Simulation-based mentalizing generates a ‘proxy’ self-reference effect in memory

The self-reference effect (SRE) in memory is thought to depend on specialized mechanisms that enhance memory for self-relevant information. We investigated whether these mechanisms can be engaged “by proxy” when we simulate other people, by asking participants to interact with two virtual partners: one similar and one dissimilar to self. Participants viewed pairs of objects and picked one for themselves, for their similar partner, or their dissimilar partner. A surprise memory test followed that required participants to identify which object of each pair was chosen, and for whom. Finally, participants were shown both partners’ object pairs again, and asked to indicate their personal preference. Four key findings were observed. Overlap between participants’ own choice and those made for their partner was significantly higher for the similar than the dissimilar partner, revealing participants’ use of their own preferences to simulate the similar partner. Recollection of chosen objects was significantly higher for self than for both partners and, critically, was significantly higher for similar than dissimilar partners. Source confusion between self and the similar partner was also higher. These findings suggest that self-reference by proxy enhances memory for non-self-relevant material, and we consider the theoretical implications for functional interpretation of the SRE

Degeneration of basal and limbic networks is a core feature of behavioural variant frontotemporal dementia

Acknowledgment We would like to acknowledge the support of the Maxwell Computer Cluster funded by the University of Aberdeen. We also gratefully acknowledge study investigators and the generosity of study participants. Funding This study was sponsored entirely by TauRx Therapeutics Ltd (PAR1577). The Maxwell Computer Cluster is funded by the University of Aberdeen.Peer reviewedPublisher PD

Subjective experiences at memory retrieval: The feeling of knowing and beyond

When we fail to retrieve an item from memory we often experience the sensation that we do know the missing item, it just cannot be recalled right now. Memory is more than retrieval or non-retrieval, it also has a number of sensations and experiences associated with it. The aim of this thesis was to examine subjective experiences at retrieval failure and their association with manipulations of memory accuracy. This was achieved by the use of an existing metacognitive judgement, the feeling of knowing (FOK), and by the development of two novel metacognitive measures, the judgement of retrieval failure (JORF) and the global feeling of knowing (GFOK). In addition to experimental manipulations of memory, these judgements were also examined within populations who typically exhibit memory deficits; healthy older adults and patients diagnosed with early stage dementia. Chapter 2 focused on semantic and episodic FOK in ageing, identifying an age-related selective deficit in episodic FOK accuracy. Chapter 2 also observed that FOK accuracy increased in young and older adults in line with increases in recall accuracy over repeated learning trials. Chapter 3 explored manipulations of retention and retrieval, observing reliable changes in FOK magnitude as recall accuracy was affected, while effects on FOK accuracy were not necessarily in agreement with recall performance. Chapter 4 considered the underlying assumptions of the FOK experience, and proposed a new model of FOK based within the signal detection theory framework. Chapter 5 established two novel measures of retrieval failure, JORF and GFOK. These measures were found to be sensitive to manipulations of memory, and also appear to be preserved in patients with early stage dementia. This thesis provides an important extension to the existing literature on the FOK as well as identifying novel directions for metacognitive theory

Selective deficits in episodic feeling of knowing in ageing: A novel use of the general knowledge task

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