Poster B85, Tuesday, August 20, 2019, 3:15 – 5:00 pm, Restaurant Hall
Word-chunk or Words-chunk? Two-stage Chunking Operation in Reading of Complex Text
Jinbiao Yang1,2, Qing Cai3,5, Xing Tian3,4;1Max Planck Institute for Psycholinguistics, 2Centre for Language Studies Nijmegen, Radboud University, 3NYU-ECNU Institute of Brain and Cognitive Science at NYU Shanghai, 4Division of Arts and Sciences, New York University Shanghai, 5Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), School of Psychology and Cognitive Science, East China Normal University
A sentence usually consists of many letters that are organized in a hierarchical structure of text chunks: short as a morpheme, long as an entire sentence, and in the middle are words and phrases. Readers incrementally segment a sentence into smaller chunks and analyze these building blocks directly, efficiently and separately. This process is termed chunking. Effective chunking during reading facilitates disambiguation and enhances efficiency for comprehension. However, the mechanisms of chunking remain elusive, especially in reading given that information arrives simultaneously yet the written systems may not have explicit cues for labeling boundaries such as Chinese. In this study, we investigated the mechanism of chunking operation that mediates reading of text that contains multiple levels of hierarchical information, and focused on the following questions: Which level(s) of chunks in the text hierarchy would serve as building blocks during chunking? If multiple levels of chunks were potential building blocks, which level has priority during the reading process? In this study, we used Chinese four-character strings to investigate the chunking operation in reading. Chinese written system is a good model to investigate the multi-level chunking because each Chinese character is a basic lexical unit with similar length and four characters can form two levels of chunks -- chunks with two characters (local level chunks) and a chunk with four characters (global level chunk). The lexicality was manipulated at both levels so that four types of stimuli were included (phrase, idiom, random words, and random characters). A line under two characters or four characters indicate the target chunk. We conducted a behavioral experiment (lexical decision task) to investigate the interaction between global and local chunks processes. Moreover, an EEG experiment (passive reading) was carried out to test the dynamics of multi-level chunking operation. The behavioral results showed that the lexical decision of lexicalized two-character local chunks was influenced by the lexical status of the four-character global chunk, but not vice versa, which suggest that the judgement of global chunks possesses priority over the local chunks. EEG results further revealed that nested chunks at both levels were detected simultaneously but further processed in different temporal orders -- the onset of lexical access for the global chunks was earlier than that of local chunks, followed by parallel processes for chunks at both levels. These consistent behavioral and EEG results suggest a workflow for processing multiple-level information in reading: The segmentation occurs in an early and short time window within which possible chunks at all levels are detected based on the familiarity of lexical-orthographic features (detection stage). The chunks at each level are further processed with distinct temporal characteristics (processing stage). Specifically, the processing of global chunks possesses priority over the local chunks, while the processing of local chunks can launch before the finish of global chunk processing. Such a partially temporal overlap that enables interaction across levels before final integration.
Themes: Reading, Control, Selection, and Executive Processes
Method: Electrophysiology (MEG/EEG/ECOG)