Seeing through space and time: Comparing the effects of exogenous spatial and rhythmic temporal attention on visual awareness

Abstract

Unlike spatial attention, the role of rhythmic temporal attention in visual awareness remains less explored. To address this issue, we investigated how rhythmic temporal attention operates with exogenous spatial attention during detection of near-threshold Gabor patch targets. Targets appeared after a series of placeholders flickering either regularly or irregularly in the left or right visual field. Each target was equally likely to occur at the same location as the rhythmic stream (spatially attended trial) or the opposite location (unattended trial). Participants first made a detection response, followed by a localization judgment. Target visibility was calibrated to 50% in Experiment 1 and 75% in Experiment 2. At 50% visibility, spatial attention induced a more conservative response criterion for unattended compared to attended trials. Unexpectedly, irregular rhythms enhanced perceptual sensitivity relative to regular rhythms. At 75% visibility, rhythms had no effect on perceptual sensitivity, whereas spatial attention improved perceptual sensitivity, sped responses, and maintained a more conservative response pattern for unattended trials. In follow-up experiments with fully visible (100%) targets, responses were faster after regular rhythms, but only when the localization response was removed, suggesting that rhythmic temporal sequences primarily facilitated response preparation under simplified task demands. Overall, these results call for caution in attributing a direct role of rhythmic temporal attention to visual awareness, at least under the current rhythmic sequences and in the presence of spatial uncertainty, while confirming a key role for exogenous spatial attention in enhancing conscious perception.