Postural control supports visual perceptual but not cognitive performance

The perception and control of body sway may be regarded as a task that utilizes central cognitive resources. For example, the integration of multisensory perceptual stimulation, which is required for postural control, may draw on central processing capacity (e.g., Lajoie, Teasdale, Bard, & Fleury, 1996). Our research originates from a different hypothesis. We have argued that there may be functional relations between body motion and visual performance, such that controlled changes in body sway could be used to facilitate performance of visual tasks (Stoffregen, Smart, Bardy, & Pagulayan, 1999). This study looks at postural sway during performance of visual and cognitive tasks. The visual task was a signal detection task where critical signals were identified and the cognitive task was mental arithmetic. The two tasks were equated in terms of difficulty using the NASA task load index, a measure of mental workload. Postural sway was reduced in the visual, but not the arithmetic conditions, suggesting that sway was influenced by the perceptual demands of the signal detection task, rather than by overall processing load, per se.