title: The Temporal Order of Word Presentation Modulates the Amplitudes of P2 and N400 during Recognition of Causal Relations.
abstract: The processing of causal relations has been constantly found to be asymmetrical once the roles of cause and effect are assigned to objects in interactions. We used a relationship recognition paradigm and recorded electroencephalographic (EEG) signals to explore the neural mechanism underlying the asymmetrical representations of causal relations in semantic memory. The results revealed that the verification of causal relations is faster if two words appear in "cause-effect" order (e.g., virus-epidemic) than if they appear in "effect-cause" order (e.g., epidemic-virus), whereas no such asymmetrical representation was found for the verification of hierarchical relations with reverse orders (e.g., bird-sparrow vs. sparrow-bird) in Experiment 1. Furthermore, the P2 amplitude elicited by "superordinate-subordinate" order was larger than that when in reverse order, whereas the N400 effect elicited by "cause-effect" order was smaller (more positive) than when in reverse order. However, no such asymmetry, as well as P2 and N400 components, were observed when verifying the existence of a general associative relation in Experiment 2. We suggested that the smaller N400 in cause-effect order indicates their increased salience in semantic memory relative to the effect-cause order. These results provide evidence for dissociable neural processes, which are related to role binding, contributing to the generation of causal asymmetry.
authors.affiliation: Institute for Advanced Study, Chengdu UniversityChengdu, China; Research Centre for Brain Function and Psychological Science, Shenzhen UniversityShenzhen, China.
authors.forename: Xiuling
authors.initials: X
authors.lastname: Liang
authors.affiliation: Department of Teacher Education, Shanxi Normal University Linfen, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Xiao
authors.affiliation: Department of Economics and Trade, Guangdong University of Finance Guangzhou, China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Wu
authors.affiliation: Institute for Advanced Study, Chengdu UniversityChengdu, China; Research Centre for Brain Function and Psychological Science, Shenzhen UniversityShenzhen, China; China Center for Special Economic Zone Research, Shenzhen UniversityShenzhen, China.
authors.forename: Qingfei
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Research Centre for Brain Function and Psychological Science, Shenzhen University Shenzhen, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Lei
authors.affiliation: Research Centre for Brain Function and Psychological Science, Shenzhen University Shenzhen, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
keywords: N400; P2; causal relations; hierarchical relations; temporal order