Abstract
When attending an object in visual space, the perception of the object remains stable despite frequent eye movements. It is assumed that visual stability is due to the process of remapping, in which retinotopically organized maps are updated to compensate for the retinal shifts caused by eye movements. Remapping is predictive when it starts before the actual saccade. Until now, most evidence for predictive remapping has been obtained in single cell studies involving monkeys. In the present study, human observers made a saccade to a location in space. Just before executing the saccade, a brief irrelevant onset was presented somewhere in the visual field to summon exogenous attention. After executing the saccade, a probe stimulus (a titled line-segment) appeared at one of four locations (spatiotopic, retinotopic and two control locations). Participants made a speeded keypress response to indicate the orientation of the probe. We show that immediately following a saccade, attention has partly shifted with the saccade. Importantly, we show that remapping is predictive and affects the locus of attention prior to saccade execution: before the saccade was executed, there was attentional facilitation at the location which, after the saccade, would retinotopically match the attended location. Subsequent experiments show that it did not matter whether spatiotopic and retinotopic locations were presented in the same or in different quadrants of the visual field and whether manual or saccadic responses were made towards the probe.
We conclude that exogenous visual attention is only partly remapped. Immediately following a saccade, attention is allocated at two locations: the original locus of attention and the location which retinotopically matches the original locus of attention. Importantly, we also show that remapping is predictive causing the locus of attention to shift in the direction of the saccade prior to its execution.
Netherlands Organization for Scientific Research NWO, grant 463-06-014.