The Impact of Dementia on the Self: Do We Consider Ourselves the Same as Others?

The decline in autobiographical memory function in people with Alzheimer's dementia (AD) has been argued to cause a loss of self-identity. Prior research suggests that people perceive changes in moral traits and loss of memories with a "social-moral core" as most impactful to the maintenance of identity. However, such research has so far asked people to rate from a third-person perspective, considering the extent to which hypothetical others maintain their identity in the face of various impairments. In the current study, we examined the impact of perspective, comparing first- and third-person perspectives, as well as memory type. This online study asked 201 participants to consider hypothetical scenarios in which either themselves or another person (their parent, partner, or a stranger) experienced different types of memory failures associated with a diagnosis of AD. For each scenario, participants rated the degree to which the depicted individual remained the same person, and how impactful the impairment was. Social semantic memory failures - involving failures to recognise a loved one - were rated as most detrimental to self-continuity, and procedural memory failures the least. Averaged across all memory types, people considered their own and their partner's self-continuity to be more resilient to memory failures than that of a parent or stranger. However, this pattern was reversed for some memory types: forgetting semantic or episodic information about close relationships was rated as more detrimental from a first-person than third-person perspective. Our findings suggest that perspective and type of memory impairment interact to impact judgements about the extent to which people maintain their identity when they experience dementia, and highlight the importance of social relationships to maintaining a sense of self.