Perceptual load and attentional boost: a study of their interaction.

Increasing attention to an item typically interferes with the ability to process other concurrent information. The attentional boost effect, however, appears to contradict the ubiquity of dual-task interference. Rather, detecting a target item for one task boosts memory for a currently presented, but unrelated background scene. To account for the apparent discrepancy between dual-task interference and attentional boost, we present and test the dual-task interaction model. This model states that dual-task interference occurs at multiple stages of processing, but the decision that an item is a target triggers a cross-task enhancement to perceptual processing. Consistent with this model, this study shows that targets, but not perceptually similar distractors, trigger the attentional boost effect. In addition, the attentional boost effect is unperturbed when the perceptual load of target detection increases. The effect can also occur for task-irrelevant background images. Consistent with the dual-task interaction model these data clearly tie the attentional boost effect to the decision that an item is a target. They also suggest that this decision can rapidly boost the availability of perceptual resources.