The term déjà vu was introduced by French philosopher and parapsychologist Émile Boirac in 1876, meaning “already seen.” This phenomenon evokes an uncanny feeling that a new experience is actually a familiar one.
For instance, visiting a specific location, such as a cafe or street, could trigger a sense of nostalgia, even if you’ve never been there before. Many might link these déjà vu moments to a “past life” or a “glitch in the matrix.”
However, there are more grounded explanations for these occurrences. The good news is that about two-thirds of the population experience déjà vu, and in most cases, it indicates healthy brain function.
Recent neuropsychological research suggests that déjà vu occurs when specific aspects of a situation trigger a sense of familiarity registered in the perirhinal cortex, part of the temporal lobe. This may happen due to similarities with previously encountered situations.
Next, the hippocampus, another vital memory structure in the temporal lobe, fails to retrieve relevant memories to account for this feeling of familiarity.
Finally, this discrepancy is processed by brain regions in the frontal lobes, such as the anterior cingulate cortex and the medial prefrontal cortex, leading to that eerie sensation of having been there before.
Psychologists refer to this last stage as metacognitive awareness, demonstrating that the brain is effectively signaling issues.
Research using memory games in brain imaging labs revealed that these frontal brain regions associated with metacognitive awareness exhibited greater activation, supporting the link between subjective déjà vu and monitoring processes.
In rare cases, an excessive form of déjà vu can occur due to pathology. For instance, individuals with temporal lobe epilepsy may experience prolonged déjà vu sensations before a seizure, described as a feeling of déjà vu that lasts for an extended period.
Moreover, some dementia patients report experiencing a syndrome known as déjà vécu (meaning “already lived”)—a more intense form of déjà vu where the person genuinely believes they have already lived through a new experience and reacts accordingly, such as turning off the TV because they think they’ve seen the news before.
If you find yourself in a typical déjà vu moment, there’s no cause for concern. Healthy déjà vu tends to be more prevalent in younger individuals and usually diminishes with age.
Psychologists suggest this decline occurs because frontal lobe error-monitoring processes become less efficient as we grow older.
So the next time you feel that strange sensation of familiarity, don’t fret. There’s nothing wrong with reality; your brain is simply operating as it should.
This article addresses the question posed by Bournemouth’s Dom Anderson: “Is experiencing déjà vu detrimental to your health?”
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Source: www.sciencefocus.com
