Centre de recherche en Neuropsychologie et Cognition, Département de psychologie, Université de Montréal, Montréal, Québec, Canada.
Psychophysiology. 2011 Jan;48(1):102-11. doi: 10.1111/j.1469-8986.2010.01040.x.
The cognitive system is able to reconfigure mental resources flexibly to adapt to new a task. While task-set switching is known to be detrimental to behavioral performance, less is known about the precise loci of these effects on stimulus processing. We measured event-related potentials to explore the neural consequences of task-set switching on semantic processing. We examined the context-sensitive N400 component evoked by the second of two target words embedded in a rapid serial visual presentation under conditions that involved either a task-set switch or no switching. Whereas the N400 was unaffected by the lag separating the targets in the absence of switching, it was delayed and attenuated in the switch condition when the targets were adjacent in the sequence. These findings indicate that task-set reconfiguration temporarily prevents semantic activation and provide evidence for the nonautomaticity of semantic processing of words.
认知系统能够灵活地重新配置心理资源以适应新任务。虽然任务集切换已知会对行为表现产生不利影响，但对于这些影响在刺激处理上的确切位置知之甚少。我们测量了事件相关电位，以探讨任务集切换对语义处理的神经后果。我们在快速序列视觉呈现的两个目标词中的第二个目标词引发的上下文敏感 N400 成分下检查了条件，该条件涉及任务集切换或无切换。虽然在没有切换的情况下，N400 不受目标之间的滞后影响，但在目标在序列中相邻的切换条件下，它会延迟和减弱。这些发现表明任务集重新配置会暂时阻止语义激活，并为单词语义处理的非自动性提供证据。
