ERI-Lectura, Universitat de València, Valencia, Spain.
Brain Lang. 2013 Apr;125(1):11-27. doi: 10.1016/j.bandl.2012.12.009. Epub 2013 Feb 26.
The encoding of letter position is a key aspect in all recently proposed models of visual-word recognition. We analyzed the impact of lexical frequency on letter position assignment by examining the temporal dynamics of lexical activation induced by pseudowords extracted from words of different frequencies. For each word (e.g., BRIDGE), we created two pseudowords: A transposed-letter (TL: BRIGDE) and a replaced-letter pseudoword (RL: BRITGE). ERPs were recorded while participants read words and pseudowords in two tasks: Semantic categorization (experiment 1) and lexical decision (experiment 2). For high-frequency stimuli, similar ERPs were obtained for words and TL-pseudowords, but the N400 component to words was reduced relative to RL-pseudowords, indicating less lexical/semantic activation. In contrast, TL- and RL-pseudowords created from low-frequency stimuli elicited similar ERPs. Behavioral responses in the lexical decision task paralleled this asymmetry. The present findings impose constraints on computational and neural models of visual-word recognition.
字母位置的编码是所有最近提出的视觉词汇识别模型的一个关键方面。我们通过检查由不同频率的单词提取的伪词诱导的词汇激活的时间动态，分析了词汇频率对字母位置分配的影响。对于每个单词（例如 BRIDGE），我们创建了两个伪词：一个字母换位的（TL：BRIGDE）和一个字母替换的伪词（RL：BRITGE）。当参与者在两个任务中阅读单词和伪词时，记录了 ERPs：语义分类（实验 1）和词汇决策（实验 2）。对于高频刺激，单词和 TL-伪词产生相似的 ERPs，但与 RL-伪词相比，单词的 N400 成分减少，表明词汇/语义激活较少。相比之下，由低频刺激产生的 TL-和 RL-伪词引起相似的 ERPs。词汇决策任务中的行为反应与这种不对称性平行。本研究结果对视觉词汇识别的计算和神经模型施加了限制。
