Experimental studies of the interaction between people and virtual humans with a focus on social anxiety

Psychotherapy has been one of the major applications of Virtual Reality technology; examples include fear of flying, heights, spiders, and post‐traumatic stress disorder. Virtual reality has been shown to be useful, in the context of exposure therapy for the treatment of social anxiety, such as fear of public speaking, where the clients learn how to conquer their anxiety through interactions with Virtual Characters (avatars). This thesis is concerned with the interaction between human participants and avatars in a Virtual Environment (VE), with the main focus being on Social Anxiety. It is our hypothesis that interactions between people and avatars can evoke in people behaviours that correspond to their degree of social anxiety or confidence. Moreover the responses of people to avatars will also depend on their degree of exhibited social anxiety – they will react differently to a shy avatar compared to a confident avatar. The research started with an experimental study on the reaction of shy and confident male volunteers to an approach by an attractive and friendly virtual woman in a VE. The results show that the participants responded according to expectations towards the avatar at an emotional, physiological, and behavioural level. The research then studied a particular cue which represents shyness – “blushing”. Experiments were carried out on how participant responds towards a blushing avatar. The results suggested that, even without consciously noticing the avatar’s blushing, the participants had an improved relationship with her when she was blushing. Finally, the research further investigated how people respond towards a shy avatar as opposed to a confident one. The results show that participants gave more positive comments to the personality of the avatar displaying signs of shyness

Participant responses to virtual agents in immersive virtual environments.

This thesis is concerned with interaction between people and virtual humans in the context of highly immersive virtual environments (VEs). Empirical studies have shown that virtual humans (agents) with even minimal behavioural capabilities can have a significant emotional impact on participants of immersive virtual environments (IVEs) to the extent that these have been used in studies of mental health issues such as social phobia and paranoia. This thesis focuses on understanding the impact on the responses of people to the behaviour of virtual humans rather than their visual appearance. There are three main research questions addressed. First, the thesis considers what are the key nonverbal behavioural cues used to portray a specific psychological state. Second, research determines the extent to which the underlying state of a virtual human is recognisable through the display of a key set of cues inferred from the behaviour of real humans. Finally, the degree to which a perceived psychological state in a virtual human invokes responses from participants in immersive virtual environments that are similar to those observed in the physical world is considered. These research questions were investigated through four experiments. The first experiment focused on the impact of visual fidelity and behavioural complexity on participant responses by implementing a model of gaze behaviour in virtual humans. The results of the study concluded that participants expected more life-like behaviours from more visually realistic virtual humans. The second experiment investigated the detrimental effects on participant responses when interacting with virtual humans with low behavioural complexity. The third experiment investigated the differences in responses of participants to virtual humans perceived to be in varying emotional states. The emotional states of the virtual humans were portrayed using postural and facial cues. Results indicated that posture does play an important role in the portrayal of affect however the behavioural model used in the study did not fully cover the qualities of body movement associated with the emotions studied. The final experiment focused on the portrayal of affect through the quality of body movement such as the speed of gestures. The effectiveness of the virtual humans was gauged through exploring a variety of participant responses including subjective responses, objective physiological and behavioural measures. The results show that participants are affected and respond to virtual humans in a significant manner provided that an appropriate behavioural model is used

Online Gaming and Emotion Representation

Abstract. The ability to simulate lifelike interactive characters has many applications in the gaming industry. A lifelike human face can enhance interactive applications by providing straightforward feedback to and from the users and stimulating emotional responses from them. Thus, the gaming and entertainment industries can benefit from employing believable, expressive characters since such features significantly enhance the atmosphere of a virtual world and communicate messages far more vividly than any textual or speech information. In this paper, we present an abstract means of description of facial expressions, by utilizing concepts included in the MPEG-4 standard. Furthermore, we exploit these concepts to synthesize a wide variety of expressions using a reduced representation, suitable for networked and lightweight applications.