Adding thermal information to multisensory input in simulated environments
- Authors: Van Doorn, George , Richardson, Barry , Symmons, Mark , Wells, Jonathan
- Date: 2009
- Type: Text , Journal article
- Relation: International Journal of Intelligent Defence Support Systems Vol. 2, no. 4 (2009 2009), p. 350-362
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- Description: Although simulated environments are improved by adding sensory information, temperature is one input that has rarely featured in them. Here we report findings from experiments that examine the efficacy of adding temperature information to the multimodal complex known to be of benefit in simulations. In the first experiment, Peltier tiles added thermal information to the kinesthetic feedback given by a hand-worn exoskeletal device and this increased ratings for 'presence' during interactions with simulated objects. In an experiment in which exploratory movements across surfaces of differing temperatures were either active or passive-guided, the degree of 'coldness' felt at the fingertip was reported as less intense when movement was active, suggesting that intentionality of movement plays a role in the attenuation of the thermal stimulus. Other work reported here suggests that the perception of temperature is not influenced by a simultaneously presented colour. For example, the perception of coldness is not enhanced when it is processed in conjunction with a blue colour. We discuss the potential value of thermal information within the context of the hypothesis that presence in simulated environments is enhanced by multisensory inputs that include redundant information.
Fitting a bionic eye to the body: how haptics can help
- Authors: Van Doorn, George , Richardson, Barry , Wuillemin, Dianne
- Date: 2013
- Type: Text , Journal article
- Relation: International Journal of Autonomous and Adaptive Communications Systems Vol. 6, no. 4 (2013), p. 377-390
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- Description: The function of any visual prosthetic will be to generate patterned stimulation of the visual cortex arising from either direct stimulation (e.g. using cortical implants) or more peripheral inputs (e.g. an artificial retina). Direct cortical stimulation may result in patterns containing relatively few elements (say 10-100) while an artificial retina may deliver more complex patterns. We propose that regardless of the site of intervention, a tactile copy of the input, delivered to the skin at the same time as it is sent to the visual cortex, will offer significant advantages, especially during early stages of testing and development in which the user must 'make sense' of the novel input. The advantages of such a display include: (1) exploitation of multisensory processes such as cross-calibration, learning to discriminate sub-threshold stimuli and perceptual redundancy, (2) a means of measuring strengths and weaknesses of the prosthetic's visual input and evaluation of improvements and (3) a way of quickly adapting the congenitally- or late-blind user to the prosthetic.
Haptics can "lend a hand" to a bionic eye
- Authors: Richardson, Barry , Van Doorn, George
- Date: 2010
- Type: Text , Conference paper
- Relation: Haptics: Generating and Perceiving Tangible Sensations p. 320-325
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- Description: Here we argue that haptics (touch and kinaesthesis) can play a key role in the development of a bionic eye. Tactile displays can supplement and complement the incomplete information that a visual prosthetic will offer the brain in early stages of the prosthetic’s development. Kinaesthetic inputs give the brain feedback about motor activities that correlate with both visual and tactile inputs, and are critical for perceptual competency. Haptic inputs can also help “teach” the new visual sense to respond to stimuli that are initially indiscriminable and enable cross-calibration of inputs to strengthen multimodal cortical connections. By using haptics to supplement and complement inputs from a visual prosthetic, a bionic eye can develop more quickly than did the Bionic Ear.
The importance of temperature information in virtual training environments
- Authors: Van Doorn, George , Symmons, Mark , Richardson, Barry
- Date: 2009
- Type: Text , Conference paper
- Relation: SimTect 2009 Conference Proceedings p. 393-397
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- Description: Thermal input is an important, but often unacknowledged, source of information in our interactions with the environment. Besides the extremes that alert us to discomfort and danger, even a small change in temperature adds to the richness of the haptic experience. Temperature assists us in establishing that we have made contact with a surface and it helps to determine what that surface might be. It is not yet clear how important or redundant that temperature information is, a question of particular importance to builders of virtual reality interfaces and environments. Indeed, it is possible that as an under-exploited channel, temperature could be used to code for other information not easily conveyed with current technologies. For example, temperature conveyed by Peltier tiles may intuitively code for hardness - and therefore material type - in simulations or teleremote applications. Temperature may also enhance the learning experience by increasing presence or immersion. The findings from several experiments are brought together to discuss the efficacy of adding temperature feedback to simulation applications. In the first, Peltier tiles are added to an exoskeleton device designed to provide kinaesthetic feedback when interacting in a virtual environment. The effects are explored in terms of useability and the potential to increase presence or realism of virtual objects. We also describe an experiment in which movement was either active or passive-guided. In the active condition the degree of "coldness" felt at the fingertip was reported as less intense than when movement was passive. It appears that intentionality of movement played some role in the attenuation of the stimulus. Other work suggests that the perception of temperature is not influenced by a simultaneously present colour. For example, perceiving cold is not enhanced when it is processed in conjunction with a blue colour. This article will review the relevant literature and, in conjunction with the data we have collected, establish whether introducing temperature to virtual training environments is advisable.
A precision-of-information explanation of sensory dominance
- Authors: Van Doorn, George , Symmons, Mark , Richardson, Barry
- Date: 2011
- Type: Text , Journal article
- Relation: Vol. , no. (2011), p.
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Cutaneous inputs yield judgments of line length that are equal to, or better than, those based on kinesthetic inputs
- Authors: Van Doorn, George , Richardson, Barry , Symmons, Mark , Howell, Jacqui
- Date: 2012
- Type: Text , Conference paper
- Relation: Haptics: Perception, Devices, Mobility, and Communication: International Confernce, EuroHaptics 2012 p. 25-30
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Touch can be as accurate as passively-guided kinaesthesis in length perception
- Authors: Van Doorn, George , Richardson, Barry , Symmons, Mark
- Date: 2013
- Type: Text , Journal article
- Relation: Multisensory Research Vol. 26, no. 5 (2013 2013), p. 417-428
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- Description: Two experiments were designed to investigate the contribution of touch and kinaesthesis to haptic perception of the length of raised lines. Experiment 1 showed that judgements based on kinaesthetic information were not more accurate than those based on cutaneous information. Instead, kinaesthetic and cutaneous inputs appear to be weighted almost equally in the haptic percept, with haptic performance more closely approximated by cutaneous performance than by kinaesthetic. In Experiment 2 it was shown that effects attributed to condition (modality) were not due to the speed with which the stimulus or exploring finger moved. Our results challenge the view that kinaesthesis is more important than touch for identification of raised line drawings.
Cognitive load can explain differences in active and passive touch
- Authors: Van Doorn, George , Dubaj, Vladimir , Wuillemin, Dianne , Richardson, Barry , Symmons, Mark
- Date: 2012
- Type: Text , Conference paper
- Relation: International Conference on Haptics: Perception, Devices, Mobility, and Communication, EuroHaptics 2012 p. 91-102
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- Description: Active touch is often described as yielding “better-quality” information than passive touch. However, some authors have argued that passive-guided movements generate superior percepts due to a reduction in demands on the haptic sensory system. We consider the possibility that passive-guided conditions, as used in most active-passive comparisons, are relatively free from cognitive decision-making, while active conditions involve cognitive loads that are quite high and uncharacteristic of normal sensory processes. Thus studies that purport to show differences in active and passive touch may instead be revealing differences in the amount of cognition involved in active and passive tasks. We hypothesized that passive-guided conditions reduce not the sensory load but the cognitive load that active explorers must bear. To test this hypothesis Blood Oxygen Level Dependent (BOLD) activity was measured using functional Magnetic Resonance Imaging (fMRI) during active and passive-guided fingertip exploration of 2D raised line drawings. Active movements resulted in greater activation (compared with passive movements) in areas implicated in higher order processes such as monitoring and controlling of goal-directed behavior, attention, execution of movements, and error detection. Passive movements, in contrast, produced greater BOLD activity in areas associated with touch perception, length discrimination, tactile object recognition, and efference copy. The activation of a greater number of higher-order processing areas during active relative to passive-guided exploration suggests that instances of passive-guided superiority may not be due to the haptic system’s limited ability to cope with sensory inputs, but rather the restriction imposed by the use of a single finger such that active exploration may require cognitive strategies not demanded in the passive condition. Our findings suggest that previous attempts to compare active and passive touch have, in order to simplify tasks, inadvertently introduced cognitive load at the expense of normal sensory inputs.
Visual and haptic influence on perception of stimulus size
- Authors: Van Doorn, George , Richardson, Barry , Wuillemin, Dianne , Symmons, Mark
- Date: 2010
- Type: Text , Journal article
- Relation: Attention, Perception & Psychophysics Vol. 72, no. 3 (2010), p. 813-822
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- Description: In six experiments, subjects judged the sizes of squares that were presented visually and/or haptically, in unimodal or bimodal conditions. We were interested in which mode most affected size judgments in the bimodal condition when the squares presented to each mode actually differed in size. Three factors varied: whether haptic exploration was passive or active, whether the choice set from which the subjects selected their responses was visual or haptic, and whether cutaneous information was provided in addition to kinesthetic information. To match the task for each mode, visual presentations consisted of a cursor that moved along a square pathway to correspond to the haptic experience of successive segments revealed during exploration. We found that the visual influence on size judgments was greater than the influence of haptics when the haptic experience involved only kinesthesis, passive movement, and a visual choice set. However, when cutaneous input was added to kinesthetic information, size judgments were most influenced by the haptic mode. The results support hypotheses of sensory integration, rather than capture of one sense by the other.