Abstract
Once attention has been disengaged from a non-predictive exogenous cue, processing of a target subsequently presented at the cued location is slowed relative to that of targets at uncued locations. This effect has been termed inhibition of return (IOR). Previous studies of IOR using multiple cueing paradigms have focused on either temporal or spatial dynamics in isolation. We argue, however, that space and time have to be considered in conjunction to understand the processes governing the allocation of attention. To test this notion, the present work examines the spatiotemporal distribution of IOR in a sequential cueing task, in which three cues were presented sequentially for 500ms each at three of six possible locations along an imaginary circle with 5° radius. Following a central reorienting cue of 500ms duration, a target appeared for 100ms at any of the six possible locations, which participants were instructed to detect by button press as rapidly as possible. In line with previous work, we found greatest IOR at the most recently cued locations, with decreasing magnitudes of IOR at locations cued earlier in the sequence. Importantly, the magnitude of IOR was affected by the spatial arrangement of the cues, such that targets appearing at the vector average of all cued locations showed greater IOR than those appearing at the edges of the spatial distribution. Therefore, we conclude that IOR is a function of both the positions and the timing of sequential cues, indicating that attention integrates spatial and temporal properties to optimize responses to new information.
Funded by NSERC granted to S.F.