Department of Psychology, and Centre de Recherche en Neuropsychologie et Cognition, Université de Montréal, Montreal, Canada.
Psychophysiology. 2011 May;48(5):687-96. doi: 10.1111/j.1469-8986.2010.01133.x. Epub 2010 Sep 27.
If object-substitution masking (OSM) arises from mask representations replacing target representations, OSM should impede the formation of representations in visual short-term memory (VSTM). We utilized event-related potentials to examine the effect of OSM on target processing. An N2pc was observed on trials with delayed-offset masks, indicating that focused attention was directed to the target. The sustained posterior contralateral negativity (SPCN), an index of VSTM storage, was observed in delayed-offset trials only on trials with correct responses. This supports the hypothesis that inaccurate performance on delayed-offset trials arises from a failure to encode the target in VSTM. On co-termination trials, accuracy was high and neither the N2pc nor SPCN was observed. This indicates that, in the absence of masking, the task was accomplished by maintaining a diffuse attentional state that enabled the joint encoding of the potential target items.
如果客体替代掩蔽（OSM）是由掩蔽表示替换目标表示引起的，那么 OSM 应该会阻碍视觉短期记忆（VSTM）中表示的形成。我们利用事件相关电位来研究 OSM 对目标处理的影响。在延迟偏移掩蔽试验中观察到 N2pc，表明集中注意力被引导至目标。仅在延迟偏移试验中，正确反应时才会观察到持续的对侧后负变（SPCN），这是 VSTM 存储的指标。这支持了这样一种假设，即延迟偏移试验中不准确的表现是由于未能在 VSTM 中对目标进行编码。在同时终止试验中，准确性很高，既没有观察到 N2pc，也没有观察到 SPCN。这表明，在没有掩蔽的情况下，通过保持弥散的注意力状态来完成任务，从而能够联合编码潜在的目标项目。
