Everything we do is a product of our brain/perception, Doc.
Deja vu seems to be a form of unconscious processing (kind of like a mental reflex) where our autonomic responses get triggered before our rational processors catch up. That's 'gut response' for the rest of us.
We are flooded by information all the time. That's what made that sensory deprivation experiment you refused to read about so very interesting. Its expected that we have evolved mechanisms to shield us from overload but, in the absence of stimulation, those mechanisms kick in on their own. Deja vu is like your conscious filter being pinged to tell you 'pay attention', this bit of data could be important/seen before/could be a pattern emerging.
Have you heard of the book "Blink"? Its a good one-off read (I gave my copy away after reading), not technical, full of interesting ancedotes & this guy's theory about how this stuff works.
[url]http://en.wikipedia.org/wiki/Blink_(book[/url])
Hope I'm not spoiling your fun too much, btw. I think the subject is fascinating, but for different reasons.