2.2 Results
Behavioral measures. Valence ratings of all Mandarin target words by all participants categorized by emotion type are illustrated inFigure 1 . Neutral words (mean=3.2, SD=0.6) were rated lower than positive words (mean=4.3, SD=0.9 ; β = 1.05, se = 0.1229, t = 8.5, p<.001 ), and higher than negative words (mean=1.6, SD=0.8; β = 1.58, se = 0.1275, t = 12.38, p<.001 ). The re-leveled model with “negative” as intercept revealed a significant difference between negative and positive words (β = 2.63, se = 0.1499, t = 17.54, p<.001). We also calculated the percentage of items that were rated per participant within the expected range for their predesignated category: negative (1 or 2), neutral (3) or positive (4 or 5). This included 80.9% of items across all participants, with less Neutral words (M=73.8%, sd=17.4%) than Positive words (M=83.0%, sd=10.5%; β =.092, se =.039, t = 2.321, p<.05) or Negative words (M=85.9%, sd=13.6%; β =.121, se =.039, t = 3.041, p<.001), while no difference was found between Positive and Negative words (β =-.028, se =.039, t = -0.720, p=.475).
ERP analyses. Analyses included all trails free from artefact, for items that were rated within the expected range for their predesignated category: negative (1 or 2), neutral (3) or positive (4 or 5). The percentage of trials lost due to artefact was 16% for the Neutral words, 14% for the Positive words and 16% for Negative words, and to ascertain whether the valence of target words induced differences in the ERP trace, we conducted a two-tailed permutation t-test (1000 random partitions) between Neutral and Negative target words, and between Neutral and Positive target words for all selected electrodes (midline: Fz, FCz, Cz, CPz, Pz, frontal central : FC1, FC3, FC5, FC2, FC4, FC6, central-parietal: C1, C3, C5, C2, C4, C6, CP1, CP3, CP5, CP2, CP4, CP6, and parietal: P1, P3, P5, P2, P4, P6), with time points of 5 ms across the entire epoch (0 to 1200 ms after stimulus onset). Only differences that persisted for 10 ms or more were considered statistically significant. The results revealed no significant differences between Neutral and Positive, or between Neutral and Negative target words at any selected electrode. Figure 2 shows the average response across all 20 participants for 9 central partiel cites; none of the permutation tests are revealed due to there being no significant effects.
To further examine possible differences induced by Valence, we modeled the data using linear mixed effect regression, with the LmerTest package (Kuznetsova & Christensen, 2017) in R (R Core Team, 2017). The models, summarized in Table 2 , included the treatment coded fixed factor Valence (Neutral, Negative, Positive), with random intercept for Item and Participant. A random slope of Valence for Participant was included. Models were performed independently at 3 ROIs for the mean voltage amplitude at the four time windows post stimulus onset, associated with the P200 (150-300 msec), N400 (300-500 msec), LPC (500-800 msec) and later component (800-1200 msec). No significant differences were found in any ROI, at any time window (cf. Table 2 ).