Investigating Embodied Interaction in Near-Field Perception-Action Re-Calibration on Performance in Immersive Virtual Environments

Immersive Virtual Environments (IVEs) are becoming more accessible and more widely utilized for training. Previous research has shown that the matching of visual and proprioceptive information is important for calibration. Many state-of-the art Virtual Reality (VR) systems, commonly known as Immersive Virtual Environments (IVE), are created for training users in tasks that require accurate manual dexterity. Unfortunately, these systems can suffer from technical limitations that may force de-coupling of visual and proprioceptive information due to interference, latency, and tracking error. It has also been suggested that closed-loop feedback of travel and locomotion in an IVE can overcome compression of visually perceived depth in medium field distances in the virtual world [33, 47]. Very few experiments have examined the carryover effects of multi-sensory feedback in IVEs during manual dexterous 3D user interaction in overcoming distortions in near-field or interaction space depth perception, and the relative importance of visual and proprioceptive information in calibrating users\u27 distance judgments. In the first part of this work, we examined the recalibration of movements when the visually reached distance is scaled differently than the physically reached distance. We present an empirical evaluation of how visually distorted movements affects users\u27 reach to near field targets in an IVE. In a between subjects design, participants provided manual reaching distance estimates during three sessions; a baseline measure without feedback (open-loop distance estimation), a calibration session with visual and proprioceptive feedback (closed-loop distance estimation), and a post-interaction session without feedback (open-loop distance estimation). Subjects were randomly assigned to one of three visual feedbacks in the closed-loop condition during which they reached to target while holding a tracked stylus: i) Minus condition (-20% gain condition) in which the visual stylus appeared at 80\% of the distance of the physical stylus, ii) Neutral condition (0% or no gain condition) in which the visual stylus was co-located with the physical stylus, and iii) Plus condition (+20% gain condition) in which the visual stylus appeared at 120% of the distance of the physical stylus. In all the conditions, there is evidence of visuo-motor calibration in that users\u27 accuracy in physically reaching to the target locations improved over trials. Scaled visual feedback was shown to calibrate distance judgments within an IVE, with estimates being farthest in the post-interaction session after calibrating to visual information appearing nearer (Minus condition), and nearest after calibrating to visual information appearing further (Plus condition). The same pattern was observed during closed-loop physical reach responses, participants generally tended to physically reach farther in Minus condition and closer in Plus condition to the perceived location of the targets, as compared to Neutral condition in which participants\u27 physical reach was more accurate to the perceived location of the target. We then characterized the properties of human reach motion in the presence or absence of visuo-haptic feedback in real and IVEs within a participant\u27s maximum arm reach. Our goal is to understand how physical reaching actions to the perceived location of targets in the presence or absence of visuo-haptic feedback are different between real and virtual viewing conditions. Typically, participants reach to the perceived location of objects in the 3D environment to perform selection and manipulation actions during 3D interaction in applications such as virtual assembly or rehabilitation. In these tasks, participants typically have distorted perceptual information in the IVE as compared to the real world, in part due to technological limitations such as minimal visual field of view, resolution, latency and jitter. In an empirical evaluation, we asked the following questions; i) how do the perceptual differences between virtual and real world affect our ability to accurately reach to the locations of 3D objects, and ii) how do the motor responses of participants differ between the presence or absence of visual and haptic feedback? We examined factors such as velocity and distance of physical reaching behavior between the real world and IVE, both in the presence or absence of visuo-haptic information. The results suggest that physical reach responses vary systematically between real and virtual environments especially in situations involving presence or absence of visuo-haptic feedback. The implications of our study provide a methodological framework for the analysis of reaching motions for selection and manipulation with novel 3D interaction metaphors and to successfully characterize visuo-haptic versus non-visuo-haptic physical reaches in virtual and real world situations. While research has demonstrated that self-avatars can enhance ones\u27 sense of presence and improve distance perception, the effects of self-avatar fidelity on near field distance estimations has yet to be investigated. Thus, we investigated the effect of visual fidelity of the self-avatar in enhancing the user\u27s depth judgments, reach boundary perception and properties of physical reach motion. Previous research has demonstrated that self-avatar representation of the user enhances the sense of presence [37] and even a static notion of an avatar can improve distance estimation in far distances [59, 48]. In this study, performance with a virtual avatar was also compared to real-world performance. Three levels of fidelity were tested; 1) an immersive self-avatar with realistic limbs, 2) a low-fidelity self-avatar showing only joint locations, and 3) end-effector only. There were four primary hypotheses; First, we hypothesize that just the existence of self-avatar or end-effector position would calibrate users\u27 interaction space depth perception in an IVE. Therefore, participants\u27 distance judgments would be improved after the calibration phase regardless of self-avatars\u27 visual fidelity. Second, the magnitude of the changes from pre-test to post-test would be significantly different based on the visual details of the self-avatar presented to the participants (self-avatar vs low-fidelity self-avatar and end-effector). Third, we predict distance estimation accuracy would be the highest in immersive self-avatar condition and the lowest in end-effector condition. Forth, we predict that the properties of physical reach responses vary systematically between different visual fidelity conditions. The results suggest that reach estimations become more accurate as the visual fidelity of the avatar increases, with accuracy for high fidelity avatars approaching real-world performance as compared to low-fidelity and end-effector conditions. There was also an effect of the phase where the reach estimate became more accurate after receiving feedback in calibration phase. Overall, in all conditions reach estimations became more accurate after receiving feedback during a calibration phase. Lastly, we examined factors such as path length, time to complete the task, average velocity and acceleration of physical reach motion and compared all the IVEs conditions with real-world. The results suggest that physical reach responses vary systematically between the VR viewing conditions and real-world

The Effect of Anthropometric Properties of Self-Avatars on Action Capabilities in Virtual Reality

The field of Virtual Reality (VR) has seen a steady exponential uptake in the last decade and is being continuously incorporated into areas of popular interest like healthcare, training, recreation and gaming. This steady upward trend and prolonged popularity has resulted in numerous extravagant virtual environments, some that aim to mimic real-life experiences like combat training, while others intend to provide unique experiences that may otherwise be difficult to recreate like flying over ancient Egypt as a bird. These experiences often showcase highly realistic graphics, intuitive interactions and unique avatar embodiment scenarios with the help of various tracking sensors, high definition graphic displays, sound systems, etc. The literature suggests that estimates and affordance judgments in VR scenarios such as the ones described above are affected by the properties and the nature of the avatar embodied by the user. Therefore, to provide users with the finest experiences it is crucial to understand the interaction between the embodied self and the action capabilities afforded by it in the surrounding virtual environment. In a series of studies aimed at exploring the effect of gender matched body-scaled self-avatars on the user\u27s perception, we investigate the effect of self-avatars on the perception of size of objects in an immersive virtual environment (IVE) and how this perception affects the actions one can perform as compared to the real world. In the process, we make use of newer tracking technology and graphic displays to investigate the perceived differences between real world environments and their virtual counterparts to understand how the spatial properties of the environment and the embodied self-avatars affect affordances by means of passability judgments. We describe techniques for creation and mapping VR environments onto their real world counterparts and the creation of gender matched body-scaled self-avatars that provides real time full-body tracking. The first two studies investigate how newer graphical displays and off-the-shelf tracking devices can be utilized to create salient gender matched body-scaled self-avatars and their effect on the judgment of passability as a result of the embodied body schema. The study involves creating complex scripts that automate the process of mapping virtual worlds onto their real world counterparts within a 1cm margin of error and the creation of self-avatars that match height, limb proportions and shoulder width of the participant using tracking sensors. The experiment involves making judgments about the passability of an adjustable doorway in the real world and in a virtual to-scale replica of the real world environment. The results demonstrated that the perception of affordances in IVEs is comparable to the real world but the behavior leading to it differs in VR. Also, the body-scaled self-avatars generated provide salient information yielding performance similar to the real world. Several insights and guidelines related to creating veridical virtual environments and realistic self-avatars were achieved from this effort. The third study investigates how the presence of body-scaled self-avatars affects the perception of size of virtual handheld objects and the influence of the person-plus-virtual-object system created by lifting the said virtual object on passability. This is crucial to understand as VR simulations now often utilize self-avatars that carry objects while maneuvering through the environment. How they interact with these handheld objects can influence what they do in critical scenarios where split second decisions can change the outcome like combat training, role-playing games, first person shooting, thrilling rides, physiotherapy, etc. It has also been reported that the avatar itself can influence the perception of size of virtual objects, in turn influencing action capabilities. There is ample research on different interaction techniques to manipulate objects in a virtual world but the question about how the objects affect our action capabilities upon interaction remains unanswered, especially when the haptic feedback associated with holding a real object is mismatched or missing. The study investigates this phenomenon by having participants interact with virtual objects of different sizes and making frontal and lateral passability judgments to an adjustable aperture similar to the first experiment. The results suggest that the presence of self-avatars significantly affects affordance judgments. Interestingly, frontal and lateral judgments in IVEs seem to similar unlike the real world. Investigating the concept of embodied body schema and its influence on action-capabilities further, the fourth study looks at how embodying self-avatars that may vary slightly from your real world body affect performance and behavior in dynamic affordance scenarios. In this particular study, we change the eye height of the participants in the presence or absence of self-avatars that are either bigger, smaller or the same size as the participant. We then investigate how this change in eye height and anthropometric properties of the self-avatar affects their judgments when crossing streets with oncoming traffic in virtual reality. We also evaluate any changes in the perceived walking speed as a result of embodying altered self-avatars. The findings suggest that the presence of self-avatars results in safer crossing behavior, however scaling the eye height or the avatar does not seem to affect the perceived walking speed. A detailed discussion on all the findings can be found in the manuscript

All Hands on Deck: Choosing Virtual End Effector Representations to Improve Near Field Object Manipulation Interactions in Extended Reality

Extended reality, or XR , is the adopted umbrella term that is heavily gaining traction to collectively describe Virtual reality (VR), Augmented reality (AR), and Mixed reality (MR) technologies. Together, these technologies extend the reality that we experience either by creating a fully immersive experience like in VR or by blending in the virtual and real worlds like in AR and MR. The sustained success of XR in the workplace largely hinges on its ability to facilitate efficient user interactions. Similar to interacting with objects in the real world, users in XR typically interact with virtual integrants like objects, menus, windows, and information that convolve together to form the overall experience. Most of these interactions involve near-field object manipulation for which users are generally provisioned with visual representations of themselves also called self-avatars. Representations that involve only the distal entity are called end-effector representations and they shape how users perceive XR experiences. Through a series of investigations, this dissertation evaluates the effects of virtual end effector representations on near-field object retrieval interactions in XR settings. Through studies conducted in virtual, augmented, and mixed reality, implications about the virtual representation of end-effectors are discussed, and inferences are made for the future of near-field interaction in XR to draw upon from. This body of research aids technologists and designers by providing them with details that help in appropriately tailoring the right end effector representation to improve near-field interactions, thereby collectively establishing knowledge that epitomizes the future of interactions in XR

The effectiveness of training in virtual environments

The research presented in this thesis explores the use of consumer virtual reality technology for training, comparing its validity to more traditional training formats. The need to evaluate the effectiveness of training in virtual environments is critical as a wider audience gains access to an array of emerging virtual reality consumer devices. Training is an obvious use case for these devices. This is motivated by the well-known success of domain-specific training simulators, the ability to train in safe, controlled environments and the potential to launch training programs when the physical components required to complete a task are not readily available. In this thesis, we present four user studies that aim to compare the effectiveness of systems with varying levels of immersion for learning transfer of several tasks, ranging from object location spatial memory to more complex assembly procedures. For every study, evaluation of the effectiveness of training took place in a real-world, physical environment. The first two studies compare geometric and self-motion models in describing human spatial memory through scale distortions of real and virtual environments. The third study examines the effect of level of immersion, self-avatar and environmental fidelity on object location memory in real and virtual environments. The fourth study compares the effectiveness of physical training and virtual training for teaching a bimanual assembly task. Results highlight the validity of virtual environments for training. The overall conclusion is that virtual training can yield a resulting performance that is superior to other, more traditional training formats. Combined, the outcomes of each of the user studies motivate further study of consumer virtual reality systems in training and suggest considerations for the design of such virtual environments

Actor & Avatar: A Scientific and Artistic Catalog

What kind of relationship do we have with artificial beings (avatars, puppets, robots, etc.)? What does it mean to mirror ourselves in them, to perform them or to play trial identity games with them? Actor & Avatar addresses these questions from artistic and scholarly angles. Contributions on the making of "technical others" and philosophical reflections on artificial alterity are flanked by neuroscientific studies on different ways of perceiving living persons and artificial counterparts. The contributors have achieved a successful artistic-scientific collaboration with extensive visual material

Presence 2005: the eighth annual international workshop on presence, 21-23 September, 2005 University College London (Conference proceedings)

OVERVIEW (taken from the CALL FOR PAPERS) Academics and practitioners with an interest in the concept of (tele)presence are invited to submit their work for presentation at PRESENCE 2005 at University College London in London, England, September 21-23, 2005. The eighth in a series of highly successful international workshops, PRESENCE 2005 will provide an open discussion forum to share ideas regarding concepts and theories, measurement techniques, technology, and applications related to presence, the psychological state or subjective perception in which a person fails to accurately and completely acknowledge the role of technology in an experience, including the sense of 'being there' experienced by users of advanced media such as virtual reality. The concept of presence in virtual environments has been around for at least 15 years, and the earlier idea of telepresence at least since Minsky's seminal paper in 1980. Recently there has been a burst of funded research activity in this area for the first time with the European FET Presence Research initiative. What do we really know about presence and its determinants? How can presence be successfully delivered with today's technology? This conference invites papers that are based on empirical results from studies of presence and related issues and/or which contribute to the technology for the delivery of presence. Papers that make substantial advances in theoretical understanding of presence are also welcome. The interest is not solely in virtual environments but in mixed reality environments. Submissions will be reviewed more rigorously than in previous conferences. High quality papers are therefore sought which make substantial contributions to the field. Approximately 20 papers will be selected for two successive special issues for the journal Presence: Teleoperators and Virtual Environments. PRESENCE 2005 takes place in London and is hosted by University College London. The conference is organized by ISPR, the International Society for Presence Research and is supported by the European Commission's FET Presence Research Initiative through the Presencia and IST OMNIPRES projects and by University College London

Interactive Motion Planning for Multi-agent Systems with Physics-based and Behavior Constraints

Man-made entities and humans rely on movement as an essential form of interaction with the world. Whether it is an autonomous vehicle navigating crowded roadways or a simulated pedestrian traversing a virtual world, each entity must compute safe, effective paths to achieve their goals. In addition, these entities, termed agents, are subject to unique physical and behavioral limitations within their environment. For example, vehicles have a finite physical turning radius and must obey behavioral constraints such as traffic signals and rules of the road. Effective motion planning algorithms for diverse agents must account for these physics-based and behavior constraints. In this dissertation, we present novel motion planning algorithms that account for constraints which physically limit the agent and impose behavioral limitations on the virtual agents. We describe representational approaches to capture specific physical constraints on the various agents and propose abstractions to model behavior constraints affecting them. We then describe algorithms to plan motions for agents who are subject to the modeled constraints. First, we describe a biomechanically accurate elliptical representation for virtual pedestrians; we also describe human-like movement constraints corresponding to shoulder-turning and side-stepping in dense environments. We detail a novel motion planning algorithm extending velocity obstacles to generate collisionfree paths for hundreds of elliptical agents at interactive rates. Next, we describe an algorithm to encode dynamics and traffic-like behavior constraints for autonomous vehicles in urban and highway environments. We describe a motion planning algorithm to generate safe, high-speed avoidance maneuvers using a novel optimization function and modified control obstacle formulation, and we also present a simulation framework to evaluate driving strategies. Next, we present an approach to incorporate high-level reasoning to model the motions and behaviors of virtual agents in terms of verbal interactions with other agents or avatars. Our approach leverages natural-language interaction to reduce uncertainty and generate effective plans. Finally, we describe an application of our techniques to simulate pedestrian behaviors for gathering simulated data about loading, unloading, and evacuating an aircraft.Doctor of Philosoph

Creating a Virtual Mirror for Motor Learning in Virtual Reality

Waltemate T. Creating a Virtual Mirror for Motor Learning in Virtual Reality. Bielefeld: Universität Bielefeld; 2018

Social Virtual Reality : Design and Potential for Social Exchange and Cohesion in Virtual Teams

Tieto ja viestintäteknologian (TVT) kautta tapahtuvan vuorovaikutuksen sujuvuus ja tehokkuus ovat tärkeäitä nykypäivän organisaatioille. Etätyön aikakaudella virtuaalitiimit ovat hajallaan ympäri maailmaa ja menestyksekäs yhteistyö ei välttämättä vaadi kasvokkain tapahtuvaa viestintää. Perinteiset etätyökalut ovat kuitenkin kaukana täydellisyydestä, erityisesti koskien niiden kykyä edistää sosiaalisten siteiden vahvistumista, tai tiimien koheesiota, jotka molemmat ovat tärkeitä virtuaalitiimien suorituskyvylle. Monet tutkijat ja ammattilaiset ennustavat, että kasvokkain tapahtuvan viestinnän puute voi merkittävästi vaikuttaa organisaatioiden pitkän aikavälin suorituskykyyn. Tämän väitöskirjan pääväite on, että monikäyttäjä-virtuaalitodellisuus (VR), jäljempänä sosiaalinen virtuaalitodellisuus (SVR), voi tarjota ratkaisun tähän ongelmaan. SVR:n potentiaali perustuu ajatukseen, jonka mukaan ihmisen kognitio on rakentunut luonnollisen, tilallisen vuorovaikutuksesta ja viestinnän ympärille. Organisaatiot ovat siksi yhä enemmän sijoittamassa SVR-teknologiaan, koska se pystyy simuloimaan tai muuttamaan lähes mitä tahansa kokemuksia, mukaan lukien kasvokkain tapahtuvan viestinnän. Emme kuitenkaan vielä tunne hyvin SVR:n mahdollisuuksia organisaation tai virtuaalitiimien viestintätehokkuuden parantamisessa. Aiemmat tutkimukset ovat osoittaneet, että tehokkaampi kommunikaatio on yksi SVR:n tärkeimmistä affordansseista organisaatioille, mutta sen potentiaalia henkilökohtaisen tai ryhmätason organisatorisen viestinnän edistämisessä ei ole tutkittu huolellisesti. Lisäksi aiemmat tutkimukset tunnistavat SVR:n kyvyn ei vain simuloida, vaan parantaa sosiaalista vuorovaikutusta muotoon, jolle ei ole vastineita todellisessa maailmassa, mutta emme vielä ymmärrä tämän vaikutusta ja potentiaalia organisaatioille. Väitöskirja ottaa kantaa tähän tutkimusaukkoon tutkimalla SVR:n potentiaalia henkilöiden välisessä, mikrotason sosiaalisessa vaihdannassa ja tiimityön koheesiossa, jotka molemmat ovat tärkeitä indikaattoreita tiimityön suorituskyvylle. Väitöskirja yhdistää laadullisia, teoreettisia, empiirisiä ja suunnittelututkimuksen (design research) menetelmiä suunnittelutoimintatutkimuksen (action design research) keinoin. Väitöskirja arvioi ensin, kuinka media synkronisuus edistää tai heikentää sosiaalista vaihtoa (eli luottamuksen ja vastavuoroisuuden välisiä prosesseja) organisaatiossa. Tämän jälkeen väitöskirja tutkii, kuinka virtuaalisten tiimien sosiaalista vaihtoa voidaan parantaa SVR:n avulla. Näitä havaintoja jatketaan tarkastelemalla SVR:n tarjoamia mahdollisuuksia virtuaalisen tiimin koheesion (eli tehtävä- ja sosiaalisen koheesion) syntymisessä. Näiden tutkimusten perusteella väitöskirja muotoilee useita konkreettisia suunnitteluperiaatteita SVR:lle virtuaalisten tiimien sosiaalisen vaihdon ja koheesion kontekstissa. Väitöskirja kuvaa myös SVR- teknologian laajempia hyötyjä organisaatioille ja antaa käytännön ohjeita niiden toteuttamiseen. Väitöskirja tarjoaa ymmärrystä siitä, kuinka SVR voi parantaa organisaation etätyötä ja kommunikaatiota lieventämällä tai poistamalla merkittäviä perinteisen ICT:n rajoituksia. Väitöskirjan tulokset osoittavat, että SVR:n etuna on sekä lähes rajaton monipuolisuus sosiaalisena simulaationa että luonnollisuus tietoisen ja tiedostamattoman viestinnän välineenä. Nämä edut korostuvat erityisesti virtuaalitiimeissä ja tietotyön kaltaisessa etätyössä, jossa korostetaan osallistujien välistä korkeaa mentaalista ja henkilökohtaista yhteistyötä, sekä erilaisten näkökulmien yhteensovittamista. Väitöskirjan tulokset viittaavat myös siihen, että nämä hyödyt voidaan saavuttaa vain, jos organisaatiot keskittyvät SVR-teknologian jatkokehitykseen, sen materiaalisten ominaisuuksien ja toiminnallisuuksien edelleen kehittämiseen, sekä SVR:n integrointiin osaksi organisaation muita työvirtoja ja tietojärjestelmiä.The success of information and communications technology (ICT)-mediated interaction is vital for organizations. In the era of remote work, virtual teams are dispersed across the globe and successful collaboration does not necessarily require a face-to-face communication. However, conventional remote work tools are far from perfect, especially in terms of their ability to facilitate the strengthening of social ties, or team cohesion, which are considered crucial for the performance of virtual teams. Respectively, many researchers and practitioners predict that the lack of face-to-face communication can significantly affect organizations’ long-term performance. The main proposition of this dissertation is that multi-user virtual reality (VR) applications, hereafter social virtual reality (SVR), has the potential to provide a solution to this problem. The biggest promise of SVR relies on the premise that human cognition is built upon natural, spatial interaction, and communication. Organizations are thus increasingly investing in SVR technology, because of its ability to simulate or transform almost any experience, including face-to-face communication. However, we do not yet know much about SVR’s ability to facilitate organizational communication. Prior research has shown that communication is one of SVR’s key affordances for organizations, but its potential of facilitating interpersonal or group level communication has not been studied elaborately. Furthermore, prior studies recognize SVR’s ability to not only simulate, but enhance social interaction to something for which there is no equivalent in the real world, but we do not yet understand the impact and potential of this to organizations. This dissertation addresses to the research gap by investigating the potential of SVR in the context of social exchange and team cohesion of SVR-enabled virtual teams, both of which are important indicators of team performance. In terms of methodology, the dissertation employs an action design research (ADR) approach which combines qualitative, theory and review, empirical, and design science research (DSR) methods. The dissertation first evaluates how media synchronicity facilitates social exchange (i.e., patterns of trust and reciprocity leading to stronger social ties) in an organization. The dissertation then outlines how social exchange can be enhanced in SVR-enabled virtual teams. These observations are continued by examining the affordances of SVR in the emergence of team cohesion (i.e., task and social cohesion) in virtual teams. Based on these examinations, the dissertation proposes several design principles for SVR in the context of social exchange and team cohesion. The dissertation also describes the wider benefits of SVR technology for organizations and provides practical guidelines of how they could be realized. The dissertation provides an understanding of how SVR can enhance organizations’ remote work and communication practices by mitigating some of the most critical limitations of conventional ICTs. Results of the dissertation indicate that SVR's fundamental advantage is both its almost limitless versatility as a social simulation and naturalness as a means of conscious and subconscious communication. These advantages come to the fore especially in virtual teams and knowledge-intensive remote collaboration that emphasize high mental and personal alignment between participants. The results of the dissertation also suggest that these benefits can only be realized if organizations focus on the further development of SVR technology, its material properties, and integration of SVR with organizational workflows and information systems (IS)

Eye tracking and avatar-mediated communication in immersive collaborative virtual environments

The research presented in this thesis concerns the use of eye tracking to both enhance and understand avatar-mediated communication (AMC) performed by users of immersive collaborative virtual environment (ICVE) systems. AMC, in which users are embodied by graphical humanoids within a shared virtual environment (VE), is rapidly emerging as a prevalent and popular form of remote interaction. However, compared with video-mediated communication (VMC), which transmits interactants’ actual appearance and behaviour, AMC fails to capture, transmit, and display many channels of nonverbal communication (NVC). This is a significant hindrance to the medium’s ability to support rich interpersonal telecommunication. In particular, oculesics (the communicative properties of the eyes), including gaze, blinking, and pupil dilation, are central nonverbal cues during unmediated social interaction. This research explores the interactive and analytical application of eye tracking to drive the oculesic animation of avatars during real-time communication, and as the primary method of experimental data collection and analysis, respectively. Three distinct but interrelated questions are addressed. First, the thesis considers the degree to which quality of communication may be improved through the use of eye tracking, to increase the nonverbal, oculesic, information transmitted during AMC. Second, the research asks whether users engaged in AMC behave and respond in a socially realistic manner in comparison with VMC. Finally, the degree to which behavioural simulations of oculesics can both enhance the realism of virtual humanoids, and complement tracked behaviour in AMC, is considered. These research questions were investigated over a series of telecommunication experiments investigating scenarios common to computer supported cooperative work (CSCW), and a further series of experiments investigating behavioural modelling for virtual humanoids. The first, exploratory, telecommunication experiment compared AMC with VMC in a three-party conversational scenario. Results indicated that users employ gaze similarly when faced with avatar and video representations of fellow interactants, and demonstrated how interaction is influenced by the technical characteristics and limitations of a medium. The second telecommunication experiment investigated the impact of varying methods of avatar gaze control on quality of communication during object-focused multiparty AMC. The main finding of the experiment was that quality of communication is reduced when avatars demonstrate misleading gaze behaviour. The final telecommunication study investigated truthful and deceptive dyadic interaction in AMC and VMC over two closely-related experiments. Results from the first experiment indicated that users demonstrate similar oculesic behaviour and response in both AMC and VMC, but that psychological arousal is greater following video-based interaction. Results from the second experiment found that the use of eye tracking to drive the oculesic behaviour of avatars during AMC increased the richness of NVC to the extent that more accurate estimation of embodied users’ states of veracity was enabled. Rather than directly investigating AMC, the second series of experiments addressed behavioural modelling of oculesics for virtual humanoids. Results from the these experiments indicated that oculesic characteristics are highly influential to the perceived realism of virtual humanoids, and that behavioural models are able to complement the use of eye tracking in AMC. The research presented in this thesis explores AMC and eye tracking over a range of collaborative and perceptual studies. The overall conclusion is that eye tracking is able to enhance AMC towards a richer medium for interpersonal telecommunication, and that users’ behaviour in AMC is no less socially ‘real’ than that demonstrated in VMC. However, there are distinct differences between the two communication mediums, and the importance of matching the characteristics of a planned communication with those of the medium itself is critical