Construction in Progress: The Cognitive Architecture of Episodic Memory and Sensory Imagination

This thesis develops a novel architecture of episodic memory and sensory imagination, which details the processes involved in producing such episodes. The proposed cognitive architecture – the Constructive Episodic Simulation Hypothesis+ (CESH+) – builds on its predecessor CESH, and adds new features of content retrieval. On top of the dissociable retrieval and recombination processes posited by CESH, the thesis makes an empirical case for adding (i) memory indices storing the addresses of content, (ii) a Bayesian ranking/selection mechanism, which functions to select the appropriate content to be retrieved, as well as (iii) more fine-grained retrieval processes. To garner support for the model, the thesis extensively discusses two recent problems in cognitive science. The first concerns how imagination could be a skill. As skills are both improvable by practice and controlled, a cognitive architecture needs to account for how this can be the case. The thesis argues that we can make sense of how this can be so by appealing to the computations carried about by the Bayesian ranking/selection mechanism. The second problem concerns a new condition called ‘aphantasia’, which is characterised by subjects’ impaired mental imagery in both memory and imagination, and which currently lacks an adequate explanation. The thesis offers the first comprehensive overview of the impairments of aphantasia, and argues that CESH+ has the resources to explain these impairments. In the light of the explanatory power of CESH+, the thesis concludes that CESH+ paves the way to an improved understanding of the workings of memory and imagination.