This strange familiarity which sometimes grips us when faced with an unprecedented situation has intrigued philosophers and scientists for centuries. We have all suffered this famous “ already seen », a sometimes very disconcerting feeling, and this one is not just a simple neurological curiosity; it is a revealing mechanism of our consciousness and the complexity of our relationship to time.
Despite the many theories, the exact causes of this phenomenon remained a little mysterious ; this was without taking into account the work of Akira O’Connor, researcher at the University of St. Andrews in Scotland, one of the rare specialists in ” already seen “. These were published almost a year ago in the review Neuroscience & Biobehavioral Reviews.
The familiar mechanic: a revealing error
THE ” already seen » occurs when the brain areas responsible for recognition send false familiarity signals. This momentary confusion causes a disturbing discrepancy between our immediate perception and a feeling of recognition that our reason knows to be unfounded. This dissonance is not the sign of any pathology, quite the contrary: it is even synonymous with the performance of our brain.
As O’Connor points out, ” Déjà vu is a mechanism that corrects an error and prevents us from believing that we really remember something. What is paradoxical is that, despite what seems like a memory error, déjà vu occurs when the brain is functioning at its best. “. Our brain is therefore blocked in its validation of an illusory memory as authentic. This is in no way a memory failure, but rather a bug temporary in the recognition system of our brain.
Behind the scenes of the memory illusion
Virtual reality experiences have made it possible to dissect more precisely the workings of the “ already seen » during O’Connor’s study. The researchers immersed participants in virtual everyday environments – a bowling alley, a garden – before confronting them with new scenes sharing the same spatial architecture.
Result: faced with these new settings with familiar resonances, the participants systematically reported this disturbing feeling of recognition without being able to identify its source. This experimental manipulation thus demonstrated how our cerebral organ can be misled by structural similaritieseven when we are unable to recall the original experience that was supposed to provoke this feeling of familiarity. We could almost say that the brain is in the grip of a micro-hallucination when this sensation occurs.
The evolving conundrum of a constructive “error”
This phenomenon therefore proves once again how complex our cognitive apparatus iscapable of both producing an illusion of recognition and identifying it as such. A particularity, which in certain people takes on a certain magnitude, particularly those suffering from dementia.
The frontal lobes (part of the brain involved in higher cognitive functions) can lose their checking ability, leading to a destabilizing multiplication of sensations of familiarity. This symptom can even delay diagnosis, as patients seem to regain their memories even though they are victims of a persistent illusion.
The most surprising thing is that this brain “error” does not appear to serve any apparent evolutionary purposewhich comes in total contradiction with the theory of evolution. It simply testifies to our propensity to seek meaning in every experienceeven the most confusing. As O’Connor explains, we are fundamentally true ” meaning-making machines », perpetually searching for patterns and understanding in our environment. This quest for meaning is even fundamental among the human species and acts as the true driving force of our existence.
- THE ” already seen » is a bug cerebral and occurs when the brain confuses a new context with a feeling of familiarity, revealing its optimal functioning.
- The brain identifies and corrects this illusion using its frontal lobes, except in cases of pathologies such as dementia.
- This phenomenon reflects our human tendency to look for meaning in every experience, even when there is none.
