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The need for speed: global optic flow speed influences steering.
Kountouriotis, Georgios K; Mole, Callum D; Merat, Natasha; Wilkie, Richard M.
Affiliation
  • Kountouriotis GK; Department of Psychology , Manchester Metropolitan University , Manchester M15 6GX , UK.
  • Mole CD; School of Psychology , University of Leeds , Leeds LS2 9JT , UK.
  • Merat N; Institute for Transport Studies , University of Leeds , Leeds LS2 9JT , UK.
  • Wilkie RM; School of Psychology , University of Leeds , Leeds LS2 9JT , UK.
R Soc Open Sci ; 3(5): 160096, 2016 May.
Article in En | MEDLINE | ID: mdl-27293789
ABSTRACT
How do animals follow demarcated paths? Different species are sensitive to optic flow and one control solution is to maintain the balance of flow symmetry across visual fields; however, it is unclear whether animals are sensitive to changes in asymmetries when steering along curved paths. Flow asymmetries can alter the global properties of flow (i.e. flow speed) which may also influence steering control. We tested humans steering curved paths in a virtual environment. The scene was manipulated so that the ground plane to either side of the demarcated path produced larger or smaller asymmetries in optic flow. Independent of asymmetries and the locomotor speed, the scene properties were altered to produce either faster or slower globally averaged flow speeds. Results showed that rather than being influenced by changes in flow asymmetry, steering responded to global flow speed. We conclude that the human brain performs global averaging of flow speed from across the scene and uses this signal as an input for steering control. This finding is surprising since the demarcated path provided sufficient information to steer, whereas global flow speed (by itself) did not. To explain these findings, existing models of steering must be modified to include a new perceptual variable namely global optic flow speed.
Key words

Full text: 1 Collection: 01-internacional Database: MEDLINE Type of study: Prognostic_studies Language: En Journal: R Soc Open Sci Year: 2016 Document type: Article Affiliation country: United kingdom

Full text: 1 Collection: 01-internacional Database: MEDLINE Type of study: Prognostic_studies Language: En Journal: R Soc Open Sci Year: 2016 Document type: Article Affiliation country: United kingdom