The main claim of the target article is that involuntary autobiographical memories (IAMs) and déjà vu are two facets of spontaneous memory, based on the same retrieval processes. The authors argue that empirical and theoretical advances can be spurred by grouping these two phenomena under one conceptual framework of spontaneous memory-related cognition. While we agree that IAMs and déjà vu build on common memory processes, we argue that considering them together can move the area forward by highlighting their differences rather than similarities. The most obvious difference is that while IAMs are experienced on a daily basis, déjà vu is a rather esoteric experience eluding people most of the time. We thus call for a line of research identifying how the common memory processes underpinning IAMs and déjà vu can result in vastly differing phenomenological manifestations, and postulate that non-memory mechanisms must be considered to understand this.
One such mechanism, which the target article mentions only briefly, is attention. Attention operates throughout the memory processes, from cue encoding, through retrieval, up to attributional processes. Although the interplay of attention and memory has long been of interest (Craik, Govoni, Naveh-Benjamin, & Anderson, Reference Craik, Govoni, Naveh-Benjamin and Anderson1996), the investigation of attention in relation to both IAMs and déjà vu is much more recent, reflecting also a relatively newer focus on spontaneous memory processes more generally. Out of these two phenomena, more empirical work has been devoted to outlining the role of attention in IAMs. This has been investigated both in naturalistic settings and in laboratory, with both lines of research demonstrating how IAMs are more likely to occur during activities that require little focused attention or concentration (e.g. Berntsen & Hall, Reference Berntsen and Hall2004; Kvavilashvili & Mandler, Reference Kvavilashvili and Mandler2004; Schlagman & Kvavilashvili, Reference Schlagman and Kvavilashvili2008).
While the importance of diffuse attention for experiencing IAMs is without doubt, the exact mechanisms by which attention impacts spontaneous memory are still debated. Vannucci, Hanczakowski, Pelagatti, and Chiorri (Reference Vannucci, Hanczakowski, Pelagatti and Chiorri2019) provided evidence that reduced incidence of IAMs with an increase of the attentional load is due to both IAMs being less likely to be retrieved and less likely to be noticed – or cross what Barzykowski and Moulin (B&M) refer to as the awareness threshold. Regarding the retrieval mechanism, recently Barzykowski, Hajdas, Radel, and Kvavilashvili (Reference Barzykowski, Hajdas, Radel and Kvavilashvili2022) suggested that high attentional load reduces the chances that potential environmental triggers of IAMs would be noticed, resulting not only in lowered incidence of retrieval of IAMs but also later in impaired recognition of these potential cues. Regarding the post-retrieval mechanism, the increased attentional load implemented by Vannucci et al. resulted in reduced ratings of meta-awareness of IAMs, which were collected when participants' task was interrupted to make participants focus instead on the contents of their minds in the moments just preceding the interruption.
Thus, the acknowledgment that attention plays a role in both eliciting and experiencing IAMs is key here, showing that IAMs are as much a result of memory processes as of attributions following retrieval. This complex picture is acknowledged by B&M, but their treatment of post-retrieval processes in relation to IAMs remains limited. The authors focus mostly on how “phenomenologically sound” memories are more likely to cross the awareness threshold while mostly neglecting how non-memory factors, such as attention, affect this threshold in the first place. The relatively sparse treatment of these issues is highlighted by the fact that the flowchart in Figure 1 includes a specific post-retrieval step for experiencing déjà vu (“Is this plausible?”) but not for IAMs, where having spontaneous access to memory contents directly leads to involuntary memories.
Interestingly, B&M do acknowledge the role of attention when discussing the awareness threshold in relation to déjà vu. They suggest that these states “may be more likely to arise when one is engaged in attention demanding activities,” which may result in an elevated awareness threshold and thus reduced chances of experiencing full recollection that would preclude déjà vu. This is an interesting suggestion as it directly pits déjà vu against IAMs, for which meta-awareness occurs precisely when one is engaged in less demanding activities (Vannucci et al., Reference Vannucci, Hanczakowski, Pelagatti and Chiorri2019). If borne out, this hypothesis would thus directly implicate attention as a “switch” mechanism responsible for whether common retrieval processes may result in such different states.
But is the involvement of attention in déjà vu limited to the appraisal and attribution of the products of retrieval? For IAMs, such involvement seems to start earlier, when the retrieval process is preceded by encoding of retrieval cues (Barzykowski et al., Reference Barzykowski, Hajdas, Radel and Kvavilashvili2022). While research on cue processing in déjà vu states is less developed, some work does point to involvement of attentional processes also at this stage. As shown by Brown and Marsh (Reference Brown and Marsh2009), a brief glance at an unfamiliar symbol increased feelings of knowing the stimulus from pre-experimental exposure when the stimulus was fully processed moments later. These and other similar demonstrations of a false sense of prior experience following a brief encounter with the stimulus (e.g. Jacoby & Whitehouse, Reference Jacoby and Whitehouse1989; Klinger, Reference Klinger2001) suggest that déjà vu may be more likely to occur when someone is engaged in attention-demanding activities and the processing of peripheral information – potential memory cues – is superficial. Again, this contrasts directly with the studies indicating that attention-demanding activities reduce the likelihood of IAMs being elicited. Thus, just as in the case of post-retrieval processing, attention may serve as a switch determining how potential retrieval cues are processed, which in turn determines whether these cues elicit retrieval as déjà vu versus IAM.
To summarize, differential engagement of attention at various stages of memory may be one of the determinants of whether common retrieval processes give rise to contextually rich episodic memories experienced as IAMs or spurious feelings of familiarity experienced as déjà vu. The full framework of these spontaneous manifestations of memory processing must involve an in-depth understanding of non-memory mechanisms, of which attention is likely to be just one example, to understand how a common process of matching cues to the contents of memory can result in such vastly different phenomenological states.
The main claim of the target article is that involuntary autobiographical memories (IAMs) and déjà vu are two facets of spontaneous memory, based on the same retrieval processes. The authors argue that empirical and theoretical advances can be spurred by grouping these two phenomena under one conceptual framework of spontaneous memory-related cognition. While we agree that IAMs and déjà vu build on common memory processes, we argue that considering them together can move the area forward by highlighting their differences rather than similarities. The most obvious difference is that while IAMs are experienced on a daily basis, déjà vu is a rather esoteric experience eluding people most of the time. We thus call for a line of research identifying how the common memory processes underpinning IAMs and déjà vu can result in vastly differing phenomenological manifestations, and postulate that non-memory mechanisms must be considered to understand this.
One such mechanism, which the target article mentions only briefly, is attention. Attention operates throughout the memory processes, from cue encoding, through retrieval, up to attributional processes. Although the interplay of attention and memory has long been of interest (Craik, Govoni, Naveh-Benjamin, & Anderson, Reference Craik, Govoni, Naveh-Benjamin and Anderson1996), the investigation of attention in relation to both IAMs and déjà vu is much more recent, reflecting also a relatively newer focus on spontaneous memory processes more generally. Out of these two phenomena, more empirical work has been devoted to outlining the role of attention in IAMs. This has been investigated both in naturalistic settings and in laboratory, with both lines of research demonstrating how IAMs are more likely to occur during activities that require little focused attention or concentration (e.g. Berntsen & Hall, Reference Berntsen and Hall2004; Kvavilashvili & Mandler, Reference Kvavilashvili and Mandler2004; Schlagman & Kvavilashvili, Reference Schlagman and Kvavilashvili2008).
While the importance of diffuse attention for experiencing IAMs is without doubt, the exact mechanisms by which attention impacts spontaneous memory are still debated. Vannucci, Hanczakowski, Pelagatti, and Chiorri (Reference Vannucci, Hanczakowski, Pelagatti and Chiorri2019) provided evidence that reduced incidence of IAMs with an increase of the attentional load is due to both IAMs being less likely to be retrieved and less likely to be noticed – or cross what Barzykowski and Moulin (B&M) refer to as the awareness threshold. Regarding the retrieval mechanism, recently Barzykowski, Hajdas, Radel, and Kvavilashvili (Reference Barzykowski, Hajdas, Radel and Kvavilashvili2022) suggested that high attentional load reduces the chances that potential environmental triggers of IAMs would be noticed, resulting not only in lowered incidence of retrieval of IAMs but also later in impaired recognition of these potential cues. Regarding the post-retrieval mechanism, the increased attentional load implemented by Vannucci et al. resulted in reduced ratings of meta-awareness of IAMs, which were collected when participants' task was interrupted to make participants focus instead on the contents of their minds in the moments just preceding the interruption.
Thus, the acknowledgment that attention plays a role in both eliciting and experiencing IAMs is key here, showing that IAMs are as much a result of memory processes as of attributions following retrieval. This complex picture is acknowledged by B&M, but their treatment of post-retrieval processes in relation to IAMs remains limited. The authors focus mostly on how “phenomenologically sound” memories are more likely to cross the awareness threshold while mostly neglecting how non-memory factors, such as attention, affect this threshold in the first place. The relatively sparse treatment of these issues is highlighted by the fact that the flowchart in Figure 1 includes a specific post-retrieval step for experiencing déjà vu (“Is this plausible?”) but not for IAMs, where having spontaneous access to memory contents directly leads to involuntary memories.
Interestingly, B&M do acknowledge the role of attention when discussing the awareness threshold in relation to déjà vu. They suggest that these states “may be more likely to arise when one is engaged in attention demanding activities,” which may result in an elevated awareness threshold and thus reduced chances of experiencing full recollection that would preclude déjà vu. This is an interesting suggestion as it directly pits déjà vu against IAMs, for which meta-awareness occurs precisely when one is engaged in less demanding activities (Vannucci et al., Reference Vannucci, Hanczakowski, Pelagatti and Chiorri2019). If borne out, this hypothesis would thus directly implicate attention as a “switch” mechanism responsible for whether common retrieval processes may result in such different states.
But is the involvement of attention in déjà vu limited to the appraisal and attribution of the products of retrieval? For IAMs, such involvement seems to start earlier, when the retrieval process is preceded by encoding of retrieval cues (Barzykowski et al., Reference Barzykowski, Hajdas, Radel and Kvavilashvili2022). While research on cue processing in déjà vu states is less developed, some work does point to involvement of attentional processes also at this stage. As shown by Brown and Marsh (Reference Brown and Marsh2009), a brief glance at an unfamiliar symbol increased feelings of knowing the stimulus from pre-experimental exposure when the stimulus was fully processed moments later. These and other similar demonstrations of a false sense of prior experience following a brief encounter with the stimulus (e.g. Jacoby & Whitehouse, Reference Jacoby and Whitehouse1989; Klinger, Reference Klinger2001) suggest that déjà vu may be more likely to occur when someone is engaged in attention-demanding activities and the processing of peripheral information – potential memory cues – is superficial. Again, this contrasts directly with the studies indicating that attention-demanding activities reduce the likelihood of IAMs being elicited. Thus, just as in the case of post-retrieval processing, attention may serve as a switch determining how potential retrieval cues are processed, which in turn determines whether these cues elicit retrieval as déjà vu versus IAM.
To summarize, differential engagement of attention at various stages of memory may be one of the determinants of whether common retrieval processes give rise to contextually rich episodic memories experienced as IAMs or spurious feelings of familiarity experienced as déjà vu. The full framework of these spontaneous manifestations of memory processing must involve an in-depth understanding of non-memory mechanisms, of which attention is likely to be just one example, to understand how a common process of matching cues to the contents of memory can result in such vastly different phenomenological states.
Financial support
This work received no specific grant from any funding agency, commercial, or not-for-profit sectors.
Competing interest
None.