Barzykowski and Moulin (B&M) provide an interesting theoretical framework for a large body of cognitive research studying phenomena that come to mind spontaneously and/or without any preceding intention to think about them. More specifically, B&M compare involuntary autobiographical memories and déjà vu regarding, among other factors, familiarity. Within this comparison, the authors propose that involuntary autobiographical memories may be considered as recollections of the personal past, whereas the “déjà vu” phenomenon rather triggers a stronger experience of familiarity.

We believe that the distinction between involuntary autobiographical memories and déjà vu, as proposed by B&M, can be enriched by considering studies in amnesia, especially in patients with Alzheimer's disease. Research has demonstrated how, while the typical retrieval of autobiographical memories in patients with Alzheimer's disease is characterized by familiarity, involuntary autobiographical memories, at least as cued by sensory cues, can trigger a strong recollection experience in these patients. Within this view, familiarity can be considered as a metacognitive process, a feeling which is generated from the fluent processing of autobiographical information. This feeling, guiding patients with Alzheimer's disease through their own phenomenological experience, can range from the general sense of familiarity (i.e., noetic experience of déjà vu) to the increased subjective experience of remembering (i.e., autonoetic experience during involuntary retrieval).

Autobiographical retrieval in patients with Alzheimer's disease is typically characterized by overgenerality, that is, a difficulty to retrieve unique memories situated in time and space (El Haj, Antoine, Nandrino, & Kapogiannis, Reference El Haj, Antoine, Nandrino and Kapogiannis2015; El Haj, Boutoleau-Bretonnière, & Gallouj, Reference El Haj, Boutoleau-Bretonnière and Gallouj2020; El Haj, Moustafa, Gallouj, & Robin, Reference El Haj, Moustafa, Gallouj and Robin2019; El Haj, Roche, Gallouj, & Gandolphe, Reference El Haj, Roche, Gallouj and Gandolphe2017b). This overgenerality can be observed regardless of methodology or memory distribution (Irish et al., Reference Irish, Hornberger, Lah, Miller, Pengas, Nestor and Piguet2011; Moses, Culpin, Lowe, & McWilliam, Reference Moses, Culpin, Lowe and McWilliam2004). Autobiographical overgenerality in patients with Alzheimer's disease can lead to a diminished subjective experience of retrieval. More specifically, overgenerality can lead to shift from an ability to mentally relive past events toward a general sense of familiarity that may be expressed by patients as a sense of “having experienced this before” (El Haj et al., Reference El Haj, Antoine, Nandrino and Kapogiannis2015). This sense of familiarity can, somehow, mirror that triggered by “déjà vu.” In other words, patients with Alzheimer's disease may tend to retrieve autobiographical memories under the lens of a “déjà vu” perspective, lacking the richness of contextual and phenomenological information, and, consequently, the autonoetic experience of retrieval.

Although autobiographical retrieval in patients with Alzheimer's disease can generally be associated with a sense of familiarity, involuntary retrieval can trigger an autonoetic experience of retrieval in the patients. This assumption can be supported by the large body of research demonstrating how sensory cuing can trigger involuntary retrieval and, consequently, an enhanced recollective experience. For instance, research on music-evoked autobiographical memories has demonstrated how these memories can trigger, thanks to involuntary retrieval, an enhanced subjective experience of retrieval in patients with Alzheimer's disease (El Haj, Fasotti, & Allain, Reference El Haj, Fasotti and Allain2012). The same thing can be said for odor-evoked autobiographical memories in patients with Alzheimer's disease (El Haj, Reference El Haj2022; El Haj, Gandolphe, Gallouj, Kapogiannis, & Antoine, Reference El Haj, Gandolphe, Gallouj, Kapogiannis and Antoine2017a). Research has also demonstrated how visual cuing (i.e., exposure to nostalgic films) may promote involuntary autobiographical retrieval and a strong subjective experience in patients with Alzheimer's disease (Rasmussen, Salgado, Daustrand, & Berntsen, Reference Rasmussen, Salgado, Daustrand and Berntsen2021).

Taken together, while autobiographical retrieval in patients with Alzheimer's disease can be associated with a general sense of familiarity, involuntary retrieval can trigger an autonoetic subjective experience during retrieval. Thus, the continuum between involuntary autobiographical memories and déjà vu, as proposed by B&M, can be better defined by considering research on autobiographical retrieval in patients with Alzheimer's disease. Familiarity may be considered as a cornerstone to the foundation of the distinction between déjà vu and involuntary retrieval, not only in the general population, as proposed by B&M, but also in amnesia.