Subjective experience as a basis for reality monitoring over memory

'Reality monitoring' is the process of establishing whether our memories were externally generated (such as a memory of something we perceived), or internally generated (such as a memory of a thought or imagination). This project aims to characterise the neural and computational mechanisms by which aspects of the phenomenology of memory are employed in the process of reality monitoring. Importantly, this ability can go awry in affective and psychotic mental health disorders. Therefore, more precise characterisation of these mechanisms will help us understand how they can malfunction, and ultimately how to target treatment for such malfunctioning.
Study 1 (April 2022 - January 2023): Do individuals differ in reality monitoring strategy?
Methods: online behavioural study, computational modelling
Training: Python Machine Learning course, Accelerate-Spark Machine Learning Academy (April-June 2022)
While there has been much research into individual differences in reality monitoring performance, there has been little investigation into individual differences in the strategies used to accomplish this. Understanding such strategy differences could inform individualised treatment for reality monitoring deficits in mental health disorders. I will investigate whether people with no mental imagery (a condition known as aphantasia) differ systematically in their strategy used for reality monitoring over memory. I will give an online reality monitoring task to aphantasic individuals and matched controls. I will use computational modelling to establish whether strategy used is modulated by trait imagery. I will follow up with a confirmatory and longitudinal replication, assessing whether individual differences are stable over a three-week delay.
Study 2 (January 2023 - December 2023): What are the neural mechanisms of the feeling vs. judgement that a memory is real?
Methods: EEG
Training: EEG course
The cognitive judgement that something is real can dissociate from the feeling that it was real, such as when the memory of a dream feels real even when we know it was a dream. However, little is known about the neural underpinnings of the phenomenological feeling of reality compared with explicit reality judgements. I will use EEG to establish if the neural time-courses of the phenomenological feeling and explicit judgement that a memory was real are dissociable.
Study 3: (January 2024-January 2025) Does cortical reactivation reflect reality monitoring strategy?
Methods: fMRI
Training: fMRI course
Reactivation of encoding-related patterns at memory retrieval varies parametrically with memory vividness and detail. However, it not known whether graded cortical reactivation supports how real a memory feels. Using a recently-developed technique to distinguish qualitative and quantitative individual differences in fMRI data, combined with multivariate pattern analysis, I will assess whether individual differences in reality monitoring are supported by qualitative or quantitative differences in cortical reactivation.
Conclusion
Overall, this project aims to characterise the neural and computational mechanisms by which (1) individuals differ in reality monitoring strategy, and (2) reality monitoring feeling and judgement may dissociate. This could pave the way for more precise treatments for reality monitoring deficits which are specifically tailored to the way in which a particular individual's reality monitoring system is malfunctioning.