Abstract
Purpose: Using the whole field of view (FOV) to extract visual information about the environment is particularly important for safe mobility. However, divided attention has a restricting effect on the FOV which may be influenced by the overall goal of a postural task (e.g., sitting vs. walking). This study investigated the effects of body posture and divided attention on the ability to detect visual stimuli with peripheral vision in healthy young adults.
Methods: Fourteen participants completed 3 visual task conditions: central task (CT) (button press), peripheral task (PT) (verbal), and divided attention task (DAT). The DAT task required participants to complete both the CT & PT during the same trial. Three postures were utilized, standing, sitting, and walking (treadmill). Visual task performance was measured by reaction time (RT) and error rate.
Results: Reaction times to the central and peripheral visual stimuli were significantly increased in the DAT (p<0.001). Peripheral stimuli presented in the upper field of view showed increased reaction times (p<0.001). Response errors to peripheral stimuli were significantly increased in the DAT (p = 0.019). Additional increased errors were observed to stimuli in the upper field of view during walking. (p=0.008).
Conclusions: Although posture does not directly affect the ability to use peripheral vision, divided attention increases the demand to respond to peripheral vision stimuli which can influence the ability to detect environmental features during walking. Increased errors to respond to stimuli in the upper FOV may indicate that individuals prioritize visual attention in the lower FOV especially during walking.
