Locomotor avoidance behaviours during a visually guided task involving an approaching object.
Collision avoidance behaviours in situations where a collision may occur and one's planned movement is restricted, reveals that one's response is not as simple as a visual input producing some motor output. In this study, the participants (N=6) walked along a 9.5m path towards an air-filled human doll (180 degrees from their travel path) that would approach them on some trials. A spatial constraint (i.e. doorframe) was placed along the path and the participants had to determine if they could pass through the constraint prior to avoiding a collision or not. The constraint was set-up so that it was either at the theoretical collision point or 1.5m before or after the theoretical collision point. This study aimed to determine: (1) how the presence of a spatial constraint affects one's ability to perceive when to avoid a collision with an approaching object; (2) if the individuals use action parameters (i.e. velocity modifications, change in heading, etc.) in a consistent manner independent of the spatial constraint location and object's approach velocity; (3) if a consistent safety zone exists independent of the object's approach velocity. The results showed that the placement of the spatial constraint, but not the velocity of the object had a significant effect on the initiation of a change in heading. Participants used two-stage avoidance behaviour; change heading and then adjust walking velocity. The initial avoidance behaviour was initiated when the object was at a constant distance away (i.e. 3.73 m). Overall, it appears as though collision avoidance with approaching objects has cognitive as well as perceptual influences.
Cinelli
Michael E
ME
Gait and Posture Laboratory, Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada. Michael_Cinelli@brown.edu
Patla
Aftab E
AE
D000056:Accident Prevention; D000328:Adult; D006801:Humans; D009068:Movement; D013037:Spatial Behavior / Q000502:physiology; D013647:Task Performance and Analysis; D016138:Walking / Q000502:physiology*; D055815:Young Adult