Publicação
Authenticity recognition in laughter and crying : an ERP study
| Resumo: | Our ability to detect authenticity in the human affective voice, whether an emotion was evoked spontaneously (reactive, genuine) or voluntarily (deliberate, controlled), is crucial in our everyday social interactions as emotions may carry different meanings and elicit different social responses. Taking laughter as an example, while a spontaneous laughter is stimulus-driven and signals positive affect, voluntary laughter deliberately signals polite agreement or affiliation without necessarily being associated with an emotional experience. Recent functional magnetic resonance (fMRI) studies have shown brain differences between these voluntary and spontaneous laughter vocalizations. While both spontaneous and voluntary laughs engage the auditory cortex, voluntary laughter requires additional involvement of brain areas typically involved in mentalizing, possibly involved in the decoding of the intentional state behind these vocal expressions. However, how authenticity affects the temporal course of voice processing is still unclear. Previous imaging studies have shed light on the areas putatively involved in the processing of authenticity in vocal emotions. Nevertheless, fMRI lacks temporal resolution and is unable to provide information about the exact time-window on which differences in the processing between spontaneous and voluntary vocalizations in the brain may occur. In the current study we used the event-related brain potentials (ERPs) methodology to shed light on how authenticity modulates the temporal course of vocal information processing in the brain. In particular, we investigated differences between spontaneous and voluntary non-linguistic affective vocalizations (crying and laughter) in both amplitude and latency of ERP components associated with early (N100, P200) and late stages (late positivity potential – LPP) of voice processing. We also aimed to replicate previous findings suggesting amplitude and latency differences as a function of emotionality in these three ERP components. In addition, we explored the extent to which sex differences may exist in both authenticity and emotionality modulation of these potentials. Twenty-three right-handed healthy participants (13 female) listened to spontaneous and voluntary non-linguistic affective vocalizations (happy, sad and neutral) while they rated the authenticity conveyed by the speaker, as the electroencephalogram (EEG) was recorded. No differences in terms of amplitude or latency were found between spontaneous and voluntary vocalizations in the N100, P200 and LPP components. Emotionality effects were found at an early processing stage (N100) with happy and sad vocalizations eliciting more negative amplitude than neutral vocalizations. Happy vocalizations elicited an enhanced P200 when compared with neutral vocalizations. At later processing stages (500 – 700 ms), happy and sad vocalizations elicited a stronger late positivity (LPP) than neutral vocalizations. No differences between emotional and neutral vocalizations were detected in the latency of these components. Lastly, no sex differences were found in the amplitude or latency of N100, P200 and LPP for emotionality or authenticity effects. Although exploratory with a small sample size and deserving further replication, all together, our results possibly suggest authenticity as unlikely to be decoded during the first 700 ms after vocalization onset. The emotional salience of the voice, on the other hand, seems to be extracted as early as 100 ms after onset. While emotional content seems to be rapidly decoded from vocal cues, authenticity may involve further elaborated processing occurring at very late stages of processing. |
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| Autores principais: | Costa, Mónica Gonçalves Barbeito |
| Assunto: | Voice processing Authenticity Emotion Non-linguistic vocalizations Event-related pontencials (ERPS) Teses de mestrado - 2018 |
| Ano: | 2018 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Our ability to detect authenticity in the human affective voice, whether an emotion was evoked spontaneously (reactive, genuine) or voluntarily (deliberate, controlled), is crucial in our everyday social interactions as emotions may carry different meanings and elicit different social responses. Taking laughter as an example, while a spontaneous laughter is stimulus-driven and signals positive affect, voluntary laughter deliberately signals polite agreement or affiliation without necessarily being associated with an emotional experience. Recent functional magnetic resonance (fMRI) studies have shown brain differences between these voluntary and spontaneous laughter vocalizations. While both spontaneous and voluntary laughs engage the auditory cortex, voluntary laughter requires additional involvement of brain areas typically involved in mentalizing, possibly involved in the decoding of the intentional state behind these vocal expressions. However, how authenticity affects the temporal course of voice processing is still unclear. Previous imaging studies have shed light on the areas putatively involved in the processing of authenticity in vocal emotions. Nevertheless, fMRI lacks temporal resolution and is unable to provide information about the exact time-window on which differences in the processing between spontaneous and voluntary vocalizations in the brain may occur. In the current study we used the event-related brain potentials (ERPs) methodology to shed light on how authenticity modulates the temporal course of vocal information processing in the brain. In particular, we investigated differences between spontaneous and voluntary non-linguistic affective vocalizations (crying and laughter) in both amplitude and latency of ERP components associated with early (N100, P200) and late stages (late positivity potential – LPP) of voice processing. We also aimed to replicate previous findings suggesting amplitude and latency differences as a function of emotionality in these three ERP components. In addition, we explored the extent to which sex differences may exist in both authenticity and emotionality modulation of these potentials. Twenty-three right-handed healthy participants (13 female) listened to spontaneous and voluntary non-linguistic affective vocalizations (happy, sad and neutral) while they rated the authenticity conveyed by the speaker, as the electroencephalogram (EEG) was recorded. No differences in terms of amplitude or latency were found between spontaneous and voluntary vocalizations in the N100, P200 and LPP components. Emotionality effects were found at an early processing stage (N100) with happy and sad vocalizations eliciting more negative amplitude than neutral vocalizations. Happy vocalizations elicited an enhanced P200 when compared with neutral vocalizations. At later processing stages (500 – 700 ms), happy and sad vocalizations elicited a stronger late positivity (LPP) than neutral vocalizations. No differences between emotional and neutral vocalizations were detected in the latency of these components. Lastly, no sex differences were found in the amplitude or latency of N100, P200 and LPP for emotionality or authenticity effects. Although exploratory with a small sample size and deserving further replication, all together, our results possibly suggest authenticity as unlikely to be decoded during the first 700 ms after vocalization onset. The emotional salience of the voice, on the other hand, seems to be extracted as early as 100 ms after onset. While emotional content seems to be rapidly decoded from vocal cues, authenticity may involve further elaborated processing occurring at very late stages of processing. |
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