Apr 24, 2013
Our PLOS ONE paper showed that near-death experiences cannot be considered as typical imagined event memories. We showed that NDE experiencers reported more characteristics for their NDE memories than for real memories (both old and recent) and their experiences are emotionally strong and closely linked to their own identity (in line with previous reports).
We believe that NDEs are remembered more clearly than other types of memories for a few reasons:
1) The high emotional value of NDE memories could explain the greater amount of remembered details in these memories—in line with previous studies showing that emotional value enhances the amount of sensory details in memories and that such strong emotional events are more likely to be repeatedly rehearsed (internally or in re-telling to others), thus enhancing their importance and promoting their availability. On the other hand, NDE memories could also be the product of a false memory or hallucination, in the sense that their origin does not come from a “real” event, thus leading to an illusory recollection. These kinds of reconstructed events can be very detailed, and it has been shown that emotional and survival contexts are linked to increased memory reconstruction including many specific details, which could be the case of some NDEs memories.
2) The greater overall amount of characteristics in NDE memories as compared with real or imagined memories could be explained by the fact that self-referential information can improve recalling performance by allowing better encoding, organization, and enrichment by extended knowledge, leading to a subjective and detailed episodic representation of the original event and associated thoughts and feelings. NDEs could have a stronger importance for personal identity and can be more closely linked to a person’s identity than other experiences (NDEs have already been reported as having short- and long-term positive consequences in an experiencer’s life). Thus, it is likely that self-referential content could have an effect on the overall characteristics of NDE memories.
3) Because of its emotionality, self-representativity, and consequentiality on the experiencers’ life, the NDE becomes a “self-defining memory.” That said, NDE memories could also be described as a “flashbulb memory.” This type of memory involves a highly emotional, personally important, and surprising event that will benefit from a preferential encoding making them more detailed and longer-lasting than everyday memories and also more prone to rehearsal.
We think it would be interesting to mention that, in general, the brain’s essential function is to organize the world we live in to promote adapted behavior. In fact, the brain organizes the chaos of information that a person constantly receives and interprets it according to the goals and knowledge of that individual. To perceive is to put meaning onto things and situations based on our experience with the world, with the use of specific schemas (general schemas or schemas related to our particular culture). The same is true for the act of remembering. In general, it is quite an optimal cognitive strategy since, most of the time, many elements will be remembered. But this strategy is not perfect as we can sometimes forget elements that are not congruent with the schema or, on the contrary, we may remember elements that did not happen but that are consistent with the schema. Moreover, we know that this kind of remembering bias is particularly likely to happen for highly emotional and survival aspects.
In conclusion, we propose that the physiological origins of NDEs could lead to a real perception although not lived in reality (i.e., being hallucination- or dream-like events), having as rich characteristics as memories of real events. We suggest that NDEs are flashbulb memories of really perceived hallucinations. Although the similarities of NDEs with hallucinations are striking, further research is needed to characterize the relationship between these phenomena more precisely, and additional neuroimaging studies are needed in order to better understand the neurophysiological signature of NDEs.