Richard Wilkie
University of Leeds, Institute of Psychological Sciences, Faculty Member
In order to carry out skilled, visually guided actions, humans need to be able to use feedback to monitor and adjust performance. Such feedback can be relatively low level, with some motor commands being recalibrated rapidly based on... more
In order to carry out skilled, visually guided actions, humans need to be able to use feedback to monitor and adjust performance. Such feedback can be relatively low level, with some motor commands being recalibrated rapidly based on visual feedback with little cognitive awareness (eg, Mon-Williams and Murray 2000). In tasks such as driving, however, awareness of performance could be important for making strategic adjustments in order to respond to road conditions. To investigate whether participants could accurately gauge ...
Laparoscopic surgery has revolutionised medicine but requires surgeons to learn new visual-motor mappings. The optimal method for training surgeons is unknown. For instance, it may be easier to learn planar movements when training is... more
Laparoscopic surgery has revolutionised medicine but requires surgeons to learn new visual-motor mappings. The optimal method for training surgeons is unknown. For instance, it may be easier to learn planar movements when training is constrained to a plane, since this forces the surgeon to develop an appropriate perceptual-motor map. In contrast, allowing the surgeon to move without constraints could improve performance because this provides greater experience of the control dynamics of the device. In order to test between ...
Research Interests:
Driving around bends at high speeds is a task performed by many on a daily basis but the underlying mechanisms of steering control remain largely unknown. Previous research has shown that when steering, gaze direction can be a critical... more
Driving around bends at high speeds is a task performed by many on a daily basis but the underlying mechanisms of steering control remain largely unknown. Previous research has shown that when steering, gaze direction can be a critical component of success. However, with increased use of in-vehicle information systems (IVIS), there is growing competition over the same resources that are needed to steer (gaze as well as associated attentional resources). Although it can be argued that locomotor steering is an automatic task that can be performed without recourse to conscious 'cognitive' control, much simpler locomotor-related tasks, such as judging one's heading, have been shown to be affected by concurrent attentional tasks (Wann, Swapp, & Rushton, 2000). Here we examined whether an attentional task placed at an offset fixation point influenced concurrent steering performance along a computer simulated road. The experiments either used gaze-fixation points that had similar properties to real-world road signs (i.e. moved relative to the vehicle) or were more akin to IVIS (i.e. fixed to the vehicle). Results showed that gaze fixation eccentric to future path caused systematic steering biases. The degree or type of cognitive load did not change the degree of steering bias, but there was some evidence of decreased lane variability when viewing the IVIS-type displays. No differences in steering performance were found between the different types of cognitive task. We conclude that where you look is critical for safe driving, and IVIS-type displays might make drivers more susceptible to cognitive interference.
Research Interests:
Retinal flow, the pattern of motion caused by self-motion through a textured world, is used to control steering. Our previous work has shown that flow asymmetries influence humans steering along demarcated paths, with different textures... more
Retinal flow, the pattern of motion caused by self-motion through a textured world, is used to control steering. Our previous work has shown that flow asymmetries influence humans steering along demarcated paths, with different textures on either side of the path causing biases consistent with participants reducing flow asymmetries (Kountouriotis et al., 2013). To test whether asymmetries in speed also bias locomotor control, participants were asked to steer a series of curved trajectories in a virtual reality simulated environment. Regions of the ground plane either side of a visible bounded path were rotated at different speeds to create flow asymmetries. The manipulation varied (i) Asymmetry Direction: whether the ground to the inside of the bend moved slower or faster than the outside of the bend, (ii) Asymmetry Size: whether the difference in speeds of the two regions was a small gap or a large gap, and (iii) Global Flow Speed: whether the average speed across both regions was ...
Research Interests:
Transcranial direct current stimulation (tDCS) of the primary motor cortex is a possible therapy to enhance motor rehabilitation after stroke. The aim of this study is to determine any potential autonomic effects of the tDCS electrode... more
Transcranial direct current stimulation (tDCS) of the primary motor cortex is a possible therapy to enhance motor rehabilitation after stroke. The aim of this study is to determine any potential autonomic effects of the tDCS electrode montage conventionally used in stroke therapy. The study was approved by the University of Leeds Ethics Committee and conducted in accordance with the Declaration of Helsinki. tDCS was applied over the primary motor cortex at 1mA with a reference electrode placed on the contralateral supraorbital region in 16 healthy subjects (20–48 years; 7 female, 9 male). Subjects visited the department twice and received active or sham tDCS for 10 minutes. Active tDCS was anodal (n=8) or cathodal (n=8). Heart rate (HR), blood pressure (BP) and respiration were recorded at baseline, during tDCS and recovery. ECG data underwent power spectral analysis to calculate heart rate variability (HRV). HRV did not change significantly (p>0.05) however there was a 32% incre...
Some studies have shown that manual asymmetries decrease in older age. These results have often been explained with reference to models of reduced hemispheric specialisation. An alternative explanation, however, is that hand differences... more
Some studies have shown that manual asymmetries decrease in older age. These results have often been explained with reference to models of reduced hemispheric specialisation. An alternative explanation, however, is that hand differences are subtle, and capturing them requires tasks that yield optimal performance with both hands. Whereas the hemispheric specialisation account implies that reduced manual asymmetries should be reliably observed in older adults, the ‘measurement difficulty’ account suggests that manual asymmetries will be hard to detect unless a task has just the right level of difficulty—i.e. within the ‘Goldilocks Zone’, where it is not too easy or too hard, but just right. Experiment One tested this hypothesis and found that manual asymmetries were only detected when participants performed in this zone; specifically, performance on a tracing task was only superior in the preferred hand when task constraints were high (i.e. fast speed tracing). Experiment Two used three different tasks to examine age differences in manual asymmetries; one task produced no asymmetries, whilst two tasks revealed asymmetries in both younger and older groups (with poorer overall performance in the old group across all tasks). Experiment Three revealed task-dependent asymmetries in both age groups, but highlighted further detection difficulties linked with the metric of performance and compensatory strategies used by participants. Results are discussed with reference to structural learning theory, whereby we suggest that the processes of inter-manual transfer lead to relatively small performance differences between the hands (despite a strong phenomenological sense of performance disparities).
Research Interests:
Introduction: Stroke often causes homonymous visual field loss, which can lead to exclusion from driving. Retention of a driving licence is sometimes possible by completing an on-road assessment, but this is not practical for all. It is... more
Introduction: Stroke often causes homonymous visual field loss, which can lead to exclusion from driving. Retention of a driving licence is sometimes possible by completing an on-road assessment, but this is not practical for all. It is important to find simple tests that can inform the assessment and rehabilitation of driving-related visual-motor function. Method: We developed novel computerised assessments: visual search; simple reaction and decision reaction to appearing pedes- trians; and pedestrian detection during simulated driving. We tested 12 patients with stroke (seven left, five right field loss) and 12 controls. Results: The homonymous visual field defect group was split into adequately compensated or inadequately compensated groups based on visual search performance. The inadequately compensated group had problems with stimuli in their affected field: they tended to react more slowly than controls and in the driving task they failed to detect a number of pedestrians. In contrast, the adequately compensated group were better at detecting pedestrians, though reaction times were slightly slower than controls. Conclusion: We suggest that our search task can predict, to a limited extent, whether a person with stroke compensates for visual field loss, and may potentially identify suitability for specific rehabilitation to promote return to driving.
Research Interests:
Optic flow can be used by humans to determine their direction of heading as well as controlling steering. Dot-flow displays have been widely used to investigate these abilities but it is unclear whether photorealistic textures would... more
Optic flow can be used by humans to determine their direction of heading as well as controlling steering. Dot-flow displays have been widely used to investigate these abilities but it is unclear whether photorealistic textures would provide better information for controlling high-speed steering. Here, we examine the accuracy of heading judgements from dot-flow displays of different densities and luminance and then compare to a scene containing a textured ground. We then examine steering behaviour using these same displays to determine whether accurate heading conditions necessarily equate to successful steering. Our findings suggest that the bright dense dot-flow displays led to equivalent performance as the ground texture when judging heading, and this was also true when steering. The intermediate dot-flow conditions (with fewer and faded dots) revealed that some conditions that led to accurate heading judgements were insufficient for accurate steering. It seems, therefore, that heading perception should not be considered synonymous with successful steering control, and displays that support one ability will not necessarily support the other.
Research Interests:
The neural systems responsible for postural control are separate from the neural substrates that underpin control of the hand. Nonetheless, postural control and eye-hand coordination are linked functionally. For example, a stable platform... more
The neural systems responsible for postural control are separate from the neural substrates that underpin control of the hand. Nonetheless, postural control and eye-hand coordination are linked functionally. For example, a stable platform is required for precise manual control tasks (e.g. handwriting) and thus such skills often cannot develop until the child is able to sit or stand upright. This raises the question of the strength of the empirical relationship between measures of postural stability and manual motor control. We recorded objective computerised measures of postural stability in stance and manual control in sitting in a sample of school children (n = 278) aged 3-11 years in order to explore the extent to which measures of manual skill could be predicted by measures of postural stability. A strong correlation was found across the whole sample between separate measures of postural stability and manual control taken on different days. Following correction for age, a signif...
Research Interests:
Research Interests:
Abstract Visual information plays an important role in maintaining posture. The role of vision changes over the lifespan with children relying more on haptic information as they mature (Wann et al., 1998). The role of vision in the... more
Abstract Visual information plays an important role in maintaining posture. The role of vision changes over the lifespan with children relying more on haptic information as they mature (Wann et al., 1998). The role of vision in the maintenance of posture is not well understood in older populations but it is possible that neuromuscular degeneration increases the reliance upon vision. Our poor understanding is particularly worrying because falls have been reported as the primary cause of premature death in older persons (Sattin, 1992). ...
Research Interests:
Abstract Skilled movements deteriorate with increased age for well-documented physiological reasons. Reduced sensory sensitivity and biomechanical attenuation can interfere with motor function making older adults more variable in their... more
Abstract Skilled movements deteriorate with increased age for well-documented physiological reasons. Reduced sensory sensitivity and biomechanical attenuation can interfere with motor function making older adults more variable in their responses. We examined the degree to which older adults manage to compensate for this increase in visual-motor variability when carrying out two skilled actions: tracing and steering. In both cases, participants generated trajectories within the boundaries of a delineated path. When ...
Research Interests:
Abstract Steering around bends is a common task performed daily by millions of people, yet the underlying neural mechanisms remain largely uncharted. It has been proposed that steering can be performed without recourse to conscious... more
Abstract Steering around bends is a common task performed daily by millions of people, yet the underlying neural mechanisms remain largely uncharted. It has been proposed that steering can be performed without recourse to conscious “cognitive” control (Gibson, 1958), however, much simpler locomotor-related tasks, such as judging one's heading, have been shown to be affected by concurrent attentional tasks (Wann et al, 2000). Here we examine whether an attentional task placed at the point of fixation influences steering. Twelve ...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
ABSTRACT Driving a car is for many in the aging population an essential part of maintaining mobility and quality of life. Older adults are more susceptible to stroke, which can cause visual field deficits that often preclude patients from... more
ABSTRACT Driving a car is for many in the aging population an essential part of maintaining mobility and quality of life. Older adults are more susceptible to stroke, which can cause visual field deficits that often preclude patients from driving based on pre-set visual field requirements (DVLA). However, despite these visual deficits some individuals may be able to adapt (e.g. by adopting compensatory eye-movement strategies such as increased scanning of the visual scene; Coeckelbergh, Brouwer, Cornelisson et al., 2002). To examine this further we used a simulated driving scenario where participants were asked to maintain one of 3 potential starting positions along a virtual roadway and measured eye movements and steering performance. We tested 15 stroke patients with either left or right homonymous hemianopia (LHH/RHH) or left visual inattention (LVI) and 16 healthy age-matched controls. Our findings showed that the nature of visual impairment differentially affected steering behaviour. VI led to marked steering deficits across all road positions compared to controls, LHH only displayed deficits when trying to maintain a leftward starting position (and RHH performed similar to controls). When examining individual performance some patients appeared to demonstrate normal steering performance despite visual deficits. Distinct gaze pattern differences may help explain these individual differences since successful steering was associated with directing eye-movements towards the regions on the road they were required to steer through (rather than being locked in a fixed direction). We suggest that our experiment indicates that compensatory eye-movement strategies may have the potential to moderate steering deficits related to visual impairment, providing an exciting avenue for directing future rehabilitative research efforts in driving after stroke.
Research Interests:
Research Interests:
How do animals and insects use visual information to move through the world successfully? Optic flow, the pattern of motion at the eye, is a powerful source of information about self-motion. Insects and humans are sensitive to the global... more
How do animals and insects use visual information to move through the world successfully? Optic flow, the pattern of motion at the eye, is a powerful source of information about self-motion. Insects and humans are sensitive to the global pattern of optic flow and try to maintain flow symmetry when flying or walking. The environments humans encounter, however, often contain demarcated paths that constrain future trajectories (e.g., roads), and steering has been successfully modeled using only road edge information. Here we examine whether flow asymmetries from a textured ground plane influences humans steering along demarcated paths. Using a virtual reality simulator we observed that different textures on either side of the path caused predictable biases to steering trajectories, consistent with participants reducing flow asymmetries. We also generated conditions where one textured region had no flow (either the texture was removed or the textured region was static). Despite the presence of visible path information, participants were biased toward the no-flow region consistent with reducing flow asymmetries. We conclude that optic flow asymmetries can lead to biased locomotor steering even when traveling along demarcated paths.
Research Interests:
Structural learning theory suggests that experiencing motor task variation enables the central nervous system to extract general rules regarding tasks with a similar structure - rules that can subsequently be applied to novel situations.... more
Structural learning theory suggests that experiencing motor task variation enables the central nervous system to extract general rules regarding tasks with a similar structure - rules that can subsequently be applied to novel situations. Complex minimally invasive surgery (MIS) requires different port sites, but switching ports alters the limb movements required to produce the same endpoint control of the surgical instrument. The purpose of the present study was to determine if structural learning theory can be applied to MIS to inform training methods. A tablet laptop running bespoke software was placed within a laparoscopic box trainer and connected to a monitor situated at eye level. Participants (right-handed, non-surgeons, mean age = 23.2 years) used a standard laparoscopic grasper to move between locations on the screen. There were two training groups: the M group (n = 10) who trained using multiple port sites, and the S group (n = 10) who trained using a single port site. A novel port site was used as a test of generalization. Performance metrics were a composite of speed and accuracy (SACF) and normalized jerk (NJ; a measure of movement 'smoothness'). The M group showed a statistically significant performance advantage over the S group at test, as indexed by improved SACF (p < 0.05) and NJ (p < 0.05). This study has demonstrated the potential benefits of incorporating a structural learning approach within MIS training. This may have practical applications when training junior surgeons and developing surgical simulation devices.
Research Interests:
Current methods of measuring gross motor abilities in children involve either high-cost specialist apparatus that is unsuitable for use in schools, or low-cost but nonoptimal observational measures. We describe the development of a... more
Current methods of measuring gross motor abilities in children involve either high-cost specialist apparatus that is unsuitable for use in schools, or low-cost but nonoptimal observational measures. We describe the development of a low-cost system that is capable of providing high-quality objective data for the measurement of head movements and postural sway. This system is based on off-the-shelf components available for the Nintendo Wii: (1) The infrared cameras in a pair of WiiMotes are used to track head movements by resolving the position of infrared-emitting diodes in three dimensions, and (2) center-of-pressure data are captured using the WiiFit Balance board. This allows the assessment of children in school settings, and thus provides a mechanism for identifying children with neurological problems affecting posture. In order to test the utility of the system, we installed the apparatus in two schools to determine whether we could collect meaningful data on hundreds of children in a short time period. The system was successfully deployed in each school over a week, and data were collected on all of the children within the school buildings at the time of testing (N = 269). The data showed reliable effects of age and viewing condition, as predicted from previous small-scale studies that had used specialist apparatus to measure childhood posture. Thus, our system has the potential to allow screening of children for gross postural deficits in a manner that has never previously been possible. It follows that our system opens up the possibility of conducting large-scale behavioral studies concerning the development of posture.
Research Interests:
Reach-to-grasp movements change quantitatively in a lawful (i.e. predictable) manner with changes in object properties. We explored whether altering object texture would produce qualitative changes in the form of the precontact movement... more
Reach-to-grasp movements change quantitatively in a lawful (i.e. predictable) manner with changes in object properties. We explored whether altering object texture would produce qualitative changes in the form of the precontact movement patterns. Twelve participants reached to lift objects from a tabletop. Nine objects were produced, each with one of three grip surface textures (high-friction, medium-friction and low-friction) and one of three widths (50 mm, 70 mm and 90 mm). Each object was placed at three distances (100 mm, 300 mm and 500 mm), representing a total of 27 trial conditions. We observed two distinct movement patterns across all trials—participants either: (i) brought their arm to a stop, secured the object and lifted it from the tabletop; or (ii) grasped the object ‘on-the-fly’, so it was secured in the hand while the arm was moving. A majority of grasps were on-the-fly when the texture was high-friction and none when the object was low-friction, with medium-friction producing an intermediate proportion. Previous research has shown that the probability of on-the-fly behaviour is a function of grasp surface accuracy constraints. A finger friction rig was used to calculate the coefficients of friction for the objects and these calculations showed that the area available for a stable grasp (the ‘functional grasp surface size’) increased with surface friction coefficient. Thus, knowledge of functional grasp surface size is required to predict the probability of observing a given qualitative form of grasping in human prehensile behaviour.
Research Interests:
Visual control of locomotion typically involves both detection of current egomotion as well as anticipation of impending changes in trajectory. To determine if there are distinct neural systems involved in these aspects of steering... more
Visual control of locomotion typically involves both detection of current egomotion as well as anticipation of impending changes in trajectory. To determine if there are distinct neural systems involved in these aspects of steering control we used a slalom paradigm, which required participants to steer around objects in a computer simulated environment using a joystick. In some trials the whole slalom layout was visible (steering “preview” trials) so planning of the trajectory around future waypoints was possible, whereas in other trials the slalom course was only revealed one object at a time (steering “near” trials) so that future planning was restricted. In order to control for any differences in the motor requirements and visual properties between “preview” and “near” trials, we also interleaved control trials which replayed a participants' previous steering trials, with the task being to mimic the observed steering. Behavioral and fMRI results confirmed previous findings of superior parietal lobe (SPL) recruitment during steering trials, with a more extensive parietal and sensorimotor network during steering “preview” compared to steering “near” trials. Correlational analysis of fMRI data with respect to individual behavioral performance revealed that there was increased activation in the SPL in participants who exhibited smoother steering performance. These findings indicate that there is a role for the SPL in encoding path defining targets or obstacles during forward locomotion, which also provides a potential neural underpinning to explain improved steering performance on an individual basis.
Research Interests:
Research Interests:
To investigate the implementation of a web-based survey for involving children in the design of assistive technology devices within the primary school environment. Children were recruited within their normal school environment. They... more
To investigate the implementation of a web-based survey for involving children in the design of assistive technology devices within the primary school environment. Children were recruited within their normal school environment. They completed tasks within the survey that sought to gather their personal preferences about assistive technology devices. From six primary schools, 257 children (mean age = 9 years and 8 months, SD = 1.51; 123 males, 134 females) including children with cerebral palsy (N = 11), varying levels of deafness (N = 7), global developmental delay (N = 2) and Down's syndrome (N = 1) participated. Observations were taken whilst the children completed the survey tasks. All children were able to complete the tasks from the survey, although children with disabilities had higher completion times and most required a form of assistance from support assistants and/or sign language interpreters. The use of the web-based survey provided a novel means with which to involve children with and without disabilities in the design of assistive technology devices within a primary school environment. In order for the survey to be utilised more widely, issues that arose when involving children with disabilities need to be addressed.
Research Interests:
Learning to write requires the repeated manual production of spatial patterns. It remains unclear whether tracing or copying provides better training: tracing provides accurate and immediate performance feedback, whereas copying may... more
Learning to write requires the repeated manual production of spatial patterns. It remains unclear whether tracing or copying provides better training: tracing provides accurate and immediate performance feedback, whereas copying may require greater use of memory and recall during training. We asked sixteen adults to copy or trace novel patterns then reproduce these from memory using a stylus and tablet PC. A week later, a retention test was performed. Sophisticated analyses indexed the extent to which participants had learned the dimensions and shape of patterns. We found that participants: (a) showed better shape and dimensional accuracy when tracing; (b) had better shape and dimensional retention immediately after tracing; (c) showed no differences between copying and tracing in their ability to redraw the pattern (shape or dimensions) 1 week later. Our methods provide a useful starting point for examining training and feedback on the generation and recall of spatial patterns.
Research Interests:
Old age is associated with poorer movement skill as indexed by reduced speed and accuracy. Nevertheless, reductions in speed and accuracy can also reflect compensation as well as deficit. We used a manual tracing and a driving task to... more
Old age is associated with poorer movement skill as indexed by reduced speed and accuracy. Nevertheless, reductions in speed and accuracy can also reflect compensation as well as deficit. We used a manual tracing and a driving task to identify generalised spatial and temporal compensations and deficits associated with old age. In Experiment 1 participants used a hand-held stylus to trace a path. In Experiment 2 participants steered along paths in a virtual reality driving simulator. In both experiments, participants were required to stay within the boundaries whilst we manipulated task difficulty by changing path width or movement speed. The older group showed worse performance in the highly constrained conditions. Corner-cutting effectively reduces the curvature of bends but yields a greater risk of error (i.e. clipping the path/road-edge). Corner-cutting is thus less risky on wider paths and we found that corner-cutting increased for both age-groups in both tasks when paths were wider. Crucially, we observed a greater degree of corner-cutting in the young group compared to the old, suggesting the old group compensated for decreased motor skill with ‘middle-of-the-road’ behaviour. Enforcing increased speed caused all participants to increase corner-cutting. Thus, older participants showed spatial compensation for decreased skill by biasing their position towards the middle of the path in both a manual and steering task. External constraints (narrow paths and fast speeds) prevented this strategy and revealed age-related declines in skills central to manual control and driving.
Research Interests:
Robust control of skilled actions requires the flexible combination of multiple sources of information. Here we examined the role of gaze during high-speed locomotor steering and in particular the role of feedback from the visible road... more
Robust control of skilled actions requires the flexible combination of multiple sources of information. Here we examined the role of gaze during high-speed locomotor steering and in particular the role of feedback from the visible road edges. Participants were required to maintain one of three lateral positions on the road when one or both edges were degraded (either by fading or removing them). Steering became increasingly impaired as road edge information was degraded, with gaze being predominantly directed towards the required road position. When either of the road edges were removed, we observed systematic shifts in steering and gaze direction dependent upon both the required road position and the visible edge. A second experiment required fixation on the road center or beyond the road edges. The results showed that the direction of gaze led to predictable steering biases, which increased as road edge information became degraded. A new steering model demonstrates that the direction of gaze and both road edges influence steering in a manner consistent with the flexible weighted combination of near road feedback information and prospective gaze information.
Looking at the inside edge of the road when steering a bend seems to be a well-established strategy linked to using a feature called the tangent point. An alternative proposal suggests that the gaze patterns observed when steering result... more
Looking at the inside edge of the road when steering a bend seems to be a well-established strategy linked to using a feature called the tangent point. An alternative proposal suggests that the gaze patterns observed when steering result from looking at the points in the world through which one wishes to pass. In this explanation fixation on or near the tangent point results from trying to take a trajectory that cuts the corner. To test these accounts, we recorded gaze and steering when taking different paths along curved roadways. Participants could gauge and maintain their lateral distance, but crucially, gaze was predominantly directed to the region proximal to the desired path rather than toward the tangent point per se. These results show that successful control of high-speed locomotion requires fixations in the direction you want to steer rather than using a single road feature like the tangent point.
Research Interests:
Eye-movements have long been considered a problem when trying to understand the visual control of locomotion. They transform the retinal image from a simple expanding pattern of moving texture elements (pure optic flow), into a complex... more
Eye-movements have long been considered a problem when trying to understand the visual control of locomotion. They transform the retinal image from a simple expanding pattern of moving texture elements (pure optic flow), into a complex combination of translation and rotation components (retinal flow). In this article we investigate whether there are measurable advantages to having an active free gaze, over a static gaze or tracking gaze, when steering along a winding path. We also examine patterns of free gaze behavior to determine preferred gaze strategies during active locomotion. Participants were asked to steer along a computer-simulated textured roadway with free gaze, fixed gaze, or gaze tracking the center of the roadway. Deviation of position from the center of the road was recorded along with their point of gaze. It was found that visually tracking the middle of the road produced smaller steering errors than for fixed gaze. Participants performed best at the steering task when allowed to sample naturally from the road ahead with free gaze. There was some variation in the gaze strategies used, but sampling was predominantly of areas proximal to the center of the road. These results diverge from traditional models of flow analysis.
Research Interests:
M. F. Land and D. N. Lee (1994) suggested that steering around a bend is controlled through the estimation of curvature using the visual direction of a single road feature: the tangent point. The aim of this study was to evaluate, using a... more
M. F. Land and D. N. Lee (1994) suggested that steering around a bend is controlled through the estimation of curvature using the visual direction of a single road feature: the tangent point. The aim of this study was to evaluate, using a simulated environment, whether the high levels of tangent point fixation reported by some researchers are indeed related to steering control. In the first experiment, gaze patterns were examined when steering along roadways of varying widths and curvatures. Experiment 2 investigated the effects of enforced fixation on steering, when gaze was directed to the road ahead at a range of lateral eccentricities, including the tangent point. All participants completed both experiments. Overall, there was no evidence for extensive tangent point fixation in the free-gaze experiment and enforced tangent point fixation did not result in more accurate steering. The present results seem to suggest that participants tend to steer in the direction of their gaze; hence, looking at the tangent point causes the driver to steer toward it. These results provide some support for the R. M. Wilkie and J. P. Wann (2002) model of steering, which proposes that drivers will direct their gaze toward points they wish to pass through.
Research Interests:
Research Interests: Psychology, Cognitive Science, Perception, Cognition, Locomotion, and 21 moreMotion perception, Optical Flow, Vision, Humans, Judgment, Computer Simulation, Walking, Movement, Orientation, Retina, Trajectory Planning, Mental processes, Eye Movements, Flow Visualization, Computer User Interface Design, Spatial Behavior, Head Movements, Visual Fields, Psychological Models, Automobile driving, and Psychomotor Performance
Research Interests: Psychology, Cognitive Science, Psychophysics, Experimental Psychology, Perception, and 19 moreCognition, Visual perception, Body, Motor Control, Locomotion, Vestibular System, Optical Flow, Vision, Humans, Computer Simulation, Optic Flow, Orientation, Retina, Motion, Steering, Rotation, Visual stimuli, Psychomotor Skills Education, and Psychomotor Performance
Visual control of locomotion is essential for most mammals and requires coordination between perceptual processes and action systems. Previous research on the neural systems engaged by self-motion has focused on heading perception, which... more
Visual control of locomotion is essential for most mammals and requires coordination between perceptual processes and action systems. Previous research on the neural systems engaged by self-motion has focused on heading perception, which is only one perceptual subcomponent. For effective steering, it is necessary to perceive an appropriate future path and then bring about the required change to heading. Using function magnetic resonance imaging in humans, we reveal a role for the parietal eye fields (PEFs) in directing spatially selective processes relating to future path information. A parietal area close to PEFs appears to be specialized for processing the future path information itself. Furthermore, a separate parietal area responds to visual position error signals, which occur when steering adjustments are imprecise. A network of three areas, the cerebellum, the supplementary eye fields, and dorsal premotor cortex, was found to be involved in generating appropriate motor responses for steering adjustments. This may reflect the demands of integrating visual inputs with the output response for the control device.
Research Interests:
Research Interests: Psychology, Cognitive Science, Experimental Psychology, Optics, Visual perception, and 15 moreAttention, Locomotion, Optical Flow, Humans, Judgment, Discrimination Learning, Orientation, Saccades, Reaction Time, Visual System, Eye Movements, Path Analysis, Motion, Computer User Interface Design, and Eye Movement
Research Interests:
Research Interests:
Research Interests: Psychology, Cognitive Science, Brain Imaging, Visual perception, Visual Neuroscience, and 20 moreMagnetic Resonance Imaging, Perception-Action, Locomotion, Brain Mapping, Humans, Cues, Optic Flow, Orientation, Female, Saccades, Male, Parietal Cortex, Posterior Parietal Cortex, Distance Perception, Young Adult, Experimental, Adult, Parietal Lobe, Oxygen Consumption, and Psychomotor Performance
Research Interests:
Research Interests:
Research Interests:
Abstract A key component of controlling our locomotion through the world is optic flow. We have previously demonstrated that even when flow is highly degraded it can support accurate steering (Wilkie & Wann,... more
Abstract A key component of controlling our locomotion through the world is optic flow. We have previously demonstrated that even when flow is highly degraded it can support accurate steering (Wilkie & Wann, 2002). But the coupling between perceived flow and action is less clear. In some models of locomotion perceived heading is considered as a fundamental part of control. We have promoted an alternative account whereby fixating points along your future path could be the basis of an efficient control solution. Here we ...
Research Interests:
Abstract Learning to drive successfully requires effective synchronisation of a range of visuo-motor tasks, not least the use of gaze to sample appropriately from the visual world whilst steering. In Wilkie... more
Abstract Learning to drive successfully requires effective synchronisation of a range of visuo-motor tasks, not least the use of gaze to sample appropriately from the visual world whilst steering. In Wilkie & Wann (2003) we found characteristic gaze patterns associated with accurate steering: exploring the centre of the road 1–2 seconds ahead. Here we wished to observe how novice drivers used their gaze to sample information from a simulated roadway, and whether their patterns of fixation changed after learning. The participants ...
Research Interests:
Abstract Field, Wilkie & Wann (2007) identified an area bordering, but distinct from the Parietal Eye-Fields (PEF) that was responsive to future path information during forward locomotion. We tested the function of... more
Abstract Field, Wilkie & Wann (2007) identified an area bordering, but distinct from the Parietal Eye-Fields (PEF) that was responsive to future path information during forward locomotion. We tested the function of this area using stimuli related to Land & Horwood (1995). Participants travelled on a sinusoidal trajectory at 8m/s across a textured ground plane, either forwards or backwards. In some conditions a distal roadway was presented 12m ahead, that indicated their direction of travel in 1.5 s time, but not their current ...
Research Interests: Optical Flow and Vision
Abstract Field, Wilkie & Wann (2007) contrasted brain activation produced by travelling a curving trajectory across a ground plane with an otherwise identical stimulus that also included road edges providing... more
Abstract Field, Wilkie & Wann (2007) contrasted brain activation produced by travelling a curving trajectory across a ground plane with an otherwise identical stimulus that also included road edges providing advance information about changes in trajectory curvature. The addition of advance information activated a superior parietal area bordering, but distinct from, the parietal eye fields (PEF). If the novel parietal activation is due to processing of advance trajectory information then it should be driven by the distant part of the road, but ...
Research Interests:
Abstract In the past, retinal flow (RF) was purported to contain sufficient information for determining our direction of motion during locomotion (Gibson, 1958). It has now been shown that other sources of information, both retinal and... more
Abstract In the past, retinal flow (RF) was purported to contain sufficient information for determining our direction of motion during locomotion (Gibson, 1958). It has now been shown that other sources of information, both retinal and extra-retinal (ER), can contribute useful information for heading judgement (Banks et al, 1996; Wann JP & Wilkie RM ARVO 2001). In the case of active steering, accuracy can be maintained if RF is highly salient and is combined with ER information, whereas if RF is degraded other retinal cues such as a ...
Research Interests:
Abstract Controlling direction of locomotion is fundamental to all mobile animals, and it is particularly critical for humans, whether as pedestrian or in vehicles. At ECVP 2006 Field, Wilkie & Wann presented an... more
Abstract Controlling direction of locomotion is fundamental to all mobile animals, and it is particularly critical for humans, whether as pedestrian or in vehicles. At ECVP 2006 Field, Wilkie & Wann presented an fMRI study exploring the neural correlates of human heading judgments and the equivalence to areas identified in macaques, including the ventral intraparietal area (VIP). Furthermore, we illustrated how the presence of a visible path, providing heading error information, activated bilateral regions focused on, but not ...
Research Interests:
Abstract At VSS 2001 & 2002 we presented data on the use of retinal flow & visual direction information in controlling steering (in press JEP: HPP &... more
Abstract At VSS 2001 & 2002 we presented data on the use of retinal flow & visual direction information in controlling steering (in press JEP: HPP & Current Biology), and also on gaze fixation patterns during heading and steering tasks. Here we link the two into a theory of path planning and locomotor control based on active gaze. In this scheme the performer fashions their future trajectory through a series of path fixations. The locomotor control system then acts as an attractor to the point of fixation by nulling the rotation components of retinal flow ...
Research Interests:
Abstract There has been an assumption that the perception of 'heading'when passively observing linear motion tells us something about the information we use when steering ourselves... more
Abstract There has been an assumption that the perception of 'heading'when passively observing linear motion tells us something about the information we use when steering ourselves along curved paths through the world. There are, however, two broad ways of categorising the information that can be derived from retinal flow in order to guide steering:'heading'or 'path'.'Heading'refers to the instantaneous rectilinear direction of motion of the observer, but this is constantly changing when travelling on a curved path. In ...
Research Interests:
Abstract We routinely locomote through the world successfully, even at high speeds. At VSS2001 Wilkie & Wann presented evidence supporting the contribution of Retinal Flow (RF) and Visual Direction (VD) to the... more
Abstract We routinely locomote through the world successfully, even at high speeds. At VSS2001 Wilkie & Wann presented evidence supporting the contribution of Retinal Flow (RF) and Visual Direction (VD) to the control of steering. When steering curved paths towards a target we observed that both RF and VD information could be used to perform the task successfully. It was still unclear whether there was any switching between information sources when there was a shift in their relative strengths. We investigated this in two ways:
Research Interests:
Abstract Detecting the time to collision (TTC) of an approaching object is imperative to species' survival. Cells in the pigeon nucleus rotundus have been found to respond to high rates of looming. This would hint that a... more
Abstract Detecting the time to collision (TTC) of an approaching object is imperative to species' survival. Cells in the pigeon nucleus rotundus have been found to respond to high rates of looming. This would hint that a similar function might be found in sub-cortical areas of primates, such as the thalamic nuclei and superior colliculus (SC). We examined whether an equivalent response to looming stimuli would be found in the human SC using fMRI. Within a Siemens 3T scanner we presented virtual footballs in five conditions: a fast ball, ...
Research Interests:
Abstract Control of steering is an essential component of successful high speed locomotion. Land & Lee (1994) recorded gaze behaviour during driving and observed extensive use of the tangent point of upcoming bends. In Wilkie... more
Abstract Control of steering is an essential component of successful high speed locomotion. Land & Lee (1994) recorded gaze behaviour during driving and observed extensive use of the tangent point of upcoming bends. In Wilkie & Wann (2003), however, we observed that gaze exploration of the centre of the road 1–2 seconds ahead was associated with accurate steering. Here we examine the relationship between gaze and steering behaviour by simulating locomotion along roads of varying width and curvature. Nine participants were ...
Research Interests:
Abstract Following on from our work investigating gaze and steering along simulated roadways (Wilkie & Wann, 2003; 2004) we examined gaze behaviour in a steering task that supported a greater degree of route selection. We... more
Abstract Following on from our work investigating gaze and steering along simulated roadways (Wilkie & Wann, 2003; 2004) we examined gaze behaviour in a steering task that supported a greater degree of route selection. We integrated a bicycle with our simulation rig that allowed more precise measurement of the paths taken, due to narrowness of the bicycle wheel. Participants steered around a series of obstacles in a simulated slalom of varying complexity. We recorded patterns of gaze sampling alongside the mean passing distance ...
Research Interests:
Abstract There has been an ongoing debate as to whether optic flow is sufficient to judge heading or whether extra-retinal information is required. A more recent debate has been whether human locomotion can be controlled purely on the... more
Abstract There has been an ongoing debate as to whether optic flow is sufficient to judge heading or whether extra-retinal information is required. A more recent debate has been whether human locomotion can be controlled purely on the basis of egocentric visual direction without reference to optic flow (Rushton et al, 1998; Warren et al, 2001). We created a driving simulation where retinal flow (RF) and visual direction (VD) information could be manipulated independent of one another. Observers sat in a projection booth ...