Chapter 2 - Digging into Déjà Vu: Recent Research on Possible Mechanisms

Abstract

Abstract The deja vu experience has piqued the interest of philosophers and physicians for over 150 years, and has recently begun to connect to research on fundamental cognitive mechanisms. Following a brief description of the nature of this recognition anomaly, this chapter summarizes findings from several laboratories that are related to this memory phenomenon. In our labs, we have found support for three possible mechanisms that could trigger deja vu. The first is split perception, which posits that a deja vu is caused by a brief glance at an object or scene just prior to a fully aware look. Thus, the perception is split into two parts and appears to be eerily duplicated. A second mechanism is implicit memory, whereby a prior setting actually has been experienced before by the person but stored in such an indistinct manner that only the sense of familiarity is resurrected. Another example of an implicit memory effect involves a single part of a larger scene that is familiar but not identified as such, with the result that the strong sense of familiarity associated with this portion inappropriately bleeds over onto the entire scene. Others have found support for gestalt familiarity, that the framework of the present setting closely resembles something experienced before in outline but not in specifics. We also present physiological evidence from brain and cognitive dysfunctions that relate to our understanding of deja vu. Finally, some important but unresolved issues in deja vu research are noted, ones that should guide future research on the topic.