The effects of spatial attention in sensory memory: the mechanism underlying phenomenal consciousness

Theories of visual consciousness have distinguished between phenomenal and access consciousness. Phenomenal consciousness has been described as a rich subjective experience and has been associated with sensory memory stages (i.e., iconic memory and fragile-VSTM). Access consciousness has been described as a narrow cognitive accessibility and has been associated with working memory storage. Although sensory memory has been denoted as a pre-attentive processing stage, the role of attention in this memory stage has not been clearly understood to date. Aiming to shed light on the mechanisms of attention in sensory memory and visual maintenance, we conducted a change detection task manipulating spatial attention with an endogenous pre-cue which could predict (i.e., valid condition) or not (i.e., invalid condition) the side of appearance of the target. An uninformative pre-cue was used as baseline (i.e., neutral condition). The behavioral data of twenty healthy subjects were analyzed. Differences in accuracy were found between neutral and invalid conditions for both iconic memory and fragile-VSTM (150ms, 600ms, 1200ms), and between valid and neutral conditions for fragile-VSTM (600ms, 1200ms). The difference in accuracy between neutral and valid condition in iconic memory was not significant. Our study extended the empirical findings on the investigation of the mechanisms of attention in sensory memory providing further insights about the early stages of visual awareness associated with the phenomenological experience.