Effects of subliminal emotional facial expressions on language comprehension as revealed by event-related brain potentials

Abstract

Emotional facial expressions often take place during communicative face-to-face interactions. Yet little is known as to whether natural spoken processing can be modulated by emotional expressions during online processing. Furthermore, the functional independence of syntactic processing from other cognitive and affective processes remains a long-standing debate in the literature. To address these issues, this study investigated the influence of masked emotional facial expressions on syntactic speech processing. Participants listened to sentences that could contain morphosyntactic anomalies while a masked emotional expression was presented for 16 ms (i.e., subliminally) just preceding the critical word. A larger Left Anterior Negativity (LAN) amplitude was observed for both emotional faces (i.e., happy and angry) compared to neutral ones. Moreover, a larger LAN amplitude was found for angry faces than for happy faces. Finally, a reduced P600 amplitude was observed only for angry faces when compared to neutral faces. Collectively, the results presented here indicate that first-pass syntactic parsing is influenced by emotional visual stimuli even under masked conditions and that this effect extends also to later linguistic processes. These findings constitute evidence in favor of an interactive view of language processing as integrated within a complex and integrated system for human communication.

Keywords: EEG; Emotional facial expression; LAN; Multimodal language; P600; Syntax.

Fig. 1

Schematic representation of the procedure. The facial expressions were masked by the scrambled stimuli. Along the audio presentation of the sentence, the critical word appeared 16 ms right after the masked face. Faces are blurred for anonymity purposes.

Fig. 2

Average-referenced waveforms corresponding to the face-related components. Main effects of Emotional Expression (A). Cluster plots for the significant contrasts for the N170 (B). No significant differences emerged between happy and neutral faces. * p < .05, ** p < .01.

Fig. 3

Grand average of LAN (A) and P600 (B) waveforms and their topographical distributions when comparing morphosyntactic correctness for each emotional expression. Note that the ERP were time-locked to the onset of the subliminal face, the critical word starting 16 ms later. Box plots for the interaction effects between Correctness and Emotional Expression during the LAN (C) and the P600 (D) time windows. * p < .05, ** p < .01, *** p < .001.