Friday, 26 April 2013


Déjà vu: Paranormal or Neurological?

     “Oh! Look the new cafe is finally open! I love how cosy and quaint it looks!” “Oh! Look the new cafe is finally open! I love how cosy and quaint it looks!” Pia was walking along the market with her mother, remarking casually on the new cafe which had opened up as an odd feeling swept over her that she had been in this exact situation before, commenting on this very cafe which had not even been in existence until a week ago! This eerie feeling of having experienced a situation before when, in fact, we know for certain we haven’t is termed “déjà vu” which is French for “already seen”. Some of us may even feel like we have “felt” something previously called déjà senti; or having had already visited a place called déjà visite.

     Deja vu is a familiar sensation that most of us have experienced and it can be somewhat unsettling due to its strange premonitory quality. 

     Parapsychologists attribute this phenomenon to clairvoyance and even to previous experiences in a past life repeating themselves. Since such a claim cannot be proved, disproved or otherwise investigated, we turn to research in neuropsychology to understand the nature and cause of déjà vu.

     Neurological causes are typically complex and varied given the complexity of the brain, only a fraction of which has rendered itself to scientific knowledge. Early investigations in to déjà vu centred around people with brain pathology as their reports of déjà vu were striking and frequent. For instance, in 1896, a prominent neurologist F.L. Arnaud described the déjà vu experience of a 34 year old man who was recovering from cerebral malaria. He claimed to recognise certain newspaper articles and seemed to “recognise” almost every situation.  

     A series of research spanning decades suggests that déjà vu is caused by misfiring of neurons in the part of the brain which is  responsible for recognising familiar stimuli. This particular system in the brain is responsible for judging if we have come across a certain situation before or not. In people suffering from epilepsy originating in their temporal lobe (which is on either sides of the brain), this recognition system falsely gives an impression of familiarity with a new situation, giving rise to a sense of déjà vu.

     In people who do not suffer from epilepsy or any other pathology of the brain, the brain areas responsible for retrieval of memory, i.e. accessing old memories to aid in the current situation, can lead to a sense of already having been there before. These brain areas have been identified by Spatt (2002) as being the prefrontal cortex (the front region of the frontal cortex) and hippocampus (a structure present in the limbic system of our brain crucial for memory processes).

     Deja vu is one of the glitches in our memory system which makes us ponder as to what makes our memories feel real or surreal as the case may be as the case may be. Oh well!