Abstract
We recently reported that the onset of motion (but not motion per se) captures attention. In the present experiments we explored the extent to which a motion onset can be ignored or its effect suppressed if the observer has advance information about the likely location of the target of a visual search. In one experiment, observers searched for letters in a display that contained easily distinguishable relevant and irrelevant items. The search target could only appear in the relevant items yet the onset of motion of an irrelevant item slowed target identification. In a second experiment the result was replicated in a display in which all of the relevant items were in continuous motion throughout the trial, indicating that the earlier effect was not due to top-down selection for motion. In a third experiment we found that offsets of motion did not slow target identification. In a final experiment we provided advance information regarding the precise target location. Even under those circumstances subjects were still affected by motion onsets occurring elsewhere in the display. We conclude that motion onset attracts attention from the bottom-up and, unlike other events that attract attention such as the appearance of a new object, the effect of motion onset cannot be eliminated by focused attention. Motion onset might be important because it may signal the presence of nearby animals, and evolutionary advantages would accrue to those who can more easily detect predators and prey.
The work reported here was supported by grant BCS-0079594 from the National Science Foundation.