Douglas Mental Health University Institute, Montréal, Québec, Canada.
Biol Psychol. 2010 May;84(2):206-20. doi: 10.1016/j.biopsycho.2010.01.014. Epub 2010 Jan 28.
Repetition has often been associated with a reduction or a suppression of semantic effects. However, several studies have reported that semantic processing can still be effective for repeated target stimuli when the context, prime word or sentence frame, changes from trial to trial. This type of context-target designs allows to study semantic associations between repeated words. However, it is not optimal to study single concepts or categories and therefore structural aspects of semantic memory. Here, we tested whether semantic effects could be observed if single-word trials were used. Concrete and Abstract words were presented multiple times in two concrete-abstract classification experiments. In the first experiment, 6 words of each category were repeatedly presented. In the second experiment, only one word of each category was used. Results of both experiments showed significant effects of concreteness on reaction times and N400-like event-related potentials (ERPs), which were comparable to those reported in non-repeated conditions. In the second experiment, in which repetitions occurring in consecutive and non-consecutive trials were contrasted, N400-like effects were observed only for non-consecutive repetitions. These findings suggest that it could be possible to study the brain activity corresponding to individual concepts in experimental designs using single-word trials, provided that consecutive repetitions are avoided.
重复通常与语义效应的减少或抑制有关。然而，有几项研究报告称，当上下文、启动词或句子框架在试验之间发生变化时，重复目标刺激仍然可以有效地进行语义处理。这种上下文-目标设计类型允许研究重复单词之间的语义关联。然而，对于研究单个概念或类别以及语义记忆的结构方面来说，这种设计并不理想。在这里，我们测试了如果使用单个单词试验是否可以观察到语义效应。在两个具体-抽象分类实验中，多次呈现具体和抽象词。在第一个实验中，每个类别重复呈现 6 个单词。在第二个实验中，每个类别仅使用一个单词。两个实验的结果都显示了具体性对反应时间和 N400 样事件相关电位 (ERP) 的显著影响，这与非重复条件下报告的结果相当。在第二个实验中，对比了连续和非连续试验中的重复，仅观察到非连续重复的 N400 样效应。这些发现表明，在实验设计中使用单个单词试验，有可能研究单个概念对应的大脑活动，只要避免连续重复即可。
