Everbody's had this experience. More so when I was younger. Sometimes when I get it now it seems to remind me of a dream I had months ago. Which is strange because who can remember a dream that far back unless it was pretty dramatic? I think science describes it as the brain shutting down for a millimicrominisecond and then takes that same information in again. Which is why it seems so familiar because we really did see it before...a split second ago. But somehow the time difference seems like it was a long time ago. I'm not sure what to believe.