The Processing Of Different Kinds Of Focus And Its Influence On Lexical Tone:Evidence From ERP Studies

Language is used for communication,which is essentially a dynamic process of information exchange.In communication,both sides encode the information they want to convey into one unit of information and transmit it to the outside world.This unit is called the information structure(IS).Information structure can be divided from different dimensions,such as theme-rheme,background-focus,old-new.Most of the studies on information structure are conducted from the perspective of focus and background,and some researchers divide the focus into the information focus(IF)which expresses pure new information and the contrast/corrective focus(CF)which contrasts with the previous information.Previous studies found different aspect of semantic integration of different information structures,among which two aspects attract most of attention.First,CF consumes more cognitive resource to integrate focused information than IF.Second,processing of wrong information acquires more cognitive resource when it is focused information than when it is background information.Two experiments were performed to observe these two phenomena,hoping to provide more understanding for processing of information structure.Experiment 1 investigated how readers process IF and CF at the clause-medial and clause-final positions in a question-answer pair using ERPs.We asked participants to read the visually presented question-answer pairs carefully and to complete a semantic comprehension task.The results show that focus elicits a larger P2/P3 a and LPC than background,possibly reflecting a process of attention allocation and immediate discourse updating.Additionally,IF elicits a larger P2/P3 a than CF at the clause-medial position,while CF elicits a larger LPC than IF at the clause-final position,indicating that IF captures more attention at the clause-medial position and CF consumes more cognitive resource to complete the process of discourse renewal and revision at the clause-final position.Above all,Experiment 1 suggests that readers use various strategies to process the two kinds of focus and focus processing is influenced by both context and focus position.Experiment 2 investigated how violation of continuous 3rd tone sandhi influenced the semantic integration and whether this process was influenced by IS.In this study,we used question-answer pairs to put target words on focus or background with three following conditions: correct tone sandhi(3rd Tone sandhi,sT3),tone sandhi violation(3rd tone unchanged,nsT3)and tone violation(4th tone violation,vT4).The participants’ task was to decide whether the tone of the speech was natural or not.The results showed that vT4 were more unnatural than nsT3 and elicited different ERPs.Specifically,vT4 elicited a larger central-posterior positivity than sT3 in 400-1000 ms,suggesting that participants devoted more effort to the re-analyze of the tone.Moreover,nsT3 elicited a larger frontal negativity than sT3 in 400-600 ms,suggesting that higher cost is needed to integrate nsT3 into the dialogue.However,these effects were not influenced by IS.In summary,Experiment 2 suggests that sandhi rule violation is processed differently from tone violation,and IS exert no influence on this pattern.The two experiments above suggest that although IS do mediate semantic processing such as the integration of focused information,its function is limited in modulating prosodic information processing such as linguistic tone.