How the eye measures reality and virtual reality

If virtual reality systems are to make good on their name, designers must know how people perceive space in natural environments, in photographs, and in cinema. Perceivers understand the layout of a cluttered natural environment through the use of nine or more sources of information, each based on different assumptions—occlusion, height in the visual field, relative size, relative density, aerial perspective, binocular disparities, accommodation, convergence, and motion perspective. The relative utility of these sources at different distances is compared, using their ordinal depth-threshold functions. From these, three classes of space around a moving observer are postulated: personal space, action space, and vista space. Within each, a smaller number of sources act in consort, with different relative strengths. Given the general ordinality of the sources, these spaces are likely to be affine in character, stretching and collapsing with viewing conditions. One of these conditions is controlled by lens length in photography and cinematography or by field-of-view commands in computer graphics. These have striking effects on many of these sources of information and, consequently, on how the layout of a scene is perceived.     

A virtual reality scenario for all seasons: the virtual classroom

Treatment and rehabilitation of the cognitive, psychological, and motor sequelae of central nervous system dysfunction often relies on assessment instruments to inform diagnosis and to track changes in clinical status. Typically, these assessments employ paper-and-pencil psychometrics, hands-on analog/computer tests, and rating of behavior within the context of real-world functional environments. Virtual reality offers the option to produce and distribute identical "standard" simulation environments in which performance can be measured and rehabilitated. Within such digital scenarios, normative data can be accumulated for performance comparisons needed for assessment/diagnosis and for treatment/rehabilitation purposes. In this manner, reusable archetypic virtual environments constructed for one purpose can also be applied for applications addressing other clinical targets. This article will provide a review of such a retooling approach using a virtual classroom simulation that was originally developed as a controlled stimulus environment in which attention processes could be systematically assessed in children with attention-deficit/hyperactivity disorder. This system is now being applied to other clinical targets including the development of tests that address other cognitive functions, eye movement under distraction conditions, social anxiety disorder, and the creation of an earthquake safety training application for children with developmental and learning disabilities.     

Reaching within video-capture virtual reality: using virtual reality as a motor control paradigm.

We have developed a virtual reality (VR) system that integrates a three-dimensional tracking device with a video-capture VR platform to record upper limb movements. The influence of target velocity on planning and execution of reaching movements was studied in five healthy subjects. Our initial results suggest that a target's velocity is considered when planning an interceptive action and that a hand reaching toward a moving virtual target is controlled in a similar way to how it is in the real visual environment.     

Apparent distance in actual,three-dimensional video-recorded,and virtual reality

This study examined how well reality was reproduced in several conditions of virtual reality, by mutually comparing the perception of distance in actual 3-dimensional space and 3-dimensional video-recorded space. Apparent distances in both indoor and outdoor situations were estimated by 10 adolescents. Analysis showed that relations between apparent distance and physical distance in the actual spaces both in indoor and outdoor situations are described by 0.95 and 1.01 power exponents, respectively. On the other hand, the underestimations of the apparent distance are shown in the 3-dimensional video-recorded and the virtual reality spaces both in indoor and outdoor situations whose exponents ranged from .53 to .80.     

Henri Bergson: Evolution,time and philosophy

Evolutionary theory is hindered by the conflict between the apparently antagonistic principles of its two founding figures, Darwin and Lamarck. Bergson's Creative Evolution outlines the means of transcending this impasse. If the evolutionary process is conceived as enduring then the atomistic model of static genetic states is never fully realisable. In the light of this, Bergson considers the germ‐plasm to be essentially “fluid.” If there is to be influence on the germ‐line it will be primarily in terms of the manner in which the genetic data is unfolded. In order to designate this influence Bergson introduces the concept of the “tendency.” The tendency will be explicated in relation to contemporary evolutionary biology. However, as the concept signifies that which is given only in the duration in which information is elaborated, it is precluded from representation. Bergson demonstrates that it is the evolutionary principle of continuous transformation which constitutes the limit to any scientific of view. For this reason, science needs to be complemented by a philosophical account of the duration of process.     

Inheritance,Originality and the Will: Bergson and Heidegger on Creation

Abstract

In the work of Henri Bergson and Martin Heidegger we find different responses to traditional ideas of ‘creation’. Bergson advances a philosophy of creation, wherein ‘creation’ is presented as the production of a ‘radical’ or ‘absolute’ novelty, not only in art, but in all forms of human experience and biological life. Heidegger, in contrast, comes to criticise ideas of ‘creation’ in art as the expression of an alienated ‘humanism’ and ‘subjectivism’ essential to the modern age. This paper illuminates this divergence by showing how Bergson and Heidegger, despite appearances, grapple with the question of art-production – and with the attendant issues of inheritance and originality – in similar ways. It is only in recognising this proximity, I argue, that it is possible to perceive adequately what essentially distinguishes their approaches: Bergson’s conception of creation as a function of the will.     

Spatial updating in virtual reality: the sufficiency of visual information

Robust and effortless spatial orientation critically relies on "automatic and obligatory spatial updating", a largely automatized and reflex-like process that transforms our mental egocentric representation of the immediate surroundings during ego-motions. A rapid pointing paradigm was used to assess automatic/obligatory spatial updating after visually displayed upright rotations with or without concomitant physical rotations using a motion platform. Visual stimuli displaying a natural, subject-known scene proved sufficient for enabling automatic and obligatory spatial updating, irrespective of concurrent physical motions. This challenges the prevailing notion that visual cues alone are insufficient for enabling such spatial updating of rotations, and that vestibular/proprioceptive cues are both required and sufficient. Displaying optic flow devoid of landmarks during the motion and pointing phase was insufficient for enabling automatic spatial updating, but could not be entirely ignored either. Interestingly, additional physical motion cues hardly improved performance, and were insufficient for affording automatic spatial updating. The results are discussed in the context of the mental transformation hypothesis and the sensorimotor interference hypothesis, which associates difficulties in imagined perspective switches to interference between the sensorimotor and cognitive (to-be-imagined) perspective.     

Bergson,human rights,and joy

Continental Philosophy Review - This article examines Henri Bergson’s conception of human rights in The Two Sources of Morality and Religion (1932). I claim that he provides an original view...     

Treatment of acrophobia in virtual reality: the role of immersion and presence

In this study the effects of virtual reality exposure therapy (VRET) were investigated in patients with acrophobia. Feelings of presence in VRET were systematically varied by using either a head-mounted display (HMD) (low presence) or a computer automatic virtual environment (CAVE) (high presence). VRET in general was found to be more effective than no treatment. No differences were found in effectiveness between VRET using an HMD or CAVE. Results were maintained at 6 months follow-up. Results of VRET were comparable with those of exposure in vivo (Cyberpsychology and Behavior 4 (2001) 335). In treatment completers no relationship was found between presence and anxiety. Early drop-outs experienced less acrophobic complaints and psychopathology in general at pre-test. They also experienced less presence and anxiety in the virtual environment used in session one as compared to patients that completed VRET.     

Chronic Conditions: Beckett,Bergson and Samuel Johnson

This article analyses the work of the twentieth-century late modernist Samuel Beckett, in light of the turn-of-the-century anti-rationalist Henri Bergson (1859-1941) and the eighteenth-century neoclassicist Samuel Johnson (1709-1784). What unites these three very different thinkers is a concern over habitual, automatic and involuntary behavior, which in all three cases has a distinctly neurological dimension. Beckett’s writing explores the Bergsonian notion, informed by medicine and experimental psychology, of the limitations of agency, of “the deep-seated recalcitrance of matter,” and of the human as always already inflicted by the mechanical, a fact that is poignantly highlighted by the case of Samuel Johnson. Through his encounter with Johnson, Beckett registers a paradigm shift in the understanding of subjectivity. Whereas Bergson aims, throughout his career, to contest the mechanical, habitual and automatic that threaten to encrust themselves upon the living, in Beckett’s often uncannily Johnsonian writing, the habitual and the automatic become progressively more central, until in the late works, habit and mechanical behavior constitute a tenuous, fraught and primitive ontology, the residues of an agential self.     

Affective interactions using virtual reality: the link between presence and emotions.

Many studies showed the ability of movies and imagery techniques to elicit emotions. Nevertheless, it is less clear how to manipulate the content of interactive media to induce specific emotional responses. In particular, this is true for the emerging medium virtual reality (VR), whose main feature is the ability to induce a feeling of "presence" in the computer-generated world experienced by the user. The main goal of this study was to analyze the possible use of VR as an affective medium. Within this general goal, the study also analyzed the relationship between presence and emotions. The results confirmed the efficacy of VR as affective medium: the interaction with "anxious" and "relaxing" virtual environments produced anxiety and relaxation. The data also showed a circular interaction between presence and emotions: on one side, the feeling of presence was greater in the "emotional" environments; on the other side, the emotional state was influenced by the level of presence. The significance of these results for the assessment of affective interaction is discussed.     

Modal truthmakers and two varieties of actualism

In this paper, I distinguish between two varieties of actualism—hardcore actualism and softcore actualism—and I critically discuss Ross Cameron’s recent arguments for preferring a softcore actualist account of the truthmakers for modal truths over hardcore actualist ones. In the process, I offer some arguments for preferring the hardcore actualist account of modal truthmakers over the softcore actualist one.     

Training cognitive skills in virtual reality: measuring performance.

Across a variety of operational environments, virtual reality (VR) is being increasingly used as a means of simulating hazardous work conditions in order to allow trainees to practice advanced cognitive skills such as problem-solving and decision-making. Replicating dangerous conditions particularly involving heavy machinery in the real world can be dangerous and costly. The use of VR is therefore appealing across many industries such as aviation, mining, and rail. However, while the number of training prototypes increase less focus is being given to appropriate evaluation of the training provided via this technology. Increasing skills acquisition and performance does not depend solely on the appropriate design of simulation training. Of equal importance are strong performance measures which can ultimately feedback on the success or otherwise of training and highlight any deficits to guide ongoing improvements. To ensure cognitive skills acquired in a virtual training environment (VTE) are transferable to the real world, training objectives need to be tied directly to realistic scenario events which in turn are directly linked to measures of specific required behaviors.     

Usability of the remote console for virtual reality telerehabilitation: formative evaluation.

The Remote Console (ReCon) is a telerehabilitation application that allows therapists to remotely communicate with patients while monitoring and controlling their virtual rehabilitation exercises. It provides therapists visual feedback of patients' movements, their exercise simulations replicated in real time and with tools to conduct training without a face-to-face session. The Recon underwent a formative evaluation (a type of usability engineering methodology) used to refine its design. Five physical therapists from different practice settings acted as representative users. During the evaluation, these users made errors related to manipulation and finding and understanding controls. Technical issues with the server and audio communication were identified. These findings were used to fine-tune the ReCon system.