Diaz Gabriel J, Parade Melissa S, Barton Sean L, Fajen Brett R
The Chester F. Carlson Center for Imaging Science, Rochester Institute of Technology, Rochester, New York, United States of America.
Cognitive Science Department, Rensselaer Polytechnic Institute, Troy, NY, United States of America.
PLoS One. 2018 Feb 5;13(2):e0192044. doi: 10.1371/journal.pone.0192044. eCollection 2018.
The present study investigated differences in the pickup of information about the size and location of an obstacle in the path of locomotion. The main hypothesis was that information about obstacle location is most useful when it is sampled at a specific time during the approach phase, whereas information about obstacle size can be sampled at any point during the last few steps. Subjects approached and stepped over obstacles in a virtual environment viewed through a head-mounted display. In Experiment 1, a horizontal line on the ground indicating obstacle location was visible throughout the trial while information about obstacle height and depth was available only while the subject was passing through a viewing window located at one of four locations along the subject's path. Subjects exhibited more cautious behavior when the obstacle did not become visible until they were within one step length, but walking behavior was at most weakly affected in the other viewing window conditions. In Experiment 2, the horizontal line indicating obstacle location was removed, such that no information about the obstacle (size or location) was available outside of the viewing window. Subjects adopted a more cautious strategy compared to Experiment 1 and differences between the viewing window conditions and the full vision control condition were observed across several measures. The differences in walking behavior and performance across the two experiments support the hypothesis that walkers have greater flexibility in when they can sample information about obstacle size compared to location. Such flexibility may impact gaze and locomotor control strategies, especially in more complex environments with multiple objects and obstacles.
本研究调查了在运动路径中获取有关障碍物大小和位置信息方面的差异。主要假设是，在接近阶段的特定时间对障碍物位置信息进行采样时最为有用，而在最后几步的任何时刻都可以对障碍物大小信息进行采样。受试者通过头戴式显示器在虚拟环境中接近并跨过障碍物。在实验1中，地面上指示障碍物位置的一条水平线在整个试验过程中都是可见的，而关于障碍物高度和深度的信息仅在受试者经过位于其路径上四个位置之一的观察窗时才可用。当障碍物直到受试者距离一步之遥时才变得可见时，受试者表现出更为谨慎的行为，但在其他观察窗条件下，行走行为受到的影响至多很微弱。在实验2中，移除了指示障碍物位置的水平线，这样在观察窗之外就没有关于障碍物（大小或位置）的信息了。与实验1相比，受试者采取了更为谨慎的策略，并且在几种测量方法中都观察到了观察窗条件与全视野控制条件之间的差异。两个实验中行走行为和表现的差异支持了这样的假设，即与位置相比，步行者在何时可以对障碍物大小信息进行采样方面具有更大的灵活性。这种灵活性可能会影响注视和运动控制策略，尤其是在具有多个物体和障碍物的更复杂环境中。
