University Medical Centre Hamburg Eppendorf, Hamburg, Germany.
J Cogn Neurosci. 2010 Mar;22(3):437-46. doi: 10.1162/jocn.2009.21204.
Attentional interference between tasks performed in parallel is known to have strong and often undesired effects. As yet, however, the mechanisms by which interference operates remain elusive. A better knowledge of these processes may facilitate our understanding of the effects of attention on human performance and the debilitating consequences that disruptions to attention can have. According to the load theory of cognitive control, processing of task-irrelevant stimuli is increased by attending in parallel to a relevant task with high cognitive demands. This is due to the relevant task engaging cognitive control resources that are, hence, unavailable to inhibit the processing of task-irrelevant stimuli. However, it has also been demonstrated that a variety of types of load (perceptual and emotional) can result in a reduction of the processing of task-irrelevant stimuli, suggesting a uniform effect of increased load irrespective of the type of load. In the present study, we concurrently presented a relevant auditory matching task [n-back working memory (WM)] of low or high cognitive load (1-back or 2-back WM) and task-irrelevant images at one of three object visibility levels (0%, 50%, or 100%). fMRI activation during the processing of the task-irrelevant visual stimuli was measured in the lateral occipital cortex and found to be reduced under high, compared to low, WM load. In combination with previous findings, this result is suggestive of a more generalized load theory, whereby cognitive load, as well as other types of load (e.g., perceptual), can result in a reduction of the processing of task-irrelevant stimuli, in line with a uniform effect of increased load irrespective of the type of load.
任务并行执行时的注意力干扰会产生强烈的、往往不受欢迎的影响。然而，干扰作用的机制仍然难以捉摸。更好地了解这些过程可能有助于我们理解注意力对人类表现的影响，以及注意力中断可能产生的不良后果。根据认知控制的负载理论，当并行注意到具有高认知需求的相关任务时，会增加对任务无关刺激的处理。这是因为相关任务会占用认知控制资源，因此无法抑制对任务无关刺激的处理。然而，也有研究表明，各种类型的负载（感知和情绪）都会导致对任务无关刺激的处理减少，这表明无论负载类型如何，负载的增加都会产生统一的影响。在本研究中，我们同时呈现了一个相关的听觉匹配任务（n 回工作记忆（WM）），其认知负荷高低不同（1 回或 2 回 WM），同时呈现三种物体可见度水平（0%、50%或 100%）的任务无关图像。在处理任务无关视觉刺激期间，测量了外侧枕叶皮层的 fMRI 激活，发现高 WM 负荷下的激活低于低 WM 负荷下的激活。结合以往的研究结果，这一结果表明存在一种更普遍的负载理论，即认知负载以及其他类型的负载（例如感知负载）会导致对任务无关刺激的处理减少，这与负载增加的统一效应一致，而与负载类型无关。
