Abstract
It is commonly agreed that the abrupt appearance of a new object captures attention, whereas the mere presence of a singleton object that differs in color or motion from other objects does not capture attention. Franconeri and Simons (2003, P&P) challenged this view presenting findings where moving or looming stimuli captured attention. They used the irrelevant feature search task, where one stimulus is singled out by its unique color, motion, or by its sudden onset. A trial started with figure-eight placeholders, which turned into letters after 1000 ms by the removal of some segments of the placeholders. They found that sudden onsets as well as motion singletons, but not color singletons, captured attention. The present study replicated and extended these results by showing that the timing of events is critical to obtain capture. Color did not capture attention when the singleton differed in color from the others from the beginning of the trial, or when the singleton changed its color at the same time as the letters appeared. However, color did capture attention when the change occurred 150 ms before or even 150 ms after the letters appeared. We suppose that all sudden, not only color, changes capture attention when it does not coincide with other changes in the display. Similar results emerged with singletons that moved for 150 ms. As in the color experiment and in accordance with Franconeri and Simons results, motion captured attention when it started 150 ms before the letters appeared. However, as argued above, this might simply be due to a sudden change (like motion onset) in the display. In the last Experiment we showed that motion did also capture attention when it started simultaneously with letter appearance. Whether this latter result supports Franconeri and Simons view that dynamic events capture attention, or whether it means that other aspects of motion captures attention, like the sudden offset of motion, is subject of further investigations.
SNF, NSERC