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.