The effectiveness of virtual environments (VEs) has often been linked to the sense of presence reported by users of those VEs. (Presence is defined as the subjective experience of being in one place or environment, even when one is physically situated in another.) We believe that presence is a normal awareness phenomenon that requires directed attention and is based in the interaction between sensory stimulation, environmental factors that encourage involvement and enable immersion, and internal tendencies to become involved. Factors believed to underlie presence were described in the premier issue of Presence: Teleoperators and Virtual Environments. We used these factors and others as the basis for a presence questionnaire (PQ) to measure presence in VEs. In addition we developed an immersive tendencies questionnaire (ITQ) to measure differences in the tendencies of individuals to experience presence. These questionnaires are being used to evaluate relationships among reported presenc...

Virtual environments (VEs) are one of the most advanced human-computer interface to date. A common measure of the effectiveness of a VE is the amount of presence it evokes in users. Presence is commonly defined as the sense of being there in a VE. In order to study the effect that technological improvements such as higher frame rate, more visual realism, and lower lag have on presence, we must be able to measure it. There has been much debate about the best way to measure presence, and we, as presence researchers, have yearned for a measure that is Reliable — produces repeatable results, both from trial to trial on the same subject and across subjects; Valid — measures subjective presence, or at least correlates well with established subjective presence measures; Sensitive — is capable of distinguishing multiple levels of presence; and Objective — is well shielded from both subject bias and experimenter bias. We hypothesize that to the degree that a VE seems real, it will evoke physiological responses similar to those evoked by the corresponding real environment, and that greater presence will evoke a greater response. Hence, these responses serve as reliable, valid, sensitive, and objective measures of presence. We conducted three experiments that support the use of physiological reaction as a reliable, valid,

Presence in Collaborative Virtual Environments (CVEs) can be divided into personal presence and co-presence. Personal presence is having a feeling of "being there" in the CVE oneself. Co-presence is having a feeling that one is in the same place as the other participants, and that one is collaborating with real people. We investigated the effects that avatar realism and functionality (in terms of simple gestures and facial expressions) have on co-presence in a collaborative virtual environment, by means of two small group behaviour experiments with 18 participants each. We measured co-presence subjectively, using a co-presence questionnaire that we developed. We found that there was a significant difference between the co-presence scores generated by avatars of different degrees of realism in their appearance. More realistic avatars generated higher levels of co-presence. We also found that avatars having gestures and facial expressions produced a significantly higher level of co-presence when compared to static avatars. We were not able to find the correlation between presence and copresence reported in some studies.

The benefits of immersion with regard to information visualization applications have rarely been explored. In this paper, we describe a user study designed to explore a variety of information visualization tasks in immersive and non-immersive 3D scatterplots. In the non-immersive version the information was displayed using only one wall of the CAVE, while the immersive version used all four walls. We also examined the effects of head tracking, giving a total of four conditions: four walls in the CAVE with head tracking, four walls without head tracking, one wall with head tracking and finally, one wall without head tracking. By separating the variables in this way, we can independently evaluate the effects of immersion and head tracking. In general, we found the fully immersive condition, (four walls with head tracking) to be most useful in viewing the datasets and performing the tasks.

Virtual environments (VEs) are the most advanced human-computer interfaces yet developed. Researchers, by the development of new methods, theories, and technologies, have endeavored to make effective VEs. The definition of effectiveness changes based on the application of the VE. For flight simulators, training transfer is important. For architectural walkthroughs, accurate perception of space is important. For treatment of phobias and post-traumatic stress disorders, presence – evoking in patients the feeling that they are near the source of their phobia or stress – is important [Hodges, 1994]. It is on this last concept, presence, that this paper focuses. Rothbaum and Hodges ’ VE system for graded exposure treatment of acrophobia strives to bring patients near the source of their phobias [Hodges, 1994]. They state that “the user’s sense of presence is the defining factor in the [successful treatment of acrophobia]. ” We believe this is true for all phobia treatment systems: the system must evoke presence in order to work. Such systems are useful as they allow much of the effectiveness of in vivo exposure with the safety, convenience, and reduced cost of in-office therapy [Hodges, 1995]. To ensure the systems evoke presence in users, developers endeavor to build the best VEs possible: stereo portrayal (as opposed to mono) in the headmounted display, realistic models and lighting, low lag, high frame rate, etc.

The effect of presenting a distributed interactive movie at different levels of control and distribution on the end user’s fun and presence experience was studied. The results suggest that an increased level of end-user control on the flow in the video increases the level of the user’s experience and impacts the feeling of presence significantly. The effects of distribution are less clear and are very much depending on the presentation devices and the content modality. These results are discussed in terms of the measurement instruments and the experimental design, and suggestions are made for further research. 1

The perceived realism of a computer generated image depends on the accuracy of the modeling and illumination calculations, the limitations of the display device, and the way in which the Human Visual System processes this information. A real environment is unlikely to be pristine but will have accumulated dirt, dust and scratches from everyday use. Although human observers do not perhaps consciously take note of these phenomena, the absence of such features from the synthetic representation of that real scene may indeed affect the viewer's perceived realism of the virtual environment. This paper presents a series of psychophysical experiments to examine whether perceived realism of a virtual environment may be improved by adding textures artistically enhanced. Categories and Subject Descriptors

Witmer and Singer have developed a questionnaire for pres- ence (PQ) as well as an immersive tendencies questionnaire (ITQ). Their research has shown that ITQ scores are positively correlated with PQ scores. This paper reports on an attempt to replicate these findings in a non-immersive, collaborative setting, by creating one virtual environment designed to engender a high sense of presence in users, and one designed to dsrupt and decrease the sense of presence felt by users. The major findings of this attempt were firsfly that while there was a dfference in the two worlds according to the definition of presence, the PQ dd not pick up this dfference, and secondly that PQ scores were correlated with ITQ scores only in the so-called "high-presence" environment, implying that Witmet and Singer's results hold only under certain con- ditions.

This paper evaluates different display devices for selection or annotation tasks in augmented reality (AR). We compare three different display types – a head mounted display and two hand held displays. The first hand held display is configured as a magic lens where the user sees the augmented space directly behind the display. The second hand held display is configured to be used at waist level (as one would commonly hold a tablet computer) but the view is still of the scene in front of the user. Making a selection or annotation in AR requires two distinct tasks by the user. First, the user must find the real (or virtual) object they want to mark. Second, the user must move a cursor to the object’s location. We test and compare our three representative displays with respect to both tasks. We found that using a hand held display in the magic lens configuration was faster for cursor movement than either of the other two displays. There was no significant difference among the displays regarding the amount of time it took users to search for either physical or virtual objects.

Collaboration at a distance has long been a research goal of distributed virtual environments. A number of recent technologies, including immersive projection technology systems (IPTs) and head-mounted displays (HMDs), promise a new generation of technologies that are more intuitive to use than desktop-based systems. This paper presents an experiment that compares collaboration in five different settings. Pairs collaborated on the same puzzle-solving task using one of: an IPT connected to another IPT, an IPT connected to an HMD, an IPT connected to a desktop system, two connected desktop systems, or face-to-face collaboration with real objects. The findings demonstrate the benefits of using immersive technologies, and show the advantages of using symmetrical settings for better performance. Some usability problems of the different distributed settings are addressed, as well as factors such as “presence ” and “copresence ” and how these contribute to the participants ’ overall experiences.