The psychologist Edward B. Titchener in his book 1928 A Textbook of Psychology, explained déjà vu as caused by a person having a brief glimpse of an object or situation, before the brain has completed "constructing" a full conscious perception of the experience. Such a "partial perception" then results in a false sense of familiarity. Scientific approaches reject the explanation of déjà vu as "precognition" or "prophecy", but rather explain it as an anomaly of memory, which creates a distinct impression that an experience is "being recalled".^[ This explanation is supported by the fact that the sense of "recollection" at the time is strong in most cases, but that the circumstances of the "previous" experience (when, where, and how the earlier experience occurred) are uncertain or believed to be impossible.

As time passes, subjects may exhibit a strong recollection of having the "unsettling" experience of déjà vu itself, but little or no recollection of the specifics of the event(s) or circumstance(s) which were the subject of the déjà vu experience itself (the events that were being "remembered"). This may result from an "overlap" between the neurological systems responsible for short-term memory and those responsible for long-term memory, resulting in (memories of) recent events erroneously being perceived as being in the more distant past. One theory is the events are stored into memory before the conscious part of the brain even receives the information and processes it. However, this explanation has been criticized that the brain would not be able to store information without a sensory input first. Another theory suggests the brain may process sensory input (perhaps allsensory input) as a "memory-in-progress", and that therefore during the event itself one believes it to be a past memory. In a survey, Brown had concluded that approximately two-thirds of the population have had déjà vu experiences.