Alle Publikationen
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2018
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(2018): Virtual Character Facial Expressions Influence Human Brain and Facial EMG Activity in a Decision-Making Game. In: IEEE Transactions on Affective Computing 9 (2), S. 285-298. DOI: 10.1109/TAFFC.2016.2601101
Abstract: We examined the effects of the emotional facial expressions of a virtual character (VC) on human frontal electroencephalographic (EEG) asymmetry (putatively indexing approach/withdrawal motivation), facial electromyographic (EMG) activity (emotional expressions), and social decision making (cooperation/defection). In a within-subjects design, the participants played the Iterated Prisoner's Dilemma game with VCs with different dynamic facial expressions (predefined or dependent on the participant's electrodermal and facial EMG activity). In general, VC facial expressions elicited congruent facial muscle activity. However, both frontal EEG asymmetry and facial EMG activity elicited by an angry VC facial expression varied as a function of preceding interactional events (human collaboration/defection). Pre-decision inner emotional-motivational processes and emotional facial expressions were dissociated, suggesting that human goals influence pre-decision frontal asymmetry, whereas display rules may affect (pre-decision) emotional expressions in human-VC interaction. An angry VC facial expression, high pre-decision corrugator EMG activity, and relatively greater left frontal activation predicted the participant's decision to defect. Both post-decision frontal asymmetry and facial EMG activity were related to reciprocal cooperation. The results suggest that the justifiability of VC emotional expressions and the perceived fairness of VC actions influence human emotional responses.
2017
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(2017): Evaluating the Sensitivity to Virtual Characters Facial Asymmetry in Emotion Synthesis. In: Applied Artificial Intelligence 31 (2), S. 103-118. DOI: 10.1080/08839514.2017.1299983
Abstract: The use of expressive Virtual Characters is an effective complementary means of communication for social networks offering multi-user 3D-chatting environment. In such contexts, the facial expression channel offers a rich medium to translate the ongoing emotions conveyed by the text-based exchanges. However, until recently, only purely symmetric facial expressions have been considered for that purpose. In this article we examine human sensitivity to facial asymmetry in the expression of both basic and complex emotions. The rationale for introducing asymmetry in the display of facial expressions stems from two well-established observations in cognitive neuroscience: first that the expression of basic emotions generally displays a small asymmetry, second that more complex emotions such as ambivalent feeling may reflect in the partial display of different, potentially opposite, emotions on each side of the face. A frequent occurrence of this second case results from the conflict between the truly felt emotion and the one that should be displayed due to social conventions. Our main hypothesis is that a much larger expressive and emotional space can only be automatically synthesized by means of facial asymmetry when modeling emotions with a general Valence-Arousal-Dominance dimensional approach. Besides, we want also to explore the general human sensitivity to the introduction of a small degree of asymmetry into the expression of basic emotions. We conducted an experiment by presenting 64 pairs of static facial expressions, one symmetric and one asymmetric, illustrating eight emotions (three basic and five complex ones) alternatively for a male and a female character. Each emotion was presented four times by swapping the symmetric and asymmetric positions and by mirroring the asymmetrical expression. Participants were asked to grade, on a continuous scale, the correctness of each facial expression with respect to a short definition. Results confirm the potential of introducing facial asymmetry for a subset of the complex emotions. Guidelines are proposed for designers of embodied conversational agent and emotionally reflective avatars.
Keywords: Asymmetrie, Augmented & Virtual Reality, Authentizität von dargestellter Emotion, dominance, Emotionserkennung, Gesichtszüge, Gestik/Mimik, Kognitionswissenschaft/Social Sciences/Humanities, Konventionen, Mensch-Technik-Relationen (MTR), Neurowissenschaften, Realtechnik, soziale Kognition, Technik 2016
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(2016): A Cultural Semiotic Aesthetic Approach for a Virtual Heritage Project. In: Techné: Research in Philosophy and Technology 20 (3), S. 198-215. DOI: 10.5840/techne201653147
Abstract: This paper presents an integrated framework applied towards the design and evaluation of a virtual museum of Byzantine art that combines the theorized fields of semiotics, virtual heritage (VH), and Byzantine art. A devised semiotic model, the case study semiosphere, synthesizes important principles from the theoretical background justifying the overall design and evaluation methodology. The approach presented has theoretical extensions to the understanding of the role technology plays in promoting a consummatory aesthetic experience for Byzantine art in virtual environments, complementing the experience received from traditional Byzantine art media. Part A of the work presents the development of the semiotic foundation of the study prior to presenting the applied potential of the approach in design and evaluation of VH for Byzantine art, which appears in Part B. The final task of the proposed approach aims to support a meaningful interpretation, assisting in the promotion of the significance (value) of the virtual museum to potential interpreters/visitors.
Keywords: Ästhetisch angemessene Präsentation von Museumsgut, Augmented & Virtual Reality, Einander-Ergänzen von Objekten und Präsentationsrahmen, Kunst und Kultur, Mensch-Technik-Relationen (MTR), Museen, Philosophie, Realtechnik, Sozialer Raum / Kultureller Kontext, Technik, Technologie, Zeitschrift: techne 2015
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(2015): The Realism and Ecology of Augmented Reality. In: Techné: Research in Philosophy and Technology 19 (1), S. 92-112. DOI: 10.5840/techne20154229
Abstract: Unlike in the phrase “Virtual Reality,” in the phrase “Augmented Reality” (AR) the stress is put on the word “reality.” It seems, though, that we still lack a concept of reality which can fit the world of both humans and computers. In connection with this philosophical issue, this paper aims to provide the background for a better insight into the meaning of Augmented Reality and its impact on human behavior. My thesis is that an ecological version of direct perception’s realism constitutes the most natural framework from which to start. The ecological approach to perception – namely, the Gibsonian theory of affordances – together with a non-dualistic, pragmatist and evolutionist notion of reality, perfectly fits this purpose. Thus, after a brief survey of the present state of AR technologies, it should become natural to interpret AR digital contents as implementations of affordances.
2013
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(2013): The Effect of Priming Pictures and Videos on a Question–Answer Dialog Scenario in a Virtual Environment. In: Presence: Teleoperators and Virtual Environments 22 (2), S. 91-109. DOI: 10.1162/PRES_a_00143
Abstract: Having a free-speech conversation with avatars in a virtual environment can be desirable in virtual reality applications, such as virtual therapy and serious games. However, recognizing and processing free speech seems too ambitious to realize with the current technology. As an alternative, pre-scripted conversations with keyword detection can handle a number of goal-oriented situations, as well as some scenarios in which the conversation content is of secondary importance. This is, for example, the case in virtual exposure therapy for the treatment of people with social phobia, where conversation is for exposure and anxiety arousal only. A drawback of pre-scripted dialog is the limited scope of the user's answers. The system cannot handle a user's response that does not match the pre-defined content, other than by providing a default reply. A new method, which uses priming material to restrict the possibility of the user's response, is proposed in this paper to solve this problem. Two studies were conducted to investigate whether people can be guided to mention specific keywords with video and/or picture primings. Study 1 was a two-by-two experiment in which participants (n = 20) were asked to answer a number of open questions. Prior to the session, participants watched priming videos or unrelated videos. During the session, they could see priming pictures or unrelated pictures on a whiteboard behind the person who asked the questions. The results showed that participants tended to mention more keywords both with priming videos and pictures. Study 2 shared the same experimental setting but was carried out in virtual reality instead of in the real world. Participants (n = 20) were asked to answer questions of an avatar when they were exposed to priming material, before and/or during the conversation session. The same results were found: the surrounding media content had a guidance effect. Furthermore, when priming pictures appeared in the environment, people sometimes forgot to mention the content they typically would mention.
Keywords: ACROPHOBIA, Augmented & Virtual Reality, Beeinflussung sozial angemessenen Verhaltens, BEHAVIOR, DISORDERS therapy, FEAR, IN-VIVO, Mensch-Technik-Relationen (MTR), METAANALYSIS, Psychologie, PUBLIC-SPEAKING ANXIETY, REALITY EXPOSURE THERAPY, Realtechnik, SOCIAL PHOBIA, Sonder-Intention beim Sprechen/Konversation, SPIDER PHOBIA, Sprachverarbeitung, Technik, technology in therapy, Therapeutische Zwecke, Triggern von angstauslösenden Begriffen, Video/picture priming 2011
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(2011): Planning Small Talk behavior with cultural influences for multiagent systems. In: Computer Speech & Language 25 (2), S. 158-174. DOI: 10.1016/j.csl.2010.04.001
Abstract: There are several factors that influence communicative behavior, such as gender, personality or culture. As virtual agents interact in a more and more human-like manner, their behavior should be dependent on social factors as well. Culture is a phenomenon that affects one's behavior without one realizing it. Behavior is thus sometimes perceived as inappropriate because there is no awareness of the cultural gap. Thus, we think cultural background should also influence the communication behavior of virtual agents. Behavioral differences are sometimes easy to recognize by humans but still hard to describe formally, to enable integration into a system that automatically generates culture-specific behavior. In our work, we focus on culture-related differences in the domain of casual Small Talk. Our model of culture-related differences in Small Talk behavior is based on findings described in the literature as well as on a video corpus that was recorded in Germany and Japan. In a validation study, we provide initial evidence that our simulation of culture-specific Small Talk with virtual agents is perceived differently by human observers. We thus implemented a system that automatically generates culture-specific Small Talk dialogs for virtual agents. (C) 2010 Elsevier Ltd. All rights reserved.
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