The role of space and time in object-based visual search

Abstract

Recently we have provided evidence that observers more readily select a target from a visual search display if the motion trajectory of the display object suggests that the observer has dealt with it before. Here we test the prediction that this object-based memory effect on search breaks down if the spatiotemporal trajectory is disrupted. Observers searched a display for a target shape among multiple distractors. The entire search display then passed behind an occluder and reemerged in either the same or a different configuration. Experiment 1 shows that the same-object benefit for selection disappears whenever a spatial disruption is involved, but that it may survive a brief temporal disruption. Experiment 2 shows that with sufficiently long gaps, a temporal disruption also destroys the same-object benefit for selective attention. Experiment 3 demonstrates that the same-object effect is even stronger when there only is a very small probability that the target can be found at the same location as before. This also made the task sensitive to brief temporal disruptions. We conclude that a coherent spatiotemporal history of a display object supports the selection of its relevant subregions.

Keywords:

• Attentional control settings
• Object-based attention
• Spatiotemporal continuity

Notes

¹We emphasize that including this person in the analyses did not alter the overall pattern of results. All main effects and interactions of importance still came out significant. The individual t-tests testing the same-object benefit against zero were more affected due to the overall strongly negative same-object effects exhibited by this participant, which led to a general downshift of the pattern in Figure 3b (while the pattern was still intact).