Visual Regulation of Gait: Zeroing in on a Solution to the Complex Terrain Problem

We examine the theoretical understanding of visual gait regulation that has emerged from decades of research since the publication of Lee, Lishman, and Thompson's (1982) classic study of elite long jumpers. The first round of research identified specific informational variables, parameters of the action system, and laws of control that capture the coupling of perception and action in this context, but left unanswered important questions about why visual information is sampled in an intermittent manner and how the strategies that actors adopt ensure stability and energetic efficiency. More recent developments lead to a refined view according to which visual information is used at a specific phase of the gait cycle to modify the parameters that govern the passive dynamics of the body. We then present the results of a new experiment designed to test the prediction that when the terrain offers multiple foothold options for a given step, walkers' choices will be constrained by a strong preference for not interfering with the natural, ballistic movement of the body throughout the single support phase of that step. The findings are consistent with this prediction and support a view of visual gait regulation that is concordant with contemporary accounts of how actors use both active and passive modes of control.