Fabri, M., Gerhard, M., Moore, D.J., Hobbs, D.J. (1999) Perceiving the Others: Cognitive Processes in Collaborative Virtual Environments, in Proceedings of 17th Eurographics-UK Conference, April 1999, Cambridge, UK
Perceiving the Others: Cognitive Processes in Collaborative Virtual Environments Marc Fabri
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Michael Gerhard
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David J. Moore
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Dave J. Hobbs
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Virtual Learning Environments Research Group School of Computing Leeds Metropolitan University http://www.lmu.ac.uk/ies/comp/staff/dhobbs/vle.htm
Extended Abstract Collaborative virtual environments (CVEs) have evolved to being virtual communities, places for communication and collaboration, today easily accessible via the World Wide Web. Inhabitants of CVEs are represented by their virtual embodiments, so-called avatars. They can meet and interact with each other and the environment, making them virtually present in the artificial world. Since each avatar is both part of the perceived environment and represents the user that is doing the perceiving (Slater and Wilbur 1997), CVEs can engender a strong sense of presence. This is crucial since the sense of presence users feel is seen as an important factor for effectively performing in CVEs (Witmer and Singer 1998). This paper investigates various aspects of how users are represented and how their representation is perceived by other inhabitants of the virtual world. It is based upon findings from an ongoing research programme examining the opportunities for effective communication between users in collaborative virtual environments (see Fabri and Hobbs 1998). Based on a review of current work in this area, the paper outlines a number of important issues and design criteria for virtual embodiments. We particularly investigate the support of non-verbal means of communication, such as facial expressions, gesture, and body posture. In this context, attention is drawn to the close relationship of the study of user representation in CVEs with research in the fields of social psychology and cognitive psychology. Social psychology sees non-verbal communication channels as of central importance for both one-to-one communication and group discussions (Argyle 1994), and it is therefore expected to be beneficial to provide such channels in CVEs in some way. They can provide valuable clues about people's direction and degree of attention. This makes them particularly significant for usage in multi-user virtual environments, where the perception of other inhabitants' current states is a crucial factor for engendering mutual awareness (Dumas et al 1998).
Cognitive psychologists use the terms sensation and perception to distinguish between what our sense organs receive and what we actually perceive (Gross and McIlveen 1997). As vision is the dominant sense modality in humans (Gross and McIlveen 1997), being an inhabitant of and interacting within CVEs clearly has the potential to actively engage a user due to the highly visual nature of the interface. The virtual world can be experienced as places visited and people met rather than as images seen. Neisser (1976) argues that perception is a dynamic, cyclic process during which we continually try to 'make sense' of the stimuli offered to our sense organs. This sense-making process is guided by what we expect to perceive, based on our knowledge of the world. The model of a conceptual cycle explains how one can perceive meaning in addition to spatial form and shape (Neisser 1976). In this paper, we apply Neisser's analysisby-synthesis model of perception to collaborative virtual environments. The relevance of the different stages of the perceptual cycle to perception CVEs is outlined, and the critical factors for the emergence of presence and mutual awareness are identified. Figure 1 shows the different stages of the perceptual cycle as proposed by Neisser (see also Gross and McIlveen 1997). The feature analysis is seen as driven purely by the data presented to the sensory receptors. In a CVE, this could be the first glance at an object, for example the avatar representation of another user or the facial expression of an avatar. The sensual stimulus results in producing a hypothesis of what the object could be, for which some grounding of, or previous experience with, CVEs is beneficial. The subsequent perceptual exploration, however, represents a purposeful synthesis of the sensory information, aiming to prove the hypothesis by actively sampling the available stimuli. This involves going beyond the immediately given evidence of the senses (Gregory 1990).
If the information provided by the CVE interface matches the features expected, the perceived object is likely to be accepted, e.g. as an avatar with a certain emotional state. This would subsequently enable the perceiving user to associate the avatar with another, real person controlling it. However, if the sample information fails to match user expectations, the hypothesis is modified accordingly and the cycle resumes. This potentially leads to confusion and can have a detrimental effect on the arousal of presence and on the acceptance of the virtual environment in general. During this exploration stage, we consider the willingness of the user to accept the offered stimuli as real, and if necessary to adapt to certain specifics of the environment, as the crucial factor for the emergence of presence and mutual awareness. We argue that users of CVEs are able to adapt their perception to the visual clues given by the interface, and that to experience a situation, the virtual environment does not necessarily have to be an exact simulation of the real world. In fact, approaches reflecting representation issues in simple or unusual ways may be more appropriate and supportive to perception and cognition.
CVE interface offers visual clues
sensory clues / features from the stimulus environment
feature analysis
grounding of CVE interface features helpful
user willingness to accept clues crucial
perceptual exploration, search for expected features
schema, knowledge based on past experience
consistent visual feedback from CVE important
Figure 1: Neisser's analysis-by-synthesis model of perception, applied to perception in CVEs
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