Parallel processing in speech perception with local and global representations of linguistic context

Speech processing is highly incremental. It is widely accepted that human listeners continuously use the linguistic context to anticipate upcoming concepts, words, and phonemes. However, previous evidence supports two seemingly contradictory models of how a predictive context is integrated with the bottom-up sensory input: Classic psycholinguistic paradigms suggest a two-stage process, in which acoustic input initially leads to local, context-independent representations, which are then quickly integrated with contextual constraints. This contrasts with the view that the brain constructs a single coherent, unified interpretation of the input, which fully integrates available information across representational hierarchies, and thus uses contextual constraints to modulate even the earliest sensory representations. To distinguish these hypotheses, we tested magnetoencephalography responses to continuous narrative speech for signatures of local and unified predictive models. Results provide...语音处理具备极强的增量特性。学界普遍认为，人类听众会持续依托语言语境预判即将出现的概念、词汇与音素（phonemes）。然而，过往研究证据却支持两种看似矛盾的模型，用以阐释预测性语境如何与自下而上的感觉输入（bottom-up sensory input）进行整合：经典心理语言学范式提出了两阶段加工模型，即声学输入首先会生成独立于语境的局部表征，随后快速与语境约束完成整合。与之相对的另一观点则认为，大脑会对输入信号构建单一连贯的统一解读，该解读会在表征层级间充分整合所有可用信息，因此甚至可借助语境约束调节最早期的感觉表征。为区分这两种假说，本研究通过检测连续叙事语音诱发的脑磁图（magnetoencephalography, MEG）响应，寻找支持局部与统一两种预测模型的特征标记。研究结果提供……