Investigating the relationship between visual working memory and consciousness: Insights from a study combining binocular rivalry and EEG

In recent decades, a significant debate has emerged in literature regarding the nature of the representations that working memory can maintain. Specifically, some researchers have suggested the possibility that working memory may be capable of holding not only conscious, but also unconscious information. It is now well established that the study of working memory is of considerable importance, as it correlates with general cognitive abilities. Although numerous studies have investigated how resources are allocated within working memory, the model that has received the most empirical support posits that the number of possible representations is discrete. Furthermore, the literature has shown great interest in Contralateral Delay Activity (CDA), an event-related potential considered to be an index of working memory capacity, as its amplitude increases linearly with the number of representations that are being held in working memory. As for the nature of these representations, it is essential to underline that consciousness represents one of the most debated topics in neuroscience. Specifically, modern neuroscience has developed several theories attempting to define consciousness or identify its neural correlates, often yielding contradictory results. Currently, since pinpointing its precise neural basis seems unattainable, research has shifted towards explaining the phenomena associated with consciousness. In this regard, Dehaene and Naccache’s Global Neuronal Workspace Theory (2001) supports the idea that certain cognitive processes may occur without conscious awareness, due to the interaction of interconnected brain regions. The present study, as described in this thesis, builds upon this principle to explore the possibility that working memory can also maintain information of which the individual is not aware. Specifically, the study analyzes the Contralateral Delay Activity using a combination of electroencephalography and a binocular rivalry paradigm. In details, participants are asked to observe pairs of Gabor patches on a monitor through a stereoscopic mirror, creating a condition of binocular rivalry, and to indicate via button press the orientation of the bars within the observed stimuli. The results support the existence of unconscious processing of visual stimuli and highlight how working memory can filter out irrelevant representations to retain only the pertinent information.