Frequency of Deja

Frequency of deja vu has been measured in three different ways. The absolute measure is how many total deja vu experiences the respondent has had. Kohr (1980) found that 14% had one or two lifetime experiences, 19% had three or four, 23% had five to eight, and 44% had nine or more. Though the highest percentage of experients had nine or more deja vu experiences, this sample consisted of members of a paranormal club.

Using a rougher cut, Palmer (1979) found that 98% of those who had deja vu have had more than one experience. Both investigations suggest that if one has experienced deja vu, it is highly likely that one has had

multiple experiences.

Deja vu frequency has also been evaluated by the following relative categories: seldom or rare, occasional, and often or frequent. The General Social Survey (NORC, 1984, 1988, 1989) revealed that most respondents fell in the seldom (44%) and occasional (44%) categories, with fewer claiming frequent (12%) deja vu. These percentages are close to the those found by Leeds (1944; 44% seldom, 39% occasional, 18% frequent) and by McCready and Greeley (1976; 49% seldom, 41% occasional, 10% frequent). Both Green (1966) and Brauer, Harrow, and Tucker (1970) discovered that 16% of respondents claimed frequent deja vu, a percentage close to that found in the other three studies.

Finally, a temporal evaluation can be made of either one’s last deja vu experience (past week? past month?) or how often one experiences a deja vu (every week? every month?). For the present analysis, these two questions were considered comparable; if an individual’s last deja vu was in the past week, it was assumed that his or her incidence was weekly.

Among investigations with a wide age range, there was moderate consistency in percentages of experients claiming monthly deja vu: 10% in Chapman and Mensh (1951), 10% in M. A. Harper (1969), and 19% in Neppe (1979). This percentage was considerably higher (54%) for Brown, Porter, and Nix (1994), but this was probably due to their young age sample (see Age Differences section).

The percentage of respondents claiming deja vu at least every year was more variable across studies: 14% in Heymans (1904), 21% in M. A. Harper (1969), 40% in Richardson and Winokur (1967, sample of neurosurgery patients), 71% in Chapman and Mensh (1951), 84% in Neppe (1983e), and 94% in Brown et al. (1994).