Introduction
Déjà vu is one of the most mysterious feelings that most people experience at least once in their lifetime. On the one hand, it is characterized by the perception of the current event as familiar. On the other hand, there is no factual or memorial evidence that such an experience had previously occurred (Urquhart et al., 2021). For this reason, most commonly, people tend to evaluate this feeling as peculiar or strange (Urquhart et al., 2021). Consequently, the reasons why human beings experience déjà vu attracted the minds of the best thinkers for a long time. Thus, the current essay seeks to present the most popular theoretical frameworks that attempt to explain this phenomenon, analyze its potential triggers, and determine the current stream of research in this sphere.
Déjà Vu Theories
Dual Processing Frameworks
The first major group of theories is based on the premise that human cognitive processes are divided into two different thinking types that work simultaneously, thus called dual processing. According to these frameworks, déjà vu appears as a consequence of a glitch that interrupts the normal parallel work of two cognitive functions (Newman, 2017). For instance, some models consider two thinking types to be perception and memory (Micali, 2017). It means that human beings perceive some objects and events and record the information about them in the memory at the same time. Yet, sometimes these two processes may overlap, which causes the perception of the current moment to be regarded as something that is retracted from memory (Newman, 2017). As a result, individuals have a feeling of false familiarity.
Theory of Divided Attention
Another popular theory that seeks to explain the phenomenon of déjà vu is the model of divided attention. Based on this framework, it is argued that on some occasions, people are highly concentrated on particular objects or events and tend to ignore other surroundings. Nevertheless, objects outside of a person’s active attention are still perceived and recorded on a subliminal level (Fu et al., 2021). Therefore, when the ‘normal’ attention level is restored, and the individual starts noticing previously ignored surroundings, he/she experiences the feeling of déjà vu because past subconsciously recorded information starts matching with more conscious experience.
Source Amnesia
Frameworks based on source amnesia argue that some situations may seem familiar because people encountered the related information in the past but simply cannot remember where and when, thus, feeling déjà vu. In this regard, Moulin (2017) provides the example of the street corner in New York that a person may have seen in the movie someday in the past without paying close attention to it. As a result, when this individual actually encounters the same street in real life, he/she will experience déjà vu.
Still, it is not necessary that the previous experience matches the current one totally; rather, there can solely be some similarities between them. For instance, the experiment of Ann Cleary and her colleagues reveals that sometimes even spatial similarity of new experience to the old one can cause feelings close to déjà vu. To test that hypothesis, the researchers created a virtual tour where the spatial configuration of the scenes matched the object location in pictures that participants previously viewed (Cleary et al., 2019). In the first scenario, people were shown a junkyard with piles of garbage, whereas the second scenario displayed the garden with the bushes located exactly at the same place as garbage piles before. As a consequence, a lot of participants claimed that they felt familiar when exposed to the second scenario, but they could not identify the reason (Cleary and Claxton, 2018). Therefore, the results indicate that there is indeed a connection between déjà vu and memory.
Triggers
Additionally to seeking the explanation of déjà vu, the scientists also noticed that there are certain factors that can trigger the phenomenon’s appearance, which can be divided into situational and psychological. The former includes conversation (54.1% of cases), being in familiar (47.6%) and unfamiliar location (21.4%), and being surrounded by familiar (41%) or unfamiliar (18.3%) people (Moulin, 2017). The latter encompasses tiredness or lack of sleep (27.5%), stress (13.5%), anxiety (10.5%), and usage of recreational drugs (5,2%) (Moulin, 2017). For example, Wells et al. (2021) found that people diagnosed with various forms of anxiety (generalized anxiety disorder, social phobia, or obsessive-compulsive) reported having déjà vu more frequently than their ‘healthy’ peers. However, despite that, there are some psychological states that can increase the possibility of ‘false remembering’ more than 25% of the déjà vu cases do not have any known trigger.
Moreover, the frequency of déjà vu occurrence is positively related to temporal lobe epilepsy. Now, thanks to neuroscience and technological development, it is found that this region is connected with short- and long-term memory, among other impairments. Yet, despite impressive progress in this sphere, there are still a lot of ‘blank spots’ that should be studied. As such, Curot et al. (2019) note that the “precise role of subhippocampal structures, i.e., perirhinal vs entorhinal cortices, remains unclear” (p. 844). Nevertheless, it is clear that future cooperation between neuroscientists and psychologists can provide a deeper understanding of déjà vu.
Prediction of the Future
Finally, recent studies have been attempting to analyze whether having déjà vu is associated with the ability to predict events in the nearest future. Such interest is explained by the existence of abundant self-reported first-hand evidence from people. For instance, Ernst Bloch writes about the experience of Emil Kraepelin – a famous psychiatrist – in Peru (Micali, 2017). On the expenditure in the unknown land, Kraepelin experienced a déjà vu and “knew in the same moment that a bridge was about to come into view” (as cited in Micali, 2017, p. 164). After some short period of time, the psychiatrist saw that “the bridge stood before him just with all details that he had anticipated” (as cited in Micali, 2017, p. 164). In order to test whether such predictions are possible, the researchers conducted a number of experiments. In this regard, Cleary et al. (2019) extended the previously discussed experiment by Cleary and Claxton (2018) with two scenarios that included junkyard and garden. During the first scenario, participants saw the virtual video tour in the junkyard. The second virtual tour repeated the route of the first one in the garden, which spatially resembled the junkyard as was mentioned previously. However, at some point, the experimenters stopped the video sequence and asked their participants to predict where the camera would turn – on the left or on the right. The results revealed that although most of the people had a sense of familiarity close to déjà vu, they could not predict the future camera move. Therefore, the experimenters concluded that déjà vu evokes the strong feeling of knowing the future, which in reality is not true.
Conclusion
Overall the current paper identified the three most popular theories that seek to explain the concept of déjà vu. They included dual processing frameworks, the theory of divided attention, and the source amnesia approach. Also, situational (conversation and (un)familiar people and places), psychological (tiredness, lack of sleep, stress, anxiety, and recreational drugs), and pathological (temporal lobe amnesia) déjà vu triggers were discussed. Finally, it was shown that modern research in this sphere concentrates on the ability of people who experience ‘false remembering’ to predict the future.
References
Cleary, A. M., & Claxton, A. B. (2018). Déjà vu: An illusion of prediction. Psychological Science, 29(4), 635-644.
Cleary, A. M., Huebert, A. M., McNeely-White, K. L., & Spahr, K. S. (2019). A postdictive bias associated with déjà vu. Psychonomic Bulletin & Review, 26(4), 1433-1439.
Curot, J., Pariente, J., Hupé, J. M., Lotterie, J. A., Mirabel, H., & Barbeau, E. J. (2021). Déjà vu and prescience in a case of severe episodic amnesia following bilateral hippocampal lesions. Memory, 29(7), 843-858.
Fu, Y., Yan, W., Shen, M., & Chen, H. (2021). Does consciousness overflow cognitive access? Novel insights from the new phenomenon of attribute amnesia. Science China Life Sciences, 64, 847–860.
Micali, S. (2017). The anticipation of the present: Phenomenology of déjà vu. Journal of the British Society for Phenomenology, 49(2), 156-170.
Moulin, C. (2017). The cognitive neuropsychology of déjà vu. Routledge.
Newman, T. (2017). Déjà vu: Re-experiencing the unexperienced. Medical News Today. Web.
Urquhart, J. A., Sivakumaran, M. H., Macfarlane, J. A., & O’Connor, A. R. (2018). fMRI evidence supporting the role of memory conflict in the déjà vu experience. Memory, 29(7), 921-932.
Wells, C. E., O’Connor, A. R., & Moulin, C. J. (2021). Déjà vu experiences in anxiety. Memory, 29(7), 895-903.