Neural measures of the role of affective prosody in empathy for pain

Abstract

Emotional communication often needs the integration of affective prosodic and semantic components from speech and the speaker's facial expression. Affective prosody may have a special role by virtue of its dual-nature; pre-verbal on one side and accompanying semantic content on the other. This consideration led us to hypothesize that it could act transversely, encompassing a wide temporal window involving the processing of facial expressions and semantic content expressed by the speaker. This would allow powerful communication in contexts of potential urgency such as witnessing the speaker's physical pain. Seventeen participants were shown with faces preceded by verbal reports of pain. Facial expressions, intelligibility of the semantic content of the report (i.e., participants' mother tongue vs. fictional language) and the affective prosody of the report (neutral vs. painful) were manipulated. We monitored event-related potentials (ERPs) time-locked to the onset of the faces as a function of semantic content intelligibility and affective prosody of the verbal reports. We found that affective prosody may interact with facial expressions and semantic content in two successive temporal windows, supporting its role as a transverse communication cue.

Figure 1

Rating results showing significant and non-significant comparisons for the interactions (upper panel and bottom left panel) and the whole pattern of results (bottom right panel). Error bars represent standard errors, asterisks represent significant comparisons; “n.s.” means “not-significant”.

Figure 2

Grand averages of ERPs time-locked to the onset of faces recorded at FC (i.e., pooled rFC and lFC), and at CP (i.e., pooled rCP and lCP), as a function of preceding utterances superimposed with ERPs elicited in the neutral condition (i.e., neutral prosody/neutral facial expression) separately for participants’ mother-tongue and fictional language.

Figure 3

(a) Bar graphs showing main effects of facial expression on the P2 and on the N2–N3 components and of the intelligibility on the P3 component. (b) Bar graphs showing the effect of prosody on empathic reactions for each ERP component. Empathic reactions are shown as the difference between painful and neutral conditions. Error bars represent standard errors, asterisks significant comparisons, “n.s.” means “not-significant”.

Figure 4

Grand-Averages of ERP time-locked to the onset of faces as a function of language and prosody of preceding utterances recorded at CP.

Figure 5

Scatter plots of the correlations between ERP empathic reactions and self-report measures of dispositional empathy.

Figure 6

Experimental Procedure.