Human control of locomotion relies heavily upon vision. Through our eyes we sample information about the illuminated environment that aids us in moving skilfully through it. The exact visual information that supports control of high-speed locomotion around bends has been a matter of debate. Two models of steering (the Tangent Point and Active Gaze model) propose different visual inputs to enable this process. In two studies (Chapter 2) these models were tested against each other, and it was found that humans look at points on their future path (consistent with the Active Gaze model). Not only do participants look where they want to go (Chapters 2 & 3), but they go where they look (Chapter 4), even when there is an additional cognitive load at the point of fixation (Chapter 7). However, gaze direction is not the sole source of information when steering: visual direction and optic flow may also play a role. Three experiments (Chapters 3, 4, & 5) highlight the importance of the visual direction information provided by road-edges. When information from road-edges was strong (Chapters 4 & 5) gaze direction ceased to bias steering. Optic flow also caused systematic steering biases when the temporal and spatial flow characteristics from regions either side of the bending roadway were manipulated (Chapter 6). Two distinct behaviours were elicited by humans steering in the presence of optic flow asymmetries: i) steering was biased towards one region in order to equalise asymmetries, and ii) oversteer increased at higher perceived speeds averaged across global flow asymmetries. The observed interaction between flow, road- edges and gaze direction is indicative of the visuomotor-control system's propensity to use multiple sources of information in a flexible manner according to information quality and availability.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:581790 |
| Date | January 2012 |
| Creators | Kountouriotis, Georgios |
| Publisher | University of Leeds |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
Page generated in 0.0115 seconds