Suddenly matching current reality to what you saw in an old dream is a peculiar feeling—perhaps as peculiar as a déjà vu. My pet theory is that they are more or

Suddenly matching current reality to what you saw in an old dream is a peculiar feeling—perhaps as peculiar as a déjà vu. My pet theory is that they are more or less the same thing. In case of a DV, one explanation (the one I’ll be sticking to here) is that a brief lag[0] in the perception of the current moment by a part of your mind results in a feeling that this moment had been perceived before. I believe that to self-repair, so to speak, your mind would scramble to look up a matching past experience. However, the lag takes place at a pretty low level, and what your mind has no access to is that this previous experience was microseconds ago, not months or years; it is not in your long-term memory and there is no match. If a dream that shares enough characteristics with the moment is readily recalled (e.g., it is especially memorable because of some circumstances in your life at the time), that dream may easily end up being adjusted (partly rewritten) to fit. If that fails, you would have a vanilla DV. [0] Not coincidentally, this seems more common during times of mental exhaustion.