Investigating virtual environments has become an increasingly interesting research topic for engineers, computer and cognitive scientists, and psychologists. Although there have been several recent studies focused on the development of multimodal virtual environments (VEs) to study human-machine interactions, less attention has been paid to human-human and human-machine interactions in shared virtual environments (SVEs), and to our knowledge, no attention paid at all to what extent the addition of haptic communication between people would contribute to the shared experience. We have developed a multimodal shared virtual environment and performed a set of experiments with human subjects to study the role of haptic feedback in collaborative tasks and whether haptic communication through force feedback can facilitate a sense of being and collaborating with a remote partner. The study concerns a scenario where two participants at remote sites must cooperate to perform a joint task in an SVE. The goals of the study are (1) to assess the impact of force feedback on task performance, (2) to better understand the role of haptic communication in human-human interactions, (3) to study the impact of touch on the subjective sense of collaborating with a human as reported by the participants based on what they could see and feel, and (4) to investigate if gender, personality, or emotional experiences of users can affect haptic communication in SVEs. The outcomes of this research can have a powerful impact on the development of next-generation human-computer interfaces and network protocols that integrate touch and force feedback technology into the Internet, development of protocols and techniques for collaborative teleoperation such as hazardous material removal, space station Part of this research, including the development of the VE set-up, was supported by a grant from Office of Naval Research. Mel Slater's work in this research was part of his involvement in the European ACTS COVEN project (Collaborative Virtual Environments). Permission to make digital / hard copy of part or all of this work for personal or classroom use is granted without fee provided that the copies are not made or distributed for profit or commercial advantage, the copyright notice, the title of the publication, and its date appear, and notice is given that copying is by permission of the ACM, Inc. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and / or a fee. repair, and remote surgery, and enhancement of virtual environments for performing collaborative tasks in shared virtual worlds on a daily basis such as cooperative teaching, training, planning and design, cybergames, and social gatherings. Our results suggest that haptic feedback significantly improves the task performance and contributes to the feeling of "sense of togetherness" in SVEs. In addition, the results show that the experience of visual feedback only at first, and then subsequently visual plus haptic feedback, elicits a better performance than presentation of visual plus haptic feedback first followed by visual feedback only.  Virtual reality involves the creation of multisensory experience through artificial means. The effectiveness of virtual environments has often been linked to the richness of sensory information and realness of the experience [Held and Durlach 1992; Ellis 1992; Barfield and Furness 1995] . The quantification of the participant's multisensory experience in these environments involves a set of objective measures that quantify a particular task performance as well as a set of measures that quantify the subjective experience [Sheridan 1992a] . Although the development of virtual worlds that can provide a multisensory experience to a single user is receiving substantial attention from researchers, less attention has been given to shared virtual environments (SVEs) and shared experience. In general, single-user VR applications involve the visualization of a scene and interaction with objects within the scene. However, the fundamental aspect of shared experience is the sensory communication that takes place between participants which enables them to display their actions and express their emotions to each other. To explore possible uses of SVEs for learning, entertainment and work, Waters and Barrus [1997] and their colleagues have developed "Diamond Park," a virtual landscape park that accommodates both bicycling and social interactions. Macedonia and Noll [1997] discuss the possibilities of constructing an SVE for conducting scientific experiments globally with remotely located participants. The applications involve the training of astronauts and telediagnosis. Jasnoch et al. [1996] describe an SVE for virtual prototyping and emphasize that such an environment can decrease product development time and cost and increase the quality and flexibility in computer-aided design. Benford and colleagues have carried out a series of studies on collaborative virtual environments, most recently [Benford et al. 1998 ] exploring boundaries between the real and the virtual in the context of a poetry performance. As part of the European Collaborative Virtual
The importance of haptic interfaces for collaborative tasks in virtual environments was investigated by REF .
An experimental study on the role of touch in shared virtual environments
TCHI
Computer Science