Department of Psychological Sciences, Vanderbilt University Nashville, TN, USA.
Department of Psychology, Yale University New Haven, CT, USA.
Front Hum Neurosci. 2014 May 27;8:334. doi: 10.3389/fnhum.2014.00334. eCollection 2014.
The load theory of visual attention proposes that efficient selective perceptual processing of task-relevant information during search is determined automatically by the perceptual demands of the display. If the perceptual demands required to process task-relevant information are not enough to consume all available capacity, then the remaining capacity automatically and exhaustively "spills-over" to task-irrelevant information. The spill-over of perceptual processing capacity increases the likelihood that task-irrelevant information will impair performance. In two visual search experiments, we tested the automaticity of the allocation of perceptual processing resources by measuring the extent to which the processing of task-irrelevant distracting stimuli was modulated by both perceptual load and top-down expectations using behavior, functional magnetic resonance imaging, and electrophysiology. Expectations were generated using a trial-by-trial cue that provided information about the likely load of the upcoming visual search task. When the cues were valid, behavioral interference was eliminated and the influence of load on frontoparietal and visual cortical responses was attenuated relative to when the cues were invalid. In conditions in which task-irrelevant information interfered with performance and modulated visual activity, individual differences in mean blood oxygenation level dependent responses measured from the left intraparietal sulcus were negatively correlated with individual differences in the severity of distraction. These results are consistent with the interpretation that a top-down biasing mechanism interacts with perceptual load to support filtering of task-irrelevant information.
视觉注意的负载理论提出，在搜索过程中，对任务相关信息的有效选择性感知处理是由显示的感知需求自动决定的。如果处理任务相关信息所需的感知需求不足以消耗所有可用的容量，那么剩余的容量就会自动且彻底地“溢出”到任务不相关的信息上。感知处理能力的溢出增加了任务不相关信息干扰表现的可能性。在两个视觉搜索实验中，我们通过使用行为、功能磁共振成像和电生理学来测量任务无关分心刺激的处理在多大程度上受到感知负载和自上而下的预期的调节，从而测试了感知处理资源分配的自动性。预期是通过一个逐次试验的线索产生的，该线索提供了关于即将到来的视觉搜索任务的可能负载的信息。当线索有效时，行为干扰被消除，并且负载对额顶叶和视觉皮层反应的影响相对于线索无效时减弱。在任务不相关信息干扰表现并调节视觉活动的情况下，从左侧顶内沟测量的平均血氧水平依赖反应的个体差异与分心严重程度的个体差异呈负相关。这些结果与自上而下的偏向机制与感知负载相互作用以支持过滤任务不相关信息的解释一致。
