Abstract
A growing body of research highlights that our ability to predict future events shapes our subjective experience of the world. For example, recent studies show that phasic alertness – i.e., increased response preparation and heightened attention following a warning signal – influences perceptual awareness. Following this research trajectory, we investigated how mental alertness and response preparation interface with visual awareness. In particular, our goal was to unravel the specific influences of pre-stimulus processes involved in response preparation over visual awareness. To that end, participants completed a target discrimination task where we combined a temporal cueing approach with a backward masking strategy, while we recorded brain activity using 64 channels electroencephalography. A temporally predictive cue preceded the target event for half of trials, thereby allowing participants to reliably estimate the latency of the target event. For each trial, participants provided an objective response, where they indicated the orientation of the target (left vs. right), as well as a subjective judgment about its visibility (seen vs. unseen). Our results show that heightened mental alertness benefits both performance (i.e., improved ideomotor response and perceptual sensitivity) and perceptual awareness (i.e., increased reports of visibility). At the neural level, cueing prompted opposite effects over the magnitude of power in frontal theta and occipital alpha oscillations, two neural responses that likely index discrete brain processes linked to response preparation and mental alertness. Consistent with our behavioral results, findings also revealed that increased alertness modulated the amplitude of the P3b, an event-related potential linked to perceptual awareness. Finally, using a computational model, we found that these effects likely reflect the influence of alertness over the rate of perceptual evidence accumulation, thereby implying that alertness primarily influence awareness through perceptual processes.
Meeting abstract presented at VSS 2018