Does the passability of apertures change when walking through human versus pole obstacles?

The current study set out to evaluate how individuals walk through apertures created by different stationary obstacles. Specifically, we examined whether the passability of apertures differed between human and pole obstacles by quantifying aperture crossing behaviors such as the critical point. Participants walked an 8m path toward a visible goal located at the end. Two obstacles were positioned 5m from the starting location and participants were instructed to pass between the obstacles without hitting them. The distance between the obstacles ranged between 1.0 and 1.8× the participant's shoulder width. Results revealed that, when the obstacles were humans, individuals rotated their shoulders more frequently at larger apertures, as evidenced by a larger critical point (1.7 vs 1.3 for poles), initiated shoulder rotations earlier, rotated to a larger degree, left a wider clearance between their shoulders and the obstacles at the time of crossing, and walked slower when approaching and passing through the obstacles compared to when the obstacles were poles. Furthermore, correlational analyses revealed that the amount of change between an individual's critical point for the poles and the critical point for the human obstacles was related to social risk-taking and changes in walking speed. Therefore, it appears that the passability of apertures changes when walking between two people versus two objects such that more space and greater caution are needed for human obstacles. It is possible that the greater caution observed for human obstacles is to account for the personal space needs of others that do not exist in the same extent for poles and that the degree of caution is related to social factors.