Abstract
In order to navigate towards a visual target while moving along a curvilinear path it has been suggested that an active fixation strategy in the direction of the goal provides a simple heuristic for reaching the target (Wann & Swapp, Nat. Neurosci., 2000). Some ground element trajectories become straight when we are on the correct path. This purportedly explains why we look inside of the curve. One problem with this technique is that it only makes use of a small part of the visual flow field that is occurring on the back of the moving eye; a large proportion of the visual flow is not used to help us steer. I have developed a new, visual-vestibular (full-flow field) theory for how we can estimate our rotation while moving along curvilinear paths (Perrone, VSS, 2017). Once the rotation has been measured it can be removed from the combined translation + rotation flow field to derive a heading estimate. This model was tested using a range of line-of-sight directions relative to heading as the simulated observer moved at 1 m/sec over a ground plane towards a wall while on a path curving to the left (rotation rate = 10°/s). A tally of the proportion of times the heading error was less than 2° in each of the four quadrants around (0°, 0°) gave .031, .027, .18, .01. Smaller heading errors occurred when the line of sight was directed down and inside the curved path (quadrant 3). A test against there being equal proportions in each quadrant was significant, χ2 (3, 289) = 45.1, p < .001. The large errors while looking in the other quadrants arise from an unusual lamellar pattern of flow vectors that cause a misperception of the correct rotation direction. Looking in the direction of the curve minimizes these errors.
Meeting abstract presented at VSS 2018