Attentional capture with various distractor and target types

Effects of nonpredictive distractors that involved changes in luminance, si ze, or shape were examined in three experiments. In Experiment 1, with two types of distractors (onsets and offsets), accuracy was better on trials wh en the distractor was near the location of either an offset or an onset tar get than on trials when the distractor was in a different location from tha t of the target, demonstrating attentional capture. Capture occurred both w hen the type of target (onset or offset) was blocked and therefore predicta ble and also when the type of target was mixed within blocks and therefore not predictable. Further experiments indicated that distractors captured at tention even when the change to distractor did not create a new perceptual object. Neither a singleton-detection mode, nor a contingent involuntary or ienting hypothesis, nor creation of a new object seems to explain all of th ese data adequately. Rather, capture may depend on a number of factors in t he task.