The visual strategies for the control of steering toward a goal include aligning one's instantaneous direction of travel (i.e., heading; J. J. Gibson, 1950) or the future path (J. P. Wann & D. K. Swapp, 2000) specified by optic flow with the target, equating the time to closure of the target-heading angle with the time to passage of the target (tau equalization, B. Fajen, 2001), or using the target egocentric direction and steering to center the target in the straight ahead or cancel the target optical drift (S. K. Rushton, J. M. Harris, M. Lloyd, & J. P. Wann, 1998). Supporting evidences for the use of these strategies in guiding steering or walking toward a goal were reported, but no consensus has been reached. In this study, by presenting participants with displays in which target egocentric direction was fixed and thus unavailable for steering to force participants to rely on information from optic flow for the control of self-motion, we systematically examined the use of the optic flow-based strategies in the visual control of steering toward a goal. We found that participants steered to align their heading with the target, supporting the use of the heading strategy. We found no evidence to support the use of the path or the tau-equalization strategy in the visual control of steering toward a goal.
Bibliographical noteThis study was supported by a grant from the Research Grants Council of Hong Kong (HKU 7480/10H) to L. Li. We thank Lee Stone for his helpful discussion, Gordon Wong, Diederick Niehorster, and Willie Xiang for their assistance in data collection, and three anonymous reviewers and Diederick Niehorster for their helpful comments on a previous draft.
- Egocentric direction
- Locomotion control
- Optic flow
- Time to contact (tau)