Vocal emotions influence verbal memory: Neural correlates and interindividual differences

Abstract

Past research has identified an event-related potential (ERP) marker for vocal emotional encoding and has highlighted vocal-processing differences between male and female listeners. We further investigated this ERP vocal-encoding effect in order to determine whether it predicts voice-related changes in listeners' memory for verbal interaction content. Additionally, we explored whether sex differences in vocal processing would affect such changes. To these ends, we presented participants with a series of neutral words spoken with a neutral or a sad voice. The participants subsequently encountered these words, together with new words, in a visual word recognition test. In addition to making old/new decisions, the participants rated the emotional valence of each test word. During the encoding of spoken words, sad voices elicited a greater P200 in the ERP than did neutral voices. While the P200 effect was unrelated to a subsequent recognition advantage for test words previously heard with a neutral as compared to a sad voice, the P200 did significantly predict differences between these words in a concurrent late positive ERP component. Additionally, the P200 effect predicted voice-related changes in word valence. As compared to words studied with a neutral voice, words studied with a sad voice were rated more negatively, and this rating difference was larger, the larger the P200 encoding effect was. While some of these results were comparable in male and female participants, the latter group showed a stronger P200 encoding effect and qualitatively different ERP responses during word retrieval. Estrogen measurements suggested the possibility that these sex differences have a genetic basis.

Preferential decoding of emotion from human non-linguistic vocalizations versus speech prosody

“…Emotion-specific modulation of the Late Positive Component (LPC) has been observed for speech prosody (Paulmann et al, 2013;Schirmer et al, 2013), with a more positive-going wave at central-posterior brain sites for expressions high in arousal Paulmann et al, 2013;Jessen & Kotz, (2011) who reported no significant LPC amplitude differences for anger, fear, and neutral vocalizations in the "audio" condition of their study). Here, the LPC amplitude between 450-700ms was strongly influenced by both voice and emotion type;…”

“…These later cognitive stages have been tied to alterations in N300 (Bostanov & Kotchoubey, 2004) or N400 (Liu, Rigoulot, & Pell, 2015;Paulmann & Pell, 2010;Schirmer & Kotz, 2003) responses to non-linguistic and speech-embedded emotions, respectively, using priming or conflict paradigms that pair emotional voices with a related or unrelated stimulus (word or face). Recent data have also linked ongoing semantic analysis of vocal emotion expressions to changes in the Late Positive Component (LPC), which exhibits differences according to emotion type (Jessen & Kotz, 2011;Paulmann et al, 2013;Schirmer et al, 2013). For example, it was reported that LPC amplitudes differ significantly for six basic emotions, and a stronger positivity was generally observed for expressions high in arousal, at central-posterior brain regions approximately 400-800ms post-onset of emotional prosody (Paulmann et al, 2013).…”

“…Based on the literature, we hypothesized that differences in emotion would modulate P200 amplitudes, for both vocal expression types, and that "raw" emotions encoded by vocalizations may promote stronger, and possibly earlier (N100), effects in the ERP data than speech-embedded emotions. We also speculated that differences due to emotion and/or expression type observed at early processing stages, which reflect differences in motivational salience (Paulmann et al, 2013), would persist at later stages of enhanced emotion processing (Schirmer et al, 2013) with increased LPC amplitudes for highly arousing or socially salient expressions that require sustained analysis for adaptive behavior.…”

“…For the ERP analyses, after rejections the mean number of trials per experimental condition and participant was 112 (VocAng = 115, VocSad = 112, VocHap = 114, SpeAng = 111, SpeSad = 110, SpeHap = 111). Mean amplitude and peak latency of components in the N100-P200 complex, as well as the Late Positive component (LPC), evoked by different auditory primes were of a priori interest (Paulmann et al, 2013;Schirmer et al, 2013). Based on visual inspection of the averaged data and consistent with previous work (Jessen & Kotz, 2011;Paulmann et al, 2013), changes in the N1-P2 complex were analyzed in the fronto-central region and surrounding electrodes (19 electrodes: F3, F1, Fz, F2, F4, FC1, FC3, FC2, FC4, C3, C1, Cz, C2, C4, CP3, CP1, CPz, CP2, CP4).…”

Tracking the Sound of Human Affection: EEG Signals Reveal Online Decoding of Socio-Emotional Expression in Human Speech and Voice

“…Diferentiation of P200 amplitude can be found between basic emotions [6] or between emotional vs. neutral speech [3,7], suggesting that this component may relect an early function of "tagging" emotional or motivational relevant stimuli. The P200 tended to be associated with higher mean and range of f0, larger mean and range of amplitude of speech, and slower speech rate [6], implicating that the early P200 modulation is partially explained by early meaning encoding as well as continued sensory processing [8]. A late centro-parietal positivity (also named LPC) evoked by vocal emotion expressions has been deined as a positive-going wave starting about 500 ms post-onset of the vocal stimuli and perhaps sustaining until 1200 ms depending on stimulus features.…”