The Physiology of Faith by N. Fakhr - HTML preview

Déjà Vu

Déjà vu is the experience in which, after seeing a scene or finding oneself in a situation, a person feels that they have seen or experienced it before. For example, someone may visit a place and find that everything seems strangely familiar. Or they may be doing something somewhere and suddenly feel that they have done exactly the same thing in exactly the same place before, even though they know that they have never done so and have never been there. This phenomenon is sometimes interpreted as evidence for reincarnation, leading a person to believe that in a previous life, when their spirit inhabited another body, they had visited that place and performed that same action, and that the memory of the place has somehow survived from that earlier life. Some Muslims likewise interpret déjà vu as evidence of a previous existence in the realm of al-Dharr.

Various estimates suggest that between 60 and 80 percent of people experience déjà vu at least once in their lives. The phenomenon is particularly common among young adults. Because it begins without warning and usually ends very quickly, it is difficult to study experimentally.

The experience of déjà vu is also common immediately before the onset of a seizure in temporal lobe epilepsy. [1]

In 2001, a case of recurrent and intense déjà vu was reported following the use of two drugs, amantadine and phenylpropanolamine. [2]

An association has also been observed between the onset of dementia and an increase in déjà vu experiences, and it has been recommended that people seek medical evaluation if these experiences become unusually frequent. [3]

Several theories have been proposed to explain déjà vu. One attributes the phenomenon to a minor disturbance in the electrical functioning of brain circuits. According to this explanation, if the brain systems involved in processing what is happening in the present and those involved in retrieving memories momentarily fail to coordinate properly, the brain may interpret something perceived now—or only a second earlier—as a memory from the distant past. In other words, the person’s sense that they have experienced the event “before” may in one sense be correct, except that this “before” does not belong to the distant past: it refers only to what was perceived a moment earlier. Because of a disturbance in the brain’s processing, however, the temporal meaning of that familiarity is misinterpreted as belonging to the distant past.