Effects of divided attention on the visual control of steering toward a goal

Daily locomotion tasks such as walking and driving often occur in a complex environment in which people frequently need to divide their attention to keep track of multiple moving objects. In this study, we examined the effects of divided attention on the visual control of goal-oriented locomotion by using a dual-task paradigm in which participants were instructed to steer a virtual vehicle toward a target while dividing their attention to a concurrent object tracking task. We found that divided attention reduced the accuracy of the early-stage control of steering and the precision of the steady-state control. We then instructed participants to rely on the target egocentric direction or optic flow cue for steering. Although we found similar effects of divided attention on the early-stage and steady-state control of steering regardless of the cue instructions, divided attention adversely affected the accuracy of the steady-state control of steering only for participants who received the optic flow instructions. Furthermore, participants consistently showed lower attentional tracking accuracy when steering at the fast (15 m/s) than the low (2 m/s) travel speed. We conclude that divided attention negatively affects the control of steering toward a goal, and steering at higher travel speeds demands more attentional resource. Compared with optic flow, relying on target egocentric direction to steer toward a goal is less affected by a secondary attention-demanding task, suggesting that target egocentric direction is the primary cue for the control of goal-oriented locomotion.

日常行进任务（如步行与驾车）常发生于复杂环境中，此时人们往往需要分配注意力以追踪多个移动物体。本研究采用双任务范式（dual-task paradigm），探究了注意力分散对目标导向行进（goal-oriented locomotion）视觉控制的影响：实验要求参与者操控虚拟车辆驶向目标，同时将注意力分配至并行的物体追踪任务中。研究发现，注意力分散会降低转向控制早期阶段的精度，以及稳态控制的精准度。随后，我们要求参与者分别依赖目标自我中心方向（target egocentric direction）或光流（optic flow）线索完成转向操控。尽管无论采用何种线索指引，注意力分散对转向早期控制与稳态控制的影响均保持一致，但仅在接受光流线索指引的参与者中，注意力分散会对转向稳态控制的精度产生负面影响。此外，参与者在高速（15 m/s）行进时的注意力追踪精度，始终低于低速（2 m/s）行进时的表现。综上，注意力分散会对目标导向的转向控制产生负面影响，且高速行进的转向操控需要占用更多的注意力资源。相较于光流线索，依赖目标自我中心方向完成目标导向转向的操控，受次级注意力负载任务的影响更小，这表明目标自我中心方向是目标导向行进控制的核心线索。