Lexical representation explains cortical entrainment during speech comprehension

Results from a recent neuroimaging study on spoken sentence comprehension have been interpreted as evidence for cortical entrainment to hierarchical syntactic structure. We present a simple computational model that predicts the power spectra from this study, even though the model’s linguistic knowledge is restricted to the lexical level, and word-level representations are not combined into higher-level units (phrases or sentences). Hence, the cortical entrainment results can also be explained from the lexical properties of the stimuli, without recourse to hierarchical syntax.近期一项针对口语句子理解的神经影像学研究结果，曾被视作皮层追踪（cortical entrainment）层级句法结构的实验证据。本文提出一款简易计算模型，可复现该研究测得的功率谱（power spectra）结果——尽管该模型的语言学知识仅局限于词汇层面，且未将词级表征整合为更高层级的单元（短语或句子）。由此可见，前述皮层追踪的实验结果，亦可通过实验刺激的词汇属性加以解释，而无需依赖层级句法。