Parafoveal preview benefit in a conflicting sentential context: Evidence from ERPs

Abstract

In natural reading, the reader's processing of a word starts when the word is located in parafoveal vision. Relative to a situation with an invalid preview, fixations are significantly shorter after a fully valid, identical preview. Although research on the identity preview benefit has been ongoing for more than 40 years, the mechanism of this preview benefit, the level of lexical processing it occurs, and its relationship to the sentential context remain unclear. This study employed EEG brain component analysis technology to address these questions in Chinese sentence reading. We manipulated the sentential context to make the target word plausible or not plausible with the sentence and manipulated the target word present or not present in preview. EEG results showed that the identity preview benefit can affect not only the early preview positivity, reflecting the early orthographic processing of words, but also the N400 and LPC components, reflecting the late and in-depth semantic processing of words. Conflicting sentential context, in which the target word is implausible and cannot be integrated into the sentence, can interfere temporarily with these processes. These findings suggest that in the process of sentence reading, an identical preview word can promote the subsequent reading process at multiple levels, and its role is modulated by contextual information.

Keywords: Chinese reading; ERP; N400; identity preview benefit; plausibility.

Figure 1

Example material and Condition. The target word was either plausible (read…newspapers) or implausible (ate up…newspapers) in the context of the sentence, and the target word either was presented in preview (newspapers-newspapers) or not present in preview (here: pseudoword-newspapers). These manipulations resulted in a 2 × 2 design (context plausibility × preview identity). The target word was always a single Chinese character. ① Target word in the preview position. ② Target word in the later foveal position.

Figure 2

Trial scheme for the experiment. Sentences were presented character-by-character in the center of the screen, flanked by the preceding character to the left and the subsequent character to the right. Character triads were displayed for 100 ms each and separated by 400 ms blank intervals. The preview word position was presented either in its identity version (newspapers) or its invalid version (pseudoword) when the sentence was plausible (left side of the figure) and implausible (right side of the figure). Participants were asked to maintain their gaze on the central character (monitored with eye-tracking). They were also asked to judge the plausibility of the sentence with a button press at the end of the trial.

Figure 3

Main effect of preview identity on the early preview positivity at occipitotemporal electrodes. Time 0 on the time axis marks the onset of the target word in the right parafoveal position. Black bars above the time axis mark the stimulus durations of the character triads. The two vertical lines mark the onset of the triad containing the target word in the parafovea and fovea, respectively. ERP waveforms show the average activity in the ROI of four electrodes (highlighted in white in the topographic map) for the identical preview condition and invalid preview condition. Scalp topographic map shows the difference in ERP activity (invalid preview conditions minus identical preview conditions) in the time window of 150–250 ms after the onset of the word in the foveal position.

Figure 4

Identity preview benefit on the N400 and LPC components when the target word was plausible in the sentence. Time 0 on the time axis marks the onset of the target word in the right parafoveal position. ERP waveforms show the average activity in the ROI of four electrodes (highlighted in white in the topographic map) for the identical preview condition and invalid preview condition. Scalp topographic maps show the difference in ERP activity (invalid preview conditions minus identical preview conditions) in the time window of 250–350 ms, 350–450 ms and 500–800 ms after the onset of the target word in the foveal position, respectively.

Figure 5

Identity preview benefit on the N400 and LPC components when the target word was implausible in the sentence. Time 0 on the time axis marks the onset of the target word in the right parafoveal position. ERP waveforms show the average activity in the ROI of four electrodes (highlighted in white in the topographic map) for the identical preview condition and invalid preview condition. Scalp topographic maps show the difference in ERP activity (invalid preview conditions minus identical preview conditions) in the time window of 250–350 ms, 350–450 ms and 500–800 ms after the onset of the target word in the foveal position, respectively.

Figure 6

ERP plausibility effects when the target word appeared in the parafovea and subsequently again in the fovea. ERP waveforms show the average activity in the ROI of four centroparietal electrodes (highlighted in white in the topographic map) for the plausible context & identical preview condition and implausible context & identical preview condition. Scalp topographic maps show the difference in ERP activity (plausible context & identical preview minus implausible context & identical preview) in the time window of 250–450 ms after the onset of the word in the parafoveal and in the foveal position, respectively.