Hohlfeld Annette, Sommer Werner
Institute of Psychology, Humboldt-University at Berlin, Rudower Chaussee 18, D-12489 Berlin, Germany.
Brain Res Cogn Brain Res. 2005 Aug;24(3):500-12. doi: 10.1016/j.cogbrainres.2005.03.001. Epub 2005 Apr 26.
Recently, we observed that the perception of word meaning, as measured with the N400 component of the event-related brain potential, is delayed but unimpaired by various additional tasks when the language task requires the processing of semantic properties of the word stimuli. In the present study, we assessed whether similar effects would be observed when the language task relates to acoustic rather than to semantic properties of the word stimuli. The N400 was elicited by synonymous and non-synonymous spoken noun pairs that were to be classified according to tone pitch. In a single task experiment, there was a small but clear synonymity effect in ERPs (N400), indicating the availability of word meaning to the semantic system. Additional processing load, imposed by an overlapping task, abolished N400 for all SOAs when stimulus-response assignments were incompatible. For compatible assignments, N400 amplitude was present but much attenuated at the longest SOA. We conclude that the availability of task-irrelevant meaning is modulated by additional task load and decay in short-term memory.
最近，我们观察到，当语言任务需要处理单词刺激的语义属性时，用事件相关脑电位的N400成分测量的词义感知会延迟，但不受各种额外任务的损害。在本研究中，我们评估了当语言任务与单词刺激的声学属性而非语义属性相关时，是否会观察到类似的效应。N400由根据音调分类的同义及非同义口语名词对诱发。在单一任务实验中，ERP（N400）中存在微小但明显的同义效应，表明语义系统能够获取词义。当刺激-反应分配不兼容时，重叠任务施加的额外处理负荷消除了所有刺激间隔下的N400。对于兼容的分配，N400波幅存在，但在最长刺激间隔时大幅衰减。我们得出结论，无关任务意义的可用性受额外任务负荷和短期记忆衰退的调节。
