The strange feeling of having been somewhere or done something before-even though there is evidence to the contrary-is called déjà vu. Although déjà vu is beginning to receive attention among scientists (Brown, 2003, 2004), few studies have empirically investigated the phenomenon. We investigated the hypothesis that déjà vu is related to feelings of familiarity and that it can result from similarity between a novel scene and that of a scene experienced in one's past. We used a variation of the recognition-without-recall method of studying familiarity (Cleary, 2004) to examine instances in which participants failed to recall a studied scene in response to a configurally similar novel test scene. In such instances, resemblance to a previously viewed scene increased both feelings of familiarity and of déjà vu. Furthermore, in the absence of recall, resemblance of a novel scene to a previously viewed scene increased the probability of a reported déjà vu state for the novel scene, and feelings of familiarity with a novel scene were directly related to feelings of being in a déjà vu state.
Most people have experienced déjà vu at some point. Déjà vu is the odd feeling of having experienced a situation before, despite the fact that the situation is new (e.g., Brown, 2004). One theory is that déjà vu is related to feelings of familiarity (Brown, 2003, 2004; Cleary, 2008). In the present study, we examined the hypothesis that, when a novel scene is similar to a previously viewed scene, it can produce a feeling of familiarity that is related to déjà vu.
Déjà Vu and Familiarity
Familiarity-based recognition occurs when one has the feeling that something has been experienced before, despite not recalling any specifics about the prior experience (e.g., Mandler, 2008). An example is recognizing a face as familiar without identifying where or when the face was seen before. The feeling of familiarity that underlies familiarity-based recognition may also contribute to experiences of déjà vu (Cleary, 2008).
Is Déjà Vu Related to Familiarity?
There are three lines of evidence that déjà vu may be related to familiarity. One line comes from correlational data. The frequency with which people report experiencing déjà vu is positively correlated with the frequency with which people report traveling (Brown, 2003), dreaming (Brown, 2003), and watching movies (Wallisch, 2007). These correlations are consistent with the idea that déjà vu relates to familiarity: People who travel, dream, or watch movies more often should have more potential sources of familiarity stored in memory than people who rarely do these things.
The second line of evidence comes from a study by Brown and Marsh (2008), in which students viewed pictures of scenes-some from the students' own campus and some from a faraway campus. The students later attempted to discriminate previously visited from non-previously visited scenes. They were more likely to judge that they had previously visited a scene from a faraway campus when that scene was previously presented within the context of the experiment. In short, when the feeling of familiarity was unaccompanied by retrieval of the familiarity's source, it led to a sense of having been there before. This hints at a potential link between familiarity and déjà vu.
The third line of evidence comes from a case study of a patient who, prior to surgical intervention, experienced déjà vu during seizures (Bowles et al., 2007). Although the surgical intervention relieved the patient of seizures, she was subsequently impaired in familiarity-based, but not recollection-based, recognition on a number of recognition tasks. This postsurgery impairment, along with the seizure-induced déjà vu that she experienced prior to surgery, also suggests a possible relationship between familiarity-based recognition and déjà vu.
What Produces Familiarity With a Novel Situation? The Role of Resemblance
Familiarity with a novel situation can be brought on by resemblance to a situation stored in memory. …