Event-related potential study on the semantic and phonological priming with spoken two-character Chinese words
- VernacularTitle:听觉呈现条件下汉语双字词语义和语音启动的事件相关电位研究
- Author:
Yong Lü
;
Yingchun DU
;
Juan SONG
;
Deli SHEN
- Publication Type:Journal Article
- From:
Chinese Journal of Tissue Engineering Research
2007;11(22):4451-4456
- CountryChina
- Language:Chinese
-
Abstract:
BACKGROUND:Researchers have done much work to investigate semantic priming with event-related potentials (ERPs) method. The ERPs component of N400 is of great importance in this research domain. N400 is a negative wave occurs at about 400 ms after the stimulus onset. It has been accepted that N400 represents the processing of semantic information. In many studies, amplitude of N400 could be reduced by semantic priming. Relatively, ERPs studies on phonological priming, especially by auditory stimuli, deserve to be further investigated. OBJECTIVE: To investigate the EPR characteristics of semantic and phonological priming with spoken two-character Chinese words, and also to testify theories about auditory word recognition.DESIGN: Repeated measurement experiment.SETTING: Center for Psychology and Behavior Studies, Tianjin Normal University. PARTICIPANTS: This experiment was carried out between August and October 2003 in Tianjin Normal University. Seventeen healthy college students (8 male and 9 female, age ranging from 19 to 23 years) with no hearing defect were involved in this experiment. All of them were Chinese native speakers. All except one male participant were right handed. Informed consents of detected items were obtained from all the participants.METHODS: In the study, lexical dicision task which required participants was used to judge if the latter words were real words or pseudowords in the auditorily presented word-pairs by pressing buttons. The stimuli materials were 640 two-character word-pairs including semantic related, initial phonological overlap, final phonological overlap, phonological and semantic unrelated and word-pseudoword (control) conditions. These five kinds of word-pairs presented randomly in the experiment. The presentation of stimuli and recording of behavioral data were realized by STIM software. The error rate and mean reaction time (RT) of reaction of subjects were calculated under four experimental conditions. The word-pseudoword items were not included in the analysis (just served as fillers). EEG were recorded referring to linked mastoids with Scan 4.3 software made by Neuroscan company in America. Participants wore the Quick-Cap32 electrode cap (International 10/20 System). EEG data were amplified and acquired with a sampling rate of 500 Hz. Offline exclusion of occular artifacts was done on the acquired continuous EEG data after experiment. Then the EEG data were segmented to epochs of 1 700 ms, each epoch was time-locked to the onset of target stimulus with a 200 ms pre-target baseline. Then the operation of baseline (with a 200ms pre-target baseline), artifact rejection (epochs with amplitude exceeded the range of -100 μV to +100 μV were rejected) and average were realized. MAIN OUTCOME MEASURES: Error rate, reaction time and caused N400 waveform change of target words under different experimental conditions.RESULTS: Data from 17 subjects were involved in the final analysis. The error rate of subjects under semantic related condition was lower (P＜ 0.05) while RT was shorter (P＜ 0.01) than that under phonological and semantic unrelated condition. The error rates of subjects under initial phonological overlap and final phonological over lap conditions were higher than that under phonological and semantic unrelated condition (P ＜ 0.01). The error reactions were discarded and the mean value of RT under 4 conditions (semantic related, initial phonological overlap, final phonological overlap and phonological and semantic unrelated) were 830 ms, 891 ms, 864 ms and 903 ms, respectively. There were significant differences of error rate and RT between semantic related and phonological and semantic unrelated conditions (P ＜ 0.01). Error rate and RT under final phonological overlap condition were significantly different from those under initial phonological overlap and phonological and semantic unrelated conditions (P ＜ 0.01). Since the largest amplitude of N400 occurred at FCZ electrode, FCZ was chosen for analyzing the effects under four different experimental conditions. The LSD multiple comparison showed that amplitude under control condition was significantly higher than that under semantic related condition (P ＜ 0.01). Latency under the control condition was the longest, then decreased gradually according to the sequence of semantic related, final phonological overlap and initial phonological overlap condition. As the results of LSD multiple comparison revealed, initial phonological overlap condition had a tendency of shortened latency, with significant difference when compared with control condition (P ＜ 0.05). Another five electrodes were selected besides FCZ standing for anterior, parietal, posterior, left and right brain area in order to investigate the scalp distribution difference of N400 under different experimental conditions. Two factors repeated measured ANOVA (Analysis of variance) was carried out for amplitude analysis, with different experimental conditions (4 levels) as the first factor and electrode positions (6 levels) as the second factor. The main effect of electrode positions was significant [F(5,80)= 13.376, P =0.000]. Among the chosen electrodes, FCZ had the largest amplitude (-7.946 μV), the second was CZ (-7.285 μV) and the other top-downsequence was FZ (-6.849 μV), PZ (-4.324 μV), T8 (-3.501 μV ) and T7 (-3.484 μV), respectively. Results of LSD multiple comparison revealed that the amplitude of FCZ was higher than all other electrodes but CZ. CONCLUSION: Two-character Chinese words presented auditorily in lexical decision task. Semantic relationship can facilitate the recognition of target words, which is shown by lower error rate, shorter RT and decreased amplitude of N400 component. Phonological congruence between prime and target words has both facilitory and interferential effects on target words, which is shown by increased error rate, shorter RT and the tendency of decreasing N400 amplitude.Interferential effect of initial phonological overlap between prime and target words is stronger than that of final phonological overlap. This finding provides evidence for initial phonological information's special function during auditory word recognition which is supported by Cohort Theory. No evidence for the existence of separate intracranial sources of semantic priming and phonological priming has been found. However, Cohort Theory should be revised while applying to the recognition of two-character words of Chinese.
