for healthy déjà vu include tiredness, stress, and travel, while chronic déjà vu is associated with neurological conditions like epilepsy and dementia. Moulin explains that déjà vu may be a healthy "fact-checking mechanism" that declines with age as metacognition, or awareness of one's memory, changes. The discussion pivots to jamais vu, which Moulin illustrates with personal anecdotes, including the feeling of strangeness when looking at his father's face, and experiments inducing the sensation through repeated writing. Brain imaging studies reveal the involvement of the prefrontal cortex in detecting conflict during déjà vu experiences, while the temporal lobes are associated with familiarity, suggesting that these phenomena offer insights into the complex relationship between perception, memory, and our cognitive systems.
