How can visual working memory be enhanced?

Working memory (WM), the ability to temporarily maintain information for further processing, is known to have limited capacity around four chunks of information (Cowan, 2001). The limited nature of WM and its critical involvement in our daily life, aging and several neuropsychological disorders, have motivated great interest in investigating effective WM enhancement interventions. However, the existing evidence in these interventions yielded discrepancies, raising concerns about the lack of theory-informed WM enhancement research, grounded in solid methodology, especially a formal and explicit assessment. Furthermore, the elusive results have questioned the replicability and robustness of previously reported effects, reflecting the replication and theory crises in the field. This PhD aims to address these concerns and crises. We first aim to empirically assess the robustness of the effects that are induced by two intervention methods, that is, transcranial direct current stimulation and WM training. We also aim to investigate the mechanisms underlying the cognitive changes from a recent theoretical account of cognitive training and transfer effects, that is, the capacity-efficiency mechanism (von Bastian et al., 2022). Finally, we aim to explore which contemporary computational visual WM models could better describe the limits of WM, especially when substantial cognitive changes are induced by interventions like WM training. The evaluation of these theory-driven, mathematically specified WM models could further facilitate a better understanding of the generalisability and replicability of implemented intervention programmes.