At a time of increased social usage of net and collaborative applications, a robust and detailed theory of social presence could contribute to our understanding of social behavior in mediated environments, allow researchers to predict and measure differences among media interfaces, and guide the design of new social environments and interfaces. A broader theory of social presence can guide more valid and reliable measures. The article reviews, classifies, and critiques existing theories and measures of social presence. A set of criteria and scope conditions is proposed to help remedy limitations in past theories and measures and to provide a contribution to a more robust theory and measure of social presence.

Toward a more robust theory and measure of social presence: review and suggested criteria

How to measure usability is an important question in HCI research and user interface evaluation. We review current practice in measuring usability by categorizing and discussing usability measures from 180 studies published in core HCI journals and proceedings. The discussion distinguish several problems with the measures, including whether they actually measure usability, if they cover usability broadly, how they are reasoned about, and if they meet recommendations on how to measure usability. In many studies, the choice of and reasoning about usability measures fall short of a valid and reliable account of usability as quality-in-use of the user interface being studied. Based on the review, we discuss challenges for studies of usability and for research into how to measure usability. The challenges are to distinguish and empirically compare subjective and objective measures of usability; to focus on developing and employing measures of learning and retention; to study long-term use and usability; to extend measures of satisfaction beyond post-use questionnaires; to validate and standardize the host of subjective satisfaction questionnaires used; to study correlations between usability measures as a means for validation; and to use both micro and macro tasks and corresponding measures of usability. In conclusion, we argue that increased attention to the problems identified and challenges discussed may strengthen studies of usability and usability research.

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Current practice in measuring usability: Challenges to usability studies and research

The science of interpersonal touch: An overview

Purpose: It is estimated that 50% to 75% of individuals who experience a stroke have persistent impairment of the affected upper limb (UL). There is a need to identify the best training strategies for retraining motor function of the UL. One intervention showing promise is virtual reality (VR), using either immersive or nonimmersive technology. Before recommending VR for use in clinical practice, it is important to understand the evidence regarding its effectiveness. Method: Two questions about the effectiveness of VR for UL rehabilitation in stroke were posed: (1) Is the use of immersive VR more effective than conventional therapy or no therapy in the rehabilitation of the UL in patients with hemiplegia? (2) Is the use of nonimmersive VR more effective than conventional therapy or no therapy in the rehabilitation of the UL in patients with hemiplegia? Results: There is level 1b evidence suggesting an advantage to training in immersive VR environments versus no therapy in UL rehabilitation, and le...

Virtual reality in stroke rehabilitation: a systematic review of its effectiveness for upper limb motor recovery.

This article reviews theories of organizational communication with a special emphasis on theories that have been used to explain computer-mediated communication phenomena. Among the theories reviewed, two--social presence and media richness--are identified as problematic and as posing obstacles to future theoretical development. While shortcomings of these theories have been identified in the past, some of these theories' predictions have been supported by empirical evidence. It is argued that this theoretical dilemma can be resolved based upon principles derived from a modern version of Darwin's theory of evolution by natural selection and the application of those principles to the understanding of human evolution. A new theoretical model called the psychobiological model is developed, which predicts variations in cognitive effort in computer-mediated collaborative tasks. The model proposes that there is a negative causal link between the "naturalness" of a computer-mediated communication medium, which is the similarity of the medium to the face-to-face medium, and the cognitive effort required from an individual using the medium for knowledge transfer. The model also states that this link is counterbalanced by what are referred to as "schema alignment" and "cognitive adaptation." The schema alignment construct refers to the similarity between the mental schemas of an individual and those of other participant(s). The cognitive adaptation construct refers to an individual's level of schema development associated with the use of a particular medium. Finally, the model states that the degree to which the medium supports an individual's ability to convey and listen to speech is particularly significant in defining its naturalness, more so than the medium's degree of support for the use of facial expressions and body language. An example is offered of how the psychobiological model can be tested in the context provided by the customer support area of an online broker.

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The Psychobiological Model: Towards a New Theory of Computer-Mediated Communication Based on Darwinian Evolution

An experimental study of interaction in a collaborative desktop virtual environment is described. The aim of the experiment was to investigate if added haptic force feedback in such an environment affects perceived virtual presence, perceived social presence, perceived task performance, and task performance. A between-group design was employed, where seven pairs of subjects used an interface with graphic representation of the environment, audio connection, and haptic force feedback. Seven other pairs of subjects used an interface without haptic force feedback, but with identical features otherwise. The PHANToM, a one-point haptic device, was used for the haptic force feedback, and a program especially developed for the purpose provided the virtual environment. The program enables for two individuals placed in different locations to simultaneously feel and manipulate dynamic objects in a shared desktop virtual environment. Results show that haptic force feedback significantly improves task performance, perceived task performance, and pereceived virtual presence in the collaborative distributed environment. The results suggest that haptic force feedback increases perceived social presence, but the difference is not significant.

Supporting presence in collaborative environments by haptic force feedback

Certec has been working on touch interfaces - haptic interfaces - since 1995, exploring the possibilities they can offer people with different kinds of disabilities. With a haptic computer interface a blind person can learn mathematics by tracing touchable mathematical curves, playing haptic computer games, and gaining better access to graphical user interfaces like Windows. This paper presents a brief overview of a set of tests that have been made and some of the results from these tests. This is followed by a set of design recommendations that we have been able to extract as an extended result of this research and development work. These guidelines are grouped under the headings navigation, finding objects, understanding objects, haptic widgets and physical interaction.

Designing haptic computer interfaces for blind people

This paper has its roots in Certec's efforts to find a way to use haptic technology (i.e. touch based interfaces) to provide new computer interaction techniques for visually impaired people and those with physical disabilities.The paper presents a set of recommendations that we have formulated during our research and development work. These rules of thumb are grouped under the headlines Navigation, Finding objects, Understanding objects, Haptic widgets and Physical interaction.

Using haptics in computer interfaces for blind people

Windows and the World Wide Web are two of the keys to the IT-explosion that we are all caught up in. Computers can do more and more and are getting easier to use. But how does a blind person handle a graphical environment like Windows?

This article deals with Certec’s efforts to find a way to use haptics, i.e. controlling with movements and getting feedback via the sense of touch, to provide new computer interaction techniques for visually impaired people and people with physical disabilities. Haptic technology makes it possible to extend the range of touch from the length of an arm to a virtually unlimited distance.

The sense of touch provides new computer interaction techniques for disabled people

The following article reports result from an extensive study with 25 blind users from Italy and Sweden performed during the summer 2001. The tasks reported here test recognition of geometrical objects, recognition of VRML objects, mathematical surfaces an

http://www.certec.lth.se/doc/navigationandrecognition/eurohaptics.pdf

Calle Sjöström

Papers

Supporting presence in collaborative environments by haptic force feedback

Designing haptic computer interfaces for blind people

Using haptics in computer interfaces for blind people

The sense of touch provides new computer interaction techniques for disabled people

Navigation and recognition in complex haptic virtual environments: Reports from an extensive study with blind users