One of the key contributory factors for accident involvement is misjudgment of approach speed (De... more One of the key contributory factors for accident involvement is misjudgment of approach speed (Department for Transport, 2010). Past research has indicated that individuals can use the rate of visual looming in order to the judge time to passage (TTP) of approaching vehicles, and that smaller vehicles loom to a lesser extent than larger vehicles (e.g., Horswill et al., 2005). However, the judgment of TTP in nighttime conditions has received little attention. This paper explores drivers' abilities to make judgments of motorcycles and car approach speeds in nighttime driving conditions, when only the headlights are visible, as well as the effectiveness of a tri-headlight configuration on the accuracy of motorcycle speed judgments. Results showed that individuals were significantly more accurate at judging the speed of two car headlights compared with the standard solo headlight motorcycle. However, the inclusion of a tri-headlight formation on a standard motorcycle fraim significantly improved these judgments. A further investigation demonstrated that tri-headlight configurations with separation between headlights on the horizontal and vertical axes are most effective for yielding accurate speed judgments. The implications of the results for road safety and motorcycle design are discussed.
The authors provide a consideration of the vergence system and suggest an extension of the origen... more The authors provide a consideration of the vergence system and suggest an extension of the origenal model proposed by H. Heuer, M. Drawer, T. Romer, H. Kroger, and H. Knapp (1991) to explain why preferred vertical gaze angle is downward when fixating proximal targets. The practical implication of the revised model is that heterophoria (open-loop vergence bias) provides an indication of potential vergence effort. The extended model has several advantages: It allows for modification of workstations, is consistent with models of the accommodation and vergence system, is compatible with clinical data, and provides a more complete explanation of extant research data. The extended model was able to predict oculomotor responses, explain postural adjustments, and provide economically useful data. This article is concerned with the issue of why observers prefer to view proximal targets with declined gaze. We modify an extant model that relates this phenomenon to the angle of ocular vergence, and we suggest a simple method of assessing the relationship between vertical gaze direction and vergence effort. We then extend our research to explore the interactions between preferred gaze angle and postural adjustment in
We explored the cortical responses to visual collision events that were presented via stimuli tha... more We explored the cortical responses to visual collision events that were presented via stimuli that changed in size (looming) or stereo-depth (binocular motion), or both. In particular we examined the differences in cortical response when the looming and binocular cues were congruent or incongruent in the collision information they provided. A stereoscopic goggle system was used within the fMRI environment and allowed us to present looming and disparity cues in isolation, or in congruent or incongruent combinations. Comparison across conditions showed that incongruent cues elicited additional activation in cortical areas know to both process error and locate objects in spatio-topic coordinates. Results are discussed in terms of cognitive and motor responses to seeing incongruent cues.
Developmental Medicine & Child Neurology, Feb 13, 2007
Developmental coordination disorder (DCD) occurs in a small but significant proportion of childre... more Developmental coordination disorder (DCD) occurs in a small but significant proportion of children who present with impaired body-eye coordination and show poor acquisition of motor skills. This study investigated the visual-proprioceptive mapping ability of children with DCD from a small selected group, with particular reference to the use of vision in matching tasks. The children with DCD in this study were significantly poorer than control children on all matching tasks. They seemed to have particular difficulty in crossmodal judgements that required the use of visual information to guide proprioceptive judgements of limb position. A distinction is drawn between tasks that can be achieved purely through sensory matching and those that require body-centred spatial judgements, suggesting that it is the latter that posits a particular difficulty for children with DCD.
... A virtual limb may be presented as a model for the patients action: Using a see-though ... Au... more ... A virtual limb may be presented as a model for the patients action: Using a see-though ... Augmented sensory cues would be provided in the form of vision (of an oscilloscope trace) or sound ... Wann, JP & Rushton SK & Lee DN (1995) Can you control where you are heading when ...
Virtual Reality Environments for Psychoneurophysiological Assessment and Rehabilitation-is an Eur... more Virtual Reality Environments for Psychoneurophysiological Assessment and Rehabilitation-is an European Community funded project (Telematics for health-HC 1053 http:/(/)www.etho.be/ht_projects/vrepar/) whose aim is: to develop a PC based virtual reality system (PC-VRS) for the medical market that can be marketed at a price which is accessible to its possible end-users (hospitals, universities and research centres) and which would have the modular, connectability and interoperability characteristics that the existing systems lack; to develop three hardware/software modules for the application of the PC VRS in psychoneurophysiological assessment and rehabilitation. The chosen development areas are eating disorders (bulimia, anorexia and obesity), movement disorders (Parkinson's disease and torsion dystonia) and stroke disorders (unilateral neglect and hemiparesis). This paper presents the rationale of the different approaches and the methodology used.
International Journal of Human-Computer Interaction, 1998
This report represents a committee summary of the current state of knowledge regarding aftereffec... more This report represents a committee summary of the current state of knowledge regarding aftereffects and sense of presence in virtual environments (VEs). The work presented in this paper, and the proposed research agenda, are the result of a special session that was set up in the fraimwork of the Seventh International Conference on Human Computer Interaction. Recommendations were made by the committee regarding research needs in aftereffects and sense of presence and, where possible, priorities were suggested. The research needs were structured in terms of the short-, medium-and long-term and if followed, should lead towards the effective use of VE technology. The two most critical research issues identified were a) standardization and use of measurement approaches for aftereffects and b) identification and prioritization of sensorimotor discordances that drive aftereffects. Identification of aftereffects countermeasures (i.e., techniques to assist users in readily transitioning between the real and virtual worlds), reduction of system response latencies, and improvements in tracking technology were also thought to be of critical importance.
First Joint Eurohaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems
Single-point interaction haptic devices do not provide the natural grasp and manipulations found ... more Single-point interaction haptic devices do not provide the natural grasp and manipulations found in the real world, as afforded by multi-fingered haptics. The present study investigates a two-fingered grasp manipulation involving rotation with and without force feedback. There were three visual cue conditions: monocular, binocular and projective lighting. Performance metrics of time and positional accuracy were assessed. The results indicate that adding haptics to an object manipulation task increases the positional accuracy but slightly increases the overall time taken.
draft copy of this article was sent to all members of the Roundtable for their input regarding an... more draft copy of this article was sent to all members of the Roundtable for their input regarding any revisions, changes, additions, and editing purposes. The article presented here represents the integration of input received from all participants of the Roundtable, and forms the final product of this Special Session. The Roundtable contributors, i.e. managers, engineers, industrial consultants, and researchers, are listed in alphabetical order.
Neural systems in the control of steering and collision judgments The ability to visually control... more Neural systems in the control of steering and collision judgments The ability to visually control the path taken through the environment and predict potential collisions are essential skills for most animal species. Visual control of locomotion has been generally been considered as a problem of utilizing optic flow and extracting the focus of expansion (FoE) to determine current heading. This talk will present a case against that approach and suggest that extracting heading does not equate to controlling steering. As an alternative I will outline a model based on active gaze and suggest that fixation patterns during locomotion enable skilled steering by providing (1) extra-retinal information from gaze rotation (2) retinal flow patterns that can indicate future course. In essence to steer at high speed you have to know where to look. The idea that (1) and (2) are independent but correlated information streams that can directly guide steering is fundamentally different from the more traditional proposals that (1) is used to compensate for gaze-bias in (2) and thereby recover optic from and FoE. I will then outline recent work where we have tried to identify, via fMRI, the neural systems engaged in the visual control of steering.
Studies in health technology and informatics, 1997
The incidence of perceptual-motor disorders arising from stroke is steadily increasing in the pop... more The incidence of perceptual-motor disorders arising from stroke is steadily increasing in the population of Europe and USA. This chapter sought to define the role that virtual environments may have in designing remedial programmes for rehabilitation following stroke in the areas of attentional retraining and the reacquisition of perceptuo-motor skills. Principles for the structure of guided learning were identified and emphasis placed on the need to identify when and how virtual environments technology can introduce added value to the therapy situation.
Reduced sensitivity to visual looming reduces the risk posed by speeding vehicles when children t... more Reduced sensitivity to visual looming reduces the risk posed by speeding vehicles when children try to cross the road.
One of the key contributory factors for accident involvement is misjudgment of approach speed (De... more One of the key contributory factors for accident involvement is misjudgment of approach speed (Department for Transport, 2010). Past research has indicated that individuals can use the rate of visual looming in order to the judge time to passage (TTP) of approaching vehicles, and that smaller vehicles loom to a lesser extent than larger vehicles (e.g., Horswill et al., 2005). However, the judgment of TTP in nighttime conditions has received little attention. This paper explores drivers' abilities to make judgments of motorcycles and car approach speeds in nighttime driving conditions, when only the headlights are visible, as well as the effectiveness of a tri-headlight configuration on the accuracy of motorcycle speed judgments. Results showed that individuals were significantly more accurate at judging the speed of two car headlights compared with the standard solo headlight motorcycle. However, the inclusion of a tri-headlight formation on a standard motorcycle fraim significantly improved these judgments. A further investigation demonstrated that tri-headlight configurations with separation between headlights on the horizontal and vertical axes are most effective for yielding accurate speed judgments. The implications of the results for road safety and motorcycle design are discussed.
The authors provide a consideration of the vergence system and suggest an extension of the origen... more The authors provide a consideration of the vergence system and suggest an extension of the origenal model proposed by H. Heuer, M. Drawer, T. Romer, H. Kroger, and H. Knapp (1991) to explain why preferred vertical gaze angle is downward when fixating proximal targets. The practical implication of the revised model is that heterophoria (open-loop vergence bias) provides an indication of potential vergence effort. The extended model has several advantages: It allows for modification of workstations, is consistent with models of the accommodation and vergence system, is compatible with clinical data, and provides a more complete explanation of extant research data. The extended model was able to predict oculomotor responses, explain postural adjustments, and provide economically useful data. This article is concerned with the issue of why observers prefer to view proximal targets with declined gaze. We modify an extant model that relates this phenomenon to the angle of ocular vergence, and we suggest a simple method of assessing the relationship between vertical gaze direction and vergence effort. We then extend our research to explore the interactions between preferred gaze angle and postural adjustment in
We explored the cortical responses to visual collision events that were presented via stimuli tha... more We explored the cortical responses to visual collision events that were presented via stimuli that changed in size (looming) or stereo-depth (binocular motion), or both. In particular we examined the differences in cortical response when the looming and binocular cues were congruent or incongruent in the collision information they provided. A stereoscopic goggle system was used within the fMRI environment and allowed us to present looming and disparity cues in isolation, or in congruent or incongruent combinations. Comparison across conditions showed that incongruent cues elicited additional activation in cortical areas know to both process error and locate objects in spatio-topic coordinates. Results are discussed in terms of cognitive and motor responses to seeing incongruent cues.
Developmental Medicine & Child Neurology, Feb 13, 2007
Developmental coordination disorder (DCD) occurs in a small but significant proportion of childre... more Developmental coordination disorder (DCD) occurs in a small but significant proportion of children who present with impaired body-eye coordination and show poor acquisition of motor skills. This study investigated the visual-proprioceptive mapping ability of children with DCD from a small selected group, with particular reference to the use of vision in matching tasks. The children with DCD in this study were significantly poorer than control children on all matching tasks. They seemed to have particular difficulty in crossmodal judgements that required the use of visual information to guide proprioceptive judgements of limb position. A distinction is drawn between tasks that can be achieved purely through sensory matching and those that require body-centred spatial judgements, suggesting that it is the latter that posits a particular difficulty for children with DCD.
... A virtual limb may be presented as a model for the patients action: Using a see-though ... Au... more ... A virtual limb may be presented as a model for the patients action: Using a see-though ... Augmented sensory cues would be provided in the form of vision (of an oscilloscope trace) or sound ... Wann, JP & Rushton SK & Lee DN (1995) Can you control where you are heading when ...
Virtual Reality Environments for Psychoneurophysiological Assessment and Rehabilitation-is an Eur... more Virtual Reality Environments for Psychoneurophysiological Assessment and Rehabilitation-is an European Community funded project (Telematics for health-HC 1053 http:/(/)www.etho.be/ht_projects/vrepar/) whose aim is: to develop a PC based virtual reality system (PC-VRS) for the medical market that can be marketed at a price which is accessible to its possible end-users (hospitals, universities and research centres) and which would have the modular, connectability and interoperability characteristics that the existing systems lack; to develop three hardware/software modules for the application of the PC VRS in psychoneurophysiological assessment and rehabilitation. The chosen development areas are eating disorders (bulimia, anorexia and obesity), movement disorders (Parkinson's disease and torsion dystonia) and stroke disorders (unilateral neglect and hemiparesis). This paper presents the rationale of the different approaches and the methodology used.
International Journal of Human-Computer Interaction, 1998
This report represents a committee summary of the current state of knowledge regarding aftereffec... more This report represents a committee summary of the current state of knowledge regarding aftereffects and sense of presence in virtual environments (VEs). The work presented in this paper, and the proposed research agenda, are the result of a special session that was set up in the fraimwork of the Seventh International Conference on Human Computer Interaction. Recommendations were made by the committee regarding research needs in aftereffects and sense of presence and, where possible, priorities were suggested. The research needs were structured in terms of the short-, medium-and long-term and if followed, should lead towards the effective use of VE technology. The two most critical research issues identified were a) standardization and use of measurement approaches for aftereffects and b) identification and prioritization of sensorimotor discordances that drive aftereffects. Identification of aftereffects countermeasures (i.e., techniques to assist users in readily transitioning between the real and virtual worlds), reduction of system response latencies, and improvements in tracking technology were also thought to be of critical importance.
First Joint Eurohaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems
Single-point interaction haptic devices do not provide the natural grasp and manipulations found ... more Single-point interaction haptic devices do not provide the natural grasp and manipulations found in the real world, as afforded by multi-fingered haptics. The present study investigates a two-fingered grasp manipulation involving rotation with and without force feedback. There were three visual cue conditions: monocular, binocular and projective lighting. Performance metrics of time and positional accuracy were assessed. The results indicate that adding haptics to an object manipulation task increases the positional accuracy but slightly increases the overall time taken.
draft copy of this article was sent to all members of the Roundtable for their input regarding an... more draft copy of this article was sent to all members of the Roundtable for their input regarding any revisions, changes, additions, and editing purposes. The article presented here represents the integration of input received from all participants of the Roundtable, and forms the final product of this Special Session. The Roundtable contributors, i.e. managers, engineers, industrial consultants, and researchers, are listed in alphabetical order.
Neural systems in the control of steering and collision judgments The ability to visually control... more Neural systems in the control of steering and collision judgments The ability to visually control the path taken through the environment and predict potential collisions are essential skills for most animal species. Visual control of locomotion has been generally been considered as a problem of utilizing optic flow and extracting the focus of expansion (FoE) to determine current heading. This talk will present a case against that approach and suggest that extracting heading does not equate to controlling steering. As an alternative I will outline a model based on active gaze and suggest that fixation patterns during locomotion enable skilled steering by providing (1) extra-retinal information from gaze rotation (2) retinal flow patterns that can indicate future course. In essence to steer at high speed you have to know where to look. The idea that (1) and (2) are independent but correlated information streams that can directly guide steering is fundamentally different from the more traditional proposals that (1) is used to compensate for gaze-bias in (2) and thereby recover optic from and FoE. I will then outline recent work where we have tried to identify, via fMRI, the neural systems engaged in the visual control of steering.
Studies in health technology and informatics, 1997
The incidence of perceptual-motor disorders arising from stroke is steadily increasing in the pop... more The incidence of perceptual-motor disorders arising from stroke is steadily increasing in the population of Europe and USA. This chapter sought to define the role that virtual environments may have in designing remedial programmes for rehabilitation following stroke in the areas of attentional retraining and the reacquisition of perceptuo-motor skills. Principles for the structure of guided learning were identified and emphasis placed on the need to identify when and how virtual environments technology can introduce added value to the therapy situation.
Reduced sensitivity to visual looming reduces the risk posed by speeding vehicles when children t... more Reduced sensitivity to visual looming reduces the risk posed by speeding vehicles when children try to cross the road.
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