For location effect, post-hoc analysis also showed an increasing trend of LPP from anterior to posterior direction, with significant differences from frontocentral to central sites ( F (1, 21) = 30.662, p < .001, η p 2 = .594) and from central to parietocentral to central sites ( F (1, 21) = 41.668, p < .001, η p 2 = .665), but not from parietocentral to parietal sites ( F (1, 21) = 4.932, p = ns) after collapsing all emotions.
Only CAMS-R was found to be significantly correlated with valence rating of negative pictures ( r (20) = .634, p = .007) and also marginally significant in correlating with valence ratings of positive pictures ( r (20) = −.459, p = .081).
Post-hoc analysis showed that LPP elicited by positive pictures was significantly more positive than LPP elicited both negative ( F (1, 21) = 8.19, p = .027, η p 2 = .281) and neutral ( F (1, 21) = 14.18, p = .003, η p 2 = .403) pictures when all locations were considered; LPP elicited by negative pictures compared to neutral ones was not significantly different, but only showed a marginal trend ( F (1, 21) = 5.273, p = .096, η p 2 = .201).