Depersonalization of Deja Experience

A final issue with the survey research is the potential unreliability of the self-report data on this particular topic. M. A. Harper (1969) suggested that the incidence of deja vu may simply be “an artefact of the interview situation and measures only the willingness of an individual to admit to an experience which may be universal” (p. 70; cf. Chapman & Mensh, 1951).

As an experimental caution, M. A. Harper (1969) compared oral and written administrations of the same deja vu questions to the same respondents and discovered only a 78% correspondence between whether the individual claimed to have experienced a deja vu through written versus oral queries (written response yielded a lower incidence).

The infrequency of deja vu experiences presents problems for remembering the specific physical and psychological details surrounding the deja vu. This difficulty can be addressed by prospective survey, but only Heymans (1904, 1906) has used this methodology.

In two separate studies, originally written in Dutch and translated into English by Sno and Draaisma (1993), college students recorded the details of each deja vu they experienced during an academic year. In the first investigation, 6 of 42 students (14%) had a total of 13 deja vu experiences during the 9-month period.

The incidence of deja vu in the second study is not available because deja vu and depersonalization experiences were reported in combination: 31 of 88 respondents (35%) reported one or both experiences during the academic year.