please pardon me for my abyssmal english =( i'm not very gd in writing.
false recognition is extremely common in schizophrenic patients, and is probably, in my opinion, responsible for the feeling of deja vu. different parts of the brain are responsible for different parts of the 'event' so remembered. when we remember past events, we tend to not only remember the different components of the event, 'item memory', but also the relationships between those components. an example would be the recall of the word 'golf' might bring forth the recollection of the entire paragraph of golf-related discussion you had with your buddy during the dinner last night, as well as what you ate during dinner, what time is was and so on. this can be classified as semantic (what happened), spatial (where), perceptual (feelings) and temporal-order (sequence of events). Also, there are different levels of cognitive processing; a quick glance of the room might not register much when you are involved in another activity but a repeat focus of any object within that glance might generate a false feeling of deja vu when you have actually processed the 'glance' on another cognitive level.
Furthermore, in schizophrenic patients, their hippocampus, frontal lobes and temporal lobes exhibit abnormal activity, that results in the generation of false memories to account for the existence of 'perceived events'. for example, the 'revisiting' of novel places in a dream that had occured in the past. in actual fact, the dream was created to 'believe' that the 'revisitation' occured, in conjunction with basic episodic memory processes, to make the 'dream' seem real. this accounts for some people's 'consciousness' in a dream which they draw upon to substantiate their claims of deja vu. 'I remember asking myself in the dream why my backpack was so heavy and why i was walking along this unfamiliar path, and days after, i find myself now walking on the exact same walkway carrying a backpack full of assessment books'
It is very important to realise that the feeling of deja vu happened just as the event is occuring, not before, for which it would have been a prediction of the future. what actually happened was that there was a mix-up/malfunction of the subject's cognitive processes (hippocampus?) that what he 'saw' was being registered by the brain as 'having seen', i.e short term memory being registered as long term memory, but because the brain has to justify the existence of the long term memory, impressions of events that never happened were created by the brain based on past events (dreams) and they were all linked together by episodic memory processes to make the entire perception seem real, thus creating the feeling of deja vu, also the feeling of familarity that results from false memory traces that were created when items were automatically linked to other items not-linked-to in reality because of lures of familarity. for example, adverts of toys are generally linked to feminine voices/children voices, especially toys for girls. False memories of 'repeat adverts' in a tv program might be created.
To almost eliminate the feeling of deja vu, keep a diary of your daily schedule - who you met, what was memorable for you. often, one feels surprised on how two separate events occuring at two different locations can be so similiar.
No matter the case, deja vu is definitely not an example of the paranormal. Might also be of interest to you would be the effect of drugs on the human brain, albeit the absence of 'deja vu' in drug abusers. Read up on schizophrenia too.
http://en.wikipedia.org/wiki/Schizophrenia
False recognition - http://www.psych.lancs.ac.uk/people/uploads/SteveDewhurst20040622T155848.pdf
Effects of Drugs on Perception of Reality - http://sulcus.berkeley.edu/mcb/165_001/papers/manuscripts/_987.html
