I. Summary
Understanding emotions of social partners is of fundamental importance in day-to-day life.
Humans share their affective states and intentions not only by language, but also by facial expressions, body posture or tone of voice. Nonverbal emotional expressions are specified as being part of an emotional episode, which additionally consists of action tendencies including underlying autonomic changes and subjective feelings. Although the communication of emotions has been studied for decades, our understanding of what exactly is communicated and how it is processed is still far from complete. Emotional expressions are frequently produced to fulfil social requirements calling into question the reliability to infer actual emotional states. As recognizing expressions that accompany underlying emotions would be of relevance for subsequent behavior, the ability to detect emotional deception seems to be essential in emotional communication.
Especially vocal expressions seem to be promising for revealing underlying emotions, due to the strong autonomic innervation of the vocal tract.
Moreover, the recognition of emotions has been found not to be invariable but to depend on the speaker-listener relation. Sharing group membership, for example, positively affected emotion recognition, which might be caused by an attention-shift towards people of higher relevance but also by facilitated empathic concern. Successfully understanding others’ emotions is closely linked to mirroring or simulating the perceived emotion internally. Research in the field of affective neurosciences could demonstrate a shared neural network during attending and experiencing emotions, which is influenced by the social relevance of the individual showing the expression. The extent to which affect sharing is necessary on the behavioral level to recognize emotional expressions and whether it is positively affected by increased speaker’s relevance, is still debated.
In this thesis, I investigated vocal emotion expressions, with the objectives to first understand the relation between spontaneous and play-acted expressions and second to broaden
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our knowledge about the importance of affect sharing and speaker’s relevance on emotion recognition.
In the first part of this thesis, I compared the recognition of spontaneous and play-acted vocal expressions in a cross-cultural study. In contrast to spontaneous expressions, acted ones were assumed to be influenced by social codes and were therefore less accurately recognized in cultures other than the culture of origin. Alternatively, emotion recognition for both conditions might rest on a universal basis. This cross-cultural comparison was conducted using 80 spontaneous vocal expressions, recorded in emotional situations by a German radio station and the re-enactments by professional actors. Short excerpts of these speech tokens were presented to participants in Germany, Romania and Indonesia with the tasks to indicate the expressed emotion and the authenticity. Generally, participants were poor in distinguishing the encoding condition and German listeners were more accurate in both tasks, independent whether the expression was play-acted or not. Emotion recognition showed a comparable pattern across all cultures, speaking for a universal basis for both encoding conditions. Recognition accuracy for all emotions was low and authenticity affected only anger, which was more frequently recognized when play-acted and sadness, which was more accurately recognized when spontaneous.
In the second part of this thesis, I aimed to understand the source of these differences and to disclose the importance of acting training on the credibility of emotion depiction. I added vocal expressions of acting-inexperienced people to the comparison, and conducted an additional acoustic analysis. Professional actors were predicted to be more suited to produce credible emotion expressions than inexperienced speaker. This was not confirmed, as professionally acted expressions were even more frequently recognized as being play-acted than the ones by inexperienced people. For professional actors I found the same pattern in the emotion recognition as in the cross-cultural study; while expressions by non-experienced speakers only deviated from the spontaneous ones by less accurate sadness recognition. Acoustically, the main difference was that acted expressions had a more vivid speech melody than the spontaneous
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ones. Both studies demonstrated a complex, universal interaction between emotion recognition and stimulus authenticity. Acted expressions were only poorly detected and not more stereotyped, and it was shown that acting inexperienced people were more suited to produce vocal expressions that resemble spontaneous ones than were professional actors.
In the third part I focused on investigating the processes of recognizing the emotions of others. To this aim, I experimentally manipulated biographical similarity between fictitious speakers and the listener. I predicted that vocal expressions spoken by the more similar character would be recognized more accurately due to the increased social relevance of the speaker. In order to disclose the impact of affect sharing on emotion recognition, I additionally measured skin conductance responses (SCR) and pupil size, which account for autonomic reactions, while participants judged joyful, angry and neutral vocal expressions. Similarity affected neither the emotion recognition nor the autonomic measurements. Overall, emotional expressions did not trigger arousal related SCR, but emotion-related responses in pupil size. This finding indicates that affective processing does not involve the whole autonomic system and is not an essential component of recognizing emotions, at least when people only attend to vocal expression.
Similarity might presumably affect emotion recognition in a more lifelike situation in which an actual tie can be established between both partners, not in a merely artificial setting. Empathic reactions presumably need a more holistic approach to be effective.
My thesis concentrated on the understanding of emotional communication by regarding vocal expressions and I could show that attending to single emotion expressions is not sufficient to reveal the actual affective state of the sender in terms of differentiating acted from spontaneous expressions. Additionally, I demonstrated that vocal expressions do not evoke strong autonomic reactions in the listener. The communication of vocal emotion expression seemingly rests more on cognitive than on affective processing.
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