The Affective Priming Effect on the N400 and LPP Components: A Three-Level Meta-Analysis

The priming of affective stimuli influences the subsequent emotional and cognitive processes. Though the affective priming effect has been widely discussed at the behavioral level, systematic reviews, and evaluations of the electrophysiological data in affective priming studies remain scarce, with findings across various research appearing inconsistent. By adopting a three-level random-effects meta-analytic approach, the present study aimed to quantitatively synthesize the event-related potential (ERP) evidence of the affective priming effect on N400 and late positive potential (LPP) components. We identified 47 studies through a search of four databases (i.e., Web of Science, PubMed, ProQuest, and PsycINFO). Meta-analysis of the N400 component in N = 1118 participants and the LPP component in N = 804 participants both indicated that affectively incongruent prime-target trials induced larger ERP amplitudes compared to affectively congruent prime-target trials, with d_N400 = 0.63 (95% CI: 0.38, 0.88; SE = 0.13; t = 5.03; p < 0.001), d_LPP = 0.24 (95% CI: 0.03, 0.46; SE = 0.11; t = 2.29; p < 0.05), respectively. Moderator analyses showed that stimulus onset asynchrony (SOA) and task demand have explained the variations in the N400 effect and the LPP effect is moderated by SOA. Potential explanations, limitations, and future research directions were discussed.