Department of Psychology, University of Milano-Bicocca, Milan, Italy.
J Exp Psychol Gen. 2013 Aug;142(3):906-22. doi: 10.1037/a0029905. Epub 2012 Sep 17.
When dealing with significant sensory stimuli, performance can be hampered by distracting events. Attention mechanisms lessen such negative effects, enabling selection of relevant information while blocking potential distraction. Recent work shows that preparatory brain activity, occurring before a critical stimulus, may reflect mechanisms of attentional control aimed to filter upcoming distracters. However, it is unknown whether the engagement of these filtering mechanisms to counteract distraction in itself taxes cognitive-brain systems, leading to performance costs. Here we address this question and, specifically, seek the behavioral signature of a mechanism for the filtering of potential distraction within and between sensory modalities. We show that, in potentially distracting contexts, a filtering mechanism is engaged to cope with forthcoming distraction, causing a dramatic behavioral cost in no-distracter trials during a speeded tactile discrimination task. We thus demonstrate an impaired processing caused by a potential, yet absent, distracter. This effect generalizes across different sensory modalities, such as vision and audition, and across different manipulations of the context, such as the distracter's sensory modality and pertinence to the task. Moreover, activation of the filtering mechanism relies on both strategic and reactive processes, as shown by its dynamic dependence on probabilistic and cross-trial contingencies. Crucially, across participants, the observed strategic cost is inversely related to the interference exerted by a distracter on distracter-present trials. These results attest to a mechanism for the monitoring and filtering of potential distraction in the human brain. Although its activation is indisputably beneficial when distraction occurs, it leads to robust costs when distraction is actually expected but currently absent.
当处理重要的感官刺激时，分心事件可能会妨碍表现。注意机制减轻了这种负面影响，使人们能够选择相关信息，同时阻止潜在的干扰。最近的研究表明，预备性大脑活动（在关键刺激之前发生）可能反映了注意力控制的机制，旨在过滤即将出现的干扰。然而，尚不清楚这些过滤机制的参与本身是否会对认知-大脑系统造成负担，从而导致表现成本。在这里，我们解决了这个问题，特别是寻求在感觉模态内部和之间过滤潜在干扰的机制的行为特征。我们表明，在潜在分心的情况下，会启用一种过滤机制来应对即将到来的分心，这会导致在快速触觉辨别任务中无分心试验中的行为成本大幅增加。因此，我们证明了由潜在但不存在的干扰引起的处理能力受损。这种效应跨越不同的感觉模态，如视觉和听觉，以及不同的上下文操作，如干扰的感觉模态和与任务的相关性，都具有普遍性。此外，过滤机制的激活依赖于策略和反应性过程，如其对概率和跨试验关联的动态依赖。至关重要的是，在参与者之间，观察到的策略性成本与干扰在干扰存在试验中施加的干扰呈反比。这些结果证明了人类大脑中对潜在干扰进行监控和过滤的机制。尽管当出现干扰时，它的激活无疑是有益的，但当实际上预期但目前不存在干扰时，它会导致强大的成本。
