Using a response competition paradigm, we investigated the ability to ignore target responsecompatible, target response-incompatible, and neutral visual and auditory distractors presented during a visual search task. The perceptual load model of attention (e.g., Lavie & Tsal, 1994) states that task-relevant processing load determines irrelevant distractor processing in such a way that increasing processing load prevents distractor processing. In three experiments, participants searched sets of one (easy search) or six (hard search) similar items. In Experiment 1, visual distractors influenced reaction time (RT) and accuracy only for easy searches, following the perceptual load model. Surprisingly, auditory distractors yielded larger distractor compatibility effects (median RT for incompatible trials minus median RT for compatible trials) for hard searches than for easy searches. In Experiments 2 and 3, during hard searches, consistent RT benefits with response-compatible and RT costs with response-incompatible auditory distractors occurred only for hard searches. We suggest that auditory distractors are processed regardlessof visual perceptual load but that the ability to inhibit cross-modal influence from auditory distractors is reduced under high visual load.

Two studies explored whether sustained attention during infants' object exploration, or examining, reflects more active processing than do other components of attention. In Experiment 1, infants examined complex objects more than simple ones and novel objects more than familiar ones. In addition, 7-month-olds examined objects more than did 10-month-olds. Looking that did not involve examining did not vary systematically with either complexity or age. These findings suggest that infants' examining is related to the amount of information to be processed. Experiment 2 tested this hypothesis more directly by evaluating how distractible 7-and 10-month-olds were during examining as compared with nonexamining phases of attention. Infants were less distractible during examining, supporting the assumption that examining involves more active cognitive processing than other aspects of visual attention.

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The interactive effects of stimulus characteristics and attentional state on infants' distraction latency were studied. As 7-month-old infants explored initial stimuli that were composed of either a single nonmoving component or multiple moving components, one of several types of distractors was presented in the periphery. Infants' distraction latencies (the amount of time they took to turn from the initial stimulus to the distractor) vaned as a hnction of the interaction between the infants' attentional state at distractor onset and the characteristics of the stimuli. Variations in the visual characteristics of the distractor stimulus (solid rectangle vs. checkerboard) had a larger effect on distraction latency when infants were in a focused attentional state than when they were in a casual attentional state. Similarly, variations in the auditory characteristic of the distractor stimulus (1 intermittent tone vs. 2 alternating tones) had a larger Requests for reprints should be sent to Lisa M. Oakes,

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