An ERPs Study Of Chinese EFL Learners’ Mental Representation Of Polysemous Senses Of AT

Starting from cognitive linguistics, spatial metaphor is defined as the mapping process that constructs from spatial concept as source domain to non-spatial concepts as target domain. Therefore, prepositions can generate polysemous senses through mapping from spatial concept domain to non-spatial concept domain. However, most of the researches related to polysemous senses of prepositions from cognitive perspective are focusing on exploring the derivation and classification of polysemous senses of prepositions from the academic level. Besides, relevant studies of polysemous senses of prepositions are concerned about prepositions, such as over, into, under etc, and few studies pay attention to AT and few researches are discussed polysemous senses of prepositions from ERPs studies. Thus, few studies has begun with spatial metaphor theory and used empirical study to deeply probe into Chinese learners’ mental representation of polysemous senses of preposition AT.The current study has divided senses of AT into six types: 1-spatial sense, 2-temporal sense, 3-number sense, 4-subject sense, 5-state sense and 6-logic relation sense. And adopted ERPs study by way of latency and amplitude of P300 and N400 as the index to explore the rationality of the six divisions of polysemous senses of AT on the basis of spatial metaphor and further test whether there is difference of Chinese EFL learners’ mental representation among the six types of spatial metaphor-based senses of AT. Accordingly, the research question is put forward: Is there any difference of the mental representation of the six types of spatial metaphor-based senses of AT?This research adopted one factor six levels(Items: spatial sense, temporal sense, number sense, subject sense, state sense, logic relation sense; Levels: spatial sense, temporal sense, number sense, subject sense, state sense, logic relation sense) repeated measures experimental design. All the experiments were conducted in the Cognitive Neuroscience Experiment Lab of Sichuan International Studies University(SISU). All the material was programmed by neuro Scan4.5 to acquire and edit electroencephalograph(EEG) data and was presented at random on the 19 inch wide screen. Subjects were required to comprehend sentences needed to fill in the blank and continued it with any key. Then a preposition was presented on the screen and subjects needed to judge whether the preposition could be correctly fill in the blank with the purpose of checking whether subjects correctly comprehended polysemous senses of prepositions and which sense of prepositions was consistent with the sentences. Behavioral data of reaction temporal and accurate rate and EEG data were manipulated by the statistical software SPSS 16.0.The study found that:(1) behavioral data showed there is significant difference between Chinese EFL learners’ spatial sense(M=11522ms, p=.002) and temporal sense(M=708ms, p=.002), subject sense(M=785ms, p=.010), state sense(M=771ms, SD=207) and logic relation sense(M=672ms, p=.001) in reaction temporal. There is no significant difference between Chinese EFL learners’ spatial sense(M=11522ms, p=.002) and number sense(M=947ms, p=.143) in reaction temporal. The further one-way ANOVA of multiple comparisons of RT of six type senses of AT indicated significantly difference among the six type senses of AT(F=3.415, p=.009).(2) Results of EEG data displayed that six types of polysemous senses of AT induced a positive ERP component(P300) in temporal window(250~400ms) and distributed in five brain areas of frontal lobe, temporal lobe, occipital lobe, central area and parietal lobe with a significant difference(F=4.639, p=.000). It showed that P300(P3) was closely associated with WM in visual task and it showed the recognition of stimuli and selection process during updating of WM representation and latency of P300 was affected by perceived complexity and task difficulty, which can be regarded as the index of stimulus evaluation and classification temporal. In temporal window(400~600ms), six types of polysemous senses of AT triggered a negative ERP component(N400) and distributed in frontal lobe, temporal lobe, central area and parietal lobe with a significant difference(F=2.28, p=.047) and no significant different(F=2.159, p=.059) in occipital lobe. It indicated that N400 mainly reflects a kind of later processing of WM and the latency of N400 is influenced by WM capacity and the degree of semantic ambiguity. Therefore, changes of amplitude of N400 can be uses as an important index of WM capacity.In a word, the basic conclusion of this paper is that on the basis of spatial metaphor theory it is rational to divide polysemous senses of AT into six types and the thesis also gave the electrophysiological evidence. Accordingly, there is difference of Chinese EFL learners’ mental representation of six types of polysemous senses of AT from spatial metaphor perspective.