The Time Course Of Meaning And Truth Value Establishing During Sentence Comprehension

Language is used for expressing meaning. It is a very important medium fortransferring information. The sentences which we hear or listen have their meaning,but this does not necessarily mean that they are also true. For instance, the sentencesuch as "The north pole is very warm" has a coherent semantic interpretation, but itcontains a proposition that is false in the light of our knowledge in memory that thenorth pole is very cold. During language comprehension, when human brainestablishes the meaning and truth value of a linguistic express? What is temporalrelationship between meaning establishing and truth value establishing? These arevery important questions for language research.Aiming at the disagreement among previous theoretical hypothesis andexperimental researches, the present study investigates the temporal feature ofmeaning and truth value establishing. In detail, the present study probes into two mainquestions. (1) When human brain relates a new coming word into the context andestablishes a united meaning during sentence comprehension? (2) What is thetemporal relationship between meaning establishing and truth value establishingduring sentence comprehension?The experiment 1 aims to explore when human brain relates a new coming wordinto the context and establishes a united meaning during sentence comprehension. It isa common knowledge that the ERP component named N400 is a very good index forinvestigating the integration of semantic-related information. The researches based onN400 effect indicated that sentence meaning establishing occurred between250-550ms after the entering of a word. The two sub-experiments, experiment 1a and1b, applies an experimental paradigm, which is related with "Perceptual SymbolTheory", to investigate when human brain relates a new word into the context and establishes a united meaning. The result shows that participants relate a word to thecontext after it entered 150ms or even earlier, and establish a united meaning. Thissuggests that N400 effect does not correspond to the processing in which thesemantic-related information is integrated into the context strictly. There happensmeaning establishing before the appearance of N400 effect. And the N400 effect maybe not a good index for investigating sentence meaning establishing.The experiment 2 aims to probe into the temporal relationship between sentencemeaning establishing and truth value establishing. Recently, some researches usedneurophysiological technique suggested that meaning and truth value establishinghappened in the same time. But these researches used N400 effect as experimentalindex, their validity was challenged by experiment 1. Experiment 2 used reaction timeas index, re-investigates the temporal relationship between sentence meaning andtruth value establishing. The result shows that it can make a distinction betweenmeaning establishing and truth value establishing, and the former happens earlier thanthe latter during sentence comprehension. This experiment also supports oneconclusion of experiment 1 that meaning establishing happens before the appearanceof N400 effect.As a whole, results of the present research lead to the following conclusions:meaning establishing happens after a new word was presented 150ms or even earlier.It can make a distinction between meaning establishing and truth value establishing.Meaning establishing happens earlier than truth value establishing during sentencecomprehension. The N400 effect does not correspond to the processing in which thesemantic-related information is integrated into the context strictly, and it only reflectsa later integration.